Benzodiazipines
Diazepam poisoning is treated by:
| A | Flumazenil | |
| B |
Hemofiltration |
|
| C | Charcoal | |
| D |
Resins |
Diazepam poisoning is treated by:
| A | Flumazenil | |
| B |
Hemofiltration |
|
| C | Charcoal | |
| D |
Resins |
Flumazenil REF: Harrison’s 17th ed Table e 35-4
See APPENDIX-42 for list of “Antidotes”
“Specific antidote for benzodiazepine poisoning is flumazenil”
Benzodiazepine antagonist ?
| A |
Flumazenil |
|
| B |
Naloxone |
|
| C | Furazolidone | |
| D |
Naltrexone |
Benzodiazepine antagonist ?
| A |
Flumazenil |
|
| B |
Naloxone |
|
| C | Furazolidone | |
| D |
Naltrexone |
Flumazenil [Ref. K.D.T. 6thIe p399-400 5th/e p 362]
- Benzodiazepine acts by enhancing presynaptic/postsynaptic inhibition through a specific BZD receptor which is an integral part of the GABA receptor-CI— channel complex.
- Flumazenil is a BZD analogue which has little intrinsic activity, but it competes with BZD agonists as well as inverse agonists for the BZD receptor and reverses their depressant or stimulant effects respectively.
- Flumazenil is the drug of choice for benzodiazepene overdose. About other options:
- Naltrexone –> Opioid antagonist
- Butorphanol –> Agonist/antagonist at opioid receptors
- Pralidoxime –> Cholinesterase reactivator
The following are the benzodiazepines of choice in elderly and those with liver disease, EXCEPT:
| A |
Lorazepam |
|
| B |
Orazepam |
|
| C |
Temazepam |
|
| D |
Diazepam |
The following are the benzodiazepines of choice in elderly and those with liver disease, EXCEPT:
| A |
Lorazepam |
|
| B |
Orazepam |
|
| C |
Temazepam |
|
| D |
Diazepam |
Diazepam generates active metabolites, has slow elimination and tends to accumulate with regular use.
Lorazepam, Oxazepam and Temazepam do not produce active metabolites and are relatively safer in elderly patients and in those with liver disease.
These agents should be used in preference to diazepam.
Ref: Essentials of Pharmacology By K D Tripathi, 5th Edtion, Page 364.
Shortest acting benzodiazepine is‑
| A |
Flurazepam |
|
| B |
Alprazolam |
|
| C |
Triazolam |
|
| D |
Diazepam |
Shortest acting benzodiazepine is‑
| A |
Flurazepam |
|
| B |
Alprazolam |
|
| C |
Triazolam |
|
| D |
Diazepam |
Ans. is ‘c’ i.e., Triazolam
o Midazolam (slightly shorter acting than triazolam) and triazolam are shortest acting BZDs.
Benzodiazepine without anticonvulsant property is‑
| A |
Nitrazepam |
|
| B |
Diazepam |
|
| C |
Clonazepam |
|
| D |
Temazepam |
Benzodiazepine without anticonvulsant property is‑
| A |
Nitrazepam |
|
| B |
Diazepam |
|
| C |
Clonazepam |
|
| D |
Temazepam |
Ans. is ‘d’ i.e., Temazepam
BZDs with significant anticonvulsant property are diazepam, clonazepam, nitrazepam, lorazepam and flurazepam.
Antagonist of Benzodiazepine is ‑
| A |
Nalorphine |
|
| B |
Carbamazepine |
|
| C |
Naloxone |
|
| D |
Flumazenil |
Antagonist of Benzodiazepine is ‑
| A |
Nalorphine |
|
| B |
Carbamazepine |
|
| C |
Naloxone |
|
| D |
Flumazenil |
Ans. is ‘d’ i.e., Flumazenil
o Flumazenil is a benzodiazepene analogue which competes with BZD agonists as well as inverse agonists for the BZD receptor and reverses their depressant or stimulant effects respectively.
o It also antagonizes the action of Zolpidem, Zopiclone and Zopeplon as these drugs also act on BZD site.
Flumazenil is –
| A |
Diazepam inverse agonist |
|
| B |
Diazepam antagonist |
|
| C |
Opioid antagonist |
|
| D |
Opioid inverse agonist |
Flumazenil is –
| A |
Diazepam inverse agonist |
|
| B |
Diazepam antagonist |
|
| C |
Opioid antagonist |
|
| D |
Opioid inverse agonist |
Ans. is ‘b’ i.e., Diazepam antagonist
A 6 yr. old child with acute onset of fever of 104° F developed febrile seizures and was treated. To avoid future recurrence of seizure attacks what should be given –
| A |
Paracetamol 400 mg + Phenobarbitone daily |
|
| B |
Oral Diazepan 6 hourly |
|
| C |
Paracetamol 400 mg 6 hourly |
|
| D |
I.V. diazepam infusion over 12 hrs |
A 6 yr. old child with acute onset of fever of 104° F developed febrile seizures and was treated. To avoid future recurrence of seizure attacks what should be given –
| A |
Paracetamol 400 mg + Phenobarbitone daily |
|
| B |
Oral Diazepan 6 hourly |
|
| C |
Paracetamol 400 mg 6 hourly |
|
| D |
I.V. diazepam infusion over 12 hrs |
Ans. is ‘b’ i.e., Oral Diazepan 6 hrly
An anxiolytic benzodiazepine which is also antidepressant :
September 2007
| A |
Lorazepam |
|
| B |
Oxazepam |
|
| C |
Alprazolam |
|
| D |
Chlordiazepoxid |
An anxiolytic benzodiazepine which is also antidepressant :
September 2007
| A |
Lorazepam |
|
| B |
Oxazepam |
|
| C |
Alprazolam |
|
| D |
Chlordiazepoxid |
Ans. C: Alprazolam
Alprazolam is approved for the short-term treatment of panic disorder, with or without agoraphobia. Alprazolam is very effective in the short-term symptomatic relief of moderate to severe anxiety, essential tremor, and panic attacks.
Alprazolam is indicated for the management of anxiety disorders or the short-term relief of symptoms of anxiety. Alprazolam is recommended for the short-term treatment of severe acute anxiety.
Alprazolam is sometimes prescribed for anxiety with associated depression.
The antidepressant effects of alprazolam may be due to its effects on beta-adrenergic receptors. Other benzodiazepines are not known to have antidepressant activity.
Benzodiazepine overdose in a patient presenting with coma, is treated by:
March 2010
| A |
Protamine |
|
| B |
Flumazenil |
|
| C |
Coumarin |
|
| D |
Midazolam |
Benzodiazepine overdose in a patient presenting with coma, is treated by:
March 2010
| A |
Protamine |
|
| B |
Flumazenil |
|
| C |
Coumarin |
|
| D |
Midazolam |
Ans. B: Flumazenil
Decontamination
– Gastric lavage is not recommended but may be considered if the presence of a lethal co-ingestant is suspected and the patient presents within 1 hour of ingestion.
– Single-dose activated charcoal is recommended for GI decontamination in patients with protected airway who present within 4 hours of ingestion.
- Respiratory depression may be treated with assisted ventilation.
- Flumazenil
– Flumazenil is a competitive BZD receptor antagonist and should be used cautiously because it has potential to precipitate BZD withdrawal in chronic users, resulting in seizures.
– Flumazenil administration is contraindicated in mixed overdoses (e.g., TCAs) because BZD reversal can precipitate seizures and cardiac arrhythmias.
– Ideal indication for flumazenil use is isolated BZD overdose, particularly if overdose is iatrogenic in nature.
Antidote for benzodiazepine poisoning:
FMGE 10, 13; NEET 14
| A |
Naloxone |
|
| B |
Atropine |
|
| C |
Flumazenil |
|
| D |
N-acetyl-cysteine |
Antidote for benzodiazepine poisoning:
FMGE 10, 13; NEET 14
| A |
Naloxone |
|
| B |
Atropine |
|
| C |
Flumazenil |
|
| D |
N-acetyl-cysteine |
Ans. Flumazenil
IV diazepam has which of the following effect which is not seen by other routes ‑
| A |
Analgesia |
|
| B |
Sedation |
|
| C |
Hypotension |
|
| D |
Coronary dilatation |
IV diazepam has which of the following effect which is not seen by other routes ‑
| A |
Analgesia |
|
| B |
Sedation |
|
| C |
Hypotension |
|
| D |
Coronary dilatation |
Ans. is ‘d’ i.e., Coronary dilatation
Mechanism of action of benzodiazepines (BZDs)
- Benzodiazepines act preferentially on midbrain ascending reticular formation (which maintains wakefulness) and on limbic system (thought and mental function).
- Muscle relaxation is produced by action on medulla.
- Ataxia is due to action on cerebellum.
- BZDs acts on GABAA receptors.
- GABA,,, receptor has 5 subunits a / p, p, a / y.
- GABA binding site is on p. subunit, while BZDs binding site is on a / y subunit.
- BZDs receptor increase the conductance of Cl- channel.
- BZDs do not themselves increase Cl- conductance, i.e. they have only GABA facilitatory but no GABA mimetic action. (Barbiturates have both GABA facilitatory and GABA mimetic actions).
Effect on CNS
- In contrast to barbiturates, BZDs are not general depressant, but exert relatively selective anxiolytic, hypnotic, muscle relaxant and anticonvulsant effects.
- The antianxiety action of BZDs is not dependent on their sedative property —› with chronic administration relief of anxiety is maintained, but drowsiness wanes off due to development of tolerance.
- Stage 2 sleep is increased, while REM, Stage 3 & 4 sleep are decreased.
- Nitrazepam is the only benzodiazepine, which increases REM sleep.
- Clonazepan and diazepam have more marked muscle relaxant property.
- Clonazepam, diazepam, nitrazepam and flurazepam have more prominent anticonvulsant activity than other BZDs.
- Diazepam (but not other BZDs) has analgesic action.
- Diazepam produces short lasting coronary dilatation on i.v. injection.
- Diazepam decreases nocturnal gastric secretion and prevents stress ulcers.
Inverse agonist of benzodiazepine receptor is –
| A |
Phenobarbitone |
|
| B |
Flumazenil |
|
| C |
Beta carboline |
|
| D |
Gabapentin |
Inverse agonist of benzodiazepine receptor is –
| A |
Phenobarbitone |
|
| B |
Flumazenil |
|
| C |
Beta carboline |
|
| D |
Gabapentin |
Ans. is `c’ i.e., Beta carboline
Antidote true is all except‑
| A |
Deferoxamine – Iron |
|
| B |
Flumazenil – BZDs |
|
| C |
Dimercaprol – Arsenic |
|
| D |
Naloxone – Dhatura |
Antidote true is all except‑
| A |
Deferoxamine – Iron |
|
| B |
Flumazenil – BZDs |
|
| C |
Dimercaprol – Arsenic |
|
| D |
Naloxone – Dhatura |
Ans. is ‘d’ i.e., Naloxone-Dhatura
Midazolam causes all except:
| A |
Anterograde amnesia |
|
| B |
Retrograde amnesia |
|
| C |
Causes tachyphylaxis during high dose infusions |
|
| D |
Decreased cardiovascular effects as compared to propofol |
Midazolam causes all except:
| A |
Anterograde amnesia |
|
| B |
Retrograde amnesia |
|
| C |
Causes tachyphylaxis during high dose infusions |
|
| D |
Decreased cardiovascular effects as compared to propofol |
Ans. b. Retrograde amnesia
At the time of peak concentration in plasma, hypnotic doses of benzodiazepines (midazolam) can be expected to cause varying degrees of lightheadedness, lassitude, increased reaction time, motor incoordination, impairment of mental and motor functions, confusion, and anterograde amnesia.”
Midazolam:
- It causes anterograde amnesiaQ
- Tolerance and tachyphylaxis may occur, particularly with longer-term infusionsQ(Shafer A. Complications of sedation with midazolam in the intensive care unit and a comparison with other sedative regimens. Crit Care Med. 1998;26(5): 947-56)
- Benzodiazepine withdrawal syndrome has also been associated with high dose/ long-term midazolam infusionsQ
- Compared with propofol infusions, midazolam infusions have been associated with a decreased occurrence of hypotension° but a more variable time course for recovery of function after the cessation of the infusion.
Shortest acting Benzodiazepine ‑
| A |
Diazepam |
|
| B |
Midazolam |
|
| C |
Alprazolam |
|
| D |
Chlordiazepoxide |
Shortest acting Benzodiazepine ‑
| A |
Diazepam |
|
| B |
Midazolam |
|
| C |
Alprazolam |
|
| D |
Chlordiazepoxide |
Ans. is ‘b’ i.e., Midazolam
- Ajay Yadav 4th/e p. 85] o Midazolam is the shortest acting benzodiazipine.
- It is 3 times more potent than diazepam.
- Midazolam is now very commonly used BZD in intraoperative period.
- Advantages of midazolam over diazepam are :
- Water based preparation, so injection is painless.
- Elimination half life is 2-3 hours, so can be safely used for day care procedures.
- Reversal with flumezanil is complete (no resedation).
- Disadvantages are that decrease in BP and peripheral vascularresistance, respiratory depression and incidence of apnea are higher and more profound than diazepam
The antidote for benzodiazepine toxicity is-
| A |
Flumazenil |
|
| B |
Naloxone |
|
| C |
Naltrexone |
|
| D |
Dimercaprol |
The antidote for benzodiazepine toxicity is-
| A |
Flumazenil |
|
| B |
Naloxone |
|
| C |
Naltrexone |
|
| D |
Dimercaprol |
Ans. is ‘a’ i.e., Flumazenil
Benzodiazepine without anticonvulsant property is ‑
| A |
Nitrazepam |
|
| B |
Diazepam |
|
| C |
Clonazepam |
|
| D |
Temazepam |
Benzodiazepine without anticonvulsant property is ‑
| A |
Nitrazepam |
|
| B |
Diazepam |
|
| C |
Clonazepam |
|
| D |
Temazepam |
Ans. is ‘d’ i.e., Temazepam
- BZDs with significant anticonvulsant property are diazepam, clonazepam, nitrazepam, lorazepam and flurazepam.
Effects of benzodiazepines
- In contrast to barbiturates, BZDs are not general depressant, but exert relatively selective anxiolytic, hypnotic, muscle relaxant and anticonvulsant effects.
- The antianxiety action of BZDs is not dependent on their sedative property with chronic administration relief of anxiety is maintained, but drowsiness wanes off due to development of tolerance.
- Stage 2 sleep is increased, while REM, Stage 3 & 4 sleep are decreased.
- Nitrazepam is the only benzodiazepine, which increases REM sleep.
- Clonazepan and diazepam have more marked muscle relaxant property.
- Clonazepam, diazepam, nitrazepam and flurazepam have more prominent anticonvulsant activity than other BZDs.
- Diazepam (but not other BZDs) has analgesic action.
- Diazepam produces short lasting coronary dilatation on injection.
- Diazepam decreases nocturnal gastric secretion and prevents stress ulcers.
Shortest acting benzodiazepine is
| A |
Flurazepam |
|
| B |
Alprazolam |
|
| C |
Triazolam |
|
| D |
Diazepam |
Shortest acting benzodiazepine is
| A |
Flurazepam |
|
| B |
Alprazolam |
|
| C |
Triazolam |
|
| D |
Diazepam |
Ans. is ‘c’ i.e., Triazolam
BENZODIAZEPINE
CLASSIFICATION:
- Long Acting
- Flurazepam 50-100 t1/2(hrs)
- Diazepam 30-60 t1/2(hrs)
- Nitrazepam 30 t1/2(hrs)
- Flunitrazepam 15-25 t1/2(hrs)
- Short-Acting
- Temazepam with t1/2 8-12 hrs
- Benzodiazepine without anticonvulsant property.
- Triazolam with t1/2 2-3 hrs
- Midazolam 2 t1/2(hrs)
- Alprazolam
- Temazepam with t1/2 8-12 hrs
MOA:
PHARMACOKINETICS:
- Short-acting BZDs:
- Eg: Midazolam – IV or IM as an induction agent.
- Rapid onset of action.
- Quick drug clearance.
- Causes anterograde amnesia, tachyphylaxis during high dose infusions.
- Decreased cardiovascular effects as compared to propofol
- Temazepam or oxazepam – Revives insomnia.
- At lower doses, relieves acute symptoms of anxiety, such as panic attacks & phobias.
- Long-acting BZDs:
- Slower onset of action following oral administration → Hence prolonged pharmacological action.
- Sedation.
- Prevents increased muscle tone of tetanus infection.
- Metabolized in liver by dealkylation and hydroxylation.
- Excreted in urine as glucuronide conjugates.
ACTIONS:
- Antianxiety
- Sedation:
- Increasing dosage produce sleep & hence considerable as hypnotic.
- I.V administration used extensively to produce conscious sedation during unpleasant procedures.
- Eg: Diazepam & midazolam.
- Cardiovascular stability – IV diazepam
- Midazolam potentiates propofol in co-induction technique.
- Anticonvulsants:
- Clonazepam & diazepam – Effective in status epilepticus.
- Muscle relaxation:
- Reduce muscle tone.
- Amnesia:
- IV benzodiazepines produces antegrade amnesia.
- Midazolam – Very intense for 20-30 minutes
- Lorazepam – Longer amnesia – 6 hr.
DRUGS:
- Inverse agonist of benzodiazepine receptor – Beta carboline.
- Benzodiazepine antagonist – Flumazenil
USES:
- As hypnotic –
- Daytime sedation (Alprazolam)
- As anxiolytic.
- Antidepressant (Alprazolam)
- As anticonvulsants, especially emergency control of status epilepticus
- To avoid future recurrence of seizure attacks Oral Diazepam 6 hourly is given.
- As centrally acting muscle relaxant.
- For anesthetic medication and IV anesthesia
- Alcohol withdrawal in dependent subjects
- Mostly given along with analgesics (NSAIDs|).
- DOC in elderly & with liver disease.
- Lorazepam, Oxazepam & Temazepam
- Spasmolytics.
- Anti-ulcer.
ADVERSE EFFECT:
- Dizziness, lassitude, vertigo, disorientation, amnesia, increased reaction time with motor incoordination, impairment of mental coordination occur.
- Weakness, blurring of vision, dry mouth and urinary incontinence.
- BZD poisoning:
- Benzodiazepine antagonist -Flumazenil
- Eg: Diazepam poisoning.
- Paradoxical stimulation, irritability, and sweating may occur with flurazepam.
- Increase in nightmares and behavioral alterations
- Increased psychological effects with usage of short-acting benzodiazepines in insomnia.
- Disturbed REM sleep patterns.
Exam Important
- Diazepam poisoning is treated by Flumazenil
- Benzodiazepine antagonist Flumazenil
- Benzodiazepines of choice in elderly and those with liver disease Lorazepam, Orazepam & Temazepam
- Shortest acting benzodiazepine is Triazolam
- Benzodiazepine without anticonvulsant property is Temazepam
- To avoid future recurrence of seizure attacks Oral Diazepam 6 hourly is given
- Alprazolam is an anxiolytic benzodiazepine with antidepressant action
- IV diazepam shows Coronary dilatation
- Inverse agonist of benzodiazepine receptor is Beta carboline
- Midazolam causes Anterograde amnesia, tachyphylaxis during high dose infusions & Decreased cardiovascular effects as compared to propofol
PELVIS MUSCULATURE
Muscles that can cause external rotation of the hip include all of the following except:
| A |
Sartorius |
|
| B |
Obturator internus |
|
| C |
Obturator externus |
|
| D |
Gluteus minimus |
Muscles that can cause external rotation of the hip include all of the following except:
| A |
Sartorius |
|
| B |
Obturator internus |
|
| C |
Obturator externus |
|
| D |
Gluteus minimus |
Ans:D.)Gluteus Minimus.
Many of the muscles of the gluteal region are external rotators of the hip. These muscles include the gluteus maximus, piriformis, obturator internus, obturator externus, quadratus femoris, superior gemellus, and inferior gemellus. The sartorius is a flexor and external rotator of the hip. The gluteus minimus is an abductor and internal rotator of the hip.
All are sphincters of lower genito urinary tract of female except?
| A |
Pubovaginalis |
|
| B |
External urethral sphincter |
|
| C |
Internal urethral sphincter |
|
| D |
Bulbospongiosus |
All are sphincters of lower genito urinary tract of female except?
| A |
Pubovaginalis |
|
| B |
External urethral sphincter |
|
| C |
Internal urethral sphincter |
|
| D |
Bulbospongiosus |
Internal urethral sphincter
There is no ‘internal urethral sphincter’ in females. It is present in males at the bladder neck and proximal urethral. Its function is to prevent retrograde ejaculation of semen into the bladder during the time of ejaculation.
In males the detrusor muscle fibers of the bladder at the region of bladde neck and proximal urethra are organized into internal urethral sphincter which is under involuntary control.
External urethral sphincter is present in both males and females.
- Vaginal sphincter is formed by the fibres of pubococcygeus known as pubovaginalis.
- There are other muscles also which contribute in compressing the vaginal orifice.
Pelvic diaphragm is formed by the following muscles:
| A |
Pubococcygeus |
|
| B |
Iliococcygeus |
|
| C |
Pubovaginalis |
|
| D |
All of the above |
Pelvic diaphragm is formed by the following muscles:
| A |
Pubococcygeus |
|
| B |
Iliococcygeus |
|
| C |
Pubovaginalis |
|
| D |
All of the above |
The pelvic diaphragm forms a broad muscular sling and provides substantial support to the pelvic viscera.
This muscle group is comprised of the levator ani and the coccygeus muscle.
Urogenital Diaphragm is made up of all of the following, EXCEPT?
| A |
Colle’s fascia |
|
| B |
Sphincter urethrae |
|
| C |
Perineal membrane |
|
| D |
Deep transverse Perineal muscle |
Urogenital Diaphragm is made up of all of the following, EXCEPT?
| A |
Colle’s fascia |
|
| B |
Sphincter urethrae |
|
| C |
Perineal membrane |
|
| D |
Deep transverse Perineal muscle |
Urogenital diaphragm is a triangular musculofascial diaphragm situated in the anterior part of perineum, filling in the gap of the pubic arch. It is formed by the sphincter urethrae, deep transverse perineal muscles enclosed between superior and inferior layer of fascia of urogenital diaphragm. Inferior layer of fascia is called perineal membrane.
Superficial perineal muscles include‑
| A |
Iliococcygeus |
|
| B |
Ischiococcygeus |
|
| C |
Bulbospongiosus |
|
| D |
Levator ani |
Superficial perineal muscles include‑
| A |
Iliococcygeus |
|
| B |
Ischiococcygeus |
|
| C |
Bulbospongiosus |
|
| D |
Levator ani |
Superficial muscles of perineum (lie in superficial perineal pouch) are ischiocavernosus, bulbospongiosus and superficial transverse perinei.
Deep muscles (lie in deep perineal pouch) are splincter urethrae, deep transverse perinei, and in females, compression urethrae and sphincter urethravaginalis.
Lateral border of ischeorectal fossa is formed by‑
| A |
Gluteus maximus |
|
| B |
Perineal membrane |
|
| C |
Pelvic diaphram |
|
| D |
Obturator internus |
Lateral border of ischeorectal fossa is formed by‑
| A |
Gluteus maximus |
|
| B |
Perineal membrane |
|
| C |
Pelvic diaphram |
|
| D |
Obturator internus |
Ans. is ‘d’ i.e., Obturator internus
Boundries of ischeoanal (ischeorectal) fossa are :-
i) Anteriorly :- Posterior border of perineal membrane .
ii) Posteriorly :- Gluteus maximus muscle, sacrotuberous ligament.
iii) Laterally :- Ischial tuberosity and obturator internus.
iv) Medially :- Sphincter ani externus (external anal sphincter) and pelvic diaphragm (levator ani).
True statement about anatomy of an organ marked by a “red box” in the picture below is?
| A |
Puborectalis is essential to maintain continence. |
|
| B |
Internal sphincter is skeletal muscle. |
|
| C |
Internal sphincter remains in the state of tonic contraction. |
|
| D |
Both A and C. |
True statement about anatomy of an organ marked by a “red box” in the picture below is?
| A |
Puborectalis is essential to maintain continence. |
|
| B |
Internal sphincter is skeletal muscle. |
|
| C |
Internal sphincter remains in the state of tonic contraction. |
|
| D |
Both A and C. |
Ans;D)Both A and C.
The organ marked by a “red box” in the picture above represents the anal canal.
In the anal canal Puborectalis is essential to maintain continence and Internal sphincter remains in the state of tonic contraction.
Structures crossing dorsal surface of the given structure marked by a “red arrow” are ?
| A |
Internal pudendal vessel. |
|
| B |
Pudendal nerve. |
|
| C |
Obturator nerve. |
|
| D |
Nerve to obturator internus. |
Structures crossing dorsal surface of the given structure marked by a “red arrow” are ?
| A |
Internal pudendal vessel. |
|
| B |
Pudendal nerve. |
|
| C |
Obturator nerve. |
|
| D |
Nerve to obturator internus. |
Ans;C).Obturator nerve
The structure marked by a red arrow represents the ischial spine.
ISCHIAL SPINE–a thin pointed triangular eminence that projects from the dorsal border of the ischium and gives attachment to the gemellus superior on its external surface and to the coccygeus, levator ani, and pelvic fascia on its internal surface
- The structure crossing dorsal surface of ischial spine is the Obturator nerve.
- Psoas major, iliacus & pectineus muscles, femoral vessels and nerve, femoral branch of genitofemoral nerve, lateral cutaneous nerve of thigh and lymphatics pass below inguinal ligament.
- ‘PIN’ structures i.e. Pudendal nerve, Internal Pudendal vessels, Nerve to obturator internus come out of greater sciatic foramen, cross the dorsal surface of ischial spine & enter into lesser sciatic foramen.
- From the posterior border of the body of the Ischium there extends backward a thin and pointed triangular eminence, the ischial spine, more or less elongated in different subjects.
Surfaces
| external surface | gives attachment to the Gemellus superior |
| internal surface | gives attachment to the Coccygeus, Levator ani, and the pelvic fascia |
| pointed extremity | the sacrospinous ligament is attached. |
It can serve as a landmark in pudendal anesthesia.
All of the following structures forms the boundary of the triangle as shown in the picture below, EXCEPT ?
| A |
Pubic rami. |
|
| B |
Ischial tuberosity. |
|
| C |
Ischio cavernosus muscle. |
|
| D |
Superficial transverse perineal muscle. |
All of the following structures forms the boundary of the triangle as shown in the picture below, EXCEPT ?
| A |
Pubic rami. |
|
| B |
Ischial tuberosity. |
|
| C |
Ischio cavernosus muscle. |
|
| D |
Superficial transverse perineal muscle. |
The triangle shown in the picture above represents Urogenital triangle.
The perineum is divided by an arbitrary line joining the ischial tuberosities into urogenital triangle and anal triangle. The urogenital triangle is bounded by pubic rami superiorly, the ischial tuberosities laterally, and the superficial transverse perineal muscle posteriorly.
All of the following are true about sphincter urethrae except?
| A |
Voluntary |
|
| B |
Supplied by pudendal nerve |
|
| C |
Arises from ischiopubic ramus |
|
| D |
Located at bladder neck |
All of the following are true about sphincter urethrae except?
| A |
Voluntary |
|
| B |
Supplied by pudendal nerve |
|
| C |
Arises from ischiopubic ramus |
|
| D |
Located at bladder neck |
Ans. d. Located at bladder neck
Support of prostate is ‑
| A |
Pubococcygeus |
|
| B |
Ischiococcygeus |
|
| C |
Ilioccygeus |
|
| D |
None of the above |
Support of prostate is ‑
| A |
Pubococcygeus |
|
| B |
Ischiococcygeus |
|
| C |
Ilioccygeus |
|
| D |
None of the above |
Ans. is ‘a’ i.e., Pubococcygeus
- Levator ani muscle is divisible into following parts :1) Puboccygeus part
- Anterior fibers of this part closely surround the prostate, in males, to form, levator prostatae. In the female these fibres surround the vagina and form sphincter vaginae. In both cases these anterior fibres are inserted into the perineal body.
- Middle fibers constitute the puborectalis. They partly form a loop or sling around the anorectal junction; and are partly continuous with longitudinal muscle coat of the rectum.
- Posterior fibers are attached to anococcygeal ligament and tip of coccyx.
- Iliococcygeus part
- This is inserted to anococcygeal ligament and last two pieces of coccyx.
- Ischiococcygeus part (or coccygeus)
- It forms posterior part of pelvic floor.
Superficial perineal space contains ‑
| A |
Sphincter urethrae muscle |
|
| B |
Ischiocavernosus muscle |
|
| C |
Deep transverse perinei muscle |
|
| D |
Bulbourethral gland |
Superficial perineal space contains ‑
| A |
Sphincter urethrae muscle |
|
| B |
Ischiocavernosus muscle |
|
| C |
Deep transverse perinei muscle |
|
| D |
Bulbourethral gland |
Ans. is ‘b’ i.e., Ischiocavernosus muscle
PELVIS MUSCULATURE
PELVIC MUSCULATURE:
The pelvic muscles of importance in gynaecology are those of the pelvic floor grouped into three layers:
| LAYER | MUSCLE |
| Pelvic Diaphragm | 2 levator ani muscles
Obturator internus
Puborectalis
|
| Urogenital Diaphragm | Sphincter urethra
Deep transverse Perineal Compressor urethra |
| Superficial Layer | Superficial transverse Perineal
Ischiocavernous bulbospongiosus The external |
| Muscle | Origin | Insertion |
| Pubococcygeus | Post. Pubic bone | Anococcygeal raphe and coccyx |
| Iliococcygeus | white line of the pelvic fascia | coccyx. |
| Ischiococcygeus | ischial spine | coccyx |
| Obturator internus | Pelvic aspect of ischium & ilium
Obturator membrane |
Greater trochantor of femur |
| Puborectalis | Posterior surface of pubis | Midline sling posterior to rectum |
| Sphincter urethra | Circular anatomical sphincter | Fuses with deep transverse perinei |
| Compressor urethra | ischiopubic ramus | Blends with its partner on the other side
anterior to urethra below external urethral sphincter |
| Superficial transverse Perineal | Ischial tuberosity | Perineal body |
| Ischiocavernous | Ischial tuberosity | Clitoris |
| bulbospongiosus | Central point of perineum | symphysis pubis |
| Deep transverse Perineal | Ramus of ischium | Perineal body |
| The external sphincter muscle of the anus |
Central point of the perineum | Surrounds the anus |
ACTION OF MUSCLES:
The roles of the pelvic floor muscles are:
- Support of abdominopelvic viscera (bladder, intestines, uterus etc.) through their tonic contraction.
- Resistance to increases in intra-pelvic/abdominal pressure during activities such as coughing or lifting heavy objects.
- Urinary and fecal continence.The muscle fibers have a sphincter action on the rectum and urethra. They relax to allow urination and defecation.Puborectalis is essential to maintain continence
Exam Important
- Muscles that can cause external rotation of the hip include Obturator internus
- Pubovaginalis, External urethral sphincter & Bulbospongiosus are sphincters of lower genito urinary tract of female
- Pelvic diaphragm is formed by Pubococcygeus,Iliococcygeus & Pubovaginalis
- Urogenital Diaphragm is made up of Sphincter urethrae , Perineal membrane & Deep transverse Perineal muscle
- Superficial perineal muscles include Bulbospongiosus
- Lateral border of ischeorectal fossa is formed by Obturator internus
- Puborectalis is essential to maintain continence
- Sphincter urethrae is Voluntary, Arises from ischiopubic ramus and are Supplied by pudendal nerve
- Pubococcygeus supports prostate
TUBERCULOSIS OF SPINE (Pott’s disease)
Pott’s spine is commonest at which spine:
| A | Thoracolumbar | |
| B |
Sacral |
|
| C | Cervical | |
| D |
Lumbosacral |
Pott’s spine is commonest at which spine:
| A | Thoracolumbar | |
| B |
Sacral |
|
| C | Cervical | |
| D |
Lumbosacral |
Thoracolumbar REF: Apley 387-389, S M Tuli 3rd edition page 192
- Most common site of skeletal tuberculosis is spine followed by hip and knee
SPINE (50%) > HIP > KNEE
- Commonest spine involved in spine TB is Thoracolumbar/Dorsolumbar T12-L1 (Lower thoracic to be precise)
LOWER THORACIC > LUMBAR > UPPER THORACIC
- Paraplegia due to pott’s spine most commonly involves upper thoracic vertebrae as in upper thoracic vertebrae there is more acute kyphosis, spinal canal is narrow and spinal cord is relatively large.
- First symptom of TB spine is “Pain on movement”
- Commonest symptom of TB spine is “Back pain”
| A | Sacral | |
| B | Cervica l |
|
| C | Lumbosacral | |
| D | Thoracolumbar |
| A | Sacral | |
| B | Cervica l |
|
| C | Lumbosacral | |
| D | Thoracolumbar |
Thoracolumbar
Most common cause of cold abscess of chest wall is‑
| A |
Pott’s spine |
|
| B |
TB abscesses of chest wall |
|
| C |
TB of ribs |
|
| D |
Intercostal lymphadenitis |
Most common cause of cold abscess of chest wall is‑
| A |
Pott’s spine |
|
| B |
TB abscesses of chest wall |
|
| C |
TB of ribs |
|
| D |
Intercostal lymphadenitis |
Ans. is ‘a’ i.e., Pott’s spine
True statement about chronic retropharyngeal abscess:
| A |
Associated with tuberculosis of spine |
|
| B |
Causes psoas spasm |
|
| C |
Suppuration of Rouviere lymph node |
|
| D |
a and c |
True statement about chronic retropharyngeal abscess:
| A |
Associated with tuberculosis of spine |
|
| B |
Causes psoas spasm |
|
| C |
Suppuration of Rouviere lymph node |
|
| D |
a and c |
- Chronic retropharyngeal abscess is associated with caries of cervical spine or tuberculous infection of retropharyngeal lymph nodes secondary to tuberculosis of deep cervical nodes (i.e. suppuration of Rouviere nodes)
- It leads to discomfort in throat, dysphagia, fluctuant swelling of postpharyngeal wall.
- Retropharyngeal abscess does not lead to psoas spasm.
Treatment
- Incison and drainage of abscess
- Full course of ATT
Commonest presenting symptom of Pott’s spine is:
March 2007
| A |
Cold abscess |
|
| B |
Back pain |
|
| C |
Decreased spinal movements |
|
| D |
Collapse of spine |
Commonest presenting symptom of Pott’s spine is:
March 2007
| A |
Cold abscess |
|
| B |
Back pain |
|
| C |
Decreased spinal movements |
|
| D |
Collapse of spine |
Ans. B: Back Pain
Tuberculosis (TB) of the spine (Pott’s disease) is the most common site of bone infection in TB. The lower thoracic and upper lumbar vertebrae are the areas of the spine most often affected.
Pott’s disease results from haematogenous spread of tuberculosis from other sites, often pulmonary. The infection then spreads from two adjacent vertebrae into the adjoining disc space.
If only one vertebra is affected, the disc is normal, but if two are involved the intervertebral disc, which is avascular, cannot receive nutrients and collapses (seen as narrowing of intervertebral space on X-rays)
The disease progresses slowly. Signs and symptoms include:
- Localised back pain is the earliest and commonest complaint
- Paravertebral swelling may be seen
- Neurological signs may occur, leading to paraplegia.
- Stiffness
- Deformity
- Constitutional symptoms
Spinal X-ray may not show early disease as 50% of bone mass must be lost for changes to be visible on x-ray. However, plain radiographs can show vertebral destruction and narrowed disc space.
MRI is useful to demonstrate the extent of spinal compression and can show changes at an earlier stage than plain radiographs. Bone elements visible within the swelling, or abscesses, are strongly indicative of Pott’s disease as opposed to malignancy.
CT scans and nuclear bone scans can also be used.
Tuberculosis in Pott’s disease involves:
September 2010
| A |
Hip Joint |
|
| B |
Knee Joint |
|
| C |
Spine |
|
| D |
Wrist Joint |
Tuberculosis in Pott’s disease involves:
September 2010
| A |
Hip Joint |
|
| B |
Knee Joint |
|
| C |
Spine |
|
| D |
Wrist Joint |
Ans. C: Spine
Pott’s disease is a presentation of extrapulmonary tuberculosis that affects the spine, a kind of tuberculous arthritis of the intervertebral joints.
It is named after Percivall Pott.
The lower thoracic and upper lumbar vertebrae are the areas of the spine most often affected.
Scientifically, it is called tuberculous spondylitis and it is most commonly localized in the thoracic portion of the spine.
Pott’s disease results from haematogenous spread of tuberculosis from other sites, often pulmonary. The infection then spreads from two adjacent vertebrae into the adjoining intervertebral disc space.
Earliest sign in X-ray in TB spine is:
March 2011
| A |
Paravertebral shadow |
|
| B |
Narrowing of disc space |
|
| C |
Gibbus |
|
| D |
Straightening of spinal curves |
Earliest sign in X-ray in TB spine is:
March 2011
| A |
Paravertebral shadow |
|
| B |
Narrowing of disc space |
|
| C |
Gibbus |
|
| D |
Straightening of spinal curves |
Ans. B: Narrowing of disc space
Reduction of the disc space is the earliest sign in the commoner, paradiscal type of tuberculosis
Skeletal TB:
- Earliest symptom of spinal TB: Back pain
- Earliest sign in Pott’s disease: Narrowing of disc space
- MC vertebrae to be involved in TB spine: T9-T12
- TB spine starts in: Vertebral body (paradiscal)
- Spina ventosa: TB dactylitis
All of the following are radiological features of tuberculosis of spine except:
| A |
Large paravertebral abscess |
|
| B |
Marked osteoblastic response |
|
| C |
Marked collapse of vertebra |
|
| D |
Deceased joint space |
All of the following are radiological features of tuberculosis of spine except:
| A |
Large paravertebral abscess |
|
| B |
Marked osteoblastic response |
|
| C |
Marked collapse of vertebra |
|
| D |
Deceased joint space |
Ans. Marked osteoblastic response
Note a feature of TB spine‑
| A |
Back pain earliest symptom |
|
| B |
Stiffness of back |
|
| C |
Exagrated lumbar lordosis |
|
| D |
All |
Note a feature of TB spine‑
| A |
Back pain earliest symptom |
|
| B |
Stiffness of back |
|
| C |
Exagrated lumbar lordosis |
|
| D |
All |
Ans. is `c’ i.e., Exagrated lumbar lordosis
Clinical features of TB of spine
- The disease is commonest in young adults.
- The presenting complains are : –
- Back pain : Commonest and earliest symptom. Initially pain occurs on sudden movement of spine.
- Stiffness of back : Is also an early symptom and occur along with pain.
- Visible deformity : Gibbus or Kyphosis
- Localized swelling : Due to cold abscess
- Paraplagia : In neglected cases
- Constitutional symptoms : Evening fever, loss of appetite, night sweat, loss of weight.
- On examination, following findings may be seen : –
- Decreased range of motion.
- Local tenderness : Over the spinous process of affected vertebra.
- Deformity : –
- Cervical spine : – Straight neck with loss of cervical lordosis.
- Thoracic : – Gibbus/kyphosis
- Lumbar : – Loss of lumbar lordosis
- Para-vertebral swelling : – Cold abscess
TUBERCULOSIS OF SPINE (Pott’s disease)
TUBERCULOSIS OF THE SPINE (Pott’s disease)
- The spine is the commonest site of bone and joint tuberculosis.
- Dorso-lumbar region affected most frequently.
Types of vertebral tuberculosis:
1. Paradiscal: commonest type
2. Central:
- Single vertebra is affected.
- This leads to early collapse of the weakened vertebra.
- The nearby disc may be normal.
- The collapse may be a ‘wedging’ or ‘concertina’ collapse
3. Anterior:
- infection is localised to the anterior part of the vertebral body.
4. Posterior:
- the posterior complex of the vertebra i.e., the pedicle, lamina, spinous process and transverse process are affected.
CLINICAL FEATURES
- Pain (back pain)
- Stiffness
- Cold abscess
- Paraplegia
- Deformity: increasing prominence of the spine – gibbus.
- Constitutional symptoms: Symptoms like fever, weight loss etc.
RADIOLOGICAL INVESTIGATIONS
X-ray examination:
- Reduction of disc space: earliest sign
- Destruction of the vertebral body
Evidence of cold abscess:
1). Para-vertebral abscess-
- fusiform para-vertebral abscess (bird nest abscess – an abscess whose length is greater than its width (Fig-23.7a);
- globular or tense abscess – an abscess whose width is greater than the length
2). Widened mediastinum-
3). Retro-pharyngeal abscess
4). Psoas abscess
- Rarefaction: diffuse rarefaction of the vertebrae above and below the lesion.
- Unusual signs: erosion of the posterior elements of pedicle, lamina etc.
- Signs of healing
CT scan:
- very useful investigation in cases presenting as ‘spinal tumour syndrome’.
MRI:
- Investigation of choice to evaluate the type and extent of compression of the cord.
Other investigations:
- ESR, Mantoux test, ELISA test for detecting anti- tubercular antibodies, chest X-ray, etc.,
COMPLICATIONS
- Cold abscess: commonest complication of TB of the spine.
- Neurological compression: At times the patient presents as a case of spinal tumour syndrome.
- First clinical symptom being a neurological deficit.
Exam Important
- Tuberculosis in Pott’s disease involves Spine.
- Pott’s spine is commonest at Thoracolumbar spine.
- Tuberculosis of spine is common at Thoracolumbar.
- Most common cause of cold abscess of chest wall is Pott’s spine.
- Commonest presenting symptom of Pott’s spine is Back pain.
- The paradiscal type is M/C type of vertebral tuberculosis.
- Wedging or Concertina collapse: in central type.
- Pott’s disease: M/C cause for kyphosis & cold abscess.
- Earliest radiological sign of spine tuberculosis is reduction of intervertebral disc space.
- M/C complication of spine tuberculosis cold abscess.
- Investigation of choice- MRI.
- M/c performed surgery- Antero lateral decompression.
- TB of spine à bony ankylosis, other bones & joints a fibrous ankylosis.
Caesarean Section
A 37-year old second gravid, previous LSCS at 37 wks of pregnancy presents with blood pressure of 150/100, urine albumin++. On pelvic examination
cervix is found to be soft with 50% effacement, station is – 3, pelvis adequate and cervical os is closed. Most appropriate step at the moment would be
| A |
Antihypertensive regime and then induce labour |
|
| B |
Wait and watch for 10 days |
|
| C |
Induce labour spontaneously |
|
| D |
Do caesarean section |
A 37-year old second gravid, previous LSCS at 37 wks of pregnancy presents with blood pressure of 150/100, urine albumin++. On pelvic examination
cervix is found to be soft with 50% effacement, station is – 3, pelvis adequate and cervical os is closed. Most appropriate step at the moment would be
| A |
Antihypertensive regime and then induce labour |
|
| B |
Wait and watch for 10 days |
|
| C |
Induce labour spontaneously |
|
| D |
Do caesarean section |
Do cesarean section [Ref- Dutta 7/e p. 227-232, COGDT 10/e p. 32-25; Williams Ohs 23/e p. 729]
- This is case of preeclampsia at 37 weeks.
- For management purpose preeclampsia is divided into two categories i.e., mild preeclampsia and severe preeclampsia.
- Severe and mild preeclampsia are managed differently.
- But this categorization does not matter in this case because of the gestational age of the patient.
– “The gestational age of the patient is 37 weeks and any case of preeclampsia 37 weeks gestational age is delivered immediately irrespective of the severity of the preeclampsia”.
- The main concern here is the mode of delivery
-The patient presents with unfavourable cervix and a history of previous LS.C.S.
– The best mode of delivery in such a patient with mild preeclampsia is performing an L.S.C.S.
Indications for caesarean section in pregnancy are all except ‑
| A |
Eisenmenger syndrome |
|
| B |
Aortic stenosis |
|
| C |
M.R. |
|
| D |
Aortic regurgitaion |
Indications for caesarean section in pregnancy are all except ‑
| A |
Eisenmenger syndrome |
|
| B |
Aortic stenosis |
|
| C |
M.R. |
|
| D |
Aortic regurgitaion |
Eisenmenger syndrome Eisenmenger’s syndrome
- Maternal mortality rate in Eisenmenger’s syndrome is 30-40%
– Because of high maternal mortality rate patient should he counselled to avoid pregnancy and if pregnant consider termination of pregnancy.
– Because of high maternal mortality rate abortion is the t/t of choice.
If any pregnancy continues upto term in Eisenmenger’s syndrome, there is no evidence to support the choice of either vaginal or cesarean delivery.
- Maternal mortality rate with normal delivery is 34% and with cesarean section is 75%.
Mitral regurgitation
- Mitral regurgitation is usually tolerated well during pregnancy. The marked decrease in systemic vascular resistance that occurs during pregnancy alleviates the abnormal physiologic stress imposed by this lesion. Rarely, reactive pulmonary hypertension and severe right heart failure may ensue.
- There are no specific recommendations for the management of mitral regurgitation during labour and delivery. Prior to labour, symptoms may be managed with diuretics and vasodilators. During labour, regional anaesthesia is usually well tolerated. However, in complicated NYHA class 3-4 cases, cesarean section and general anaesthesia may be required.
Aortic stenosis
- In general the symptoms of aortic stenosis are masked by progressive left ventricular hypertrophy and are thus easily missed. Overall, patients who were asymptomatic prior to pregnancy usually tolerate pregnancy relatively uneventfully.
- Echocardiographic determination of valve area is the best guide to severity of aortic stenosis. The hyperdynamic circulation of pregnancy frequently leads to overestimation of the degree of stenosis.
- These patients tolerate tachycardia, hypovolaemia and systemic vasodilatation poorly, since coronary perfusion is critically dependent upon maintaining aortic diastolic pressure. General anaesthesia and caesarean section, with the aid of invasive haemodynamic monitoring, appears to be the safest means of successful delivery.
Aggressive maintenance of systemic blood pressure with vasopressors (e.g. phenylephrine), is paramount to the avoidance of severe hypotension, acute left ventricular failure and cardiac arrest.
- Spinal anaesthesia is generally contraindicated in these patients. There are reports of the successful management of vaginal delivery under carefully introduced and limited epidural analgesia, but this should be restricted to very experienced hands.
Aortic regurgitation
- Aortic regurgitation also reduces both cardiac output and coronary blood flow. Like M.R. it is well tolerated in pregnancy. The preferred mode of delivery in A.R. vaginal delivery unless obstetrical indications for cesarean exist. The crux is
i) Both Aortic regurgitation and mitral regurgitation are well tolerated during pregnancy. Vaginal delivery is the preferred mode of termination of pregnancy unless there are obstetrical indications for cesarean section.
ii) Aortic stenosis carries more risk than the above two disorders and the preferred mode of delivery is cesarean section.
iii) Eisenmenger syndrome carries great risk in pregnancy. The maternal mortality reaches 50%. So, ideally pregnancy should be terminated in patients with Eisenmenger syndrome.
We are not sure, if we have got the correct question.
A patient undergoing caesarean section following prolonged labour under subarachnoid block developed carpopedal spasm. Lignocain was used as anesthetic agent. The most likely diagnosis is:
| A |
Amniotic fluid embolism |
|
| B |
Lignocaine toxicity |
|
| C |
Hypocalcemia |
|
| D |
Hypokalemia |
A patient undergoing caesarean section following prolonged labour under subarachnoid block developed carpopedal spasm. Lignocain was used as anesthetic agent. The most likely diagnosis is:
| A |
Amniotic fluid embolism |
|
| B |
Lignocaine toxicity |
|
| C |
Hypocalcemia |
|
| D |
Hypokalemia |
Pain due to prolonged labour may lead to hyperventilation and resultant respiratory alkalosis.
This will cause a decrease in the level of free ionized calcium in the ECF,
resulting in hypocalcemia and precipitating carpopedal spasm.
Ref: Primer on The Metabolic Bone Diseases and Disorders of Mineral Metabolism Edited By Clifford J. Rosen, 7th Edition, Page 354 ; Nutrition Therapy and Pathophysiology By Marcia Nahikian Nelms, 2007, Page 196 ; Essentials of Medical Pharmacology By KD Tripathi, 5th Edition, Page 479
A Lower Segment Caesarean section (LSCS) can be carried out under all the following techniques of anaesthesia, EXCEPT:
| A |
General anaesthesia |
|
| B |
Spinal anaesthesia |
|
| C |
Caudal anaesthesia |
|
| D |
Combined Spinal Epidural anaesthesia |
A Lower Segment Caesarean section (LSCS) can be carried out under all the following techniques of anaesthesia, EXCEPT:
| A |
General anaesthesia |
|
| B |
Spinal anaesthesia |
|
| C |
Caudal anaesthesia |
|
| D |
Combined Spinal Epidural anaesthesia |
Caudal anaesthesia may be used for perenial operations.
It is not indicated in Lower segment caesarian section.
Further it is associated with potential risk of penetrating the fetal head in obstetric practice.
Ref:Textbook of Anaesthesia By Aitkinhead, 4th Edition, Pages 568, 641, 643
Absolute indication for caesarean section in pregnancy are all except?
| A |
Advanced Carcinoma Cervix |
|
| B |
Central Placenta Praevia |
|
| C |
Non reassuring FHR (Fetal distress) |
|
| D |
Contracted Pelvis |
Absolute indication for caesarean section in pregnancy are all except?
| A |
Advanced Carcinoma Cervix |
|
| B |
Central Placenta Praevia |
|
| C |
Non reassuring FHR (Fetal distress) |
|
| D |
Contracted Pelvis |
Non reassuring FHR is a Relative indication for C-section.
Which of the following is the contraindication for trial of normal labour after caesarean section?
| A |
History of previous classical CS |
|
| B |
History of previous CS due to CPD |
|
| C |
No history of prior vaginal delivery |
|
| D |
History of previous CS due to malpresentation |
Which of the following is the contraindication for trial of normal labour after caesarean section?
| A |
History of previous classical CS |
|
| B |
History of previous CS due to CPD |
|
| C |
No history of prior vaginal delivery |
|
| D |
History of previous CS due to malpresentation |
Prior classical or T-shaped uterine incisions are considered contraindications to labor.
The highest risks of uterine rupture are present with prior vertical incisions extending into the fundus such as the classical incision.
Women with a transverse scar confined to the lower uterine segment have the lowest risk of symptomatic scar separation during a subsequent pregnancy.
- One previous prior low-transverse cesarean delivery
- Clinically adequate pelvis
- No other uterine scars or previous rupture
- Physician immediately available throughout active labor capable of monitoring labor and performing an emergency cesarean delivery
- Availability of anesthesia and personnel for emergency cesarean delivery
A primigravida at 37 week of gestation reported to labour room with central placenta previa with heavy bleeding per vaginum. The fetal heart rate was normal at the time of examination. Which of the following is the best management option for her?
| A |
Caesarean section |
|
| B |
Expectant management |
|
| C |
Induction and vaginal delivery |
|
| D |
Induction and forceps delivery |
A primigravida at 37 week of gestation reported to labour room with central placenta previa with heavy bleeding per vaginum. The fetal heart rate was normal at the time of examination. Which of the following is the best management option for her?
| A |
Caesarean section |
|
| B |
Expectant management |
|
| C |
Induction and vaginal delivery |
|
| D |
Induction and forceps delivery |
- Severe degree placenta previa (type-II (marginal), type-III (incomplete or partial central), type-4 (central or total).
- Lesser degree of placenta previa where amniotomy fails to stop bleeding or fetal distress appears.
- Complicating factors associated with lesser degrees of placenta previa where vaginal delivery is unsafe.
Vaginal delivery usually is reserved for patients with a marginal implantation and a cephalic presentation. If vaginal delivery is elected, the membranes should be artificially ruptured prior to any attempt to stimulate labor (oxytocin given before amniotomy is likely will cause further bleeding).
Which of the following is an absolute indication for Caesarean section?
| A |
Placenta Previa |
|
| B |
CPD |
|
| C |
Previous Cesarean section |
|
| D |
Breech presentation |
Which of the following is an absolute indication for Caesarean section?
| A |
Placenta Previa |
|
| B |
CPD |
|
| C |
Previous Cesarean section |
|
| D |
Breech presentation |
Cephalopelvic disproportion is an absolute indication for Caesarean section. Other absolute indications includes central placenta praevia, pelvic mass causing obstruction (cervical or broad ligament fibroid), advanced cervical carcinoma and vaginal obstruction (as in atresia, stenosis).
- Previous caesarean delivery
- Non reassuring FHR
- Dystocia due to relatively large fetus, small pelvis or inefficient contractions
- Antepartum hemorrhage
- Malpresentation
- Failed surgical induction of labour, failure to progress in labour
- Bad obstetric history
- Hypertensive disorders
- Medical gynecological disorders
Which of the following is an indication of Caesarean section after a previous caesarean section?
| A |
Hypertension |
|
| B |
Type 1 placenta previa |
|
| C |
CPD |
|
| D |
Multigravida |
Which of the following is an indication of Caesarean section after a previous caesarean section?
| A |
Hypertension |
|
| B |
Type 1 placenta previa |
|
| C |
CPD |
|
| D |
Multigravida |
Indications of C section after a previous caesarean section includes: contracted pelvis, previous two casesarean sections, features of scar dehiscence and previous classical caesarean section.
In classical caesarean section more chances of rupture of uterus is in :
| A |
Upper uterine segment |
|
| B |
Lower uterine segment |
|
| C |
Utero cervical junction |
|
| D |
Posterior uterine segment |
In classical caesarean section more chances of rupture of uterus is in :
| A |
Upper uterine segment |
|
| B |
Lower uterine segment |
|
| C |
Utero cervical junction |
|
| D |
Posterior uterine segment |
Upper uterine segment
Best management in Mento-posterior presentation:
| A |
Vaginal delivery |
|
| B |
Forceps delivery |
|
| C |
Manual rotation |
|
| D |
Caesarean section |
Best management in Mento-posterior presentation:
| A |
Vaginal delivery |
|
| B |
Forceps delivery |
|
| C |
Manual rotation |
|
| D |
Caesarean section |
Caesarean section
Which of the following is an absolute indication for caesarean section in pregnancy associated with heart disease?
| A |
Pulmonary stenosis |
|
| B |
Coarctation of aorta |
|
| C |
Eisenmenger syndrome |
|
| D |
Ebstein’s anomaly |
Which of the following is an absolute indication for caesarean section in pregnancy associated with heart disease?
| A |
Pulmonary stenosis |
|
| B |
Coarctation of aorta |
|
| C |
Eisenmenger syndrome |
|
| D |
Ebstein’s anomaly |
Coarctation of aorta
True about transient tachypnoea of new born is ‑
| A |
Air bronchogram seen |
|
| B |
Common in preterm infants |
|
| C |
Interlobar fissure effusion |
|
| D |
Respiratory distress resolves in 6-10 days |
True about transient tachypnoea of new born is ‑
| A |
Air bronchogram seen |
|
| B |
Common in preterm infants |
|
| C |
Interlobar fissure effusion |
|
| D |
Respiratory distress resolves in 6-10 days |
Ans. is ‘c‘ i.e., Interlobar fissure effusion
A 26 year old third_gravida mother delivered a male baby weighing 4-2 kg at 37 weeks of gestation through an emergency caesarean section, for obstructed labour. The child developed respiratory distress one hour after birth. He was kept nil per orally (NPO) and given intravenous fluids. He maintained oxygen saturation on room air. No antibiotics were given. Chest radiograph revealed fluid in interlobar fissure. Respiratory distress settled by 24 hours of life. What is the most likely diagnosis ?
| A |
Transient tachypnea of the newborn |
|
| B |
Meconium aspiration syndrome |
|
| C |
Persistent fetal circulation |
|
| D |
Hyaline membrane disease |
A 26 year old third_gravida mother delivered a male baby weighing 4-2 kg at 37 weeks of gestation through an emergency caesarean section, for obstructed labour. The child developed respiratory distress one hour after birth. He was kept nil per orally (NPO) and given intravenous fluids. He maintained oxygen saturation on room air. No antibiotics were given. Chest radiograph revealed fluid in interlobar fissure. Respiratory distress settled by 24 hours of life. What is the most likely diagnosis ?
| A |
Transient tachypnea of the newborn |
|
| B |
Meconium aspiration syndrome |
|
| C |
Persistent fetal circulation |
|
| D |
Hyaline membrane disease |
Ans. is ‘a’ i.e., Transient tachypnea of newborn
o Respiratory distress, which resolves within 24 hours without any respiratory support and fluid in interlobar fissure on chest X-ray suggest the diagnosis of TTN.
A 21 year old lady with a history of hypersensitivity to neostigmine is posted for an elective caesarean section under general anesthesia. The best muscle relaxant of choice in this patient should be:
| A |
Pancuronium |
|
| B |
Atracurium |
|
| C |
Rocuronium |
|
| D |
Vecuronium |
A 21 year old lady with a history of hypersensitivity to neostigmine is posted for an elective caesarean section under general anesthesia. The best muscle relaxant of choice in this patient should be:
| A |
Pancuronium |
|
| B |
Atracurium |
|
| C |
Rocuronium |
|
| D |
Vecuronium |
B i.e. Atracurium
You might be thinking that this Q has never been asked, but think a while and try to understand that around which concept the Q is based. In other words, they are trying to ask that which muscle relaxant will not require reversal? I think now you need no explanation
– In pancuronium reversal is often required d/ t its longer duration of action
– Ve/Ro-curonium seldom require reversal unless repeated doses have been given
– In atracurium & cis-atracurium reversal is mostly not required due to its unique feature of spontaneous non eyzmatic degradation (Hoffmann elimination) Q.
A 30 year old woman with coarctation of aorta is admitted to the labour room for elective caesarean section. Which of the following is the anaesthesia technique of choice:
| A |
Spinal anaesthesia |
|
| B |
Epidural anaesthesia |
|
| C |
General anaesthesia |
|
| D |
Local anaesthesia with nerve block |
A 30 year old woman with coarctation of aorta is admitted to the labour room for elective caesarean section. Which of the following is the anaesthesia technique of choice:
| A |
Spinal anaesthesia |
|
| B |
Epidural anaesthesia |
|
| C |
General anaesthesia |
|
| D |
Local anaesthesia with nerve block |
C i.e. General anesthesia
In coarctation of aorta any decrease in cardiac output or cardiac return is deleterious to the fetus because the placental circulation is already comprised on account of coarctation. So any anesthetic procedure/drug which causes hypotension should be avoided.
Regional anaesthic procedure such as spinal anesthesia and epidural anesthesia should be avoidedQ in these patients because hypotension is the most common side effect of these procedure.
General anesthesia is technique of choiceQ for performing cesarian section in a patient with coarctation of aorta, as it has advantage of – rapid induction, better airway & ventilation and less hypotension.
A multigravida woman was posted for emergency caesarean section. Correct statements are all of the following except-
September 2006
| A |
Cricoid pressure is applied while intubating |
|
| B |
Isoflurane should not be used as it causes placental insufficiency |
|
| C |
CS is done to prevent fetal distress and meconiumm aspiration |
|
| D |
Cord clamping to be done after a few minutes |
A multigravida woman was posted for emergency caesarean section. Correct statements are all of the following except-
September 2006
| A |
Cricoid pressure is applied while intubating |
|
| B |
Isoflurane should not be used as it causes placental insufficiency |
|
| C |
CS is done to prevent fetal distress and meconiumm aspiration |
|
| D |
Cord clamping to be done after a few minutes |
Ans. B: Isoflurane should not be used as it causes placental insufficiency
General anaesthesia for CS:
It is given for fetal distress/if there is contraindication for spinal anaesthesia.
- Prophylaxis against aspiration should be taken.
- Intubation with Sellick’s manoeuvre (cricoid pressure)
- Give drugs in minimum doses
- Avoid premedication
- Induction by thiopentone in minimum doses
- All inhalational agent relax the uterus and cause post-partum hemorrhage in dose related manner.
- Isuflurane is the agent of choice as it maintains the cardiac output thus minimally compromising the fetal circulation.
Absolute indication for caesarean section is:
March 2013
| A |
Previous LSCS |
|
| B |
Type IV placenta previa |
|
| C |
Fetal distress |
|
| D |
Breech presentation |
Absolute indication for caesarean section is:
March 2013
| A |
Previous LSCS |
|
| B |
Type IV placenta previa |
|
| C |
Fetal distress |
|
| D |
Breech presentation |
Ans. B i.e. Type IV placenta previa
Caesarean section
Indications of classical caesarean section
- Previous classical cesarean section
- Neglected shoulder with anhydramnios
- Structural abnormality making approach to lower segment difficult
- Constriction ring due to neglected labor
- Fibroids in lower segment
- Anterior placenta accreta and praevia
- Very preterm fetus, where lower segment is poorly formed.
Ideal management of a 37 weeks pregnant elderly primigravida with placenta praevia and active bleeding:
September 2007
| A |
Labour induction |
|
| B |
Caesarean section |
|
| C |
Vaginal delivery |
|
| D |
Expectant treatment |
Ideal management of a 37 weeks pregnant elderly primigravida with placenta praevia and active bleeding:
September 2007
| A |
Labour induction |
|
| B |
Caesarean section |
|
| C |
Vaginal delivery |
|
| D |
Expectant treatment |
Ans. B: Caesarean Section
An initial assessment to determine the status of the mother and fetus is required.
It is now considered safe to treat placenta praevia on an outpatient basis if the fetus is at less than 30 weeks of gestation, and neither the mother nor the fetus are in distress.
Immediate delivery of the fetus may be indicated if the fetus is mature or if the fetus or mother are in distress. Blood volume replacement (to maintain blood pressure) and blood plasma replacement (to maintain fibrinogen levels) may be necessary.
In cases of fetal distress, associated complicating factors like malpresentation, elderly primigravidae, pregnancy with a previous caesarean section and contracted pelvis, a caesarean section is indicated.
Caesarean section is contraindicated in cases of disseminated intravascular coagulation.
Placenta praevia increases the risk of puerperal sepsis and postpartum haemorrhage because the lower segment to which the placenta was attached contracts less well post-delivery
Which of the following types of placenta complicates third stage of labour and is associated with a past history of caesarean section:
September 2011
| A |
Placenta succenturita |
|
| B |
Placenta extracholis |
|
| C |
Placenta membranecae |
|
| D |
Placenat accrete |
Which of the following types of placenta complicates third stage of labour and is associated with a past history of caesarean section:
September 2011
| A |
Placenta succenturita |
|
| B |
Placenta extracholis |
|
| C |
Placenta membranecae |
|
| D |
Placenat accrete |
Ans. D: Placenta accreta
Most important risk factors for placenta accreta are the placenta praevia and prior caesarean delivery It complicates 3rd stage of labour (haemorrhage, shock, infection and rarely inversion of the uterus) Other types of placenta:
- Biscoidal placenta: Placenta have 2 discs
- Lobed placenta: Placenta divided into lobes
- Placenta succenturita: Small part of placenta separated from the rest
- Febestrated: Placenta having a hole in centre
- Circumvallate: Edge of placenta is covered by circular fold of decidualis
Incidence of scar rupture in previous lower segment caesarean section:
March 2012
| A |
1% |
|
| B |
5% |
|
| C |
6% |
|
| D |
7% |
Incidence of scar rupture in previous lower segment caesarean section:
March 2012
| A |
1% |
|
| B |
5% |
|
| C |
6% |
|
| D |
7% |
Ans: A i.e. 1%
Incidence of scar rupture in lower segment CS is less (0.5-1.5%) whereas there is more risk of scar rupture in classical CS (4-9%).
Risk of rupture of uterus with previous classical caesarean section is:
March 2011
| A |
0.5-1.5% |
|
| B |
2-4% |
|
| C |
4-8% |
|
| D |
8-16% |
Risk of rupture of uterus with previous classical caesarean section is:
March 2011
| A |
0.5-1.5% |
|
| B |
2-4% |
|
| C |
4-8% |
|
| D |
8-16% |
Ans. C: 4-8%
Classical caesarean section carries more risk of scar rupture (4-8%) Scar rupture in lower segment CS is less (0.5-1.5%)
Cesarean Section
DEFINITION:
- It is an operative procedure whereby the fetuses after the end of 28th weeks are delivered through an incision on the abdominal and uterine walls.
FACTORS FOR RISING CESARIAN SECTION RATE:
- Rising incidence of primary cesarean delivery
- Identfication of at risk fetuses before term (FGR)
- Identfication of high-risk pregnancy
- Wider use of repeat CS
- Rising rates of induction of labor and failure of induction
- Decline in operative vaginal delivery & vaginal breech delivery
- Increased number of women with age >30 years
- Wider use of electronic fetal monitoring and increased diagnosis of fetal distress
- Fear of litigation
INDICATIONS:
Absolute Indications:
- Vaginal delivery is not possible
- Central placenta previa
- Contracted pelvis or cephalopelvic disproportion
- Pelvic mass
- Advanced carcinoma cervix
- Vaginal obstruction
Relative Indications:
- Previous cesarean delivery
- Fetal distress
- Dystocia
- Antepartum hemorrhage
- Placenta previa
- Abruptio placenta
- Malpresentation
- Failed surgical induction
- Recurrent fetal loss
- Hypertensive disorders
- Medical-gynecological disorders
- Diabetes
- Coarctation of aorta
- MS, AR, AS
- Marfan’s syndrome
- Mechanical obstruction
TYPES OF OPERATIONS:
- Lower segment CS.
- Upper segment (classical) CS.
- Modified classical (de-lee) CS.
Lower segment cesarean section (LSCS):
PATIENT PREPARATION
- Counseling.
- Written informed consent.
- Pre-operative evaluation.
- Preparation of incision area
- Bladder catheterization
- Blood arrangements
- Antibiotics
- Heparin therapy.
PATIENT PREPARATION IN OPERATION THEATRE
- Left lateral tilt at least 15 degree
- Oxygen inhalation
- Pediatrician should be available
- Auscultation of fetal hearts before starting.
ANESTHESIA
- General anesthesia
- Spinal anesthesia
- Epidural anesthesia
- Local infiltration.
SKIN INCISIONS :
- Pfannenstiel incision
- Joel-Cohen incision.
- Midline incision
- Para-median incision
Uterine incision:
- Peritoneal incision: Transverse cut across lower segment with convexity downwards
- Muscle incision: Low transverse(90%):Slightly below peritoneal incision
- Ease of operation
- Less bladder dissection
- Less blood loss
- Easy to repair
- Complete reperitonization
- Less adhesion
- Less risk of scar rupture
Other:
- Lower vertical
- Classical incision (upper segment).
- “J” incision
- Inverted “T” incision
PROCEDURE:
- Two index fingers are then inserted through the incision down to the membranes and the muscles of the lower segment are split transversely.
Delivery of the head:
- Membranes are ruptured
- Suction of blood mixed amniotic fluid
- Hooking the head with fingers by elevation and flexion using the palm
- If the head is jammed push up the head by fingers introduced into the vagina
- Wrigley’s or Barton’s forceps also be used
- Mucus from the mouth, pharynx and nostrils is sucked
Delivery of the trunk
- After delivery of shoulders IV oxytocin 20 units or methergine 0.2 mg is to be administered
- Head tilted down for gravitational drainage
- Cord is cut between two clamps
- The Doyen’s retractor is reintroduced.
- The optimum interval between uterine incision and delivery should be less than 90 seconds.
Removal of the placenta and membranes:
- Traction on the cord with simultaneous pushing of the uterus towards the umbilicus per abdomen using left hand
Suture of the uterine wound:
- Allis tissue forceps or Green Armytage hemostatic clamps are used to pick margins of the wound
The uterine incision is sutured in three layers:
First layer:
- Suture material is No “0” chromic catgut or vicryl
- Continuous running suture taking deeper muscles excluding or including the decidua
Second layer:
- Continuous suture placed taking superficial muscles and adjacent fascia overlapping first layer of suture.
- Uterine muscles may be closed taking full thickness muscle and decidua
- The peritoneal flaps may be apposed by continuous inverting suture
- Concluding part: The mops placed inside are removed and the number verified.
- Peritoneal toileting is done and the blood clots are removed meticulously
- After being satisfied that the uterus is well contracted, the abdomen is closed in layers.
CLASSICAL CESAREAN SECTION:
- Abdominal incision is always longitudinal (paramedian)12.5 cm (5″) starting from below the fundus
- Delivery commonly as breech extraction.
- The uterus is eventrated.
- The placenta is extracted by traction on the cord or removed manually
| Lower Segment | Classical | |
| Techniques | Difficult | Easy |
| Blood loss is less | More | |
| Wall is thin and as such apposition is perfect | Wall is thick and apposition of the margins is imperfect | |
| Perfect peritonization possible | Not possible | |
| Technical Difficulty in placenta previa or transverse | Comparatively safer | |
| Post-operative | Less Hemorrhage and shock | More |
| Peritonitis is less | More | |
| Convalescence is better | Relatively delayed | |
| Morbidity and mortality are much lower | Morbidity and mortality are high | |
| Less Peritoneal adhesions and intestinal obstructions | More | |
| Wound healing | Perfect muscle apposition | Imperfect |
| Minimal wound hematoma | More | |
| Wound Quiescent during healing process | Wound in state of tension | |
| Chance of gutter formation is unlikely | More | |
| During future pregnancy |
Scar rupture(0.5–1.5%) | More risk of scar rupture(4–9%) |
COMPLICATIONS:
Maternal:
INTRAOPERATIVE::
- Extension of uterine incision
- Uterine lacerations
- Bladder injury
- Ureteral injury
- Gastrointestinal tract injury
- Hemorrhage
- Morbid adherent placenta (placenta accreta)
POSTOPERATIVE COMPLICATIONS:
IMMEDIATE:
- Postpartum hemorrhage
- Shock
- Anesthetic hazards:Mendelson’s syndrome
- Infections
- Intestinal obstruction
- Deep vein thrombosis and thromboembolic disorders
Wound complications:
- Sanguineous or frank pus
- Hematoma
- Dehiscence
- Burst abdomen
- Necrotizing fasciitis
- Secondary postpartum hemorrhage
REMOTE:
- Gynecological: Menstrual excess or irregularities, chronic pelvic pain or backache.
- General surgical: Incisional hernia, intestinal obstruction due to adhesions and bands.
- Future pregnancy: There is risk of scar rupture
FETAL:
- Iatrogenic prematurity
- RDS
- MATERNAL AND PERINATAL MORTALITY
Exam Important
- Indications for caesarean section in pregnancy are Aortic stenosis, M.R. & Aortic regurgitaion
- Lower Segment Caesarean section (LSCS) can be carried out under
- General anaesthesia
- Spinal anaesthesia
- Combined Spinal Epidural anaesthesia
- Absolute indication for caesarean section in pregnancy are
- Advanced Carcinoma Cervix
- Central Placenta Praevia
- Contracted Pelvis
- History of previous classical CS is the contraindication for trial of normal labour after caesarean section
- Cephalopelvic disproportion is an absolute indication for Caesarean section.
- In classical caesarean section more chances of rupture of uterus is in Upper uterine segment
- Best management in Mento-posterior presentation Caesarean section
- Absolute indication for caesarean section is Type IV placenta previa
- Ideal management of a 37 weeks pregnant elderly primigravida with placenta praevia and active bleeding is Caesarean section
- Placenat accrete complicates third stage of labour and is associated with a past history of caesarean section
- Incidence of scar rupture in previous lower segment caesarean section 1%
- Risk of rupture of uterus with previous classical caesarean section is 4-8%
ENZYME INHIBTION
The presence of a noncompetitive inhibitor can be implicated in which of the outcome?
| A |
Leads to both an increase in the Vmax of a reaction and an increase in the Km |
|
| B |
Leads to a decrease in the observed Vmax |
|
| C |
Leads to a decrease in Km and Vmax |
|
| D |
Leads to an increase in Km without affecting Vmax |
The presence of a noncompetitive inhibitor can be implicated in which of the outcome?
| A |
Leads to both an increase in the Vmax of a reaction and an increase in the Km |
|
| B |
Leads to a decrease in the observed Vmax |
|
| C |
Leads to a decrease in Km and Vmax |
|
| D |
Leads to an increase in Km without affecting Vmax |
In the presence of a noncompetitive inhibitor, Vmax is decreased, whereas Km is unchanged. The steady-state concentration of ES is decreased.
A competitive inhibitor of an enzyme will?
| A |
Alter the Vmax of the reaction |
|
| B |
Bind to the same site as the substrate |
|
| C |
Decrease the apparent Km for the substrate |
|
| D |
Decrease the turnover number |
A competitive inhibitor of an enzyme will?
| A |
Alter the Vmax of the reaction |
|
| B |
Bind to the same site as the substrate |
|
| C |
Decrease the apparent Km for the substrate |
|
| D |
Decrease the turnover number |
Substances that reduce the activity of an enzyme are called inhibitors.
Reversible inhibitors bind to an enzyme but rapidly dissociate from it [in contrast to irreversible inhibitors , which bind tightly and dissociate very slowly from the enzyme].
There are several types of reversible inhibitors:
True about competitive inhibition of enzyme:
| A |
T Km |
|
| B |
Km |
|
| C |
T Vmax |
|
| D |
No change in Km and Vmax |
True about competitive inhibition of enzyme:
| A |
T Km |
|
| B |
Km |
|
| C |
T Vmax |
|
| D |
No change in Km and Vmax |
In noncompetitive antagonism, the true statement is:
| A |
Km value decrease; V max normal |
|
| B |
Km value decreased; V max decreased |
|
| C |
Km value normal; V max decreased |
|
| D |
Km value decreased; V max increased |
In noncompetitive antagonism, the true statement is:
| A |
Km value decrease; V max normal |
|
| B |
Km value decreased; V max decreased |
|
| C |
Km value normal; V max decreased |
|
| D |
Km value decreased; V max increased |
Non competitive inhibitor of carbonic anhydrase‑
| A |
Allopurinol |
|
| B |
Acetazolamide |
|
| C |
Bimatoprost |
|
| D |
Dipivefrine |
Non competitive inhibitor of carbonic anhydrase‑
| A |
Allopurinol |
|
| B |
Acetazolamide |
|
| C |
Bimatoprost |
|
| D |
Dipivefrine |
Ans. is ‘b’ i.e., Acetazolamide
o Acetazolamide is non-competitive , reversible inhibitor of carbonic anhydrase.
Which of the following is known as suicidal enzyme?
| A |
Lipoxygenase |
|
| B |
Cyclooxygenase |
|
| C |
Thromboxane synthatase |
|
| D |
5′ nucleotidase |
Which of the following is known as suicidal enzyme?
| A |
Lipoxygenase |
|
| B |
Cyclooxygenase |
|
| C |
Thromboxane synthatase |
|
| D |
5′ nucleotidase |
Suicidal enzyme is one, which undergoes self-destruction in order to terminate its own acitivity, e.g. Cyclooxygenase.
Suicidal Inhibition is conversion of a substrate by the enzyme into a metabolite, which is a potent inhibitor of the enzyme; example: Xanthine oxidase converts allopurinol to alloxanthine (oxypurinol), which is a more potent inhibitor of allopurinol.
ENZYME INHIBITION
ENZYME INHIBITION
- Enzyme inhibitor binds with enzyme and decreases a catalytic activity.
Types of Enzyme Inhibition-
- Reversible
- Irreversible
- Allosteric
- Reversible Inhibition– binds through non-covalent bonds and activity of enzyme is restored. Divided into-
a) Competitive inhibitor– Km increased, Vmax unchanged.
- E.g.- Succinate dehydrogenase by melanate.
b) Non competitive inhibitor- Km unchanged, Vmax decrease, mostly irreversible.
- E.g.- Cyanide by Cytochrome C Oxidase.
- Carbonic anhydrase by Acetazolamide
2. Irreversible Inhibition– binds covalently with an enzyme.
a) Suicidal Inhibitor– irreversible binding to enzyme and inhibit enzyme.
- E.g. Allopurinol inhibit Xanthine oxidase, cyclooxygenase.
3. Feedback Inhibition- called as end product inhibition.
- E.g. AMP inhibits first step in purine synthesis.
Exam Important
- Reversible Inhibition- binds through non-covalent bonds and activity of enzyme is restored.
- Competitive inhibitor- Km increased, Vmax unchanged.
- Competitive inhibitor- Succinate dehydrogenase by melanate.
- Non competitive inhibitor- Km unchanged, Vmax decrease, mostly irreversible.
- Non competitive inhibitor- E.g.- Cyanide by Cytochrome C Oxidase.
- Suicidal Inhibitor- Allopurinol inhibit Xanthine oxidase.
| Type of inhibitor | Km | Vmax | |
| Reversible inhibbitor | Increased | No effect | |
| Competitive | No effect | Decreased | |
| Non-competitive | Decreased | Decreased | |
| Uncompititive | No effect | Decreased | |
| Irrversible inhibitor (same as reversible | Increased | No effect | |
