Organophosphates Poisoning

Organophosphates Poisoning

Q. 1

Most specific test for organophosphorous poisoning is:

 A

RBC cholinesterase level

 B

Plasma cholinestrase level

 C

RBC uroporphyrin level

 D

Measurment of serum level of organophosphorous

Q. 1

Most specific test for organophosphorous poisoning is:

 A

RBC cholinesterase level

 B

Plasma cholinestrase level

 C

RBC uroporphyrin level

 D

Measurment of serum level of organophosphorous

Ans. B

Explanation:

B i.e. Plasma cholinesterase level


Q. 2

In acute organophosphorus poisoning which of the following is seen :

 A

Dry lungs

 B

Edematous lungs

 C

Pneumonia

 D

All

Q. 2

In acute organophosphorus poisoning which of the following is seen :

 A

Dry lungs

 B

Edematous lungs

 C

Pneumonia

 D

All

Ans. B

Explanation:

B i.e. Edematous lung


Q. 3

Which is not a feature of organophosphorus poisoning:

 A

Sweating

 B

Miosis

 C

Tachycardia

 D

Resp. depression

Q. 3

Which is not a feature of organophosphorus poisoning:

 A

Sweating

 B

Miosis

 C

Tachycardia

 D

Resp. depression

Ans. C

Explanation:

C i.e. Tachycardia

Quiz In Between


Q. 4

In organophosphorous poisoning, following are seen except:

 A

Pupillary dilatation

 B

Salivation

 C

Bronchospasm

 D

Sweating

Q. 4

In organophosphorous poisoning, following are seen except:

 A

Pupillary dilatation

 B

Salivation

 C

Bronchospasm

 D

Sweating

Ans. A

Explanation:

A i.e. Pupillary dilation


Q. 5

Organophosphate inhibits –

 A

Anionic site ofAchEs

 B

Esteratic site ofAchEs

 C

Ach

 D

None

Q. 5

Organophosphate inhibits –

 A

Anionic site ofAchEs

 B

Esteratic site ofAchEs

 C

Ach

 D

None

Ans. B

Explanation:

Ans. is ‘b’ i.e., Esteratic site of AchEs

  1. Acetylcholinesterase has two sites:

i)         Catalytic or esteratic site –9 Active site

ii)       Anionic site

  • It is quite obvious that to inhibit the action of acetylcholinesterase the active site has to be inhibited and it is esteratic site:

i)        Organophosphates phosphorylate esteratic site.

Carbamates carbomylate esteratic site.


Q. 6

Antidote for organophosphorous poisoning is ‑

 A

Atropine

 B

Neostigmine

 C

Succinylcholine

 D

D-Tubocurarine

Q. 6

Antidote for organophosphorous poisoning is ‑

 A

Atropine

 B

Neostigmine

 C

Succinylcholine

 D

D-Tubocurarine

Ans. A

Explanation:

Ans. is ‘a’ i.e., Atropine

Pharmacological treatment of organonhosphatepoisoning

Atropine

o Atropine is the mainstay of treatment (antidote of choice).

o Atropine antagonizes the muscarinic parasympathetic effects of organophosphate (excessive secretion and vasodilation), but does not antagonize nicotinic effects, i.e., neuramuscular blockers (Atropine blocks muscarinic receptors, i.e., it is an antimuscarinic)

o Atropine antagonizes both peripheral as well as central nervous system effects of organophosphates. Cholinesterase regenerator compounds (oximes)

o Pralidoxime is most commonly used oxime.

o Unlike atropine, they antagonize both muscarinic and nicotinic effects.

o They antagonize only peripheral effects, but not central effects except for diacetylmonoxime (DAM) which crosses BBB and antagonizes central effects also.

Quiz In Between


Q. 7

Atropine is useful in organophosphate poisoning because it –

 A

Reactivates acetylcholinesterase

 B

Competes with acetylcholine release

 C

Binds with both nicotinic and muscarinic acetylcholine receptors

 D

Is a competitive antagonist of acetylcholine

Q. 7

Atropine is useful in organophosphate poisoning because it –

 A

Reactivates acetylcholinesterase

 B

Competes with acetylcholine release

 C

Binds with both nicotinic and muscarinic acetylcholine receptors

 D

Is a competitive antagonist of acetylcholine

Ans. D

Explanation:

Ans. is ‘d’ i.e., Is a competitive antagonist of acetylcholine

o Atropine acts as competitive antagonist at muscarinic receptors. It has no activity on nicotinic receptors and has nothing to do with Ach release.


Q. 8

Atropine-mechanism of action in organophosphate poisoning-

 A

Reactivation of choline-esterase

 B

Acts on central and peripheral post.ganglionic receptors

 C

Acts on central and peripheral cholinergic receptors

 D

Acts on peripheral cholinergic receptors only

Q. 8

Atropine-mechanism of action in organophosphate poisoning-

 A

Reactivation of choline-esterase

 B

Acts on central and peripheral post.ganglionic receptors

 C

Acts on central and peripheral cholinergic receptors

 D

Acts on peripheral cholinergic receptors only

Ans. C

Explanation:

Ans. is ‘c’ i.e., Acts on central and peripheral cholinergic receptors

o In organophosphate poisoning, atropine counteracts the peripheral muscarinic symptoms and at higher doses central effects as well.

o Atropine does not reverse nicotinic action i.e., peripheral muscular paralysis.


Q. 9

All are organophosphorus poison, except ‑

 A

Abate

 B

Dibenanone

 C

Propoxur

 D

Malathione

Q. 9

All are organophosphorus poison, except ‑

 A

Abate

 B

Dibenanone

 C

Propoxur

 D

Malathione

Ans. C

Explanation:

Ans. is ‘c’ i.e., Propoxur 

Quiz In Between


Q. 10

Organophosphate insecticides are all except 

 A

Dieldrin

 B

Fenthion 

 C

Diazinon

 D

All

Q. 10

Organophosphate insecticides are all except 

 A

Dieldrin

 B

Fenthion 

 C

Diazinon

 D

All

Ans. A

Explanation:

Ans. is `a’ i.e., Dieldrin


Q. 11

NOT a feature of organophosphate poisoning:

March 2013 (a, c, d, e, g)

 A

Diarrhea

 B

Dilated pupil

 C

Salivation

 D

Bradycardia

Q. 11

NOT a feature of organophosphate poisoning:

March 2013 (a, c, d, e, g)

 A

Diarrhea

 B

Dilated pupil

 C

Salivation

 D

Bradycardia

Ans. B

Explanation:

Ans. B i.e. Dilated pupil


Q. 12

Drug of choice for organophosphorous poisoning:

March 2013 (e)

 A

EDTA

 B

BAL

 C

PAM

 D

All of the above

Q. 12

Drug of choice for organophosphorous poisoning:

March 2013 (e)

 A

EDTA

 B

BAL

 C

PAM

 D

All of the above

Ans. C

Explanation:

Ans. C i.e. PAM

Treatment of organophosphate poisoning

  • Current antidotes for OP poisoning consist of a pretreatment with carbamates to protect AChE from inhibition by OP compounds and post-exposure treatments with anti-cholinergic drugs.
  • Anti-cholinergic drugs work to counteract the effects of excess acetylcholine and reactivate AChE.
  • Atropine can be used as an antidote in conjunction with pralidoxime or other pyridinium oximes (such as trimedoxime or obidoxime)

Quiz In Between


Q. 13

Antidote for organophosphates poisoning are all except:          

September 2009 March 2013 (b, d)

 A

Physostigmine

 B

Activated charcoal

 C

Pralidoxime

 D

Atropine

Q. 13

Antidote for organophosphates poisoning are all except:          

September 2009 March 2013 (b, d)

 A

Physostigmine

 B

Activated charcoal

 C

Pralidoxime

 D

Atropine

Ans. A

Explanation:

Ans. A: Physostigmine

The mainstays of medical therapy in organophosphate (OP) poisoning include ‑

  • Atropine-arrests muscarinic effects,
  • Pralidoxime (2-PAM)-acts by competing for the phosphate moiety of the organophosphorus compound and release it from the cholinesterase enzyme
  • Benzodiazepines (e.g., diazepam)-For convulsions

Intravenous glycopyrrolate or diphenhydramine may provide an alternative centrally acting anticholinergic agent used to treat muscarinic toxicity if atropine is unavailable or in limited supply


Q. 14

Best indicator for beneficial effect of atropine in a patient with organophosphorous poisoning is:

March 2012

 A

Heart rate

 B

Pupil

 C

Blood pressure

 D

Ventilation

Q. 14

Best indicator for beneficial effect of atropine in a patient with organophosphorous poisoning is:

March 2012

 A

Heart rate

 B

Pupil

 C

Blood pressure

 D

Ventilation

Ans. A

Explanation:

Ans: A i.e. Heart rate

In organophosphate poisoning, atropine should be administered in doses of 0.6-2 mg i.v., repeated every 10-25 minutes until secretions are controlled, the skin is dr./ and there is sinus tachycardia.


Q. 15

Organophosphorus insecticides are all, except:

MP 11

 A

Chlorpyriphos

 B

Gardona (tetrachlorvinphos)

 C

Dimethoate

 D

Diethyltoluamide (DEET)

Q. 15

Organophosphorus insecticides are all, except:

MP 11

 A

Chlorpyriphos

 B

Gardona (tetrachlorvinphos)

 C

Dimethoate

 D

Diethyltoluamide (DEET)

Ans. D

Explanation:

Ans. Diethyltoluamide (DEET)

Quiz In Between


Q. 16

Not an organophosphate: 

AFMC 12

 A

Diazinon

 B

Endrin

 C

Malathion

 D

Parathion

Q. 16

Not an organophosphate: 

AFMC 12

 A

Diazinon

 B

Endrin

 C

Malathion

 D

Parathion

Ans. B

Explanation:

Ans. Endrin


Q. 17

All are features of organophosphorus poisoning, except:           

UPSC 07; DNB 10; SGPGI 11; FMGE 13

 A

Mydriasis

 B

Bradycardia

 C

Lacrimation

 D

Sweating

Q. 17

All are features of organophosphorus poisoning, except:           

UPSC 07; DNB 10; SGPGI 11; FMGE 13

 A

Mydriasis

 B

Bradycardia

 C

Lacrimation

 D

Sweating

Ans. A

Explanation:

Ans. Mydriasis


Q. 18

Which of the following is not a phase of organophosphorus poisoning:           

Odisha 11

 A

Acute cholinergic phase

 B

Intermediate syndrome

 C

OPC induced delayed polyneuropathy

 D

Late onset proximal myopathy

Q. 18

Which of the following is not a phase of organophosphorus poisoning:           

Odisha 11

 A

Acute cholinergic phase

 B

Intermediate syndrome

 C

OPC induced delayed polyneuropathy

 D

Late onset proximal myopathy

Ans. D

Explanation:

Ans. Late onset proximal myopathy

Quiz In Between


Q. 19

A patient is admitted with acute organophosphorus insecticide poisoning, develops ptosis, inability to lift the head and difficulty in breathing on the third day. The most likely diagnosis is:         

TN 06

 A

Hypokalemia

 B

Inflammatory polyneuropathy

 C

Intermediate syndrome

 D

Polymyositis

Q. 19

A patient is admitted with acute organophosphorus insecticide poisoning, develops ptosis, inability to lift the head and difficulty in breathing on the third day. The most likely diagnosis is:         

TN 06

 A

Hypokalemia

 B

Inflammatory polyneuropathy

 C

Intermediate syndrome

 D

Polymyositis

Ans. C

Explanation:

Ans. Intermediate syndrome


Q. 20

Type II paralysis in organophosphorous poisoning treatment is ‑

 A

Atropine

 B

Oximes

 C

Symptomatic treatment 

 D

No treatment

Q. 20

Type II paralysis in organophosphorous poisoning treatment is ‑

 A

Atropine

 B

Oximes

 C

Symptomatic treatment 

 D

No treatment

Ans. C

Explanation:

Ans. is ‘c’ i.e., Symptomatic treatment 

  • Paralysis due to organophosphate (OP) poisoning can be three types ‑

1. Type I (cholinergic phase)

  • It involves acute paralysis secondary to persistent depolarization at the neuromuscular junction caused by persistent stimulation by excessive Ach.
  • Treatment of choice is atropine with or without oximes.

2. Type II

  • It is also called as intermediate syndrome.
  • It develops 1-4 days after resolution of acute cholinergic symptoms.
  • It is manifested as paralysis and respiratory distress.
  • It involves proximal muscles with relative sparing of distal muscle groups.
  • The pathogenesis presumed to be dysfunction of neuromuscular junction caused by downregulation of presynaptic and postsynaptic nicotinic receptors due to release of excessive Ach and Ca’ respectively.
  • Atropine is ineffective, symptomatic treatment is given.

3. Type III

  • It involves OP-induced delayed polyneuropathy (OPIDN).
  • It occurs 1-3 weeks after exposure and is associated with demyelination of axons.
  • It is not caused by cholinesterase inhibition but rather by neuropathy target esterase (NTE) inhibition.
  • It involves distal muscles with relative sparing of neck muscles, cranial nerves, and proximal muscles.

Quiz In Between



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