Trigeminal neuralgia

TRIGEMINAL NEURALGIA

Q. 1

 Drug of choice for trigeminal neuralgia is?

 A Chlorpromazine
 B

 Carbamezapine

 C Gabapentine
 D

Fluoxetine

Q. 1

 Drug of choice for trigeminal neuralgia is?

 A Chlorpromazine
 B

 Carbamezapine

 C Gabapentine
 D

Fluoxetine

Ans. B

Explanation:

Carbamezapine REF: Harrison’s 17th ed chapter 371

  • Drug of choice for trigeminal neuralgia – Carbamezapine
  • If drug treatment fails, surgical therapy should be offered. The most widely applied procedure creates a heat lesion of the trigeminal (gasserian) ganglion or nerve, a method termed radiofrequency thermal rhizotomy.
  • Gamma knife radiosurgery is also utilized for treatment
  • A third surgical treatment, microvascular decompression to relieve pressure on the trigeminal nerve as it exits the pons, requires a suboccipital craniotom

Q. 2

Which statement is true about carbamazepine ?

 A

Used in trigeminal neuralgia

 B

Carbamazepine is an enzyme inhibitor

 C

Can cause megaloblastic anemia

 D

It is the drug of choice for status epilepticus

Q. 2

Which statement is true about carbamazepine ?

 A

Used in trigeminal neuralgia

 B

Carbamazepine is an enzyme inhibitor

 C

Can cause megaloblastic anemia

 D

It is the drug of choice for status epilepticus

Ans. A

Explanation:

Used in trigeminal neuralgia [Ref K.D.T. 6thie p 406-407]

  • Trigeminal neuralgias are characterized by attacks of high intensity electric shock like stabbing pain, set off by even trivial stimulation of certain trigger zones in the mouth or on the face.
  • Carbamazepine is not an analgesic but has a specific action in these neuralgias. It acts by interrupting temporal summation of afferent impulses (by a selective action on high frequency nerve impulses).
  • “Carbamazepine has become the drug of choke for Trigeminal neuralgias”.
  • Other antiepileptics such as phenytoin and Baclofen are less efficacious alternatives.

More on carbamazepine

  • The most important action of carbamazepine is blockade of voltage dependent sodium ion channels, reducing membrane excitability.
  • It is considered the drug of choice for partial seizures

Pharamacokinetics

  • Carbamazepine is an extensively metabolized drug.
  • One of the notable property of carbamazepine is its ability to induce microsomal enzymes (Paso)
  • The t1/2 of carbamazepine decreases from 36 hrs, seen initially, to as short as 8-12 hrs due to its enzyme inducing property (it induces its own metabolism).
  • Due to its enzyme inducing property, carbamazepine effects the metabolism of other drugs too.

Toxicity:-

  • The most cocoon dose related adverse effects of carbamazepine are diplopia and ataxia.
  • It may also cause hyponatretnia and water intoxication.
  • One more important adverse effect is idiosyncratic blood dyscrasias which may cause aplastic anemia and agranulocytosis.

Q. 3

A Patient presents with recurrent episodes of sharp pain over his right cheek that is precipitated on chewing. Between attacks patient is otherwise normal. The most probable diagnosis is?

 A

Preherpetic neuralgia

 B

Trigeminal neuralgia

 C

Mumps

 D

Thalamic syndrome

Q. 3

A Patient presents with recurrent episodes of sharp pain over his right cheek that is precipitated on chewing. Between attacks patient is otherwise normal. The most probable diagnosis is?

 A

Preherpetic neuralgia

 B

Trigeminal neuralgia

 C

Mumps

 D

Thalamic syndrome

Ans. B

Explanation:

Answer is B (Trigeminal Neuralgia):

Recurrent attacks of sharp pain over the cheek precipitated .from trigger areas or trigger factors such as chewing with the patient being normal in the interval period strongly suggests a diagnosis of Trigeminal Neuralgia. Trigeminal Neuralgia is typically characterized by Paroxysmal attacks of brief electric shock-like pains, abrupt in onset and termination, limited to the distribution of one or more divisions of the trigeminal nerve lasting for a brief period from a fraction of a second to 2 minutes. The most common division of the trigeminal nerve involved in trigeminal neuralgia is the Maxillary division (V2) followed by the mandibular division (V3). The ophthalmic Division (VI) is rarely involved

The pain often evokes spasm of the muscle of the face on the affected side. The clinical association between Trigeminal Neuralgia and hemifacial spasm is called Tic Douloureux.

Typical Features of Trigeminal Neuralgia (Prosopalgia, Fothergill’s disease)

  • Sudden/ Abrupt onset and termination
  • Sharp superficial, stabbing or burning in quality
  • Severe in intensity
  • Brief in duration (lasting for a brief period from a fraction of a second to 2 minutes)
  • Intermittent (Between paroxysms the patient is usually asymptomatic. Following a painful paroxysm there is usually a refractory period during which pain cannot be triggered)
  • Unilateral (The pain never crosses to the opposite side but it may rarely occur bilaterally in which case a central cause such as multiple sclerosis must be considered)
  • Precipitated from trigger areas or by trigger factors in the trigeminal area such as eating or chewing, washing the face, shaving, smoking, talking or brushing the teeth
  • There is no clinically evident neurological deficit

Note :

Trigeminal Neuralgia is More common with advancing age

Trigeminal Neuralgia is More common in women

Trigeminal Neuralgia is More common on right side

Trigeminal Neuralgia attacks are most frequent during the day (but may awaken the patient at night) Trigeminal Neuralgia most frequently arises from the maxillary division of Trigeminal nerve (V2)


Q. 4

All of the following statements about Trigeminal Neuralgia are true Except:

 A

Most commonly involves Ophthalmic Division (V3) of Maxillary Nerve

 B

Attacks most commonly occur during the day

 C

Affects women more than men

 D

More common on the Right Side

Q. 4

All of the following statements about Trigeminal Neuralgia are true Except:

 A

Most commonly involves Ophthalmic Division (V3) of Maxillary Nerve

 B

Attacks most commonly occur during the day

 C

Affects women more than men

 D

More common on the Right Side

Ans. A

Explanation:

Answer is A (Most commonly involves Ophthalmic Division (V3) of Maxillary Nerve):

The most common division of the trigeminal nerve involved in trigeminal neuralgia is the Maxillary division (V2) followed by the mandibular division (V3). The maxillary division (V2) is the most common site ofpain either alone or in combination with the mandibular division (V3). The ophthalmic Division (VI) is rarely involved (<5%). Pain arising from the maxillary division is usually referred to the upper lip nose and cheek while the pain arising from the mandibular division is often referred to the lower lip.

Features of Trigeminal Neuralgia

  • The most common division of the trigeminal nerve involved in trigeminal neuralgia is the Maxillary division (V2)
  • More common with advancing age
  • More common in women
  • More common on right side
  • Attacks are most frequent during the day (but may awaken the patient at night)

Q. 5

Most common cause of trigeminal neuralgia ‑

 A

Infection

 B

Trauma

 C

Vascular compression

 D

Iatrogenic

Q. 5

Most common cause of trigeminal neuralgia ‑

 A

Infection

 B

Trauma

 C

Vascular compression

 D

Iatrogenic

Ans. C

Explanation:

Ans. is ‘c’ i.e., Vascular compression

  • Trigeminal neuralgia (tic douloureux) is characterized by intermittent, shooting pain in the face.
  • It is due to involvement of trigeminal nerve.
  • 95% of causes of trigeminal neuralgia are due to pressure on trigeminal nerve close to where it enters the brain stem, past the Gasserian ganglion. In most cases, this pressure seems to be caused by an artery or vein compressing trigeminal nerve.
  • Other causes are tumor, cysts, AV malformation and multiple sclerosis.
  • Most commonly used drugs for treatment of trigeminal neuralgia are carbamazepine, gabapentin and valproate.


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