Central Nervous System I MCQs
Posted by Dr KAMAL DEEP on June 4, 2012
Action potentials normally are generated by the opening of sodium channels and the inward movement of sodium ions down the intracellular concentration gradient. Depolarization of the neuronal membrane opens potassium channels, resulting in outward movement of potassium ions, repolarization, closure of the sodium channel, and hyperpolarization. Sodium or potassium channel subunit genes have long been considered candidate disease genes in inherited epilepsy syndromes, and recently such mutations were identified. These mutations appear to alter the normal gating function of these channels, increasing the inherent excitability of neuronal membranes in regions where the abnormal channels are expressed.
All of the following are neurologic channelopathies
except – (AI 05)
a) Hypokalemic periodic paralysis
b) Episodic ataxia type 1
c) Familial hemiplegic migraine
d) Spinocerebellar ataxia 1
Ans is ‘d’ i.e., Sphinocerebellar Ataxia -1 [Ref Harrison 16 1"/e p. 2339 & 15’h/e p. 2321]
All of the following are calcium channelopathies,
except – (AIIMS May 05)
a) Episodic ataxia -1
b) Spinocerebellar ataxia-6
c) Familial hemiplegic migraine
d) Hypokalemic periodic paralysis
Episode weakness is due to – (PG1 87)
a) Hypokalaemia b) Dermatomyositis
c) Paramyotonia congenita d) Myasthenia gravis
e) Hypophosphatemia
Cataract is associated with PGI 88
a) Pseudo muscular hypertrophy b) myotonia congenita c) myotonic dystrophy d) SLE
In a patient, muscle cramps on exercise, +ve
myoglobulinemia, the disorder is – (PGI 98)
a) Pompe’s disease b) Myotonia congenita
c) Myotonic dystrophy d) Mc ardle’s disease
Whereas the specific clinical manifestations of channelopathies are quite variable, one common feature is that manifestations tend to be intermittent or paroxysmal, as occurs in epilepsy, migraine, ataxia, myotonia, or periodic paralysis. Exceptions are clinically progressive channel disorders such as autosomal dominant hearing impairment.
Review of Critical Care Medicine 
Hildegarde Presser said
Central Nervous System I MCQs
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