Neurology: amyotrophic lateral sclerosis: practice question

A General Medicine question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Medicine · Neurology: amyotrophic lateral sclerosis

Sample item

A 58-year-old man has progressive wasting and fasciculations of the hands with brisk reflexes and spasticity in the legs. Sensation, eye movements and bladder control are normal and EMG shows widespread denervation. He is started on riluzole. What is its mechanism of action?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Inhibition of presynaptic glutamate release

Amyotrophic lateral sclerosis combines upper and lower motor neuron signs with sparing of sensory, oculomotor and sphincter function. Riluzole reduces glutamate-mediated excitotoxicity by inhibiting presynaptic glutamate release and blocking sodium channels, and prolongs survival by a few months. Respiratory support and nutrition are central to care.

Option by option

  • A. Inhibition of presynaptic glutamate release (correct)

    Correct. Reduced glutamate release lessens excitotoxic motor neuron injury.

  • B. Inhibition of acetylcholinesterase

    Acetylcholinesterase inhibition is the mechanism of pyridostigmine and donepezil.

  • C. Potentiation of GABA-A receptors

    GABA-A potentiation is the mechanism of benzodiazepines, which can worsen respiratory weakness.

  • D. Blockade of postsynaptic dopamine D2 receptors

    D2 receptor blockade is the mechanism of antipsychotics.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More General Medicine questions

Questions about this General Medicine question

What is the answer to this General Medicine question?

The best answer is A, Inhibition of presynaptic glutamate release. Amyotrophic lateral sclerosis combines upper and lower motor neuron signs with sparing of sensory, oculomotor and sphincter function.

Why is "Inhibition of acetylcholinesterase" not the answer?

Acetylcholinesterase inhibition is the mechanism of pyridostigmine and donepezil.

Why is "Potentiation of GABA-A receptors" not the answer?

GABA-A potentiation is the mechanism of benzodiazepines, which can worsen respiratory weakness.

Why is "Blockade of postsynaptic dopamine D2 receptors" not the answer?

D2 receptor blockade is the mechanism of antipsychotics.

What concept does this question test?

It tests Neurology: amyotrophic lateral sclerosis in General Medicine. Riluzole reduces glutamate-mediated excitotoxicity by inhibiting presynaptic glutamate release and blocking sodium channels, and prolongs survival by a few months. Respiratory support and nutrition are central to care.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Neurology: amyotrophic lateral sclerosis?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.