Toxicology: cholinesterase estimation: practice question

A Forensic 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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Forensic Medicine · Toxicology: cholinesterase estimation

Sample item

A farmer exposed to an organophosphate pesticide is being monitored. Which statement about cholinesterase testing is correct?

ARed cell acetylcholinesterase is the same enzyme as at nerve synapses and better reflects neural inhibitionBRed cell cholinesterase recovers within hours after exposure endsCPlasma pseudocholinesterase is the same enzyme as at synapses and the better indicatorDCholinesterase estimation is of no value in diagnosis

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

The answer and the reasoning

A. Red cell acetylcholinesterase is the same enzyme as at nerve synapses and better reflects neural inhibition

Red cell (true) acetylcholinesterase is identical to the synaptic enzyme and correlates better with neuronal inhibition and with severity, and recovers slowly as red cells are replaced. Plasma (pseudo) cholinesterase is easier to estimate and falls early, but it is less specific and recovers faster.

Option by option

A. Red cell acetylcholinesterase is the same enzyme as at nerve synapses and better reflects neural inhibition (correct)
Correct. The red cell enzyme parallels the synaptic enzyme.
B. Red cell cholinesterase recovers within hours after exposure ends
Red cell enzyme recovers slowly over weeks, as new red cells are formed.
C. Plasma pseudocholinesterase is the same enzyme as at synapses and the better indicator
Plasma pseudocholinesterase is a different enzyme and is less specific.
D. Cholinesterase estimation is of no value in diagnosis
The estimation is useful to confirm exposure and to follow severity and recovery.

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.

Questions about this Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is A, Red cell acetylcholinesterase is the same enzyme as at nerve synapses and better reflects neural inhibition. Red cell (true) acetylcholinesterase is identical to the synaptic enzyme and correlates better with neuronal inhibition and with severity, and recovers slowly as red cells are replaced.

Why is "Red cell cholinesterase recovers within hours after exposure ends" not the answer?

Red cell enzyme recovers slowly over weeks, as new red cells are formed.

Why is "Plasma pseudocholinesterase is the same enzyme as at synapses and the…" not the answer?

Plasma pseudocholinesterase is a different enzyme and is less specific.

Why is "Cholinesterase estimation is of no value in diagnosis" not the answer?

The estimation is useful to confirm exposure and to follow severity and recovery.

What concept does this question test?

It tests Toxicology: cholinesterase estimation in Forensic Medicine. Plasma (pseudo) cholinesterase is easier to estimate and falls early, but it is less specific and recovers faster.

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 Toxicology: cholinesterase estimation?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic 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.