Nephrology: dialysis complications: 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 · Nephrology: dialysis complications

Sample item

A 60-year-old man with a urea of 280 mg/dL undergoes his first haemodialysis session. Towards the end he develops headache, nausea and then a generalised seizure, with a normal glucose. What is the mechanism?

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

The answer and the reasoning

C. Cerebral oedema from a rapid fall in plasma urea and osmolality

Dialysis disequilibrium syndrome occurs when urea is removed rapidly from plasma while brain urea falls slowly. The osmotic gradient moves water into brain cells and causes cerebral oedema. It is prevented in high-risk first sessions by short, slow, low-efficiency dialysis.

Option by option

  • A. Hypoglycaemia from insulin retention

    Glucose is stated to be normal, excluding hypoglycaemia.

  • B. Intracranial haemorrhage from heparin

    Heparin-related haemorrhage is possible, but the setting is classic for disequilibrium.

  • C. Cerebral oedema from a rapid fall in plasma urea and osmolality (correct)

    Correct. A rapid osmotic shift into brain cells explains the headache, nausea and seizures.

  • D. Hypocalcaemia from citrate anticoagulation

    Citrate anticoagulation is uncommon in routine dialysis, and the first-session timing points to the osmotic mechanism.

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.

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Questions about this General Medicine question

What is the answer to this General Medicine question?

The best answer is C, Cerebral oedema from a rapid fall in plasma urea and osmolality. Dialysis disequilibrium syndrome occurs when urea is removed rapidly from plasma while brain urea falls slowly.

Why is "Hypoglycaemia from insulin retention" not the answer?

Glucose is stated to be normal, excluding hypoglycaemia.

Why is "Intracranial haemorrhage from heparin" not the answer?

Heparin-related haemorrhage is possible, but the setting is classic for disequilibrium.

Why is "Hypocalcaemia from citrate anticoagulation" not the answer?

Citrate anticoagulation is uncommon in routine dialysis, and the first-session timing points to the osmotic mechanism.

What concept does this question test?

It tests Nephrology: dialysis complications in General Medicine. The osmotic gradient moves water into brain cells and causes cerebral oedema. It is prevented in high-risk first sessions by short, slow, low-efficiency dialysis.

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 Nephrology: dialysis complications?

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.