During Hemodialysis, a patient complains of a headache, nausea, and restlessness. The nurse suspects "Disequilibrium Syndrome." This is caused by:

Appeared in: RML 2023

Explanation

Dialysis Disequilibrium Syndrome (DDS) is caused by a rapid decrease in blood urea concentration during hemodialysis.
The blood-brain barrier is less permeable to urea, so urea levels in the brain decrease more slowly than in the blood.
This creates a transient osmotic gradient, causing water to shift from the blood into the brain.
The influx of water leads to cerebral edema and increased intracranial pressure, resulting in neurological symptoms like headache, nausea, and restlessness.

Option A: Rapid fluid removal causes hypovolemia and hypotension, not the specific neurological symptoms of DDS.
Option C: An incorrect dialysate concentration would lead to specific electrolyte disturbances, not the global neurological symptoms of cerebral edema.
Option D: An allergic reaction to the dialyzer presents as an acute hypersensitivity reaction, not the slower onset neurological symptoms of DDS.

Clinical Relevance

Nursing practice connection: Use the key finding related to Pathophysiology of Dialysis Disequilibrium Syndrome (DDS) to guide bedside assessment, documentation, and the next nursing action.
Nurses must recognize the signs of DDS (headache, nausea, restlessness) early, especially in new dialysis patients or those with very high pre-dialysis BUN levels.
Prevention is key. For high-risk patients, the initial dialysis sessions should be shorter and performed at a lower blood flow rate to slow down solute removal.
If DDS is suspected, the nurse should slow or stop the treatment and notify the physician immediately. Treatment may involve administering hypertonic saline or mannitol to draw fluid out of the brain.

How to Approach the Question

First, analyze the clinical scenario: a patient is undergoing hemodialysis.
Next, identify the key symptoms presented: headache, nausea, and restlessness. These are primarily neurological symptoms.
Recognize that this cluster of symptoms during or shortly after hemodialysis is the classic presentation of Dialysis Disequilibrium Syndrome (DDS).
Recall the underlying pathophysiology of DDS, which involves fluid shifts related to solute concentration gradients across the blood-brain barrier.
Evaluate each option based on this pathophysiology. Option B directly describes the osmotic shift caused by the differential rate of urea removal between blood and brain.
Rule out the other options by linking them to their correct associated complications: rapid fluid removal causes hypotension, incorrect dialysate causes electrolyte issues, and an allergic reaction causes anaphylactoid symptoms.

Concept Tested & Keywords

Concept Tested: Pathophysiology of Dialysis Disequilibrium Syndrome (DDS)
Stem keywords: Hemodialysis, headache, nausea, restlessness, Disequilibrium Syndrome
Lead-in keywords: caused by
Clinical cues: The combination of hemodialysis treatment with acute neurological symptoms (headache, nausea, restlessness) is the classic presentation for Disequilibrium Syndrome.

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E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 531-533

E6 Medicine Harrison 22e Part 2 p. 304-306

Practise the full RML 2023

Attempt every question from this paper in a timed mock, then review the full solution for each one.