Electrolyte Disorders USMLE Step 1 Practice Question
A 64-year-old woman with SIADH-related chronic hyponatremia presents with mild confusion. Vital signs: BP 128/76, HR 88, RR 16, Temp 37°C, SpO2 98%. Serum sodium on admission is 112 mEq/L; osmolality is 228 mOsm/kg. She denies recent medications. Twenty-four hours after hypertonic saline initiation, sodium rises to 128 mEq/L. She now develops dysarthria and quadriparesis. Which of the following best explains her acute neurologic deterioration?
Answer choices
- AAcute disseminated encephalomyelitis
- BSubarachnoid hemorrhage from uncontrolled hypertension
- CWernicke encephalopathy from thiamine deficiency
- DCentral pontine myelinolysis from overly rapid correctionCorrect answer
- ECerebral edema from persistent hyponatremia
- FOsmotic demyelination syndrome affecting the lateral geniculate nucleus
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