A 59 year-old man is admitted for expedited workup of rapidly-progressive dementia. He undergoes evaluation with several blood tests, neuroimaging (MRI brain w/w/o contrast), and CSF analysis. On day 2 of admission, the patient's nurse notifies you that his urine output has decreased, and was 100mL these past two hours. You review his recent BMPs.
Yes. His serum creatinine has increased by ≥ 0.3mg/dL within the past two days. (The urinary output criterion would be oliguria-- < 20mL/hr for 6 hours.)
What could the cause be? We don't have enough information yet. Let's say we sent off a urine sodium and it came back at a value of 11. That's low, and combining that information with a low serum sodium and chloride, with rising BUN and Cr, the patient may simply be hypovolemic. We can try giving a liter of isotonic crystalloid and reassessing for any improvement.
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