Quick case summary as presented in Renal Grand Rounds today: A 54 year-old man presents with altered mental status, a sky-high ammonia level (>200) and anemia requiring blood transfusion. Other unusual lab values include hypophosphatemia and hypokalemia with a significant non-anion gap metabolic acidosis. Subsequent workup reveals 3+ glucosuria and aminoaciduria. What's the underlying diagnosis?
This patient had multiple myeloma, as revealed by an M spike on serum protein electrophoresis. The diagnosis can explain all the major aspects of his presentation:
-myeloma is the cause of his anemia.
-myeloma is a cause of hyperammonemia (plasma cells for whatever reason have the ability to produce large amount of ammonia)
-myeloma and other paraproteinemias are a major cause of adult-onset Fanconi's Syndrome, which this patient has, as demonstrated by his aminoaciduria, glucosuria, phosphaturia, proximal renal tubular acidosis.