Physical Examination and Workup
Upon examination, the patient appears thin and chronically ill. His vital signs include a temperature of 96.8 °F (36 °C) and a sitting blood pressure of 90/60 mm Hg with a heart rate of 82 beats/min, which decreases to 75/50 mm Hg with a heart rate of 90 beats/min within 3 minutes of standing. His respiration rate is 16 breaths/min. His cardiopulmonary examination is unremarkable, with 2+ peripheral edema in both lower extremities.
His complete blood cell count is within normal ranges, except for anemia (hemoglobin level, 9.8 g/dL [reference range, 13.8-17.2 g/dL]) and thrombocytopenia (98,000 cells/μL [reference range, 150,000-450,000 cells/μL]). His basic metabolic panel shows low serum albumin (3.2 g/dL [reference range, 3.5-5.3 g/dL]), low total protein (6 g/dL [reference range, 6-8.2 g/dL]), and elevated creatinine (1.6 mg/dL [reference range, 0.6-1 mg/dL]) levels. Other laboratory parameters are unremarkable. His urinalysis findings are "bland," with no hematuria or pyuria. Renal ultrasonography reveals a distended bladder but no hydronephrosis.
A review of the patient's records shows that the creatinine level ranged between 1.1 and 1.3 mg/dL for the past 3 years, peaking at 2.1 mg/dL during prerenal azotemia associated with diarrhea and hypovolemia episodes. Over the past year, his creatinine level ranged between 1.5 and 1.6 mg/dL, with an estimated glomerular filtration rate (eGFR) of 42-46 mL/min based on the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. He had 300 mg of proteinuria in a 24-hour urine collection (normal level < 150 mg in 24 hours) without evidence of albuminuria.
Approximately 2 years ago, an immunoglobulin (Ig) A lambda monoclonal band was identified on serum immunofixation (772 mg/dL [reference range, 82-453 mg/dL]), but serum and urine electrophoresis results were unremarkable. His free light chain ratio was reported as normal (0.39 [reference range, 0.26-1.65]), with free kappa light chains of 17.6 mg/L (reference range, 3.3-19.4 mg/L) and free lambda light chains of 45.6 mg/L (reference range, 5.7-26.3 mg/L).
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Cite this: C. Elena Cervantes. Nephrology Case Challenge: Man on Keto Diet Has Severe Diarrhea and Neurogenic Bladder - Medscape - Feb 06, 2023.