Nephrology Case Challenge: Man on Keto Diet Has Severe Diarrhea and Neurogenic Bladder

C. Elena Cervantes, MD


February 06, 2023

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A 68-year-old man presents to the nephrology clinic for evaluation of an elevated creatinine level. He has small intestinal bacterial overgrowth (SIBO) with chronic diarrhea, a neurogenic bladder, and monoclonal gammopathy of undetermined significance (MGUS).

He developed severe diarrhea 10 years ago, which initially resolved after he eliminated carbohydrates and began a keto diet. Five years later, he had a flare that did not improve with dietary modifications. He has undergone extensive workup, including small bowel biopsies, which revealed only SIBO. His malabsorptive symptoms have been complicated by severe fatigue, a 50-lb weight loss over the past 3 years, and more recently, postural dizziness and syncopal episodes. He reports urinary urgency and nocturia, which have been attributed to his neurogenic bladder.

He has no significant family history of illness. He does not take any medications or supplements. He does not report a history of smoking and alcohol or drug use.


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