Case Report: Tubulovillous Adenoma With Secretory Diarrhea Responding to NSAIDs

Abstract

A 74-year-old male presented with diarrhea. He noted a >3 month history of intermittent (˜4/day) loose stools (watery, small-volume, non-bloody) that recently increased in frequency (1/hour). He denied any unintentional weight loss. No recent travel, changes in diet, or antibiotic use. No nausea, vomiting, or rhinorrhea. The patient's mother died of colon cancer at 86 years of age. Initial labs showed hyponatremia (129), hypokalemia (2.8), hypochloremia (83), WBC >20, BUN 148, Cr 4.5, and Hgb 17.4. An infectious workup (O&P, Stool Cultures, C. diff Toxin,) was sent and returned negative. CT imaging revealed an irregular, asymmetric circumferential thickening of the wall of the distal sigmoid colon and rectum concerning for a colonic mass. Colonoscopy revealed 3 medium-sized, semi-sessile, non-bleeding polyps in the sigmoid colon, the ascending colon, and the cecum. A large partially obstructing mass was seen in the anus. Small sessile polyps were seen throughout. Biopsy results indicated tubular adenoma with areas of villous features. Follow-up EUS confirmed a 20X35X17mm mass located 5cm from the anal verge and occupying 70% of the wall circumference. In the setting of possible secretory diarrhea secondary to a tubulovillous adenoma, indomethacin was started with a remarkable decrease in bowel movements. Along with fluid resuscitation, the use of indomethacin was associated with correction of the patient's electrolyte disturbance and kidney injury. Most colonic polyps are asymptomatic, however tubulovillous adnenomas can cause a diarrhea with significant fluid and electrolyte losses. The diarrhea observed is rich in electrolytes (Na, K), and this secretory diarrhea is believed to be driven by the secretagogue, Prostaglandin E (PGE)2. The McKittrick-Wheelock Syndrome describes the clinical scenario of oversecretion of fluid/electrolytes in association with a villous adenoma. Hallmarks of the syndrome - secretory diarrhea with dehydration, hyponatremia, hypokalemia - can lead to renal (AKI, metabolic acidosis), CNS (seizures), cardiac (arrhythmias), and musculoskeletal complications, that require prompt fluid resuscitation3. Another treatment method uses the observed pathophysiology and seeks to counteract PGE2. Using Indomethacin, a PGE antagonist, reductions in fluid losses as high as 50% can be achieved4; thus preventing the massive fluid losses and organ dysfunction seen in McKittrick-Wheelock Syndrome.