Intractable Diarrhea: A Diagnostic Dilemma

Abstract

As per the American Gastroenterological Association, chronic diarrhea is defined as a decrease in fecal consistency lasting greater than four weeks. Co-morbidities, socio-economic status, family history, diet and immune status must be taken into account when searching for a diagnosis. A 47-year old female with past medical history of DMI with nephropathy, right BKA and hypothyroidism was admitted to the Medical ICU for DKA and septic shock due to HCAP. After a prolonged course complicated by chronic respiratory failure, she was unable to be weaned off the ventilator and underwent tracheostomy and PEG tube placement. Throughout her hospitalization, she was found to have severe, intractable diarrhea, often stooling up to 12 times per day with significant volumes. Differential diagnoses included osmotic diarrhea due to tube feeds vs malabsorption due to bowel edema/ischemia vs secretory diarrhea of unknown etiology. GI was consulted, and work-up included multiple rounds of fecal fat testing, C difficile toxin, celiac antibodies, stool studies, culture and gram stain, all which resulted as normal. Octreotide scan showed no evidence of primary or secondary neuroendocrine tumour. CT Abdomen/Pelvis showed evidence of colitis and the patient underwent colonoscopy with biopsies consistent with ischemic colitis. The patient finished a course of antibiotics, however, continued to have intractable diarrhea for >4 months inpatient duration despite aggressive medical therapy. Concomitantly, she developed a skin rash, which when biopsied, was consistent with small vessel-vasculitis. It was then postulated that this could be the underlying etiology, and she was started on high dose steroids with resolution of rash, however, diarrhea persisted. Eventually when the patient was medically stable, she underwent repeat colonoscopy with colonic biopsies showing regenerative ischemic changes. To this day, there is still no clear consensus among specialists for the cause of the patient's prolonged symptomatology. Chronic diarrhea has a wide differential whose etiology depends largely on the unique characteristics of a patient. It is a difficult entity to diagnose as clinicians are often faced with multiple medical co-morbidities that can easily confound diagnosis. Unfortunately, an ideal strategy for work-up of chronic diarrhea has yet to be established and, ultimately, a cause may never be uncovered, as was the case with our patient.