1618 TB or Not to Be: What’s Truly Going On?

Abstract

INTRODUCTION: Granulomatous disease of the colon has a constellation of symptoms that is usually attributed to an inflammatory condition such as ulcerative or crohn's colitis. Generally, suspicion for Mycobacterium Tuberculosis (TB) or Mycobacterium Avium (MAC) colitis is low and diagnosis can be difficult. We present a case of abdominal pain in a young individual found to be MAC colitis. CASE DESCRIPTION/METHODS: Our patient was a 29-year-old male with history of hemorrhoids and appendectomy 1 month prior who presented with complaints of recurrent and diffuse abdominal pain. Patient stated the pain had been ongoing for the last two months, denying constitutional symptoms but endorsed alternating constipation and diarrhea with episodic blood in the stool for ten years. He denied any family history of inflammatory bowel disease or malignancy and recently immigrated from Pakistan 4 years ago. Physical examination only exhibited abdominal tenderness upon palpation. Review of pathology report from recent appendectomy showed granulomatous appendicitis suggestive of TB. Investigations revealed a positive beta-quantiferon with mild elevation of fecal calprotein, ASCA, and normal inflammatory markers. Stool studies were negative for infectious organisms but showed growth of acid-fast bacilli with Mycobacterium Avium Complex being isolated. CT scan of abdomen displayed extensive colitis of ascending colon and cecum with dilatation of the terminal ileum. Patient underwent colonoscopy revealing a polypoid mass in the cecum with biopsy consistent with prolapse of mucosa. DISCUSSION: Mycobacterium tuberculosis and Avium Complex are infections predominantly seen in immuno-deficient individuals and in those from developing countries. Diagnosis can be difficult because there are no specific symptoms for colonic infection and less than a quarter of cases have radiological evidence of active or healed pulmonary infection. TB infections of the abdomen comprises roughly 5% of worldwide TB infections with mycobacterium avium being the rarest. Predominatly infections in the GI tract are seen within the terminal ileum due to the bacilli’s affinity for lymphoid tissue with large colon infection being uncommon. Although, TB has been labeled “the great imitator,” other disease states such as MAC colitis may also present as possible IBD versus TB and a broader differential should be considered.