Case Presentation: A 53-year-old Filipino woman with a history of lupus nephritis status post renal transplantation presented with 1 month of the right upper quadrant (RUQ), lower abdominal pain and a new fever. Her RUQ pain radiated to her back and worsened after meals, while her lower abdominal pain had no clear triggers. She reported no nausea, bowel habit changes, gastrointestinal (GI) bleeding, or constitutional symptoms. She also denied a cough, hemoptysis, or dyspnea. Her medications included prednisone, tacrolimus, and mycophenolate mofetil. She denied recent travel.
Physical examination was notable for RUQ and hypogastric tenderness. Laboratory studies were remarkable for leukocytosis (13.2 [normal 4-10.4]) and elevated alkaline phosphatase (425). CT abdomen/pelvis showed terminal ileitis with prominent lymphadenopathy and cholelithiasis with mild gallbladder wall edema. Because the patient was hypotensive on arrival, she was started on Vancomycin and Piperacillin/Tazobactam. Her initial blood and stool studies finalized as negative hence the antibiotics were stopped after 3 days. However, she developed high spiking fevers to 102.8 with repeat CT demonstrating worsening bowel wall thickening and regional lymphadenopathy concerning for colon adenocarcinoma or posttransplant lymphoproliferative disease (PTLD). Subsequent colonoscopy disclosed an obstructive ileocecal mass. Pathology showed caseating granulomas and numerous acid-fast bacilli (AFB). A stool AFB smear was positive. Rifabutin, isoniazid, pyrazinamide, and ethambutol (RIPE) were promptly started. A stool culture and 1 out of 3 induced sputum cultures eventually grew Mycobacterium tuberculosis.
Discussion: Transplant recipients are at a significantly elevated risk for abdominal TB because of their immunocompromised status. Mortality in this vulnerable population can reach 20-30%. While TB had been considered since the outset for our patient, her relatively acute presentation, concomitant biliary disease, and minimal pulmonary involvement compelled us to consider alternate etiologies. However, the persistence of ileocecal mass on repeat imaging as well as fever on appropriate anti-bacterial agents ultimately led to an endoscopic biopsy for a tissue diagnosis confirming TB.
TB should be considered in patients who present with subacute GI complaints, terminal ileitis, and a plausible prior exposure. When intestinal TB is found, the ileocecal region is implicated in 75% of the patients (as in our case). Patients frequently report abdominal pain, constipation, diarrhea, or lower GI bleeding. Endoscopic biopsy is indicated to distinguish intestinal TB from other causes of terminal ileitis, which include Crohn’s disease, colon cancer, and lymphoma (including PTLD).
Antimycobacterial therapy in transplant recipients poses a unique set of challenges characterized by increased side effects, drug interactions, and disease complications. In our patient, rifampicin, part of the traditional RIPE regimen, lowered tacrolimus levels and was replaced with rifabutin.
Conclusions: #Tuberculosis should be considered in immunocompromised patients who present with subacute GI complaints, terminal ileitis, and a plausible prior exposure.
#Antimycobacterial therapy in transplant recipients poses a unique set of challenges characterized by increased side effects, drug interactions, and disease complications.