Concomitant Diagnosis of Pulmonary Histoplasmosis and Latent Tuberculosis During Tumor Necrosis Factor Inhibitor Treatment in IBD Patient: A Case Report

Background: The monoclonal antibody against tumor necrosis factor (TNF-α inhibitor) transformed the approach to patients with severe autoimmune conditions, such as inflammatory bowel disease (IBD). Although this therapy can be highly effective, the increased risk for serious infections and malignant neoplasms secondary to immunosuppression is a major concern during this treatment. It is important to point out that Histoplasmosis and Tuberculosis (TB) can be found in immunosuppressed hosts, but concomitant diagnosis is rare in IBD patients. Case Presentation: A 45-years-old man followed with ileocolonic Crohn’s disease in clinical and endoscopic remission using infliximab for 3 years. Prior to treatment with infliximab the TB screening result was negative tuberculosis skin tests (TST) and normal chest x-ray. After 2 years with biologic monotherapy, the patient started to manifest respiratory complaints, such as rhinorrhea and productive cough, for about 2 months, and was investigated for different lung diseases. Initially we discarded the diagnosis of native tuberculosis, malignancy, autoimmune diseases, and bacterial or viral infections. After the third month, the patient was hospitalized with weight loss, shortness of breath and worsening cough. The sputum smear microscopy was negative for acid-fast bacilli (AFB). After the patient underwent bronchoscopy, the bronchoalveolar lavage (BAL) and culture was positive for Histoplasma capsulatum. In this context, infliximab was suspended and itraconazole was introduced to treatment of the fungal infection. The routine screening to restart immunobiologic was performed and interferon gamma (IGRA) test was positive, confirming the diagnosis of latent tuberculosis (LTB). The treatment of LTB was chosen with isoniazid, concerning possible drug interaction of rifampicin and itraconazole. Due to safety, vedolizumab was preferred to restart immunobiological therapy of Crohn’s disease and was started after 30 days of LTB treatment. Conclusions: We report a rare case of Crohn’s disease patient treated with TNF-α inhibitor that received diagnosis of pulmonary histoplasmosis and latent tuberculosis. Both conditions can be found in immunosuppressed hosts, but concomitant diagnosis is uncommon in IBD patient.