TB or not TB?

A 26-year-old male with no past medical history presented to the emergency department (ED) for chest pain and cough. The patient was seen in urgent care prior to arrival and was sent to the ED due to chest x-ray findings of diffuse pulmonary opacities. The patient was originally from India and immigrated to the United States 2 years earlier. He had 2 weeks of shortness of breath, cough, and central chest pain that worsened with inspiration. The patient reported hemoptysis began the day of presentation. He denied fevers or chills. Social history revealed that he smoked occasionally and worked as a computer programmer. Computed tomography angiography of the chest revealed diffuse miliary opacities in the lung concerning for tuberculosis (Figure 1). The vitals were as follows: temperature 36.8°C, heart rate 110, respiratory rate 20, and pulse oximetry 95%. He was ill appearing with diffuse rales on the physical examination. The patient was admitted and started on Rifampin, Izoniazid, Pyrazinamide, and Ethambutol (RIPE) therapy with high suspicion for miliary tuberculosis (TB) given the clinical picture, imaging findings, and history of immigration from India. Despite negative acid-fast bacilli (AFB) sputum culture, the patient was discharged with follow-up in the infectious disease (ID) clinic. The patient returned to the ED after a generalized tonic-clonic seizure followed by a postictal period. The history was limited as the patient was persistently somnolent on arrival but able to answer some questions. He reported compliance with RIPE therapy. The workup revealed computed tomography (CT) head with multiple ring-enhancing lesions concerning for brain abscesses with vasogenic edema, which raised suspicion for disseminated tuberculosis (Figure 2). Neurology, ID, and neurosurgery were consulted. The patient was admitted, infectious work-up was broadened, and therapy was broadened to RIPE, along with broad-spectrum antibiotics and steroids for vasogenic edema. Central nervous system (CNS) involvement is only found in about 1% of patients with tuberculosis; however, the rate is believed to be between 10% and 30% in miliary tuberculosis cases.1 In this patient's case, pulmonology was consulted for tissue biopsy of the lung for definitive diagnosis, as AFB sputum cultures were negative (x3). AFB urine culture and blood cultures were also negative. Bronchoscopy with bronchoalveolar lavage and endobronchial ultrasound was performed with pathology that demonstrated primary adenocarcinoma of the lung with metastases to the brain (notably rather than miliary tuberculosis). Non-small cell lung cancer has been associated with a relatively high incidence of CNS metastasis with roughly 10% presenting with CNS involvement.2 This patient was then taken off RIPE therapy with consults placed to radiation oncology and medical oncology. The patient underwent radiation of brain lesions with a plan to begin systemic therapy after radiation therapy is complete. This case highlights the importance of considering alternative diagnoses and not anchoring on a preliminary diagnosis despite a compelling history. The patient was maintained on broad antimicrobial therapies while further workup was done, and the final diagnosis of metastatic lung cancer could be made.