A 34-year-old man presents to his primary care physician with a 7-week history of cough that he describes as non-productive. He has had a poor appetite during this time and notes that his clothes are loose on him. He has felt febrile at times, but has not measured his temperature. He denies dyspnoea or haemoptysis. He is originally from the Philippines. He denies any history of TB or TB exposure. Physical examination reveals a thin, tired-appearing man but is otherwise unremarkable.
The presentation of pulmonary TB is varied, as patients may present early or late in the course of the disease, or have different host factors (e.g., HIV, age) that may impact disease presentation. Classic findings, including haemoptysis, night sweats, and weight loss, make the diagnosis obvious, but may be absent. A number of features associated with the misdiagnosis of TB include lack of pulmonary symptoms, a sputum smear that is acid-fast bacilli-negative, negative tuberculin skin test, atypical CXR findings, and the presence of other diseases that may alter immune status. Careful attention to epidemiological risk factors (e.g., residence or work in a congregate setting, birth or long-term living in TB-prevalent counties, history of latent TB infection, or recent exposure to an infectious case) will often lower the threshold to consider TB as part of the differential diagnosis.