Presentation
3/52 history of fevers, cough and night sweats. Recent hiking trip to New Zealand. Background rheumatoid arthritis, on TNF alpha inhibitor.
Patient Data
An initial chest radiograph shows subtle reticular opacifications and peribronchial thickening, slightly more confluent in the lower zones.
Repeat CXR 2 weeks later shows now marked diffuse micro-nodular opacifications throughout all lung fields, appearing relatively uniform in size and distribution.
CT confirms miliary pulmonary opacifications with a random/hematogenous pattern of distribution, with asymmetric mediastinal and hilar lymphadenopathy.
Some of these pulmonary opacifications are more confluent (e.g. within the right upper lobe and left lower lobe). Cluster of peri-bronchovascular confluent nodules left lower lobe with a tree-in-bud like appearance.
CT Abdomen reveals diffuse mesenteric prominence, mild mesenteric lymphadenopathy, omental hyperattenuation and pelvic free fluid, consistent with diffuse peritoneal pathology (peritoneal spread of TB in this case).
Case Discussion
This case demonstrates classic CXR and chest CT appearances of miliary TB. The case is also interesting for the rapid disease progression on CXR over a period of just two weeks. The subtle findings on the initial chest radiograph were not appreciated at the time but the suspicion for TB was raised after the striking appearance of the follow-up CXR, which was later confirmed on microbiology. Differentials for this appearance include fungal infection and diffuse metastasis. The patient demographics were also atypical for miliary TB presentation, with the major risk factor being the patient's immunocompromised status.