Introduction A typical radiological presentations of TB may lead to unnecessary and costly tests, delayed or missed diagnoses, and increased transmission. Feeling that such presentations were increasing, we retrospectively reviewed our thoracic TB patients' radiology.
Methods The London TB Register (LTBR) was queried for patients at our Trust with intrathoracic lymph node or pleural disease (January 2006–December 2008), or pulmonary disease (January 2008–December 2008). Chest radiographs (CXRs) and CT scans from symptom onset to diagnosis were analysed by a consultant radiologist. Clinical data was obtained from hospital records.
Results 118 patients were identified: male=75 (64%); median age=33 years; HIV-infected=10 (8%). 118 (100%) had CXRs and 57 (48%) additional CTs. From LTBR 16 had intrathoracic lymphadenopathy, 16 pleural diseases, 73 pulmonary diseases, and three mixed. One pre-diagnosis CXR was performed in 7/10 (70%) HIV-positive and 63/108 (58%) HIV-negative/unknown; two in 3/10 (30%) HIV-positive, 27/108 (25%) HIV-negative/unknown; >3 CXR (maximum eight) were performed in 18/108 (17%) HIV-negative/unknown. We focused on radiologically pneumonic cases. 63/118 (53%) had consolidation on initial CXR, 66/118 (56%) on final. 29/66 (44%) had multifocal disease; all but 8/29 (28%) had either lymphadenopathy, cavitation, or nodules. 37/66 (56%) had disease in one zone (see Abstract P58 Table 1). 18/37 (49%) were right UZ; eight with/without pleural involvement but no other suggestive features such as cavitation or nodularity. 7/37 (19%) were left UZ patients; 4/7 (57%) with no other suggestive features. 8/37 (22%) had solely LZ consolidation; 2/8 (25%) with no other suggestive features. Of 17 presentations that could mimic standard pneumonia (zonal disease with/without pleural involvement but no suggestive TB features) one was HIV positive; 15 had sputum samples—4/15 (27%) were smear positive, 12/15 (80%) were culture positive. Progression to CT was 10/17 (59%). With any consolidation, 20/32 (63%) CTs accessible yielded additional information, often minimal (e.g. 14/32 (44%) showed nodules in addition to lymphadenopathy). 13/32 (41%) were women, 9/13 (69%) under 40-years-old.
Discussion In our cohort the majority of patients had typical diagnostic features on presenting CXR. Lower zone cases were not uncommon but most had features suggestive of TB. The high frequency of CT with questionable clinical gain and high radiation exposure, particularly in young women, is of concern.