Background Between January 2017 and November 2018, 2678 former gold miners from South African mines were examined and sputum screened with GeneExpert at Mafeteng Occupational Health Service Centre in Lesotho. Mean duration since last exposure was 12 years. A high prevalence of silicosis (42.5%), HIV (30.7%) and tuberculosis (active TB 6.8%, history of past TB treatment 53.4%) was found. Of the TB cases, 54,7% were symptom screen negative (had no TB symptoms in WHO Guidelines), and 9,3% had normal chest x-rays. In total, 60% of the sample had lung features on x-ray read as either silicosis, silicotuberculosis, or tuberculosis. It was observed that many silicosis cases had been repeatedly treated for TB, and some even documented as MDR-TB, on the basis of x-ray alone, even when bacteriologic tests gave negative results.

Objectives To illustrate the challenges in diagnosing active TB in this setting, including distinguishing pulmonary TB (past and current) from pneumoconiosis (silicosis, CWP, asbestosis).

Methods Several cases will be discussed. For each case, a complete medical scenario is described, including occupational history, past and current medical history, physical examination, radiological and laboratory findings.

The following were noted (1) Poor agreement between radiological findings and clinical presentation; (2) Poor agreement between radiographs suggestive of TB and positive GeneExpert sputum results; and (3) Similarity of clinical and radiological presentation of silicosis and tuberculosis.

Conclusion TB screening of former gold and other miners needs to take these diagnostic challenges into account. There should be systematic digital record keeping of chest x-rays. Records, including those from the mines, should be accessible to all healthcare providers who attend to former miners in the community. Training on occupational lung disease with emphasis on pneumoconiosis and TB is needed for all community healthcare providers.