Tuberculosis heralding connective tissue disorder

Case report

A 50-year-old male, a smoker, working as a shop keeper, suffering with type-II diabetes mellitus for the past four years, presented with fever, breathlessness and cough with whitish, non-mucoid expectorations for two months associated with 5 kg weight loss in four months and appetite loss. He had been treated with amoxicillin clavulanate 625 mg for 10 days in another hospital. Computed tomography (CT) thoracic scan showed multiple diffuse consolidation with surrounding ground glass opacities (halo sign) predominantly in both lower lobes with minimal pleural effusions.

Full blood count, renal and liver function tests and HIV serology were normal. The ANA test was strongly positive (4+) with a fine speckled pattern. ANA blot was positive for Scl-70 and Jo-1 suggestive of systemic sclerosis and polymyositis overlap syndrome. Rheumatoid factor was <l U/ml (N: 0–19 U/ml). Fibreoptic bronchoscopy (FOB) revealed normal tracheobronchial anatomy. Histology of a Trans-bronchial lung biopsy (TBLB) showed alveolar spaces having plugs of fibro-myxoid connective tissue (Masson's bodies) with type-II pneumocyte hyperplasia highlighted by Masson trichrome stain suggestive of organising pneumonia (OP) (Figure 1), but BAL detected Mycobacterium tuberculosis (MTB) by polymerase chain reaction. OPEN IN VIEWER

Antitubercular therapy (ATT) was commenced, with resolution of pulmonary changes after six months. The patient started developing skin tightening with difficulty in squatting during the six-month follow-up period suggesting OP can be a presenting feature in connective tissue diseases. Further follow-up later and evaluation with muscle biopsy and electromyography were suggestive of polymyositis.

Discussion

OP was first described by Davison in 1983 after observation of intra-alveolar organisation for which no aetiology was established. ¹ OP is an inflammatory lung disease, rather than a fibrosing process, and is commonly seen in interstitial pneumonia which will generally respond to steroid therapy. ²

Patients presenting with fever, malaise, cough, shortness of breath who fail to respond to antibiotic therapy should raise the suspicion of OP. Among non-infectious causes, established connective tissue diseases (CTDs) such as rheumatoid arthritis, Sjogren’s syndrome, systemic lupus erythematosus and systemic sclerosis are common. ² OP may also occur with dermatomyositis–polymyositis, where it may be the presenting manifestation. ³

The radiological pattern described for OP includes bilateral diffuse alveolar opacities with air bronchograms and bronchial dilatation. Even with clinical and radiological suspicion of OP, histological confirmation is essential for its diagnosis.

In our case, there was a clinical history of failed antibiotic therapy with CT findings suggestive of OP without any clinical evidence of CTD. Further serology testing suggested both polymyositis and systemic sclerosis, and the histopathology from the right middle lung lobe was consistent with OP.

When the aetiology of OP is unknown or secondary to auto immune disease, administration of oral steroids will give a satisfactory response in most individuals. However, since MTB was detected, standard anti-tubercular therapy alone was commenced, with complete resolution of lesions at six months.

To our knowledge, only a few case reports described MTB as the aetiological agent for OP.^4,5 In all these cases, successful resolution of lung lesions was achieved with ATT without use of steroids.