Chronic Eosinophilic Pneumonia As A Diagnostic Mimic of Tuberculosis : A Case Report.

Abstract

Background :
Pulmonary tuberculosis (PTB) is endemic in Sri Lanka, and many patients with chronic cough, constitutional symptoms and upper-zone opacities are treated empirically when microbiological confirmation is unavailable. This practice risks diagnostic anchoring and delayed recognition of important mimics. Chronic eosinophilic pneumonia (CEP) is an uncommon, steroid-responsive eosinophilic lung disease that can closely resemble PTB clinically and radiographically particularly when infiltrates involve upper lobes. A key clue is the presence of “flitting” (migratory) consolidations, supported by peripheral or bronchoalveolar lavage (BAL) eosinophilia.
Case report:
A 25-year-old woman presented with a 6-month dry cough and a 3-week history of low-grade evening fever with night sweats, anorexia, myalgia/arthralgia and 4-kg weight loss. Examination was unremarkable aside from low body mass index (16.2 kg/m²). Initial investigations showed elevated inflammatory markers (ESR 118 mm/h; CRP 36 mg/dL), mild eosinophilia (697 cells/μL), Mantoux
induration 10 mm, negative sputum AFB smear and a right upper-zone opacity on chest radiograph. She was started on standard anti-tuberculosis treatment for clinically diagnosed PTB. Within one week, symptoms persisted with vomiting and a markedly raised CRP (174 mg/dL), rising eosinophils (3289 cells/μL) and repeat radiography showing resolution of the right-sided lesion with new left
upper-zone consolidation. HRCT demonstrated bilateral apical peripheral consolidations with ground-glass opacities. Parasitic studies, filarial antibodies, HIV testing and ANCA were negative and IgE was elevated (620 IU/mL). Bronchoscopy was normal; BAL showed 90% eosinophils with negative AFB smear, GeneXpert, bacterial cultures, and pyogenic cultures. Anti-tuberculosis therapy was stopped and oral prednisolone 30 mg/day initiated leading to complete clinical and radiological resolution within two weeks.
Conclusion:
In tuberculosis-endemic settings, CEP should be considered when presumed PTB is bacteriologically unconfirmed, fails to improve on therapy and demonstrates migratory infiltrates with eosinophilia. Early BAL differential counts and prompt corticosteroid treatment can rapidly reverse disease and prevent unnecessary anti-tuberculosis exposure.