Eosinophilic Pneumonia: An unusual Clinical Course Causing a Diagnostic Conundrum

Background: We present the case of a 9 year old boy referred to the tertiary respiratory team for investigation of recurrent chest infections, persistent chest x-ray findings and faltering growth. He developed an acute, prolonged fever unresponsive to broad-spectrum antibiotics, respiratory distress with an oxygen requirement, and dramatic blood eosinophilia.

Objective: To describe the clinical course of this presentation of eosinophilic pneumonia, and discuss the need to exclude alternative diagnoses.

Methods and Results: On initial referral, the patient underwent flexible bronchoscopy showing profuse, thick secretions, with cytology revealing Charcot Leyden crystals. He had a raised total IgE, but other investigations were unremarkable. He had a working diagnosis of ‘Idiopathic eosinophilic plastic bronchitis’ and responded well to a 4 week course of antibiotics. He re-presented acutely unwell 4 months later with a rash, followed by fevers unresponsive to antibiotics. Striking investigations included increasing peripheral blood eosinophilia, peaking at 63 ×109cells/L, and troponin of 1155. His case was discussed with multiple teams, and extensive investigations performed. Blood serology was negative for both fungi and parasites and a bone marrow aspirate excluded malignancy. After 3 weeks of investigations and exclusion he was diagnosed with eosinophilic pneumonia.

Conclusion: Chronic eosinophilic pneumonia (CEP) is an extremely rare disease in childhood, with diagnosis largely based on adult criteria. It is characterised by massive accumulation of eosinophils in the lungs and the bloodstream. Patients present with symptoms including cough, dyspnoea, fatigue, fevers and weight loss. The exact pathophysiology is unknown but environmental triggers and allergic diasthesis have been implicated in causality. In adults, CEP may occur in isolation or alongside rheumatological, vasculitic, or oncological disorders, making thorough investigation crucial. In children, diagnosis remains one of exclusion. Treatment is with high dose steroids, following which, the patient improved significantly both clinically and with normalisation of his blood parameters.