Abstract 428: The Unusual Suspect ‐ Hypereosinophilia as the Cause for Acute Stroke
Authors: Chishti M. A. , Fournier L. 
Published: January 2025

Background
Eosinophilic granulomatosis with polyangiitis (EGPA) causes inflammation of small blood vessels. EGPA is rare, with an annual incidence of 1 per million, with a mean age of onset of 40‐60 years. EGPA is divided into 2 phenotypes, ANCA‐positive vasculitis type and ANCA‐negative eosinophilia type. There is an overlap between other hypereosinophilic syndromes and EGPA. There are no diagnostic criteria for EGPA, however clinical features of asthma, chronic rhinosinusitis with polyps, eosinophilia, neuropathy, lung infiltrates, and eosinophilic cardiomyopathy or gastroenteritis are supportive. Central nervous system involvement manifests as cerebral infarcts and subarachnoid hemorrhages.

Case:
Here we present a 53‐year‐old Caucasian female with no past medical history who presented with chest pain and shortness of breath. She reported dyspnea on exertion for 8 months prior, and more recently paroxysmal nocturnal dyspnea and orthopnea, with minimal relief from inhalers. She was noted to have pansinusitis and was started on amoxicillin‐clavulanic acid without improvement. She noted acute right upper extremity weakness. Initial workup showed elevated troponin and a white blood cell (WBC) count of 28.4 with 11.64 eosinophils. CT chest showed bilateral bronchial wall thickening with bilateral nodular consolidative opacities in the right upper lobe and left lower lobe. She was started on a heparin drip. Coronary angiography was negative, and the initial echocardiogram revealed mild circumferential pericardial effusion without tamponade. CT head showed an 11 mm right cerebellar hemorrhage. Heparin was stopped. MRI brain revealed multiple scattered areas of restricted diffusion in bilateral cerebral hemispheres and a right cerebellar hemisphere. CTA head and neck showed normal vessels, and after transfer to our facility, a repeat MRI brain revealed scattered new infarcts in the left parietal and occipital regions. A repeat echocardiogram showed a small loculated pericardial effusion anterior to the right ventricle but no intracardiac shunt. The patient was exposed to wildfire smoke before symptom onset, raising suspicion of fungal infection. The patient underwent fungal evaluation in both serum and sinus aspirate, including beta‐D‐glucan in the serum, which was negative, and a bronchoscopy, which revealed white plaques and nodules with negative fungal and tuberculosis studies. Lumbar puncture revealed an elevated opening pressure of 30 mmHg but otherwise unremarkable infectious studies. Antibiotic therapy included vancomycin, cefepime, and amphotericin, but with consistently elevated WBCs of more than 24 with eosinophilic predominance. Endomyocardial biopsy showed numerous eosinophils. Subsequent endobronchial biopsy showed eosinophilic infiltrates and features suspicious for vasculitis. ANCA and bone marrow biopsy were negative. The primary diagnosis was considered hypereosinophilic syndrome. She was started on pulse dose steroids, and WBC count fell from 24.1 to 11.8 with a decrease in eosinophils from 13.05 to 0.01. Outpatient rheumatology was planned to initiate cyclophosphamide or rituximab. Dual antiplatelet therapy was initiated before discharge.

Conclusion
Central nervous system sequelae of EGPA are rare, but this diagnosis should be considered in patients with symptoms of sinusitis, elevated eosinophils, and acute stroke, especially without other risk factors. Since ANCA is only positive in about 30‐40% of patients, an early biopsy is needed for confirmation and early treatment with steroids.