A 62-year-old woman developed bronchial asthma in 2015. She had no history of smoking. She had never been diagnosed with dyslipidemia, diabetes, or hypertension before. She experienced atelectasis in May 2018, but it resolved spontaneously. In August 2018, she developed leg edema and purpura with eosinophilia and was referred to our hospital.
On admission, she complained of numbness in her distal extremities. She was alert. Findings of the physical examination were as follows: height, 163 cm; weight, 41 kg; body temperature, 36.8 °C; blood pressure, 125/84 mmHg; and O2 saturation in room air, 95%. Diminished breathing sounds were noted in the left upper back, with no abnormal findings in the head, neck, or abdomen. Pitting edema and a few palpable purpuras were detected in both lower legs. Neurological examination revealed peripheral sensory neuropathy in the lower extremities but no CNS disorder. The laboratory values were as follows: white blood cells, 43,400/μL (eosinophil count, 36,890/μL); platelets, 26.5 × 104/μL; and C-reactive protein, 1.31 mg/dL (normal range < 0.15 mg/dL). Protein uria, hematulia, or any other abnormal findings were not found in urinalysis. Rheumatoid factor was 72 IU/mL (normal range < 15 IU/mL); however, test for proteinase 3-antineutrophil cytoplasmic antibodies and myeloperoxidase- ANCAs were negative. Ultrasound echocardiography showed no impairment of cardiac function. Chest computed tomography (CT) showed left lower lobe collapse (Fig. 1a). Diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) of the brain magnetic resonance imaging (MRI) showed a high-intensity area in the occipital lobe, which indicated subacute brain infarction (Fig. 2a). A biopsy of a skin sample taken from the purpura in the lower leg revealed leukocytoclastic vasculitis and eosinophil filtrations around the blood vessels. The patient was finally diagnosed with EGPA based on physical, laboratory, and histological findings.
After the initiation of 40 mg/day of prednisolone (PSL), her numbness and purpura quickly improved. Eosinophil count also decreased to 13,450/μL on day 7 after initiating PSL. Chest CT on day 7 also showed the disappearance of lung collapse (Fig. 1b). In January 2019, brain MRI showed high intensity, indicating an old ischemic change (Fig. 2b).
The clinical course of this patient is shown in Fig. 3. Although the patient remained symptom free, it was difficult to reduce the PSL dose without an eosinophil increase. In January 2020, a high-intensity area near the previous lesion emerged in FLAIR but not in DWI without any symptoms (Fig. 2c). With an increase in eosinophil count to 1105/μL with a PSL dose of 8.0 mg/day in April 2020, chest CT showed recurrence of atelectasis without any symptoms (Fig. 1c). After increasing to 20 mg/day of PSL, atelectasis quickly disappeared on chest radiography. Follow-up brain MRI showed no new abnormal lesion in July 2020.
After the initiation of mepolizumab (300 mg/4 weeks), the PSL dose was reduced to 5 mg/day, and remission was maintained.