ANCA-negative eosinophilic granulomatosis with polyangiitis complicated by peripheral nerve damage: A case report

Rationale: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare autoimmune disease that can affect multiple systems of the body and is characterized by asthma, blood and tissue eosinophilia, and small vascular inflammation. Eosinophilic tissue infiltration and extravascular granuloma formation can lead to any organ damage, but peripheral neuropathy is relatively rare.

Patient concerns: A 29-year-old male patient was admitted to the hospital due to fever and rash on both lower extremities for 18 days. The patient complained of muscle pain in both lower extremities, with nausea, anorexia, abdominal pain, and diarrhea. He had a 2-year history of asthma and bronchiectasis. The physical examination results were as follows: temperature, 37.8 °C; multiple patchy red rashes on both lower extremities; and no obvious abnormalities in other systems. The patient was negative for anti-neutrophil cytoplasmic antibody (ANCA). Chest computed tomography showed bilateral ground-glass opacities, small nodules, and bronchiectasis. Histopathology of rectal tissues revealed numerous eosinophilic infiltrations. One week after admission, the patient developed symptoms of peripheral nerve damage, presenting with distal weakness in both lower extremities, foot drop, cross-threshold gait, and hypoalgesia on the lateral sides of both lower legs. Electromyography showed that the motor sensory fibers of the lower extremities were damaged.

Diagnoses: Referring to the diagnostic criteria of the American College of Rheumatology in 1990, the patient was diagnosed with systemic EGPA (vasculitic phase) with rare peripheral nerve damage.

Interventions: After diagnosis, the patient was administered oral prednisone (60 mg/d; 1.0 mg/kg/d), and cyclophosphamide (900 mg) was infused on the 5th and 18th days of hormone therapy. Prednisone was reduced to 50 mg/d 1 month thereafter.

Outcomes: After 1+ months of treatment, most of the symptoms disappeared. Limb weakness did not improve. Currently, the patient is undergoing outpatient follow-up and is adhering to treatment.

Lessons: EGPA is a rare disease that can affect multiple systems and has diverse clinical manifestations, with no specific manifestations in the early stage. Diagnosis is difficult, and there is a high misdiagnosis rate. The rate of ANCA positivity for this disease is not high, and clinicians should consider the possibility of ANCA-negative EGPA.