Avoiding painful needles: A case report on diagnosing eosinophilic granulomatosis with polyangiitis.
Nair V, and Mishra K. Avoiding painful needles: A case report on diagnosing eosinophilic granulomatosis with polyangiitis. J Gen Intern Med 2018; 33(2):473.
J Gen Intern Med
Learning Objective #1: Recognize Eosinophilic Granulomatosis with Polyangiitis as a cause of eosinophilia despite negative anti-neutrophil cyto-plasmic antibodies CASE: A 73 year old male with a past medical history of asthma and chronic left lower extremity pain presented to the Emergency Department with the primary complaint of acute left lower extremity pain and numbness, as well as subacute bilateral lower extremity swelling. Upon further questioning, he did admit to dyspnea on exertion without orthopnea, PND, fever, chills, cough, sputum production, weight loss, or malaise. Initial chest X-ray was concerning for an interstitial process and CT chest showed lower lung ground glass and tree-in-bud opacities, bronchial wall thickening, mucous plugging, and inter-lobular septal thickening. Laboratory work-up was significant for leukocytosis with 70% eosinophilia, total IgE > 3000, erythrocyte sedimentation rate 102, C-reactive protein 1.3, Rheumatoid Factor 300, and negative p and c-Anti-neutrophil cytoplasmic antibodies. Bronchoscopy guided biopsy results were negative for vasculitis in medium sized pulmonary vessels. EMG study showed left leg and foot sensory and motor neuropathy. Skin punch biopsy for a transient petechial rash over the shins showed leukocytoclastic vasculitis rash. Sural nerve biopsy showed extravascular eosinophilia and granulomatous vasculitis, consistent with EGPA. The patient was then discharged home on high dose steroids. IMPACT: EGPA is a rare, but not uncommon, multiorgan disease that should be suspected in patients presenting with asthma, sinusitis and eosinophilia. Although p-ANCA testing is commonly done on initial work up, it is neither sensitive nor specific. Special attention should be paid to ANCA negative patients presenting with mononeuritis multiplex, as nerve biopsy can confirm the diagnosis. This will avoid other invasive procedures, such as surgical lung biopsy. DISCUSSION: Characteristic laboratory tests to diagnose EGPA include eosinophilia, elevated IgE and p-ANCA positivity. However, ANCA is not considered specific toEGPA as it is positive in only 30 to 60 percent of patients with definite vasculitis. As discussed in the case above, when there is a high clinical suspicion of EGPA, biopsy should be pursued to confirm the presence of vasculitis. Although surgical lung biopsy is the gold standard, if skin or nerve involvement is present, pursuing biopsies of a less invasive site is preferred. In terms of extrapulmonary organ involvement, nerve involvement has the highest prevalence (78%), followed by joint and muscle (57% each), and skin and kidney (48% each). In one case series, 71% of patients with EGPA associated neuropathy developed mononeuritis multiplex, presenting as sensory impairments of the extremities. The most common distribution of nerve involvement was the common peroneal nerve, followed by sural nerve. On sural nerve biopsy, eosinophilic infiltrates were seen on 7 out of 15 cases, which is considered to be the hallmark of EGPA.