AM is a 29-year-old carpenter with history of environmental allergies, history of asthma and sinusitis. He was in a fair state of health until, following a recent sinus infection, he presented with 3 weeks’ history of migratory joint pains, swelling on dorsum of feet and a petechial rash on the lower third of his legs. A few weeks ago he had swelling and pain involving both wrists that resolved spontaneously. He had some cough but denied phlegm, hemoptysis or wheezing. He experienced fever and chills once but denied symptoms of night sweats or weight loss. He denied history of recent travel, jaundice of blood transfusion. He had no urinary symptoms or history of urethral discharge. His appetite was fair and he didn’t have symptoms of abnormal bowel movements, bleeding per rectum or melena.
AM’s medications included Ventolin as required, Singulair 10 mg a day, Claritin as required, and allergy shots for the past 6 months. He doesn’t smoke and denied substance abuse. He had no pets.
Physical examination was remarkable for a man of AM’s age, average build with blood pressure of 116/70 mm Hg and regular rhythm. There was no thyromegaly, bruits or lymphadenopathy. Heart sounds were normal. Chest was resonant with increased expiration without crackles or wheezes. Abdomen was benign. There was induration on the outer aspect of the dorsum of both feet with a petechial rash involving the lower third of both legs. There was no tenderness or swelling of the wrists, interphalangeal or metacarpophalangeal joints. There was mild tenderness of both ankles but no tenderness or swelling of the knees. He has difficulty with weight bearing but a neurological exam was non-focal.
Laboratory data showed hemoglobin of 125 g/L, slightly high white blood cells of 13.2, eosinophilia with eosinophil count of 5.79, ESR of 33, CRP of 44, normal electrolytes with serum potassium of 4.2, BUN of 8.9 and serum creatinine of 69, normal AST, ALT and GGT. Urinalysis was negative for blood and protein. Collagen workup done a few days before showed negative anti-nuclear antibody, weakly positive rheumatoid factor with titre of 28 [Normal < 14], and normal chest and ankle x-rays.
The history of environmental allergies, sinusitis, asthma and new onset of arthralgias following a recent episode of sinus or upper respiratory tract infection, petechial rash, tenosynovitis and eosinophilia raised the possibilities of acute sarcoid arthropathy [Lofgren’s syndrome], vasculitis such as Henoch-Schönlein purpura, Churg-Strauss syndrome or Wegener’s granulomatosis. All of these were entertained and anti-neutrophilic cytoplasmic auto-antibodies [P- and C-ANCA] were tested while a CT scan of the chest was requested to assess for hilar adenopathy and rule out pulmonary infiltrates. A skin biopsy was also performed. AM was started on oral prednisone while awaiting the results of these investigations.
What’s your diagnosis?
The CT scan of AM’s chest was unremarkable and essentially ruled out sarcoidosis. C-ANCA was negative but P-ANCA was positive at 8 [normal <0.2]. Skin biopsy showed moderate mixed inflammation with numerous eosinophils, lymphocytes and neutrophils mostly in the mid to deep dermis with perivascular accentuation. There was no vascular fibrinoid necrosis to suggest active vasculitis.
He presented 2 weeks later with ongoing symptoms of arthralgias. Although the skin rash had improved, he developed bilateral foot drop, despite being on oral prednisone. After consultation with a rheumatologist, azathioprine was added to oral prednisone and oral Septra (trimethoprim and sulfamethoxazole) for PCP prophylaxis.
Turn for the worse
His symptoms continued and about 2-3 weeks later, azathioprine was changed to oral cyclophosphamide. But within a month, he presented with respiratory failure, and a CT scan now showed patchy diffuse pulmonary infiltrates and the possibility of diffuse infectious process or pulmonary hemorrhages was raised. He developed acute renal failure as well. AM was intubated, ventilated and, because of the aggressive nature of the disease process, was transferred to a tertiary care centre for consideration of plasma exchange and supportive care.
Churg-Strauss syndrome (CSS) or allergic granulomatous angiitis, is a rare syndrome (1-3 cases per 100,000 adults per year) that affects small- to medium-sized vessels (microscopic angiitis) and is associated with antibodies to neutrophil cytoplasmic antigens (ANCAs). In 1951, Churg and Strauss first described the syndrome in 13 patients who had asthma, eosinophilia, granulomatous inflammation, necrotizing systemic vasculitis, and necrotizing glomerulonephritis. The principal causes of morbidity and mortality in CSS are myocarditis and myocardial infarction secondary to coronary arteritis. With treatment, the 1-year survival rate is 90% and the 5-year survival rate is 62%.
The American College of Rheumatology (ACR) has proposed 6 criteria for the diagnosis of CSS. The presence of 4 or more criteria yields a sensitivity of 85% and a specificity of 99.7%. These criteria include 1) asthma (wheezing, expiratory rhonchi), 2) eosinophilia of more than 10% in peripheral blood, 3) paranasal sinusitis, 4) pulmonary infiltrates (may be transient), 5) histological proof of vasculitis with extravascular eosinophils, and 6) mononeuritis multiplex or polyneuropathy.
CSS has 3 phases — 1) allergic rhinitis and asthma; 2) eosinophilic infiltrative disease, such as eosinophilic pneumonia or gastroenteritis; and 3) systemic medium- and small-vessel vasculitis with granulomatous inflammation. The vasculitic phase usually develops within 3 years of the onset of asthma, although it may be delayed for several decades. The most prominent symptoms and signs are those related to pulmonary, cardiac, dermatologic, renal, and peripheral nerve involvement. Mononeuritis multiplex is a major clinical finding.
Glucocorticoids alone are usually adequate for the majority of patients with CSS. Cytotoxic drugs are required in less than 20% of patients. Infliximab therapy has been used in patients with steroid-dependent CSS. Aggressive disease with life-threatening organ involvement may require pulse doses of intravenous corticosteroids and other cytotoxic agents. Cyclophosphamide is typically given in intravenous pulses for 3 months followed by either oral mycophenolate or azathioprine.
The benefit of plasma exchange in CSS and other ANCA-positive vasculitides remains unclear. Plasma exchange has been used but hasn’t added benefit to the treatment of patients who were treated with prednisone or cyclophosphamide. This is based on a meta-analysis of 140 patients with glomerulonephritis and CSS and microscopic polyangiitis.
ESR and peripheral blood eosinophilia are helpful in monitoring disease activity and response to therapy.
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