CHURG-STRAUSS

Clinical features & diagnosis & treatment of eosinophilic granulomatosis with polyangiitis (Churg-Strauss)

 

Clinical features & diagnosis & treatment of eosinophilic granulomatosis with polyangiitis (Churg-Strauss)

 

Eosinophilic granulomatosis with polyangiitis (EGPA) (Churg-Strauss), formerly named Churg-Strauss syndrome (CSS) or allergic granulomatosis & angiitis, is a multisystem disorder characterizing by chronic rhinosinusitis, asthma + prominent peripheral blood eosinophilia (≥ 1500 cells/microL and/or >10 % eosinophils on differential WBCs). The real aetiology of EGPA is idiopathic.  Asthma is the main feature of EGPA (seen in > 95 % of ptns) and often preceding the vasculitic phase by about 8-10 ys.  

 

Peripheral neuropathy, often mononeuritis multiplex, is observed in up to 75 % of ptns. CNS features may include subarachnoid & brain hemorrhage, brain infarction, cranial nerve palsy, & lost visual acuity. 2/3^rd of EGPA ptns show skin affection including palpable purpura, SC nodules, & macular or papular erythematous rash. Skin biopsy is usually helpful to confirm the Dgx.  Cardiac affection is one of the more serious features of EGPA, involving ½ of deaths related to EGPA. It should be expected with presence of resistant dyspnoea, heart failure, or arrhythmias, (may be symptomless).  

 

EGPA ptns mostly show peripheral blood eosinophilia (typically > 1500/microL, usually 5000-9000/microL), that may be obscured by use of steroid therapy to control asthma. Antineutrophil cytoplasmic AB (ANCAs) are seen in 30-60 % of EGPA ptns. ANCAs that mostly related to EGPA & directed to myeloperoxidase with a perinuclear staining pattern (MPO-ANCA or P-ANCA). Typically, chest high resolution computed tomography (HRCT): patches of parenchymal consolidation or ground glass opacities; nodules.  

 

Dgx of EGPA is expected by the finding of asthma, rhinosinusitis, & eosinophilia that can be confirmed by lung biopsy or other affected organs (e.g., skin, peripheral nerve). 2 sets of diagnostic parameters; American College of Rheumatology (ACR) criteria for classification of EGPA & the Lanham criteria. Main disorders in DD of EGPA are aspirin-exacerbated respiratory disorder, eosinophilic pneumonia, allergic bronchopulmonary aspergillosis, hypereosinophilic syndrome, granulomatosis with polyangiitis & microscopic polyangiitis

 

TTT: EGPA is classified as a vasculitis of small & medium sized arteries, despite vasculitis is often not clinically evident in the early phase of the disease.  

The 1^st step in the EGPA management is to evaluate the severity of disease. A commonly used system is the "five-factors score" (FFS) that is relied on the presence/ absence of 5 clinical factors: age >65 ys; cardiac affection; kidney dysfunction (stabilized peak Cr 1.7 mg/dL [150 micromol/L]); GIT affection; + absence of ENT involvement (presence = better prognosis).  

 

ALL EGPA ptns + systemic vasculitis > systemic steroids is recommended. Prednisone 0.5-1 mg/kg/d typically given for 6-12 weeks, or until remission is reached, then tapered gradually. For fulminant disease initial administration of iv steroids.  Ptns with severely intense disease manifested by FFS=2 or higher, adding cyclophosphamide (Cph) to systemic steroids is recommended. Ptns with FFS= 1 (particularly ptns with cardiac or CNS affection), adding Cph + systemic steroids is suggested.

 

Induction of remission with Cph should be followed by maintenance therapy with azathioprine (Aza) to stabilize the remission. Methotrexate & leflunomide are alternatives that can be used if Aza is not tolerated or is non effective. The latter agents are preferred to long-term Cph that may induce significant toxicity. Maintenance im/m. therapy should be maintained for 12-18 mo. Longer/indefinite maintenance therapy may be required with frequent relapses. Adding to maintenance therapy, concurrent steroids (prednisone or equivalent) is suggested. Steroids is gradually tapered to the least dose warranted to manage Sns & Sms of active EGPA.  

 

Ptns with  FFS <2 + suboptimal control of asthma with oral steroids or difficult tapering oral steroids to a tolerated dose, adding mepolizumab, 300 mg/4 wks, alternating to im/m. therapy. Role of rituximab in EGPA may need more prospective RCT.