A Curious Case of Myocarditis

Case Overview

In morning report, we discussed a case of a patient with a history of poorly controlled asthma, requiring frequent courses of steroids, who presented with eosinophilia and multisystem disease including colitis and myocarditis. ANCA was negative, yet a biopsy confirmed extravascular eosinophilic infiltration, in keeping with a diagnosis of Eosinophilic Granulomatosis with Polyangiitis (EGPA). EGPA is formerly known as Churg-Strauss syndrome.

1. Clinical Manifestations of EGPA

  • EGPA is a rare and potentially life-threatening vasculitis involving the small and medium-vessels that is associated with asthma and eosinophilia.
  • It almost invariably involves the respiratory system, but may present with extra-pulmonary manifestations (e.g., polyneuropathy, eosinophilic colitis and glomerulonephritis).
  • The diagnosis is based on the American College of Rheumatology or Lanham criteria
  • Although classified as an ANCA-associated vasculitis, ANCA is detected in only 40-60% of cases.
  • The three stages of EGPA (allergic prodromal phase; eosinophilic infiltrative phase and the vasculitis phase) are described below

2.Differential Diagnosis for Eosinophilia

Eosinophilia may be due to:

  • Allergy/Asthma
  • Drug Hypersensitivity including DRESS
  • Autoimmune Disorders (e.g., sarcoidosis, RA, IBD, IgG4 disease and other connective tissue diseases)
  • Infections (e.g., parasitic, fungal, HIV)
  • Neoplastic disorders
  • Other: Idiopathic hypereosinophilic syndrome; immunodeficiencies; Loeffler’s syndrome, hypoadrenalism, cholesterol emboli
  • The degree of eosinophilia may help to narrow the differential diagnosis.
  • If absolute eosinophil count >1.5x 10^9/L, usually warrants further work up

3. Diagnosis of EGPA

  • Suspect if:
    • Eosinophils >1.5x 10^9/L
    • Late onset asthma
  • Serology:
    • Not very sensitive, as p-ANCApositive only in 40-60% of patients
  • Biopsy:
    • Skin, nerve and muscle commonly biopsied but may biopsy kidney, GI tract or myocardium.
    • Biopsies strongly supportive if shows:
      • Extravascular eosinophilic infiltration
      • Necrotizing Vasculitis
      • Perivascular Granulomas
  • ACR Criteria are below The presence of 4 or more is 85% sensitive, 99.7% specific for EGPA
Churg-Strauss Syndrome

4. Investigations in Suspected EGPA

  • Diagnosis straightforward when all diagnostic criteria met
  • But may mimic other diseases!
  • See Consensus Guidelines for details of full investigations to be ordered depending on the presenting symptoms

5. Management of EGPA

  • Immunosuppression is key
  • Initially:
    • 1 mg/kg/day prednisone for organ-threatening manifestations
    • Methylprednisolone pulse x 3 days first if there are life-threatening manifestations
  • If severe manifestations:
    • Will receive another immunosuppressant (e.g. cyclophosphamide) in addition to steroids
  • Maintenance therapy:
    • Azathioprine or MTX after remission induction
  • PLEX not generally recommended

6. Cardiac Manifestation and Treatment in EGPA

  • Cardiac involvement (myopericarditis, CHF etc) described in 20-50% of cases
  • More common if ANCA-negative
  • Myocarditis may result from microvascular ischemia and myocardial eosinophilic infiltration
  • Early detection and treatment of myocarditis essential- 50% risk of mortality (leading cause of death in EGPA)
  • Important investigations: chest imaging, ECG, TTE, BNP, troponin
  • Cardiac PET and/or MRI are more specific for myocarditis (MRI sensitivity of 88%, specificity 72%)
  • Treatment: prevent myocardial fibrosis with immunosuppression

7. Take Home Points:

  1. EGPA can present with pulmonary and extra-pulmonary manifestations including eosinophilic myocarditis and colitis
  2. EGPA can present with a normal ANCA in up to 60% of patients and a high index of clinical suspicion is required to make the diagnosis
  3. Cardiac involvement contributes to morbidity and mortality in EGPA, emphasizing the need for early detection and treatment

Further Reading

  1. Cereda, A. F., Pedrotti, P., De Capitani, L., Giannattasio, C., & Roghi, A. (2017). Comprehensive evaluation of cardiac involvement in eosinophilic granulomatosis with polyangiitis (EGPA) with cardiac magnetic resonance. European journal of internal medicine39, 51-56.
  2. Groh, M., Pagnoux, C., Baldini, C., Bel, E., Bottero, P., Cottin, V., … & Humbert, M. (2015). Eosinophilic granulomatosis with polyangiitis (Churg–Strauss)(EGPA) Consensus Task Force recommendations for evaluation and management. European journal of internal medicine26(7), 545-553.

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