Patient handout

Cardiogenic shock — Eosinophilic myocarditis (hypersensitivity / parasitic / HES / EGPA)

PRODUCTION

1. Your condition

This handout is for cardiogenic shock — eosinophilic myocarditis (hypersensitivity / parasitic / hes / egpa). Your care team identified this based on: peripheral absolute eosinophil count >1500/µl (often >5000) + new severe lv dysfunction + shock physiology — eosinophilic myocarditis until proven otherwise.

Other reasons your team may use this plan: dress syndrome (fever + rash + lymphadenopathy + eosinophilia + multi-organ involvement) + new cardiac dysfunction → drug-induced hypersensitivity eosinophilic myocarditis; cardiac mri: lake louise criteria positive (edema on t2 + early gadolinium enhancement + lge) with subendocardial/endocardial-predominant lge pattern + eosinophilia → eosinophilic myocarditis; bedside echo: wall thickening + lv dysfunction + apical mural thrombus (endocardial eosinophil-mediated damage promotes thrombus) + peripheral eosinophilia.

2. Your medications

Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.

Medication	Starting dose	How	When	What it does
methylprednisolone	1 g IV daily × 3–5 d (pulse therapy)	IV	daily × 3–5 d	AHA 2020 myocarditis statement + Brambatti JACC 2017 — pulse steroids are foundation of therapy; dramatic response in 24–72 h in most cases; MUST exclude strongyloides hyperinfection risk first
prednisone	1 mg/kg/d (max 80 mg/d) PO	PO	daily, taper over 6–12 mo	AHA 2020 myocarditis statement — slow taper over 6–12 mo to prevent recurrence; recurrence rate ~25% with rapid taper
imatinib	100–400 mg PO daily	PO	daily	Cools NEJM 2003 — dramatic response in FIP1L1-PDGFRA+ clonal HES; can be sole therapy or steroid-sparing; check echo + EF before to monitor for cardiotoxicity
mepolizumab	300 mg SC q4wk	SC	q4wk	Roufosse NEJM 2008 — anti-IL-5 antibody; steroid-sparing in HES + EGPA; FDA approved for HES (2020) and EGPA (2017)
cyclophosphamide	0.5–1 g/m² IV monthly × 3–6 mo	IV	monthly	EULAR 2016 EGPA + severe organ involvement — induction therapy; combine with steroids; transition to maintenance with rituximab/azathioprine/mepolizumab
rituximab	375 mg/m² IV weekly × 4 (or 1 g IV × 2)	IV	per induction protocol	EULAR 2016 EGPA — alternative or maintenance after cyclophosphamide induction; useful if fertility preservation concern
albendazole	400 mg PO BID × 5–14 d (varies by organism)	PO	BID	WHO antiparasitic guidelines; combine with steroids cautiously after parasite treatment initiated to prevent inflammation flare
ivermectin	200 µg/kg PO daily × 1–2 d (repeat in 2 wks for strongyloides)	PO	daily	CDC strongyloidiasis treatment — empiric in high-risk patients before steroids; prevents fatal hyperinfection syndrome
norepinephrine	0.05–0.5 µg/kg/min titrate to MAP ≥65	IV	continuous	SOAP-II PMID 20200382 — NE first-line in CS; standard CS support while steroids take effect (24–72 h)
warfarin	5 mg daily; INR target 2–3	PO	daily × 3 mo	AHA 2022 Class IIa for LV thrombus; eosinophilic myocarditis carries elevated thrombus risk from endocardial damage (Loeffler endocarditis pattern)
apixaban	5 mg BID (or 2.5 mg BID per dose-reduction criteria)	PO	BID × 3 mo for mural thrombus prophylaxis	Off-label-but-rational DOAC alternative for LV thrombus prophylaxis

Plan: Eosinophilic myocarditis CS — STEROIDS as foundation (after parasite exclusion); etiology-specific add-ons (imatinib for FIP1L1-PDGFRA+ HES; mepolizumab for refractory HES; cyclophosphamide/rituximab for EGPA; antiparasitic for parasitic; drug withdrawal for hypersensitivity); standard CS support per parent

3. When to call your provider

Contact your care team if any of the following happen:

Recurrence with rising eosinophil count → urgent multidisciplinary reassessment + steroid re-pulse
Restrictive cardiomyopathy progression → advanced HF eval (transplant candidacy if young)
Refractory VT/VF → ICD
Chronic kidney disease from cyclophosphamide → renal protective regimen

4. When to seek emergency care

Call 911 or go to the nearest emergency room right away if you have:

FIP1L1-PDGFRA mutation positive (clonal hypereosinophilic syndrome) — add IMATINIB 100–400 mg/d immediately; dramatic response expected within days; can be sole therapy or steroid-sparing
DRESS syndrome (fever + rash + lymphadenopathy + eosinophilia + multi-organ failure including hepatitis + nephritis) with cardiac involvement — DISCONTINUE offending drug + steroids; high mortality if not recognized(life-threatening)
Parasite serology or stool O&P positive (toxocara, schistosoma, trichinella, strongyloides) — initiate organism-specific antiparasitic; coordinate with steroids carefully (treat parasite first or simultaneously to prevent inflammatory flare)
No clinical response to steroids at 72 h + rising troponin + persistent eosinophilia + echo showing endocardial fibrosis pattern → progression to restrictive cardiomyopathy (Loeffler endocarditis); add second-line therapy + advanced HF evaluation(life-threatening)
Recurrent VT/VF or progressive heart block from eosinophilic infiltration of conduction system despite steroid therapy → temporary pacing → permanent pacemaker if persistent; ICD evaluation for VT/VF(life-threatening)

5. Follow-up

Repeat echo at 4–8 wks for LV recovery assessment; CMR at 3 mo for endocardial fibrosis screen (Loeffler endocarditis progression); steroid taper over 6–12 mo (slow taper given recurrence risk); long-term mepolizumab/imatinib if HES; rheumatology long-term care if EGPA; ICD evaluation if persistent severe LV dysfunction or refractory VT/VF; recurrence ~25% if rapid steroid taper

6. Sources

Guideline: ESC 2013 myocarditis position paper (Caforio et al PMID 23824828); AHA 2020 myocarditis scientific statement (Cooper et al); EULAR 2016 EGPA management; Klion 2015 hypereosinophilic syndromes; Brambatti JACC 2017 eosinophilic myocarditis case series