How to manage a patient with myocarditis and multiple myeloma?

Management of Myocarditis in Multiple Myeloma Patients

Patients with myocarditis and multiple myeloma require immediate discontinuation of potentially cardiotoxic therapies, high-dose corticosteroids, and hospital admission for cardiac monitoring. 1

Diagnosis and Initial Assessment

• Cardiac biomarkers: Obtain troponin I or T, brain natriuretic peptide (BNP) or N-terminal pro-BNP, and total CK immediately 1
• ECG: Perform immediately and monitor serially for arrhythmias or conduction abnormalities 1
• Echocardiography: Perform 2D echocardiography to assess ventricular function and exclude other cardiac pathologies 1
• Cardiac MRI with gadolinium: Consider for confirmation of myocarditis diagnosis 2
• Endomyocardial biopsy: May be necessary in unclear cases to rule out other causes like amyloidosis 2

Immediate Management

1. Hospital admission: All patients with suspected or confirmed myocarditis should be admitted for cardiac monitoring 1
2. Discontinue cardiotoxic agents: Immediately stop any potentially cardiotoxic medications, particularly:
   • Proteasome inhibitors (bortezomib, carfilzomib) 2, 3
   • Immunomodulatory drugs if causing cardiovascular complications 4, 5
3. High-dose corticosteroids: Start immediately for confirmed myocarditis 1
   • Methylprednisolone 1000 mg IV daily for 3 days, followed by oral prednisone taper

Supportive Care

• Heart failure management: Standard heart failure therapy with ACE inhibitors/ARBs and beta-blockers as tolerated
• Arrhythmia management: Continuous cardiac monitoring and treatment of arrhythmias as needed 2
• Consultation: Immediate cardiology consultation for collaborative management 1, 5

Multiple Myeloma Treatment Considerations

1. Modify myeloma therapy:

   • Avoid proteasome inhibitors in patients with confirmed myocarditis 2, 3
   • Consider alternative regimens based on risk stratification 1:
     • For standard-risk MM: Lenalidomide-based regimens with careful monitoring
     • For high-risk MM: Alternative non-cardiotoxic combinations

2. Treatment options after myocarditis resolution:

   • For patients not eligible for autologous stem cell transplantation: Oral melphalan and prednisone 1
   • For patients <65 years without severe comorbidities: Consider autologous stem cell transplantation when cardiac function normalizes 1
   • For urgent cytoreduction: High-dose dexamethasone alone or dexamethasone-containing regimens 1

Monitoring and Follow-up

• Serial cardiac biomarkers: Monitor troponin and BNP/NT-proBNP regularly
• Follow-up echocardiography: Assess for recovery of cardiac function
• Regular ECGs: Monitor for development of arrhythmias or conduction abnormalities
• Close monitoring during subsequent MM therapy: Especially when reintroducing potentially cardiotoxic agents 5

Prevention Strategies for High-Risk Patients

• Baseline cardiovascular risk assessment: Prior to initiating MM therapy 5
• Regular cardiac monitoring: During treatment with proteasome inhibitors and immunomodulatory drugs 4
• Dose modification: Consider reduced doses of potentially cardiotoxic agents in patients with pre-existing cardiac disease 3
• Thromboprophylaxis: For patients on immunomodulatory drugs to prevent thromboembolic complications 1

Common Pitfalls and Caveats

1. Delayed diagnosis: Symptoms of myocarditis may be attributed to MM or other comorbidities; maintain high index of suspicion
2. Misdiagnosis: Cardiac amyloidosis can mimic myocarditis in MM patients; consider this in differential diagnosis
3. Underestimation of cardiac risk: Elderly MM patients often have pre-existing cardiovascular disease that increases risk 6
4. Medication interactions: Be aware of potential interactions between cardiac medications and MM therapies
5. Inadequate monitoring: Failure to monitor cardiac function during treatment with cardiotoxic agents

By following this algorithm, clinicians can effectively manage the complex interplay between myocarditis and multiple myeloma, optimizing outcomes for these challenging patients.