Is lactic acidosis present in patients with myopericarditis?

Lactic Acid Elevation in Myopericarditis

Lactic acid elevation is not a characteristic feature or diagnostic marker of myopericarditis based on current clinical guidelines and evidence.

Definition and Pathophysiology of Myopericarditis

Myopericarditis is defined as inflammation of the pericardium with concurrent myocardial involvement. According to the 2015 European Society of Cardiology (ESC) guidelines, it represents a primarily pericarditic syndrome with minor myocardial involvement 1. The diagnosis is established when patients with definite criteria for acute pericarditis show elevated biomarkers of myocardial injury (troponin I or T, CK-MB fraction) without newly developed focal or diffuse impairment of left ventricular function 1.

Diagnostic Markers in Myopericarditis

The key laboratory findings in myopericarditis include:

• Elevated cardiac biomarkers: Troponin I or T and CK-MB are the primary markers of myocardial injury used to diagnose myopericarditis 1
• Inflammatory markers: C-reactive protein (CRP) is often used to guide treatment duration and assess response to therapy 1

Notably, lactic acid or lactic acidosis is not mentioned in any of the guidelines or research evidence as a characteristic feature or diagnostic marker of myopericarditis.

Clinical Presentation and Diagnostic Approach

The classical presentation of myopericarditis includes:

• Chest pain (present in 100% of pediatric cases in one study) 2
• Signs of pericarditis (pericardial rubs, ST-segment elevation, pericardial effusion)
• Elevation of markers of myocardial damage (troponins) 1
• Possible upper respiratory symptoms (25% of cases) or shortness of breath (25% of cases) 2

The 2021 AHA/ACC guideline recommends the following diagnostic approach for suspected myopericarditis 1:

1. Cardiac Magnetic Resonance (CMR) with gadolinium contrast is effective to:

   • Distinguish myopericarditis from other causes including MINOCA
   • Determine the presence and extent of myocardial and pericardial inflammation and fibrosis

2. Transthoracic echocardiography (TTE) is effective to determine:

   • Presence of ventricular wall motion abnormalities
   • Pericardial effusion
   • Valvular abnormalities
   • Restrictive physiology

Etiology and Pathophysiology

Viral infections are among the most common causes of myopericarditis in developed countries 1, 3. Cardiotropic viruses can cause pericardial and myocardial inflammation via:

• Direct cytolytic or cytotoxic effects
• Subsequent immune-mediated mechanisms 1, 3

These inflammatory processes lead to myocardial damage (reflected by troponin elevation) but do not typically cause systemic metabolic derangements like lactic acidosis.

Management Implications

Since lactic acid is not a characteristic feature of myopericarditis, monitoring lactate levels is not part of the standard management approach. Instead, clinicians should focus on:

• Monitoring cardiac biomarkers (troponins)
• Assessing left ventricular function via imaging
• Evaluating inflammatory markers like CRP
• Providing appropriate anti-inflammatory treatment

Clinical Course and Prognosis

Despite markedly elevated cardiac enzymes, the clinical evolution of myopericarditis is generally benign without myocardial dysfunction 2. The inflammatory involvement of the myocardium appears to be self-limited without short-term overt sequelae 2, 3. Unlike in acute coronary syndromes, elevated troponin levels in myopericarditis do not seem to carry an adverse prognosis 2.

In conclusion, while myopericarditis is characterized by elevated cardiac biomarkers (troponins), there is no evidence in current guidelines or research that lactic acid elevation or lactic acidosis is a feature of this condition.