myocardial and pericardial diseases hippo EM

Myocardial and Pericardial Diseases

Pericarditis

General Overview

  • Definition: Pericarditis is the inflammation of the pericardium, which is a double-walled sac that contains the heart and the roots of the great vessels.

  • Fluid Accumulation: Typically, the pericardial sac holds about 10-15 cc of fluid; an increase in this fluid can be problematic.

Etiologies

  • Idiopathic: No identifiable cause but accounts for many cases.

  • Viral: Common viruses include coxsackievirus, echovirus, cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human immunodeficiency virus (HIV).

  • Bacterial: Especially tuberculosis, responsible for about 70% of cases in developing countries.

  • Fungal: Rare but can occur.

  • Malignancy: Typically indicates metastatic cancer.

  • Posttraumatic: Often following injury to the chest.

  • Medications: Certain drugs can induce pericarditis, including procainamide, hydralazine, isoniazid, and phenytoin.

  • Autoimmune: Conditions like systemic lupus erythematosus (SLE) and rheumatoid arthritis can trigger pericarditis.

  • Metabolic: Disorders such as hypothyroidism or uremia.

  • Dressler’s Syndrome: A specific type of pericarditis that occurs after a myocardial infarction (MI).

Clinical Presentation

  • Chest Pain: Characterized as sharp retrosternal pain that may radiate to the neck, back, shoulder, or arm. The pain is notably worse when lying supine and relieved by sitting up and leaning forward.

  • Pleuritic Pain: Pain can be exacerbated by movement and swallowing.

  • Friction Rub: An intermittent sound best heard at the left lower sternal border when the patient leans forward.

  • Other Symptoms: Patients may also experience dyspnea, low-grade fevers, and dysphagia.

Diagnosis

  • Electrocardiogram (EKG) Stages:
      - Stage 1: Visible PR depression in leads II, aVF, V4-6, and diffuse ST elevations (greater than 0.25 amp).
      - Stage 2: Normalization of ST and PR intervals.
      - Stage 3: T wave inversion where ST elevations previously occurred.
      - Stage 4: Return to normal EKG.

  • Spodick Sign: A downsloping TP segment seen in approximately 30% of patients, best visualized in lead II and lateral precordial leads.

  • Chest X-ray (CXR): Usually normal unless an effusion is present.

  • Echocardiogram: To assess for any pericardial effusion.

  • Troponin Test: A positive troponin level or persistent tachycardia indicates the need to evaluate for myocarditis.

Treatment

  • First-Line:
      - NSAIDs: Ibuprofen at 400-800 mg TID for 7-14 days; thereafter, decrease dose by 200-400 mg every 1-2 weeks.
      - Colchicine: Dosing of 0.5 mg daily if the patient weighs less than 70 kg or 0.5 mg twice daily if over 70 kg for 3 months.

  • Second-Line:
      - Corticosteroids: Considered if NSAIDs and colchicine are not effective.

  • Admission: Required for patients displaying myocarditis, significant cardiomegaly, pericardial effusion, uremia, or hemodynamic instability.

Constrictive Pericarditis

General Overview

  • Definition: A condition characterized by abnormal diastolic filling due to inflammation or injury of the pericardium.

Etiologies

  • Similar to pericarditis, including idiopathic, trauma, viral, bacterial, fungal causes, and uremia. Conditions post-surgery can also lead to constrictive pericarditis.

Clinical Presentation

  • Symptoms: Include dyspnea upon exertion, pedal edema, hepatomegaly, jugular venous distension (JVD), and Kussmaul's sign (an increase in JVD with inspiration).

  • The clinical presentation may mimic right-sided heart failure or restrictive cardiomyopathy.

Diagnosis

  • ECG: Typically nonspecific but may reveal inverted T waves and low QRS voltage.

  • CXR: Often normal but may show signs of pericardial calcifications.

  • Echocardiogram: Can reveal a thickened pericardium and abnormal septal motion.

  • CT and MRI: Considered the best imaging modalities.

Treatment

  • First-line: NSAIDs and colchicine.

  • Surgical: Pericardiectomy may be necessary if there is significant constriction or impaired ventricular filling.

Pericardial Tamponade

General Overview

  • Definition: Occurs when fluid accumulation in the pericardial space raises pressure on the right ventricle, restricting its filling and diminishing cardiac output.

Etiologies

  • Can be idiopathic, associated with bacterial infections, malignancies, radiation therapy, anticoagulation effects, uremia, myxedema, or lupus.

Clinical Presentation

  • Symptoms: Commonly includes dyspnea with varying shocks, where tachycardia, decreased systolic blood pressure (SBP), narrow pulse pressure, JVD, right upper quadrant (RUQ) pain, and distant heart sounds are present.

  • Pulsus Paradoxus: Noted as a decrease in systolic BP by more than 10 mmHg during inspiration.

Diagnosis

  • ECG: Tachycardia is generally the most prevalent finding, often accompanied by low-voltage QRS complexes.

  • Electrical Alternans: Considered classic but uncommon.

  • CXR: Shows possible cardiomegaly.

  • Echocardiogram: The test of choice for diagnosing pericardial tamponade; may show
      - The myocardium-epicardium distance indicating fluid volume, and effusion measurements (3e20 mm indicates a large effusion),
      - Right ventricular collapse in diastole or atrial collapse early in diastole/systole,
      - Plethoric inferior vena cava with lack of inspiratory variation.

Treatment

  • Resuscitative Measures: Administer intravenous fluids to restore right heart filling and improve hemodynamic stability.

  • Avoidance of Mechanical Ventilation: If feasible, to prevent increased intrathoracic pressure which reduces venous return and cardiac output.

  • If Hemodynamically Stable: Conduct pericardiocentesis by an interventional cardiologist or create a pericardial window.

  • If Hemodynamically Unstable: Perform bedside pericardiocentesis.

Myocarditis

General Overview

  • Definition: Inflammation of the myocardium, often leading to dilated cardiomyopathy and potential sudden cardiac death.

Etiologies

  • Viral Causes: Commonly associated with infections from Coxsackievirus B, adenovirus, influenza, HIV, hepatitis viruses, Parvovirus B19, CMV, and EBV.

  • Bacterial: Includes Borrelia burgdorferi, Streptococcus pyogenes, and Mycoplasma pneumoniae.

  • Parasitic Infections: Such as Trypanosoma cruzi (Chagas disease) and toxoplasmosis.

  • Autoimmune Diseases: SLE, scleroderma, and giant cell arteritis.

  • Toxic Causes: Doxorubicin, antiretroviral medications, clozapine, and cocaine exposure can induce myocarditis.

  • Idiopathic: Cases where the cause cannot be determined.

  • Common Associations: Myocarditis is often found alongside pericarditis.

Clinical Presentation

  • Symptoms: The presentation can vary widely - often includes dyspnea, chest pain (pleuritic or anginal), myalgias, palpitations, headaches, and fever.

  • Unresolving Tachycardia: Frequently occurs and is disproportionate to the fever.

  • History: Often there is a recent respiratory or gastrointestinal viral illness leading up to myocarditis.

  • Severe Cases: May evolve into congestive heart failure (CHF).

Diagnosis

  • Troponin Levels: Positive in most cases, not always elevated.

  • Electrocardiogram (ECG): Generally can be normal, but sinus tachycardia is common. Non-specific ST-T wave changes may be visible.

  • Chest X-ray (CXR): May show signs of cardiomegaly or pulmonary edema.

  • Echocardiogram: Can reveal normal or decreased ejection fraction (EF), chamber enlargement, regional wall motion abnormalities, or global hypokinesis.

  • Myocardial Biopsy: Traditionally considered the gold standard for diagnosis.

  • Cardiac MRI: Emerging as the preferred study due to the risks associated with biopsy.

Treatment

  • Supportive Care: Includes standard heart failure therapy, supplemental oxygen, and non-invasive positive pressure ventilation.

  • Pacing: Transcutaneous or transvenous pacing may be warranted.

  • Antidysrhythmic Medications: To manage arrhythmias.

  • Antiviral Therapy: May include interferon alfa or ribavirin during the acute phase.

  • Antimicrobial Therapy: Necessary if there is a secondary bacterial or parasitic infection.

  • Advanced Supports: ECMO, intra-aortic balloon pump, or ventricular assist devices may be required in cases of cardiovascular collapse.

References

  1. Singh M, Niemann JT. Chapter 55: Cardiomyopathies and Pericardial Disease. In: Tintinalli JE, Ma OJ, Yealy DM, Meckler GD, Stapczynski JS, Cline DM, Thomas SH, eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. New York, NY: McGraw-Hill; 2020.

  2. Ismail TF. Acute pericarditis: Update on diagnosis and management. Clin Med (Lond). 2020;20(1):48-51. PMID: 31941732.

  3. Chiabrando JG, Bonaventura A, et al. Management of Acute and Recurrent Pericarditis: JACC State-of-the-Art Review. J Am Coll Cardiol. 2020;75(1):76-92. PMID: 31918837.

  4. Caforio AL, Pankuweit S, et al. Current state of knowledge on aetiology, diagnosis, management, and therapy of myocarditis: a position statement of the European Society of Cardiology Working Group on Myocardial and Pericardial Diseases. Eur Heart J. 2013;34(33):2636-2648d. PMID: 23824828.