Pericarditis

GENERAL PRINCIPLES

• A diagnosis of acute pericarditis (inflammation of the pericardium) can be made with at least two of the following four criteria: pleuritic chest pain, pericardial rub, new widespread ST-segment elevation or PR depression, and new or worsening pericardial effusion.

• Viruses are the most common infectious etiology. Staphylococci, S. pneumonia, M. tuberculosis, and histoplasmosis are occasional causes.

TREATMENT

• If an infectious etiology is identified, specific treatment should be initiated. The role of antiviral therapies in viral pericarditis remains unclear.

• Aspirin (750-1000 mg q8h for 1-2 weeks) or NSAIDs (ibuprofen 600 mg q8h for 1-2 weeks) are recommended as first-line therapy for acute pericarditis.

• Adjuvant colchicine (0.5 mg PO qday [from viral pharyngitis on clinical grounds alone is difficult.

Diagnostic Testing

• Diagnostic testing is usually reserved for symptomatic patients with exposure to a case of streptococcal pharyngitis, those with signs of significant infection (fever, tonsillar exudates, and cervical adenopathy) or whose symptoms persist despite symptomatic therapy, and patients with a history of rheumatic fever. Testing for SARS-CoV-2 should be considered.

• Rapid antigen detection testing (RADT) is useful for diagnosing GABHS (>90% sensitivity and specificity), which requires antimicrobial therapy to prevent suppurative complications and rheumatic fever. A negative test does not reliably exclude GAS, making throat culture necessary if clinical suspicion is high.

• Serology for Epstein-Barr virus (e.g., heterophile agglutinin or monospot) and examination of a peripheral blood smear for atypical lymphocytes should be performed when infectious mononucleosis is suspected.

• A NAAT pharyngeal swab for gonococcal pharyngitis is recommended in those with risk factors for sexual transmitted diseases, particularly receptive oral intercourse.

TREATMENT

• Most cases of pharyngitis are self-limited and do not require antimicrobial therapy.

• Treatment for GABHS is indicated with a positive culture or RADT, if the patient is at high risk for development of rheumatic fever, or if the diagnosis is strongly suspected, pending culture results. Treatment options include penicillin V 500 mg PO q12h for 10 days, clindamycin 300 mg PO q8h for 10 days, azithromycin 500 mg PO on day 1 followed by 250 mg qday on days 2-5, or benzathine penicillin G 1.2 million units IM as a one-time dose.¹⁶ In some communities, up to 15% of the GABHS isolates are resistant to macrolides.

• Gonococcal pharyngitis is treated with ceftriaxone 500 mg IM as a single dose, plus doxycycline for 7 days or a single dose of azithromycin (if the patient is pregnant) if coinfection with chlamydia is identified.