What causes pericarditis in a 31-year-old female with left-sided chest pain and left shoulder pain?

How Pericarditis Develops

Pericarditis develops through multiple pathways, with viral infections being the most common cause in developed countries (accounting for most idiopathic cases), while tuberculosis is the leading cause worldwide, particularly in developing regions. 1, 2

Infectious Causes

Viral Pericarditis

• Viruses are the predominant infectious etiology in North America and Western Europe, including enteroviruses, Coxsackie viruses (A and B), echoviruses, adenoviruses, cytomegalovirus, Epstein-Barr virus, herpes simplex virus, influenza, parvovirus B19, hepatitis C, and HIV 1
• Viral pericarditis results from direct viral attack on pericardial tissue and/or immune-mediated responses (antiviral or anticardiac antibodies) 1
• Enteroviral pericarditis follows seasonal epidemics of Coxsackie and Echovirus infections 1
• In your 31-year-old female patient, a recent viral illness would be the most likely trigger 3

Bacterial Pericarditis

• Tuberculosis causes 70-80% of pericarditis cases in sub-Saharan Africa, often associated with HIV infection 1
• Bacterial causes include Staphylococcus aureus, Klebsiella pneumoniae, Mycobacterium avium, and Streptococcus pneumoniae 1, 4
• Purulent pericarditis from bacterial pneumonia occurs via intrathoracic spread and carries high mortality without antibiotics 4

Non-Infectious Causes

Autoimmune and Inflammatory Disorders

• Approximately 5-15% of acute or recurrent pericarditis cases involve systemic autoimmune diseases, including systemic lupus erythematosus, Sjögren syndrome, rheumatoid arthritis, scleroderma, systemic vasculitides, Behçet syndrome, and sarcoidosis 1
• These conditions trigger pericardial inflammation through immune-mediated mechanisms with pro-inflammatory cytokines and autoantibodies 5
• Pericardial involvement typically reflects the activity level of the underlying systemic disease 1

Post-Cardiac Injury Syndromes

• Post-cardiac injury syndromes develop through autoimmune pathogenesis triggered by initial tissue damage from myocardial necrosis, surgical trauma, accidental thoracic trauma, or iatrogenic procedures 1, 2
• These include post-myocardial infarction pericarditis (Dressler syndrome), post-pericardiotomy syndrome, and post-traumatic pericarditis 1
• The mechanism involves a latent period of several weeks before manifestations appear, supporting immune-mediated pathogenesis 1
• Pericardial bleeding and pleural incision are key triggers for these syndromes 1
• Emerging iatrogenic causes include percutaneous coronary interventions, pacemaker insertion, and catheter ablation 1, 2

Neoplastic Causes

• Primary tumors (especially pericardial mesothelioma) and secondary metastatic tumors from lung cancer, breast cancer, and lymphomas can cause pericarditis 1, 2
• Malignancy accounts for 10-25% of pericardial effusions in developed countries 6

Metabolic Disorders

• Uremia, myxedema (hypothyroidism), and anorexia nervosa can trigger pericardial inflammation 1, 2
• Uremic pericarditis occurs in renal failure patients, both before and during dialysis 6

Drug-Induced Pericarditis

• Lupus-like syndrome from procainamide, hydralazine, methyldopa, isoniazid, and phenytoin 1, 7
• Antineoplastic drugs (doxorubicin, daunorubicin) often associated with cardiomyopathy 1
• Other medications include amiodarone, methysergide, mesalazine, clozapine, and anti-TNF agents 1

Cardiovascular Causes

• Hypertension and chronic heart failure are associated with pericarditis development 1, 2

Clinical Context for Your Patient

For a 31-year-old female with left-sided chest pain and left shoulder pain, the most likely causes in order of probability are:

1. Idiopathic/viral pericarditis (most common in this demographic) 3
2. Autoimmune disease (particularly if she has other systemic symptoms) 1
3. Post-viral immune-mediated response (even without active viral replication) 1, 5

Men aged 16-65 years have higher risk than women, making viral or idiopathic causes even more likely in your female patient 2. The left shoulder radiation is classic for pericarditic chest pain due to phrenic nerve irritation 1.