Pericarditis

Definition

Inflammation of the pericardium presenting with characteristic pleuritic chest pain (sharp, relieved by sitting up/leaning forward), which may be accompanied by pericardial friction rub, ECG changes (diffuse ST elevation, PR depression), new pericardial effusion, and elevated inflammatory markers.

Key Concepts

Epidemiology

• Accounts for 0.1% of hospital admissions and 5% of ED chest pain evaluations sources/pericarditis-acc-2025 (very high)
• More common in men aged 16–65 years; incidence declines ~51% per 10-year increase in age
• Recurrent pericarditis is more common in women
• Idiopathic/viral most common in high-income countries; tuberculosis predominates in low-income/TB-endemic countries
• ~15% of cases have concomitant myocarditis (peri-myocarditis or myo-pericarditis, manifested by troponin elevation and LV systolic dysfunction)

Diagnostic Criteria (ACC 2025 — Novel)

ACC 2025 novel diagnostic criteria sources/pericarditis-acc-2025 (very high):

• Mandatory: Pleuritic chest pain or clinical equivalent
• Additional criteria — scored: 0 = unlikely; 1 = possible; ≥2 = definite diagnosis:
  1. Pericardial friction rub (<1/3 of patients)
  2. ECG: diffuse ST-segment elevation and/or PR-segment depression (up to 60%)
  3. Elevated inflammatory markers (CRP, ESR)
  4. New or worsening pericardial effusion on imaging (up to 60%)
  5. Pericardial inflammation on CMR (LGE/edema) or CT
• Key change from ESC 2015 criteria: chest pain is now mandatory; CMR/imaging inflammation incorporated as equal criterion; definite/possible/unlikely scoring introduced

Clinical Classification by Duration

sources/pericarditis-acc-2025 (very high):

• Acute: full symptom resolution within 4 weeks
• Incessant: symptoms persist 4–6 weeks to <3 months before resolution (more aggressive course)
• Chronic: symptoms >3 months
• Recurrent: relapse after ≥4–6 week symptom-free interval following completion of medical therapy
• Recurrence rates: 15–30% after first episode; up to 50% after first recurrence

Phenotypes (clinically important for treatment selection)

sources/pericarditis-acc-2025 (very high):

• Inflammatory phenotype (80–90%): elevated CRP, fever, neutrophilic leukocytosis, effusions → anti-IL-1 agents preferred for refractory disease
• Non-inflammatory phenotype (10–20%): near-normal CRP, often autoimmune-mediated → corticosteroids preferred for refractory disease

Risk Factors for Poor Prognosis and Recurrence

sources/pericarditis-acc-2025 (very high):

• Failure to respond to NSAIDs
• Early use of corticosteroids (increases recurrence risk)
• High CRP
• Severe pericardial LGE on CMR
• Large pericardial effusion with tamponade physiology
• Concomitant myocarditis
• High fever, subacute course

Multimodality Imaging

TTE (First-Line)

• Identifies: pericardial effusion, tamponade physiology, constrictive physiology, myocardial involvement sources/pericarditis-acc-2025 (very high)
• Main limitation: cannot tissue-characterize pericardial inflammation
• Often normal in uncomplicated pericarditis

CMR (Second-Line — Critical for Complex/Recurrent)

• Recommended for: complicated acute, incessant, recurrent, or chronic pericarditis; treatment non-responders; escalation planning; suspected constrictive physiology sources/pericarditis-acc-2025 (very high)
• Key sequences: LGE (inflammation/neovascularization, ideally fat-suppressed PSIR), T2-STIR (edema), black-blood (thickening >3 mm), free-breathing cine (septal shift), myocardial tagging (wall tethering)
• CMR LGE interpretation pattern:
  • LGE+/T2-STIR+: acute/subacute or recurrent flare (active inflammation)
  • LGE+/T2-STIR−: subacute or chronic phase
  • LGE−/T2-STIR−: resolution or end-stage/calcific
• LGE lags behind clinical improvement; a new LGE grading scale has been proposed (2025)
• NOT recommended for routine monitoring in uncomplicated acute pericarditis

CCT (Selected Indications)

• Preferred for pericardial calcifications in constrictive pericarditis and preoperative planning sources/pericarditis-acc-2025 (very high)
• Not recommended for routine pericarditis diagnosis
• Useful for ruling out other chest pain causes (aortic syndromes, PE, CAD)

Management

First-Line (All Patients)

sources/pericarditis-acc-2025 (very high):

• Dual anti-inflammatory therapy: NSAID/aspirin + colchicine
  • Aspirin 500–1,000 mg TID (preferred with concomitant ischemic heart disease); Ibuprofen 600–800 mg TID (alternative); both with weekly tapering after symptom resolution + CRP normalization
  • Colchicine 0.6 mg BID (0.6 mg once daily if <70 kg, renal/hepatic impairment); 3 months (acute), ≥6 months (recurrent)
  • PPI co-prescription for gastric protection
• Exercise restriction: ≥1 month, max HR <100 bpm, until clinical remission
• For autoimmune pericarditis: treat underlying autoimmune disease first

Second-Line Hierarchy (Paradigm Shift 2025)

For recurrent/incessant pericarditis after failure of first-line therapy sources/pericarditis-acc-2025 (very high):

• Inflammatory phenotype (elevated CRP): Anti-IL-1 agents now preferred over corticosteroids
  • Anakinra 1–2 mg/kg/day up to 100 mg; >12 months; LOE A
  • Rilonacept 320 mg once then 160 mg weekly; >12 months; LOE A (RHAPSODY trial)
  • Goflikicept 80 mg every 2 weeks (not yet US-available); LOE B
  • Screen for hepatitis, HIV, TB before initiation
  • Sequential weaning of other agents once established (prednisone → NSAID → colchicine)
  • ~50–75% recurrence upon discontinuation; prolonged therapy (>18 months) associated with better outcomes (RHAPSODY extension)
• Non-inflammatory phenotype (normal CRP) or autoimmune-predominant: corticosteroids (prednisone 0.2–0.5 mg/kg/day with slow taper)

Corticosteroid Caveats

• Reserve for: refractory/intolerant to first-line therapy; non-inflammatory phenotype; autoimmune disease
• Avoid early use in acute pericarditis — increases recurrence risk
• PCP/osteoporosis prophylaxis if >20 mg/day for ≥1 month

Salvage Therapies

• Azathioprine 1–2 mg/kg/day; IVIG 400–500 mg/kg/day × 5 days; LOE C
• Radical pericardiectomy: last resort at high-volume centers; consider for medically refractory disease

Pericarditis in Oncology

sources/pericarditis-acc-2025 (very high):

• Pericarditis in cancer patients is often treatment-related (chemo/immunotherapy/radiation) rather than direct malignant involvement
• Immunotherapy-associated pericarditis: may be subclinical or severe; concomitant myocarditis common
• Radiation pericarditis/constrictive pericarditis when radiation field includes pericardium
• Hemorrhagic or complex effusion increases likelihood of malignant pericardial involvement
• Treatment tailored to etiology; improving underlying disease generally improves pericardial inflammation

Contradictions / Open Questions

• Optimal anti-IL-1 duration: ~50–75% of patients have recurrence upon stopping anti-IL-1 agents; prolonged therapy (>18 months) may be needed but optimal stopping method unknown sources/pericarditis-acc-2025 (very high)
• Colchicine + anti-IL-1 combination: limited evidence for additive benefit; some data suggest reduction in recurrences vs monotherapy, particularly with anakinra sources/pericarditis-acc-2025 (very high)
• CMR LGE grading: newly proposed grading criteria require prospective validation
• Non-inflammatory phenotype management: predominantly expert-consensus driven; limited RCT evidence for corticosteroids in this specific subgroup

Connections

• Related to concepts/Constrictive-Pericarditis
• Related to concepts/Pericardial-Effusion
• Related to concepts/Cancer-Therapy-Related-CV-Toxicity
• Related to concepts/Clonal-Hematopoiesis — IL-1β/inflammasome dysregulation common mechanism

Sources

• sources/pericarditis-acc-2025 — Primary source; 2025 ACC Expert Consensus Statement