Cardiovascular · Topic 25 of 48

Acute Pericarditis

Cardiovascular · pericardial disease

Acute Pericarditis

Sharp pleuritic pain that eases leaning forward, diffuse ST elevation with PR depression — treat with an NSAID plus colchicine for 3 months.

Key numbers

Colchicine for 3 monthscolchicine × 3 months

01 · Look forDiffuse ST elevation with PR depression

ECG: diffuse concave ST elevation with PR depression, opposite changes only in aVR (and V1), no reciprocal ST depression elsewhere and no pathologic Q waves.

02 · GiveNSAID or aspirin plus colchicine

First-line: aspirin 325–650 mg every 4–6 hours or ibuprofen 600–800 mg every 6–8 hours, plus colchicine, with a PPI for gastric protection; continue until symptoms, effusion and CRP resolve.

03 · GiveColchicine for 3 months

Add colchicine 0.5 mg twice daily (once daily if 70 kg or less) for 3 months to a first episode; it halves incessant or recurrent pericarditis (ICAP: 16.7% vs 37.5%, NNT about 5).

Causes & risk factors

Why it happens

Admit for high-risk featuresAdmit for moderate or large effusion, fever, subacute onset, immunosuppression, recent trauma, oral anticoagulation, myopericarditis or failure of initial NSAID therapy — to find the cause and watch for tamponade.

Most cases are viral or idiopathicIn the US most acute pericarditis is idiopathic or viral; other causes include MI, cardiac surgery, uremia, autoimmune disease, cancer, radiation, tuberculosis and drugs (hydralazine, procainamide, isoniazid, checkpoint inhibitors).

Presentation

What you'll see

Sharp pleuritic pain, eased by leaning forward must knowPericarditic pain is sharp or dull precordial pain, worse with breathing, coughing or swallowing and relieved by sitting up and leaning forward; it may radiate to the trapezius ridge.

Pericardial friction rubThe key exam finding is a triphasic or systolic–diastolic friction rub; it is often intermittent and may be heard only in systole.

High troponin suggests myopericarditisTroponin is often raised by epicardial inflammation and cannot separate pericarditis from MI or PE; very high troponin or new LV dysfunction suggests myopericarditis.

Diagnosis & monitoring

Work-up

Typical pain plus supporting findings must knowDiagnose with typical pericarditic pain plus supporting findings: friction rub, diffuse ST elevation or PR depression, new or worsening effusion, raised CRP or ESR, or pericardial edema or enhancement on cardiac MRI.

Do right now

In this order

First moves

Diffuse ST elevation with PR depression

→

Echocardiogram for effusion and tamponade

→

Admit for high-risk features

→

NSAID or aspirin plus colchicine

Why each step

Diffuse ST elevation with PR depressionECG: diffuse concave ST elevation with PR depression, opposite changes only in aVR (and V1), no reciprocal ST depression elsewhere and no pathologic Q waves.

Echocardiogram for effusion and tamponadeGet an echocardiogram for effusion, tamponade physiology and wall-motion abnormalities, and CRP to support the diagnosis and guide duration; a purely fibrinous pericarditis can have a normal echo.

NSAID or aspirin plus colchicineFirst-line: aspirin 325–650 mg every 4–6 hours or ibuprofen 600–800 mg every 6–8 hours, plus colchicine, with a PPI for gastric protection; continue until symptoms, effusion and CRP resolve.

Management

Orders

Steroids are not first-lineGlucocorticoids are reserved for NSAID contraindication or noninflammatory refractory disease, at low–moderate dose (prednisone 0.2–0.5 mg/kg/day), after excluding tuberculous and bacterial pericarditis; recurrence is common on taper.

IL-1 inhibitors for recurrent inflammatory pericarditisIf NSAID plus colchicine fails in an inflammatory phenotype (fever, high CRP, pericardial enhancement on MRI), IL-1 inhibitors (anakinra, rilonacept) are the preferred second-line, steroid-sparing therapy.

Red flags & don'ts

Avoid harm

Avoid anticoagulation in acute pericarditis avoidAnticoagulants are usually avoided in acute pericarditis because they can cause intrapericardial bleeding and fatal tamponade; early pericarditis complicating acute MI is the exception.

Pericarditis or STEMI?

Commonly confused

ST elevation	Diffuse, concave, most leads
Reciprocal ST depression	None, except aVR and V1
PR segment	PR depression
Anticoagulation	Usually avoided (hemorrhagic effusion risk)

Teach & follow up

Patient education

Restrict strenuous exercise during treatmentRestrict strenuous exercise and competitive sports while inflammation is active, then return gradually.

More detail

Reference

Show 6 reference facts

Recurrent pericarditis returns after a 4–6 week symptom-free interval (15–30% of idiopathic cases); incessant lasts over 4–6 weeks without remission; chronic persists beyond 3 months.

ECG evolves in 4 stages: diffuse ST elevation with PR depression, ST normalization with T flattening, diffuse T inversion after the ST returns to baseline, then resolution.

Post-cardiac injury syndromes include postpericardiotomy syndrome (5–30% of cardiac operations) and post-MI (Dressler) syndrome, now rare with early reperfusion; aspirin is used for pericarditis with acute MI.

Recurrences are treated with NSAIDs and twice-daily colchicine for 6–12 months with a slow taper; hydroxychloroquine is an option when steroids or IL-1 inhibitors fail.

Tuberculous pericarditis requires pericardial fluid culture for diagnosis; in patients without HIV, adjunctive glucocorticoids help prevent constriction. Uremic pericarditis responds to more frequent dialysis.

Constrictive pericarditis is a later complication: venous congestion, Kussmaul sign and a pericardial knock with preserved ejection fraction; chronic symptomatic disease usually needs pericardiectomy.

Pearl

Lean forward, look for PR depression, and never forget the colchicine.

Sources · Merck Manual Professional — Pericarditis (cites 2025 ESC and 2025 ACC pericarditis guidance) · Imazio M et al. A randomized trial of colchicine for acute pericarditis (ICAP). N Engl J Med 2013;369:1522–1528 — Europe PMC abstract · ACC Journal Scan — 2025 Concise Clinical Guidance: ACC Expert Consensus on the Diagnosis and Management of Pericarditis (JACC 2025;86:2691–2719) · Merck Manual Professional — Acute Myocardial Infarction (MI) · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).