Inflammation of the pericardium — pleuritic chest pain improved by leaning forward, friction rub, diffuse ST elevation with PR depression.
Also known as: acute pericarditis, pericarditis, viral pericarditis
Overview
Inflammation of the pericardial sac with or without pericardial effusion, defined by at least 2 of: characteristic chest pain, pericardial friction rub, new widespread ST elevation or PR depression on ECG, or new/worsening pericardial effusion.
Epidemiology
Accounts for ~5% of ED chest pain visits with non-ischemic etiology. Most often idiopathic or viral; men 20-50 years most commonly affected.
Try two board-style Acute Pericarditis questions
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Question 1CardiovascularMedium
A 44-year-old woman has 3 days of sharp left-sided chest pain that worsens when she lies flat and improves when she leans forward, two weeks after a viral upper respiratory illness. ECG shows diffuse ST-segment elevation with PR-segment depression. Troponin I is mildly elevated at 0.06 ng/mL (upper reference limit 0.04 ng/mL). Which of the following is the most likely diagnosis?
ACostochondritis
BST-elevation myocardial infarction
CMyopericarditis
DTakotsubo cardiomyopathy
EPulmonary embolism
Reveal answer & full explanation
Correct answer: C — Myopericarditis
ACostochondritis
BST-elevation myocardial infarction
CMyopericarditis✓
DTakotsubo cardiomyopathy
EPulmonary embolism
Why myopericarditis is correct
Positional, pleuritic chest pain (worse supine, better leaning forward) after a recent viral illness, with diffuse ST-segment elevation and PR-segment depression, is the classic picture of acute pericarditis
The mildly elevated troponin indicates accompanying myocardial inflammation, making this myopericarditis rather than isolated pericarditis
Management is NSAIDs plus colchicine, with exercise restriction for at least 1 month and until clinical remission (ESC 2025), longer while myocardial involvement persists
Why the others are wrong
Costochondritis — reproducible chest-wall pain that does not cause diffuse ST elevation, PR depression, or troponin elevation (premature closure on a benign musculoskeletal cause)
ST-elevation myocardial infarction — coronary occlusion produces convex ST elevation confined to a vascular territory with reciprocal depression and a markedly higher troponin, not diffuse concave elevation with PR depression (anchoring on the ST elevation itself)
Pulmonary embolism — shares pleuritic pain, but the ECG would show sinus tachycardia or right-heart strain rather than diffuse ST elevation with PR depression (buzzword-matching pleuritic pain)
Takotsubo cardiomyopathy — stress cardiomyopathy also produces ST elevation with a modest troponin rise, mostly in women, but it typically follows an emotional or physical stressor, causes nonpositional ischemic-type pain, and PR depression is not part of its ECG picture; positional pain after a viral illness with diffuse ST elevation and PR depression is pericardial (pattern-matching ST elevation plus troponin in a woman)
Question 2CardiovascularMedium
A 38-year-old man presents with 2 days of sharp, pleuritic chest pain that improves when he sits up and leans forward, 3 weeks after a viral upper respiratory infection. Temperature is 37.6°C. ECG shows diffuse saddle-shaped ST-segment elevation with PR-segment depression. Echocardiography shows a small pericardial effusion without chamber collapse. Troponin is normal. Which of the following is the most appropriate initial treatment?
ANSAIDs plus colchicine
BColchicine monotherapy
CIntravenous antibiotics
DUrgent pericardiocentesis
EHigh-dose corticosteroids
Reveal answer & full explanation
Correct answer: A — NSAIDs plus colchicine
ANSAIDs plus colchicine✓
BColchicine monotherapy
CIntravenous antibiotics
DUrgent pericardiocentesis
EHigh-dose corticosteroids
Why NSAIDs plus colchicine is correct
The picture is acute viral (idiopathic) pericarditis: pleuritic positional chest pain, low-grade fever, diffuse saddle-shaped ST elevation with PR depression, a small effusion, and normal troponin after a viral URI
First-line therapy is an NSAID at anti-inflammatory doses plus colchicine for 3 months, per current ESC pericardial disease guidance
Adding colchicine roughly halves the recurrence rate (COPE trial)
Exercise is restricted for at least 1 month and until clinical remission (ESC 2025), judged individually by symptoms and CRP
Why the others are wrong
Urgent pericardiocentesis — drainage is for tamponade, suspected purulent or malignant effusion, or large symptomatic effusions; a small effusion without chamber collapse needs none (trap: anchoring on the word "effusion")
Intravenous antibiotics — a post-viral presentation with low-grade fever and stable hemodynamics is viral, not purulent, pericarditis (trap: buzzword-matching fever to a bacterial infection)
High-dose corticosteroids — steroids increase the recurrence rate and are reserved for NSAID/colchicine failure or contraindication, or specific indications such as autoimmune disease (trap: right-diagnosis-wrong-step, reaching for the strongest anti-inflammatory first)
Colchicine monotherapy — colchicine is the agent that roughly halves recurrence, which makes it tempting to use alone, but it is recommended as an adjunct to an anti-inflammatory dose of an NSAID or aspirin, not as a stand-alone first-line regimen for the acute attack (trap: right-drug-wrong-regimen, dropping the NSAID backbone)
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Tuberculosis (most common cause worldwide in endemic regions)
Radiation therapy, certain drugs (hydralazine, procainamide, isoniazid)
Pathophysiology
Inflammation of the visceral and parietal pericardium produces increased capillary permeability, fibrin deposition, and exudate. The roughened layers generate friction rub. Phrenic nerve (C3-C5) sensory fibers from the inflamed parietal pericardium refer pain to the trapezius ridge. Inflammation may extend to the epicardium (myopericarditis) or produce significant effusion.
Clinical presentation
Symptoms
Sharp, pleuritic, retrosternal or left precordial chest pain
Worse supine, better leaning forward
Radiation to trapezius ridge (highly specific — phrenic nerve)
Low-grade fever, dyspnea, fatigue
Antecedent viral prodrome (URI, GI symptoms) common
Signs / physical exam
Pericardial friction rub — three-component, scratchy, best at LLSB with patient leaning forward
Tachycardia
Low-grade fever
Signs of effusion (muffled heart sounds, Beck triad) if progressing to tamponade
Differential diagnosis
Acute coronary syndrome / STEMI — Regional (not diffuse) ST elevation with reciprocal changes; high troponin; risk factor profile
Pulmonary embolism — Pleuritic pain with dyspnea and hypoxia; S1Q3T3, right heart strain; D-dimer / CTPA
Pneumonia / pleurisy — Fever with productive cough, focal lung findings, infiltrate on CXR
Early repolarization variant — ST elevation on ECG in young men WITHOUT PR depression or evolution; benign
Myocarditis / myopericarditis — Pericarditis features + elevated troponin and possibly LV dysfunction
Costochondritis — Reproducible chest wall tenderness, no rub, normal ECG
Diagnostic workup
Diagnostic criteria
Classic 2015 ESC criteria (still the most widely taught): ≥2 of 4: (1) sharp pleuritic pain improved leaning forward, (2) pericardial friction rub, (3) new widespread ST elevation or PR depression, (4) new/worsening pericardial effusion. Supporting features: elevated CRP/ESR, evidence of pericardial inflammation on CT or CMR. The 2025 ESC guidelines count elevated CRP and pericardial edema/LGE on CMR as additional criteria: a compatible presentation (typically pericarditic chest pain) plus ≥2 of rub, ECG changes, elevated CRP, new/worsening effusion, or CMR pericardial inflammation = definite pericarditis; plus only 1 = possible.
CBC, CRP, ESR (elevated CRP supports diagnosis and guides response to therapy)
BMP, BUN/Cr (uremic etiology)
ANA, RF, TSH if autoimmune cause suspected; HIV and TB testing in appropriate populations
Blood cultures if febrile and effusion present
Imaging
12-lead ECG — diffuse concave ST elevation with PR segment depression (PR elevation in aVR is reciprocal — early sign)
Echocardiography — assess for pericardial effusion and ventricular function (rule out tamponade and myocarditis)
CXR — typically normal; cardiomegaly only with large effusion
Cardiac MRI — late gadolinium enhancement of pericardium; useful for myopericarditis or recurrent disease
Chest CT for suspected purulent or constrictive disease
Diagnostic algorithm
Feature
Pericarditis
STEMI
Early repolarization
ST elevation distribution
Diffuse, concave
Regional, convex
Often precordial
PR depression
Present (PR elevation in aVR)
Absent
Absent
Reciprocal ST depression
Absent (except aVR, V1)
Present
Absent
Q waves
Absent
May develop
Absent
Troponin
Normal or mildly elevated
Markedly elevated
Normal
Evolution
Diffuse ST resolves over days then T inversion
ST resolves, Q waves and T inversion form
Stable over time
ECG and biomarker comparison: pericarditis vs STEMI vs benign early repolarization.
Treatment
First-line
NSAIDs — ibuprofen 600-800 mg PO TID × 1-2 weeks then taper, OR aspirin 750-1000 mg PO TID (preferred post-MI pericarditis)
Colchicine 0.5 mg PO BID (0.5 mg daily if <70 kg) × 3 months — added to NSAID for FIRST episode reduces recurrence (COPE / ICAP trials)
Proton pump inhibitor while on high-dose NSAIDs
Restrict strenuous/competitive exercise for at least 1 month and until clinical remission (ESC 2025), judged individually by symptoms, CRP, ECG and echo; 1 month is a minimum, not a clearance date; with troponin rise, follow the myocarditis return-to-play pathway
Treat underlying cause: dialysis for uremia, antimicrobials for purulent, TB therapy if confirmed
Second-line / adjunct
Corticosteroids (prednisone 0.25-0.5 mg/kg/day with slow taper) — reserved for NSAID/colchicine failure, contraindication, or specific indications such as active systemic autoimmune disease (uremic pericarditis is treated with dialysis) — increases recurrence risk in idiopathic disease
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