Cardiovascular

Acute pericarditis: diagnosis and outpatient management

Clinical Overview and When to Suspect Acute Pericarditis

— Sharp, pleuritic chest pain (often positional, worse supine, relieved leaning forward)

— Pericardial friction rub on auscultation

— New widespread ST elevation or PR depression on ECG

— New or worsening pericardial effusion on imaging

— Viral (coxsackie, echovirus, EBV, influenza, SARS-CoV-2)

— Post-cardiac injury syndromes (post-MI Dressler, post-pericardiotomy, post-ablation)

— Autoimmune (SLE, RA, scleroderma, IBD)

— Uremic (BUN typically >60), malignancy (lung, breast, lymphoma)

— TB (consider in immigrants, HIV+, immunocompromised)

— Radiation, drug-induced (hydralazine, procainamide, isoniazid, immune checkpoint inhibitors)

— Young adult, viral URI 1–2 weeks prior, now sharp anterior chest pain better leaning forward

— Post-MI patient days 2–4 (early post-infarction pericarditis) or weeks later (Dressler)

— Recent cardiac surgery, ablation, or PCI with chest pain + low-grade fever

— Lupus flare with pleuritic pain and effusion

Step 3 management: Most idiopathic/viral acute pericarditis cases in hemodynamically stable patients without high-risk features are managed entirely outpatient with NSAIDs + colchicine and a 1-week follow-up — but you MUST screen for high-risk features (covered in chunk 6) before sending home. Missing tamponade physiology or large effusion is the classic Step 3 cognitive error here.

Definition: Inflammation of the pericardium presenting with chest pain, friction rub, ECG changes, or pericardial effusion. Diagnosis requires ≥2 of 4 criteria:

Epidemiology: ~5% of non-ischemic chest pain ED visits; most common in men aged 20–50. Recurrence in 15–30% after first episode without colchicine.

Etiology in the US (~80–90% idiopathic/presumed viral):

When to suspect on Step 3 stems:

Initial framing question: Is this uncomplicated (low-risk, outpatient candidate) or high-risk (admit)? This determines disposition before any further workup.

Presentation Patterns and Key History

— Pleuritic — worse with inspiration, cough

— Positional — worse supine, relieved sitting up and leaning forward

— Pointed/sharp — retrosternal or left precordial

— Persistent — hours to days, not minutes like angina

— Low-grade fever (>38°C is a high-risk feature)

— Recent URI or GI viral prodrome 1–3 weeks prior

— Dyspnea (may suggest effusion)

— Palpitations

— Post-MI early (24–96 hr): Transmural infarct, often anterior; pain returns after initial resolution

— Dressler (2–8 weeks post-MI or cardiac surgery): Autoimmune; fever, malaise, pleuritis

— Uremic: Missed dialysis sessions, BUN typically >60 mg/dL

— TB pericarditis: Subacute fever, weight loss, night sweats, HIV, immigrant from endemic area

— Autoimmune: Rash, arthralgias, Raynaud, oral ulcers — order ANA/dsDNA

— Drug-induced lupus: Hydralazine, procainamide, isoniazid, minocycline (anti-histone Ab+)

— Neoplastic: Bloody effusion, weight loss, known malignancy

— Immune checkpoint inhibitors (pembrolizumab, nivolumab) — rising cause

— Recent cardiac procedures (ablation, CABG, PCI with perforation)

— Chest radiation history (early or delayed up to years)

— Reproducible with position change, not exertional, not relieved by rest

— Pain lasting days, not crescendo over minutes

Board pearl: Trapezius ridge radiation + relief leaning forward in a young patient post-URI = pericarditis until proven otherwise. Do not anchor on this, however — always still obtain troponin and ECG to rule out myopericarditis and ACS, both of which can mimic and coexist.

Classic chest pain features (4 P's of pericarditis):

Radiation: Trapezius ridge radiation is pathognomonic (phrenic nerve innervation of pericardium).

Associated symptoms:

High-yield historical clues by etiology:

Medication and exposure review:

Pertinent negatives that lower pretest probability for ACS:

Physical Exam Findings and Hemodynamic Assessment

— Triphasic in ~50%: atrial systole, ventricular systole, early diastolic filling

— Scratchy/leathery, best heard at left lower sternal border, patient leaning forward, end-expiration

— Highly specific but evanescent — listen repeatedly; absence does not exclude pericarditis

— Distinguishes from pleural rub: persists when patient holds breath

— Tachycardia common

— Low-grade fever typical; T >38°C is a high-risk feature suggesting purulent or systemic process

— Hypotension, tachypnea, cool extremities → suspect tamponade

— Hypotension

— Muffled heart sounds

— JVD with prominent x descent, absent y descent

— Drop in SBP >10 mmHg with inspiration

— Measured with manual cuff: note pressure at which Korotkoff sounds heard only in expiration, then where heard throughout — difference is pulsus

— Also seen in severe asthma, COPD, RV infarct, constriction (rarely)

— Kussmaul sign (paradoxical JVP rise with inspiration) — suggests constrictive pericarditis, not acute uncomplicated

— Ewart sign — dullness/bronchial breathing below left scapula from large effusion compressing LLL

— Skin (malar rash, livedo), joints (synovitis), thyroid, lymph nodes

Key distinction: Acute pericarditis ± small effusion = manage as pericarditis. Tamponade physiology = emergency pericardiocentesis, regardless of effusion size. Tamponade is a clinical + echocardiographic diagnosis (RA/RV diastolic collapse, IVC plethora, respirophasic transvalvular flow variation), not defined by effusion volume alone. A rapidly accumulating 200 mL effusion can tamponade while a chronic 800 mL effusion may be hemodynamically silent.

Pericardial friction rub — the signature finding:

Vitals and general appearance:

Signs of hemodynamically significant effusion / tamponade (Beck triad):

Pulsus paradoxus:

Other findings:

Targeted exam in suspected systemic etiology:

Diagnostic Workup — Initial Labs, Imaging, ECG, Biomarkers

— Stage 1 (hours–days): Diffuse concave-up ST elevation + PR depression (PR elevation in aVR is the reciprocal — highly specific)

— Stage 2: ST and PR normalize

— Stage 3: Diffuse T-wave inversions

— Stage 4: ECG returns to baseline

— Pericarditis: diffuse ST elevation (not in a coronary distribution), concave-up, no reciprocal depression (except aVR/V1), PR depression, no Q waves

— STEMI: regional, convex/tombstone, reciprocal changes, evolves to Q waves

— Spodick sign: down-sloping TP segment — supports pericarditis

— Troponin — elevation indicates myopericarditis (myocardial involvement); doesn't necessarily worsen prognosis in acute pericarditis but mandates admission and echo

— CBC (leukocytosis), CRP/ESR — CRP elevated in ~75%; used to track response and guide duration of therapy

— BMP (uremia screen), LFTs

— TSH if effusion present (myxedema)

— HIV in appropriate populations

— Often normal; cardiac silhouette enlarges only when effusion >200 mL ("water bottle heart")

— Evaluates for pneumonia, mass, pulmonary edema

— Detects effusion, size, location, hemodynamic impact

— Assesses LV function (myopericarditis)

— Normal echo does NOT exclude pericarditis (~40% have no effusion)

Step 3 management: ECG + troponin + CRP + CXR + echo is the initial outpatient bundle. If troponin is elevated → reclassify as myopericarditis, admit, cardiology consult, restrict exercise. If CRP is normal but clinical picture fits, diagnosis still stands — but CRP is your tool to time NSAID/colchicine tapering at follow-up.

ECG — order in every suspected case; evolves in 4 classic stages:

ECG distinction from STEMI:

Biomarkers and labs (every patient):

Chest X-ray:

Transthoracic echocardiogram — order in every patient:

Diagnostic Workup — Advanced or Confirmatory Studies

— Idiopathic/viral presumed; no further etiologic workup required if patient is low-risk, responds to NSAIDs, and CRP trends down

— Diagnostic uncertainty (atypical pain, equivocal ECG)

— Suspected myopericarditis with elevated troponin → confirms myocardial late gadolinium enhancement

— Recurrent or incessant pericarditis to assess ongoing inflammation (pericardial LGE, edema on T2)

— Suspected constriction

— Suspected purulent, tuberculous, or neoplastic pericarditis

— Large effusion (>20 mm on echo) without clear etiology

— Therapeutic indication: tamponade

— Send fluid for: cell count, Gram stain, culture, AFB smear/culture + ADA, cytology, glucose, protein, LDH, triglycerides

— Rarely indicated; reserved for persistent (>3 weeks) effusion of unknown etiology after pericardiocentesis

— ANA, RF, anti-dsDNA, complement — if autoimmune features

— Quantiferon-gold or PPD + HIV — if TB risk factors

— BUN/Cr — uremia

— Blood cultures — purulent pericarditis (rare, often post-thoracic surgery, immunosuppressed, S. aureus)

— TSH — myxedema

— Pericardial thickening, calcification (constriction), malignancy staging

Board pearl: Do not order an exhaustive autoimmune/infectious panel on every patient. In a young, otherwise healthy patient with a viral prodrome and classic features, idiopathic pericarditis is a clinical diagnosis — no further etiologic testing is needed if response to first-line therapy is brisk. Save advanced workup for high-risk, recurrent, or treatment-refractory cases. Over-ordering on Step 3 stems is often the wrong answer.

When initial workup is sufficient (most cases):

Cardiac MRI — when to obtain:

Pericardiocentesis — diagnostic indications:

Pericardial biopsy:

Etiology-directed testing (selective, not routine):

CT chest:

Risk Stratification and Outpatient vs Inpatient Decision

— Fever >38°C

— Subacute onset (days–weeks, indolent)

— Large pericardial effusion (>20 mm echo-free space in diastole)

— Cardiac tamponade

— Failure of NSAIDs after ≥1 week of adequate therapy

— Myopericarditis (elevated troponin or new LV dysfunction)

— Immunosuppression

— Trauma (recent chest trauma)

— Oral anticoagulant therapy (hemorrhagic effusion risk)

— None of the above features

— Hemodynamically stable

— Normal or small effusion on echo

— Normal troponin

— Adequate social support and ability to follow up in 1 week

— Low-risk → discharge with NSAID + colchicine, 1-week follow-up with repeat CRP and clinical assessment

— Any high-risk feature → admit for telemetry, serial troponins, echo, etiology workup

— Tamponade → emergent pericardiocentesis, ICU

CCS pearl: On a CCS case, after confirming pericarditis, immediately order ECG, troponin, CBC, CMP, CRP, TSH, CXR, echocardiogram. Then assess for high-risk features. If low-risk: "discharge home, prescribe ibuprofen 600–800 mg TID + colchicine 0.5 mg BID, schedule follow-up in 7 days, counsel exercise restriction." Advance the clock to follow-up. If high-risk: "admit to telemetry, consult cardiology, NPO if pericardiocentesis anticipated."

The most important decision in acute pericarditis is disposition. Per ESC guidelines (adopted in US practice), screen every patient for major and minor predictors of poor prognosis.

Major poor-prognosis features (ANY ONE → admit):

Minor poor-prognosis features (ANY ONE → admit):

Low-risk patient profile (safe for outpatient management):

Disposition workflow:

Pharmacotherapy — First-Line Drug Regimen

— Ibuprofen 600–800 mg PO TID (preferred outpatient) × 1–2 weeks, then taper over 2–4 weeks

— Aspirin 750–1000 mg PO TID × 1–2 weeks then taper — drug of choice in post-MI pericarditis (other NSAIDs impair myocardial healing and are contraindicated)

— Indomethacin 25–50 mg TID — older option, more GI toxicity

— Add PPI (omeprazole 20 mg daily) for gastroprotection in all patients on high-dose NSAIDs

— 0.5 mg BID (≥70 kg) or 0.5 mg daily (<70 kg or intolerant) × 3 months for first episode

— × 6 months for recurrent pericarditis

— Major SE: diarrhea (10%), myotoxicity, neutropenia

— Contraindications/cautions: severe renal impairment (CrCl <30), severe hepatic impairment, concurrent strong CYP3A4 inhibitors (clarithromycin, ritonavir) or P-gp inhibitors → dose-reduce or avoid

— Do NOT use loading doses (older protocols abandoned — caused GI intolerance)

— Treat until symptom-free AND CRP normalized, then taper NSAID over 2–4 weeks

— Continue colchicine full 3 months regardless of symptom resolution

— Reserved for: NSAID/colchicine failure or contraindication, autoimmune etiology, uremic, pregnancy after 20 weeks

— Prednisone 0.2–0.5 mg/kg/day (low-dose preferred); slow taper over months

— Steroids increase recurrence risk when used first-line — major board trap

Board pearl: Three Step 3 high-yield rules: (1) post-MI pericarditis → aspirin, not ibuprofen; (2) always add colchicine; (3) avoid steroids first-line unless contraindication to NSAIDs or autoimmune etiology. Memorize these — they appear repeatedly.

First-line dual therapy: NSAID + colchicine. Combination reduces recurrence by ~50% vs NSAID alone (CORP, ICAP, COPE trials).

NSAID selection (any of):

Colchicine — add to NSAID in all patients without contraindication:

Tapering strategy:

Corticosteroids — second-line, NOT first-line:

Refractory and Recurrent Disease — Expanded Pharmacology

— Incessant: symptoms persist >4–6 weeks despite therapy

— Recurrent: new episode after symptom-free interval ≥4–6 weeks (occurs in 15–30% of first episodes)

— Chronic: >3 months duration

— Step 1: Restart NSAID + colchicine. Colchicine duration extended to 6 months minimum. Confirm patient was compliant first time — non-adherence is the #1 cause of "recurrence."

— Step 2: Add low-dose prednisone 0.2–0.5 mg/kg/day if NSAID/colchicine fails or contraindicated. Taper slowly (months); rapid taper triggers relapse. Maintain colchicine throughout steroid taper.

— Step 3 — biologics for refractory/steroid-dependent disease:

— Anakinra (IL-1 receptor antagonist) — well-established efficacy; 100 mg SC daily; consider in steroid-dependent recurrent pericarditis

— Rilonacept (IL-1α/β trap) — FDA-approved 2021 for recurrent pericarditis; weekly SC dosing

— Azathioprine — steroid-sparing alternative

— IVIG — selected autoimmune cases

— Last resort for refractory recurrent pericarditis or constrictive pericarditis

— Performed at high-volume centers; significant perioperative morbidity

— Pericardiocentesis: Indicated for tamponade, suspected purulent/TB/neoplastic effusion, or large symptomatic effusion. Echo- or fluoro-guided subxiphoid approach. Send fluid for full panel.

— Pericardial window: Surgical drainage for recurrent malignant effusions

— Colchicine: CBC, CK, LFTs, Cr at baseline and periodically

— Anakinra/rilonacept: screen for latent TB, hepatitis before initiation; injection-site reactions common

Step 3 management: A patient with second recurrence despite adherent NSAID + colchicine → add low-dose prednisone + extend colchicine to 6+ months + slow taper. A patient with third recurrence or steroid-dependence → referral to specialized center, consider anakinra or rilonacept. Avoid the trap of escalating steroid doses; low-dose + prolonged taper is correct.

Definitions:

Stepwise approach to recurrence:

Pericardiectomy:

Procedural management when relevant:

Drug-specific monitoring:

Special Populations — Elderly and Renal/Hepatic Impairment

— Higher risk of NSAID adverse effects: GI bleeding, AKI, fluid retention worsening HF, hypertension

— Screen carefully for CKD, HF, prior GI bleed, anticoagulant use before prescribing high-dose ibuprofen

— Consider aspirin 750 mg TID as alternative (more cardiac-friendly), or shorter NSAID course with earlier transition

— Always co-prescribe PPI in patients >65 or with any GI risk factor

— Lower threshold for hospitalization given polypharmacy and frailty

— Consider drug-drug interactions: NSAIDs + ACEi/ARB + diuretic = "triple whammy" AKI risk

— CrCl <30 mL/min: Avoid NSAIDs entirely; consider colchicine + low-dose prednisone as first-line

— Colchicine dose adjustment: CrCl 30–60 → 0.5 mg daily; CrCl <30 → 0.3 mg every other day or avoid; contraindicated in dialysis (poor clearance, accumulation, neuromyotoxicity)

— Uremic pericarditis (ESRD, BUN typically >60): Treatment is intensified dialysis (daily HD for 1–2 weeks), NOT NSAIDs/colchicine. Steroids second-line if refractory.

— Key distinction: Dialysis-associated pericarditis (in stable HD patient) — treat with intensified dialysis ± NSAID

— Severe cirrhosis (Child-Pugh C): avoid NSAIDs (variceal bleed risk, hepatorenal syndrome)

— Colchicine: dose-reduce in severe hepatic impairment; avoid with strong CYP3A4 inhibitors

— Acetaminophen for analgesia (limited anti-inflammatory effect)

— Continue anticoagulation if indication is strong (mechanical valve, recent VTE, AFib with high stroke risk)

— Hold/reduce only if hemorrhagic pericardial effusion or active bleeding

— NSAIDs increase bleeding risk — use lowest effective dose + PPI; consider colchicine + low-dose prednisone alternative

Board pearl: Uremic pericarditis = dialyze, don't NSAID. This is one of the most testable etiology-specific management pearls. Likewise, NSAID-induced AKI in an elderly CKD patient on ACEi/diuretic is a classic Step 3 misstep.

Elderly patients (>65 yr):

Chronic kidney disease:

Hepatic impairment:

Anticoagulated patients:

Special Populations — Pregnancy and Pediatrics

— Incidence rises in second and third trimester

— NSAIDs: Safe up to 20 weeks gestation (ibuprofen, aspirin standard doses). After 20 weeks: avoid due to risk of oligohydramnios, fetal renal injury, and premature closure of ductus arteriosus

— Colchicine: Historically avoided; updated evidence (large FMF cohorts) shows safe in pregnancy and lactation — continue if needed

— After 20 weeks gestation: First-line shifts to low-dose prednisone (preferred) ± colchicine; avoid NSAIDs

— Low-dose aspirin (≤100 mg/day): Safe throughout pregnancy

— Multidisciplinary care: cardiology + maternal-fetal medicine

— Delivery planning: avoid Valsalva-heavy labor if large effusion; epidural anesthesia generally safe

— Most cases idiopathic/viral, similar to adults

— Ibuprofen weight-based 30–50 mg/kg/day divided + colchicine weight-based (0.5 mg daily if <5 yr, 1 mg daily if 5–10 yr, adult dosing >10 yr) × 3 months

— Aspirin avoided in children <16 due to Reye syndrome risk — exception: Kawasaki, rheumatic fever

— Higher rate of recurrence in pediatric population; aggressive colchicine adherence important

— Screen for familial Mediterranean fever in recurrent pediatric pericarditis (especially Mediterranean/Middle Eastern descent) — MEFV gene testing

— Universal exercise restriction during active disease (see chunk 16)

— Return-to-play after CRP normalization, troponin negative, echo without effusion — minimum 3 months if myopericarditis, until symptom-free for uncomplicated

Key distinction: In a pregnant patient at 28 weeks with acute pericarditis, the answer is NOT ibuprofen (causes ductus arteriosus closure). It is prednisone + colchicine, or low-dose aspirin if mild. In a child with chest pain, never reach for aspirin — Reye risk. These swaps are frequent Step 3 distractors.

Pregnancy:

Postpartum: Increased relapse risk; continue colchicine through breastfeeding (compatible)

Pediatrics:

Athletes and young adults:

Complications and Adverse Outcomes

— Present in ~60% of acute pericarditis cases; most are small and asymptomatic

— Size by echo: small <10 mm, moderate 10–20 mm, large >20 mm (diastolic echo-free space)

— Large effusion is a high-risk feature mandating admission

— Life-threatening; clinical + echocardiographic diagnosis

— Echo: RA collapse (systole), RV diastolic collapse, IVC plethora >2.1 cm without inspiratory collapse, exaggerated respirophasic mitral/tricuspid inflow variation

— Treatment: emergent pericardiocentesis (echo-guided subxiphoid). IV fluids as temporizing measure; avoid intubation/positive-pressure ventilation if possible (drops preload, precipitates arrest)

— Myopericarditis = predominantly pericarditis with elevated troponin (myocardial involvement, preserved LV function)

— Perimyocarditis = predominantly myocarditis with pericardial component and LV dysfunction

— Both require admission, telemetry, exercise restriction × 3–6 months, cardiac MRI

— Late complication (months–years); chronic inflammation → fibrotic, rigid pericardium

— Most common after TB, radiation, post-cardiac surgery

— Presentation: progressive right HF (edema, ascites, JVD with Kussmaul sign), preserved EF

— Diagnosis: echo (septal bounce, respirophasic septal shift), CT/MRI (pericardial thickening >4 mm, calcification), cath (equalization of diastolic pressures, dip-and-plateau "square root sign")

— Treatment: pericardiectomy is definitive

— Effusion + underlying constriction; tamponade physiology persists after fluid drainage

Board pearl: A young patient who presents with pericarditis and is later found to have pulsus paradoxus + JVD + hypotension is in tamponade — call for bedside echo and pericardiocentesis. Do NOT delay for CT or transfer. Conversely, a patient with progressive edema/ascites years after pericarditis or radiation = constrictive pericarditis → pericardiectomy referral.

Pericardial effusion:

Cardiac tamponade:

Myopericarditis vs perimyocarditis:

Constrictive pericarditis:

Effusive-constrictive pericarditis:

Recurrence: 15–30% after first episode without colchicine; ~10% with colchicine

When to Escalate Care — ICU, Consult, or Inpatient Triage

— Cardiac tamponade or pre-tamponade physiology

— Hemodynamic instability requiring vasopressors

— Purulent pericarditis (sepsis risk)

— Concurrent severe myocarditis with LV dysfunction, arrhythmia, or shock

— Post-procedural pericardial bleeding (post-PCI, post-ablation perforation)

— Any major or minor poor-prognosis feature (see chunk 6)

— Moderate–large effusion without tamponade

— Myopericarditis with stable hemodynamics and preserved LVEF

— Need for IV therapy or pericardiocentesis

— Concerning etiology (TB, malignancy, autoimmune flare)

— Cardiology: All admitted patients; outpatient referral if recurrent or refractory; any moderate–large effusion

— Cardiothoracic surgery: Tamponade with failed/insufficient drainage, pericardial window for recurrent effusion, pericardiectomy candidates

— Rheumatology: Suspected autoimmune etiology (SLE, RA, vasculitis)

— Infectious disease: Purulent or TB pericarditis

— Oncology: Malignant effusion (cytology+); for systemic therapy and palliative window planning

— Nephrology: Uremic pericarditis — intensified dialysis planning

— Performed at bedside in ICU (echo-guided) or in cath lab (fluoro-guided)

— Indwelling pericardial drain often left 24–72 hr until output <25 mL/day

— Complications: ventricular puncture, coronary laceration, pneumothorax, arrhythmia

— Refractory recurrent pericarditis for biologic therapy

— Suspected constrictive pericarditis for pericardiectomy

— Complex effusion of unclear etiology

CCS pearl: On a CCS case with hemodynamic instability and large effusion: order echo STAT, then emergent pericardiocentesis. Simultaneously: IV fluids (preload support), 2 large-bore IVs, type and screen, cardiology and CT surgery consult. Do NOT order intubation reflexively — it can crash the patient by removing intrathoracic negative pressure that supports venous return.

Indications for ED-to-ICU transfer:

Indications for telemetry floor admission (not necessarily ICU):

Consult triggers:

Pericardiocentesis logistics:

Transfer to tertiary center:

Key Differentials — Same-Category (Cardiac) Causes

— #1 must-rule-out. ST elevation overlaps with pericarditis morphologically

— Features favoring STEMI: regional (not diffuse) ST elevation, reciprocal depression, convex/tombstone morphology, evolving Q waves, ischemic risk factors, crushing exertional substernal pain

— Features favoring pericarditis: diffuse ST elevation, PR depression, pleuritic positional pain, friction rub, young patient without ischemic risk

— When in doubt: troponin trend, urgent echo (wall motion abnormality favors MI), and emergent cath if any uncertainty in high-risk patient — never miss a STEMI

— Viral prodrome, dyspnea, HF symptoms, arrhythmia

— Elevated troponin, reduced LVEF on echo, late gadolinium enhancement on MRI (mid-myocardial/epicardial pattern)

— Management: supportive HF therapy, restrict exercise, no NSAID benefit (and may worsen in severe LV dysfunction)

— Tearing/ripping pain radiating to back, BP differential between arms, mediastinal widening on CXR

— Can cause hemopericardium and tamponade (proximal dissection)

— Diagnosis: CT angiography of aorta; NEVER give anticoagulants reflexively if dissection suspected

— Dyspnea, orthopnea, edema; pleuritic positional pain absent

— BNP elevated, CXR shows pulmonary edema

— Subset of pericarditis 2–8 weeks post-MI or cardiac surgery

— Treatment identical: aspirin + colchicine (avoid other NSAIDs post-MI)

— Emotional/physical stressor, apical ballooning on echo, mildly elevated troponin

— Can present with chest pain and ST elevation; coronary angiography normal

Key distinction: Diffuse concave ST elevation + PR depression = pericarditis. Regional convex ST elevation + reciprocal depression = STEMI. When ECG is ambiguous in a patient with cardiac risk factors, err toward cath lab — missed STEMI carries higher morbidity than unnecessary angiogram.

STEMI / Acute MI:

Myocarditis (without pericardial component):

Aortic dissection:

Heart failure exacerbation:

Post-cardiac injury syndrome (Dressler):

Stress cardiomyopathy (Takotsubo):

Key Differentials — Other-Category Causes

— Pulmonary embolism: Pleuritic chest pain, dyspnea, tachycardia. ECG: S1Q3T3, RV strain. D-dimer, CTPA. Risk stratify with Wells/PERC.

— Pneumonia / pleuritis: Productive cough, fever, focal lung findings, consolidation on CXR; pleural rub disappears with breath-hold (unlike pericardial)

— Pneumothorax: Sudden pleuritic pain, decreased breath sounds, hyperresonance; CXR diagnostic

— GERD / esophagitis: Burning retrosternal pain, related to meals/recumbency; PPI trial helpful

— Esophageal spasm: Mimics angina; relieved by nitrates (confusing!)

— Esophageal rupture (Boerhaave): Severe pain after vomiting, mediastinal air, surgical emergency

— Acute cholecystitis / pancreatitis: Referred chest pain; check lipase, RUQ ultrasound

— Costochondritis: Reproducible tenderness on palpation, normal ECG, no effusion. Diagnosis of exclusion in young patients — but never assume in older patients with risk factors.

— Tietze syndrome: Costochondritis with visible swelling

— Rib fracture, intercostal strain

— Dermatomal burning pain preceding rash by days; consider in older or immunosuppressed

— Diagnosis of exclusion; only after objective workup negative

— Cocaine-induced chest pain: Vasospasm, MI, dissection; tox screen; treat with benzos + nitrates, avoid β-blockers (unopposed α)

— Sickle cell acute chest syndrome: Hb-electrophoresis–known patient with chest pain, hypoxia, infiltrate

Board pearl: A young patient with pleuritic chest pain and unilateral leg swelling 3 weeks after a long flight is PE, not pericarditis. Always integrate risk factors + associated symptoms + ECG pattern — pericarditis has diffuse ST elevation and PR depression; PE has S1Q3T3, sinus tachycardia, and Wells/PERC features. Order the right test (CTPA vs echo) based on pretest probability.

Pulmonary causes:

GI causes:

Musculoskeletal:

Herpes zoster (pre-eruptive):

Anxiety / panic disorder:

Less common but high-stakes:

Secondary Prevention, Discharge Medications, and Long-Term Plan

— Ibuprofen 600–800 mg PO TID × 1–2 weeks (or aspirin 750–1000 mg TID if post-MI), then taper over 2–4 weeks based on symptom and CRP response

— Colchicine 0.5 mg PO BID (≥70 kg) or daily (<70 kg) × 3 months

— Omeprazole 20 mg PO daily for GI prophylaxis during NSAID course

— Avoid acetaminophen-only regimens — inadequate anti-inflammatory effect

— Exercise restriction until symptom-free AND CRP normalized AND no effusion (minimum 1 month for uncomplicated, 3–6 months for myopericarditis/athletes)

— Take NSAID with food

— Report: recurrent chest pain, fever, dyspnea, syncope, edema → return to ED

— Adherence is critical — non-adherence is the #1 cause of "recurrence"

— Colchicine for the full 3 months even after symptom resolution — cuts recurrence by ~50%

— Slow NSAID taper, not abrupt discontinuation

— Avoid corticosteroids first-line (paradoxically increase recurrence risk)

— For recurrent disease: extend colchicine to 6 months, slow steroid taper if needed

— Autoimmune flare → optimize disease-modifying therapy with rheumatology

— Uremic → intensify dialysis

— TB → multidrug anti-TB therapy

— Malignant → oncology with chemotherapy/radiation; pericardial window for recurrence

— Drug-induced → discontinue offending agent

— Annual influenza vaccine (reduces viral triggers)

— Up-to-date COVID-19 vaccination

Step 3 management: Discharge prescription order set: (1) Ibuprofen 800 mg TID × 14 days then taper, (2) Colchicine 0.5 mg BID × 90 days, (3) Omeprazole 20 mg daily × 14 days, (4) Return precautions, (5) Cardiology clinic in 1 week with repeat CRP and ECG. This is the canonical Step 3 outpatient pericarditis discharge.

Discharge medication bundle for low-risk acute pericarditis:

Patient counseling at discharge:

Recurrence prevention strategies:

Treat underlying cause when identified:

Vaccinations and risk-factor modification:

Follow-Up, Monitoring Parameters, and Rehab/Counseling

— 1 week: Clinic visit — symptom assessment, repeat CRP (key biomarker), repeat ECG, medication tolerance check

— 2–4 weeks: Repeat CRP; if normalized and asymptomatic, begin NSAID taper

— 3 months: Confirm colchicine completion, repeat echo if initial effusion present, clear for return to full activity

— 6 months / 1 year: Surveillance for recurrence; reassess if any return of symptoms

— CRP — guides therapy duration; continue NSAIDs until CRP normalized AND symptom-free

— Symptoms — chest pain, dyspnea, palpitations

— ECG — resolution of ST/PR changes

— Echo — resolution of effusion (especially if initially moderate–large)

— Renal function and CBC — colchicine and NSAID monitoring at 4–6 weeks

— Troponin in myopericarditis cases — repeat until normal

— Uncomplicated acute pericarditis: Restrict to non-competitive light activity until symptom-free, CRP normal, no effusion — minimum 1 month

— Myopericarditis or competitive athletes: Restrict for 3–6 months with normal exam, ECG, echo, ambulatory monitor, and exercise stress test before return

— Educate that exertion during active inflammation worsens myocardial injury and increases arrhythmia risk

— Alcohol limitation (interacts with NSAIDs/colchicine, GI bleeding)

— Adequate hydration with NSAIDs (renal protection)

— Recognize prodromal symptoms of recurrence — seek care early

— Recurrent pericarditis carries significant anxiety and reduced quality of life — screen for depression; consider patient support groups (Myocarditis Foundation)

Board pearl: CRP is your decision biomarker — do not taper NSAID until CRP normalizes. Step 3 stems will test this: a patient at 2-week follow-up with persistent CRP elevation should continue full-dose NSAID, not begin taper. Persistent CRP at 4 weeks despite therapy = consider treatment failure → escalate to steroid or biologic.

Follow-up cadence:

Parameters to monitor:

Exercise and return-to-activity counseling:

Lifestyle counseling:

Mental health:

Ethical, Legal, and Patient Safety Considerations

— Discuss risks: cardiac perforation (~1%), coronary artery laceration, pneumothorax, arrhythmia, infection, recurrence

— Document risks/benefits/alternatives, including surgical window

— Emergency exception: In unresponsive tamponade patient, consent may be implied — proceed and document attempts to reach surrogate; this is a tested ethics scenario

— Pericarditis discharges fail when colchicine is not filled or not understood. Best practice: have patient verbalize medication regimen and follow-up plan; provide written instructions; medication reconciliation; ensure 7-day follow-up booked before discharge

— Telephone follow-up at 48–72 hr reduces ED readmission

— Patient/coach pressure to return prematurely is common; physician must document clear criteria (symptom resolution, normal CRP, normal echo, time threshold) and not yield to non-medical pressure

— Sudden cardiac death in athletes returning to competition with active myopericarditis is a documented and litigated event

— TB pericarditis: Reportable disease — notify state/local health department; initiate contact tracing

— HIV-associated pericarditis: counseling, partner notification per state law

— Colchicine + clarithromycin/azole/statin combinations have caused fatal toxicity — always reconcile medications and screen renal function

— NSAID-related AKI and GI bleeding are leading causes of post-discharge readmission in elderly

— Confirm pregnancy status before prescribing NSAIDs in reproductive-age women — teratogenic risk and 3rd-trimester ductus closure

— Confirm patient understands "complete the colchicine course even when feeling better" — equivalent of antibiotic compliance counseling

Step 3 management: Best safety intervention to reduce pericarditis recurrence and readmission = structured discharge with medication reconciliation, written instructions, 7-day cardiology follow-up, and 48–72 hr nurse call. This is the systems-level answer increasingly favored on Step 3.

Informed consent for pericardiocentesis:

Transitions of care — high-risk discharge:

Athlete return-to-play disputes:

Mandatory reporting and public health:

Drug safety alerts:

Pregnancy disclosure:

Health literacy:

High-Yield Associations and Rapid-Fire Clinical Facts

— Viral URI 1–3 weeks prior → idiopathic/viral (80–90%)

— 2–8 weeks post-MI or cardiac surgery → Dressler syndrome (autoimmune)

— 1–4 days post-MI → early post-infarction pericarditis (direct extension from transmural MI)

— ESRD with missed HD or BUN >60 → uremic pericarditis

— HIV/immigrant with subacute fever/weight loss → TB pericarditis

— Hydralazine/procainamide/isoniazid → drug-induced lupus → pericarditis

— Lung/breast cancer with bloody effusion → malignant pericarditis

— Recent chest radiation (months–years) → radiation pericarditis ± constriction

— PR depression is highly specific for pericarditis

— PR elevation in aVR = reciprocal PR change = pathognomonic

— Spodick sign (down-sloping TP) supports pericarditis

— Electrical alternans = large pericardial effusion (swinging heart)

— Low voltage QRS = large effusion

— Post-MI pericarditis → aspirin only (other NSAIDs impair healing)

— Colchicine duration: 3 months first episode, 6 months recurrence

— Steroids → ↑ recurrence; second-line only

— Pregnancy after 20 weeks → prednisone, not NSAID

— Children → no aspirin (Reye)

— Uremic → dialyze, don't NSAID

— Trapezius ridge pain → pathognomonic radiation

— Beck triad → tamponade (hypotension, muffled sounds, JVD)

— Kussmaul sign → constrictive pericarditis

— Pulsus paradoxus >10 mmHg → tamponade (or severe asthma/COPD)

— Water-bottle heart on CXR → effusion >200 mL

— Pericardial thickening + calcification on CT → constrictive

— Septal bounce + IVC plethora → constrictive on echo

Board pearl: If the stem mentions trapezius pain + relief leaning forward + diffuse ST elevation with PR depression → answer is NSAID + colchicine + 1-week follow-up, every time.

Etiology associations:

ECG pearls:

Drug pearls:

Physical findings:

Imaging pearls:

Board Question Stem Patterns

— 28-year-old man, URI 2 weeks ago, sharp chest pain worse supine and relieved leaning forward, friction rub heard. ECG: diffuse ST elevation, PR depression.

— Answer: Ibuprofen + colchicine, outpatient management, 1-week follow-up

— 65-year-old with anterior STEMI 3 days ago develops pleuritic chest pain and friction rub. New diffuse ST elevation.

— Answer: Aspirin (NOT ibuprofen/other NSAID — impairs myocardial healing) + colchicine

— Acute pericarditis patient develops hypotension, JVD, muffled heart sounds, pulsus paradoxus 18 mmHg.

— Answer: Emergent echocardiogram + pericardiocentesis. NOT intubation, NOT diuretics.

— ESRD patient missed 3 dialysis sessions, presents with pericarditis and friction rub.

— Answer: Intensified dialysis (daily HD), NOT NSAID

— 28-week pregnant woman with classic pericarditis.

— Answer: Low-dose prednisone ± colchicine (NOT ibuprofen — ductus closure risk after 20 weeks)

— Patient asks "What can I do to prevent recurrence?"

— Answer: Complete the full 3-month colchicine course (not "avoid steroids," not "rest")

— Patient with first episode of idiopathic pericarditis — what is first-line?

— Answer: NSAID + colchicine. NOT prednisone (increases recurrence)

— Patient with TB pericarditis years ago now with edema, ascites, JVD with Kussmaul sign, preserved EF.

— Answer: Pericardiectomy referral; CT/MRI for pericardial thickening

— Pericarditis patient has elevated troponin.

— Answer: Admit, telemetry, cardiac MRI, exercise restriction 3–6 months

— Patient with pericarditis + fever 38.5°C + large effusion 25 mm.

— Answer: Admit (high-risk features), not discharge

Step 3 management: Memorize these 10 patterns. ~80% of pericarditis questions are recognizable variants. Key wrong-answer distractors include: steroids first-line, ibuprofen post-MI, NSAIDs in 3rd-trimester pregnancy, intubation in tamponade, NSAIDs in uremia, and discharging high-risk patients.

Pattern 1 — Classic diagnosis:

Pattern 2 — Post-MI:

Pattern 3 — Tamponade recognition:

Pattern 4 — Uremic:

Pattern 5 — Pregnancy:

Pattern 6 — Recurrence prevention:

Pattern 7 — Steroid trap:

Pattern 8 — Constrictive:

Pattern 9 — Myopericarditis:

Pattern 10 — Disposition:

One-Line Recap

Acute pericarditis is a clinical diagnosis (≥2 of: pleuritic positional chest pain, friction rub, diffuse ST elevation with PR depression, pericardial effusion) treated outpatient in low-risk patients with high-dose NSAID + colchicine × 3 months, with admission reserved for fever >38°C, large effusion, tamponade, myopericarditis, immunosuppression, anticoagulation, or NSAID failure.

Board pearl: The three highest-yield wrong-answer traps are (1) starting steroids first-line (↑ recurrence), (2) using ibuprofen in post-MI pericarditis (impairs myocardial healing — use aspirin), and (3) discharging a patient with any major poor-prognosis feature. The three highest-yield right answers are NSAID + colchicine for low-risk, emergent pericardiocentesis for tamponade, and intensified dialysis for uremic pericarditis.

Diagnostic core: ECG (diffuse ST elevation + PR depression, PR elevation in aVR) + troponin + CRP + CXR + echo in every patient; cardiac MRI for diagnostic uncertainty or myopericarditis

First-line therapy: Ibuprofen 600–800 mg TID (or aspirin if post-MI) + colchicine 0.5 mg BID × 3 months + PPI; taper NSAID once symptoms resolve AND CRP normalizes; avoid steroids first-line

High-risk = admit: Fever >38°C, large effusion (>20 mm), tamponade, NSAID failure, myopericarditis (elevated troponin), immunosuppression, trauma, or anticoagulation

Special-population swaps: Post-MI → aspirin only; pregnancy >20 weeks → prednisone; uremic → intensified dialysis; children → no aspirin (Reye); CKD/dialysis → avoid colchicine, dose-adjust

Follow-up: Cardiology clinic at 1 week with repeat CRP; complete full 3-month colchicine course (cuts recurrence ~50%); exercise restriction until asymptomatic + CRP normalized + no effusion (3–6 months for myopericarditis/athletes)