Acute Pericarditis in the Hospitalized Patient: Master Risk Stratification, NLRP3, and Why Steroids Cause Relapse

In this episode of Hospital Medicine Unplugged, we sprint through pericarditis—diagnose fast, cool the inflammation, prevent tamponade, crush recurrences.

We open with the do-firsts: history/exam (rub), ECG, CRP/ESR + leukocytosis/fever, and TTE to size the effusion and exclude tamponade/constriction. CMR is reasonable in complicated/recurrent/incessant cases to confirm pericardial inflammation or myocardial involvement.

Call the diagnosis when ≥2 of 4: typical chest pain, pericardial rub, diffuse ST↑/PR↓, new/worsening effusion. Support with ↑CRP and CMR LGE/pericardial edema when the picture is hazy.

Risk-stratify for admission (any = admit): fever >38°C, subacute course, large effusion (>2 cm), tamponade, failed outpatient NSAIDs, immunosuppression/trauma, or suspected TB/malignancy. In-house: serial TTE and trend CRP.

Treatment—build the anti-inflammatory backbone: • First-line: High-dose aspirin (650–1000 mg TID) or NSAID (e.g., ibuprofen 600–800 mg q8h) + colchicine (0.5–0.6 mg BID if >70 kg; QD if ≤70 kg) for 3 months (≥6 months for recurrent). Aspirin preferred if ischemic heart disease. Add PPI. • Exercise restriction: keep HR <100 and no strenuous activity for ≥1 month (longer with myopericarditis).

If the backbone buckles: • Corticosteroids (pred 0.2–0.5 mg/kg/day) only when NSAID/colchicine fail or are contraindicated (autoimmune, pregnancy, etc.). Slow taper, CRP-guided—early steroids ↑ recurrence. • Anti–IL-1 (anakinra, rilonacept) for refractory/recurrent with inflammatory phenotype (↑CRP) after infection screen. • Azathioprine or IVIG if still refractory. • Radical pericardiectomy in high-volume centers for truly unresponsive disease.

Etiology plays (treat the cause): • TB pericarditis: RIPE regimen; consider steroids if constrictive/inflammatory. • Uremic pericarditis: intensify dialysis. • Malignancy: oncologic therapy + tailored pericardial management. • Post–cardiac injury: standard NSAID + colchicine, cautious steroid use.

Pericardial effusion & tamponade—don’t miss it: look for hypotension, JVD, pulsus paradoxus. Echo signs: RA/RV diastolic collapse, plethoric IVC, respiratory inflow variation. Action: emergent echo-guided pericardiocentesis with slow drainage; gentle IV fluids while prepping; avoid PPV if possible. For recurrent/purulent/neoplastic cases, pericardial window is reasonable. Always send fluid for cell count, Gram/culture, AFB/TB PCR, cytology.

Monitoring & tapering that sticks: trend CRP to steer NSAID taper, check renal/hepatic function and CBC, and schedule serial TTE for moderate/large effusions. Colchicine adherence is your recurrence shield.

Recurrence reality check: without prevention, ~30% recur. With colchicine, recurrences drop and remissions improve—finish the course. Keep activity limited until symptoms resolve + CRP normal.

Medication pitfalls you don’t want to meet: early steroids (↑ recurrence), NSAID renal/GI toxicity (use PPI), dose-adjust colchicine in renal/hepatic impairment and watch for interactions (e.g., strong CYP3A4/P-gp inhibitors).

We close with the system moves: a pericarditis bundle that (1) pre-checks ECG/CRP/TTE ± CMR; (2) defaults to NSAID(or aspirin) + colchicine + PPI with weight/renal dosing; (3) auto-admits high-risk features; (4) runs a CRP-guided taper and exercise-restriction protocol; (5) fires a tamponade pathway (STAT TTE → pericardiocentesis → full fluid studies); (6) launches a steroid-sparing track (early anti–IL-1 for recurrent/incessant); (7) routes to etiology-specific tracks (TB, uremia, malignancy, autoimmune) with multidisciplinary consults; (8) embeds lab safety monitoring.

Fast, imaging-led, and recurrence-proof—build the NSAID+colchicine core, reserve steroids, treat the cause, and never miss tamponade.