Pericarditis: Dry Pericarditis and Pericardial Effusion

1. Anatomy of the Pericardium

2. Etiology

3. Dry (Fibrinous) Pericarditis

Pathology

Acute suppurative (purulent) pericarditis caused by extension from pneumonia. Note the shaggy exudate on the pericardial surface. — Robbins & Kumar Basic Pathology, Fig. 9.29

Clinical Features

• Chest pain: Sharp, pleuritic, retrosternal; can radiate to the trapezius ridge, neck, shoulder, or arms. Relieved by sitting forward, worsened by lying flat, deep inspiration, or swallowing. — ROSEN's EM
• Pericardial friction rub: The hallmark sign. A "scratchy," leathery sound classically with three components (atrial systole, ventricular systole, ventricular diastole — the "to-and-fro" rub). Best heard at the lower left sternal border with the diaphragm, patient leaning forward in full expiration. Tends to be intermittent and migratory. — ROSEN's EM
• Fever and myalgias are common.
• Dyspnea, cough, hiccups, dysphagia may also be present.

Diagnostic Criteria

1. Characteristic chest pain
2. Pericardial friction rub
3. Characteristic ECG changes
4. New or worsening pericardial effusion

ECG Changes — The Four Stages

Classic 12-lead ECG of acute pericarditis: diffuse concave ("saddle-shaped") ST elevation across leads I, II, V2–V6; PR-segment depression in lead II; reciprocal PR elevation and ST depression in aVR.

Laboratory Findings

• ESR and CRP elevated (CRP useful for monitoring disease activity and guiding duration of therapy)
• Leukocytosis
• Troponin may be elevated if concurrent myopericarditis (myocardial involvement)
• Other labs directed at non-idiopathic causes (ANA, RF, BUN/creatinine, cultures, TSH)
• Serology (antiviral titers) has low yield and does not alter management

4. Pericardial Effusion

Definition and Causes

Clinical Features

• Often asymptomatic, especially if accumulation is slow
• Symptoms (cough, fever, chest pain, dyspnea) may reflect the underlying pericarditis
• Large or rapidly accumulating effusions → risk of cardiac tamponade

Imaging

• Requires ≥200–250 mL of fluid to produce cardiomegaly on CXR
• Water-bottle (flask) sign: globular enlargement of the cardiac silhouette with a broad base
• Effacement of normal cardiac borders; bilateral hilar overlay
• Epicardial fat pad sign on lateral view: a pericardial stripe >2 mm between epicardial and mediastinal fat bands
• "Sandwich sign": on lateral CXR, a wide band of higher density in the retrosternal space flanked by two bands of lower density (fat)
• Interval enlargement of cardiac silhouette on serial films should raise strong suspicion — Grainger & Allison; Goldman-Cecil Medicine

Fig. 4.31 — Pericardial effusion in a 30-year-old man with chronic kidney disease. Lateral chest X-ray shows the sandwich sign: the denser fluid in the pericardium outlined by two lucent bands of epicardial and pericardial fat. — Grainger & Allison's Diagnostic Radiology

• Highly sensitive and specific; first-line imaging
• Echo-free (anechoic) space between the pericardium and the epicardium
• Up to 60% of pericarditis patients have a detectable effusion on echo
• Distinguishes pericardial fluid from pleural fluid and from cardiac chamber dilation
• A normal echo does not exclude pericarditis

POCUS showing pericardial effusion (anechoic space around left ventricle) with the pericardium, descending aorta, and left ventricle labeled. — ROSEN's Emergency Medicine, Fig. 68.5

• Useful when echo is technically limited (obese/emphysematous patients)
• MRI with gadolinium: pericardial delayed hyperenhancement indicates active inflammation
• CT delineates the extent of effusion and underlying causes

Sizing and Hemodynamic Impact

5. Cardiac Tamponade

Pathophysiology

• Equalization of pressures: right atrial pressure = left atrial pressure = PCWP = pericardial pressure
• Blunted or absent y descent on right atrial tracing (impaired early diastolic filling)
• Ventricular interdependence exaggerated: RV filling during inspiration reduces LV filling

Clinical Features — Beck's Triad (classic)

1. Hypotension (falling cardiac output)
2. Raised JVP (right-sided venous distension)
3. Muffled heart sounds

• Tachycardia (first compensatory mechanism)
• Pulsus paradoxus (>10 mmHg drop in systolic BP on inspiration) — key sign
• Kussmaul's sign is absent in tamponade (present in constriction)
• ECG: electrical alternans (alternating QRS amplitude — heart swinging in fluid) + sinus tachycardia + low voltage

Echo in Tamponade (key findings):

• Right atrial systolic collapse (most sensitive)
• Right ventricular diastolic collapse (more specific for hemodynamic compromise)
• Reciprocal respiratory variation in ventricular volumes (RV expands on inspiration while LV contracts)
• IVC dilation with absent respiratory collapse
• Respiratory variation in mitral/tricuspid Doppler flows >25–40% — Textbook of Clinical Echocardiography

Treatment

• Urgent pericardiocentesis (echo-guided preferred) — both diagnostic and therapeutic
• Avoid vasodilators and diuretics (they reduce preload); give IV fluids as a bridge
• Inotropes may be required
• Surgical drainage (pericardial window) for recurrent or loculated effusions

6. Management of Acute Pericarditis

First-Line (Non-specific / Idiopathic)

• Add a proton pump inhibitor (gastroprotection)
• Colchicine (0.5–1 mg/day for 4–6 weeks): recommended as adjunct; reduces recurrence rate; avoid in severe hepatic/renal impairment

Second-Line

• Corticosteroids: avoided unless all other treatments have failed — associated with higher relapse rates. Acceptable as first-line only in autoimmune disease (SLE) or uremic pericarditis where NSAIDs are contraindicated. — Textbook of Family Medicine

Surgical

• Pericardiectomy: reserved for recurrent pericarditis unresponsive to aggressive medical therapy. May not always eliminate symptoms. — Textbook of Family Medicine

Activity Restriction

• Athletes and physically active patients: restrict strenuous activity until symptom resolution and normalization of CRP/ECG/echo

Indications for Hospitalization

• First episode (for observation)
• Large effusion or tamponade
• High-risk features: fever >38°C, subacute onset, immunosuppression, anticoagulation use, elevated troponin (suggesting myopericarditis), failure of NSAIDs

7. Outcomes and Complications

8. Special Contexts

• Autoimmune diseases: Pericarditis affects 40–80% of SLE patients (necropsy studies) and 40% of RA patients; usually associated with disease flare. Cardiac tamponade is rare in SLE (1–2%). In SSc, small effusions are common but rarely hemodynamically significant. — Braunwald's Heart Disease
• Dressler syndrome: Post-MI autoimmune pericarditis (develops weeks after MI) due to antibodies against injured myocardium; presents with fever, chest pain, and pleuritis
• Purulent pericarditis: Life-threatening; Streptococcus and Staphylococcus most common; requires pericardiocentesis for diagnosis and drainage; treatment is pericardiectomy or indwelling catheter + fibrinolytics + IV antibiotics — ROSEN's EM
• Malignant effusion: ~40% of cancer patients with pericardial effusion actually have radiation-induced or idiopathic pericarditis, not malignant involvement — Braunwald's Heart Disease