What are the signs and symptoms of acute pericarditis?

Signs and Symptoms of Acute Pericarditis

Acute pericarditis presents with sharp, pleuritic chest pain that worsens when lying supine and improves when sitting up or leaning forward—this positional characteristic occurs in approximately 90% of cases and is the hallmark feature distinguishing it from acute coronary syndrome. 1

Cardinal Clinical Features

Chest Pain Characteristics

• Sharp, pleuritic retrosternal chest pain that worsens with inspiration, coughing, and lying flat 1, 2
• Pain typically radiates to the trapezius ridge, neck, back, or left shoulder 1
• Relief occurs when sitting up or leaning forward—this positional nature is pathognomonic 2, 3
• Pain is central rather than localized, distinguishing it from myocardial infarction 1

Pericardial Friction Rub

• Highly specific but transient, audible in only approximately one-third of patients with confirmed acute pericarditis 1, 2
• Best heard at the left lower sternal border with the patient sitting upright, leaning forward, and briefly holding their breath 1
• Can be mono-, bi-, or triphasic in character, with triphasic being most characteristic 1
• May disappear and reappear during the illness, necessitating repeated auscultatory examinations 1
• The rub can persist even with large effusions 4

Electrocardiographic Changes

• Diffuse concave upward ST-segment elevation in multiple leads (present in 25-60% of cases) 2
• PR-segment depression accompanying ST elevation 1, 2
• These changes differ from the localized convex ST elevation seen in myocardial infarction 1

Associated Symptoms and Findings

• Fever (high fever >38°C indicates high-risk disease requiring admission) 2
• Dyspnea may be present 5
• Diminished or muffled heart sounds occur with moderate to large pericardial effusions 1

Important Clinical Distinctions

Myopericarditis Features

• Elevated troponin occurs in up to 50% of acute pericarditis cases, indicating myocardial involvement 6, 2
• Arrhythmias like atrial fibrillation suggest myocardial involvement beyond isolated pericarditis 6
• Troponin elevation in myopericarditis does not predict worse outcomes when left ventricular function is preserved 6

Special Populations

Uremic/Dialysis-Associated Pericarditis:

• Many patients are asymptomatic despite disease 4
• Heart rate may remain slow (60-80 beats/min) during tamponade due to autonomic impairment, despite fever and hypotension 4
• ECG does not show typical diffuse ST/T wave elevations due to lack of myocardial inflammation 4
• Pericardial rubs may persist even with large effusions or be transient 4

Tuberculous Pericarditis:

• Variable presentation including acute pericarditis with or without effusion, cardiac tamponade, silent large effusions with relapsing course, toxic symptoms with persistent fever, or constrictive patterns 4

Common Pitfalls to Avoid

• Absence of a friction rub does not exclude pericarditis—it is only audible in less than one-third of confirmed cases 1
• Normal echocardiogram does not exclude pericarditis—pericardial effusion is detectable in only about 60% of cases 1, 2
• Relief with nitroglycerin should not be used as a diagnostic criterion—a positive response neither confirms nor excludes pericarditis or myocardial ischemia 1
• Left arm pain is not a classical feature of pericarditis and should raise suspicion for myocardial involvement or acute coronary syndrome 1
• Multiple auscultatory examinations are necessary because the friction rub can be intermittent 1

Diagnostic Approach

At least 2 of 4 clinical criteria are required for diagnosis: 2

• Characteristic pleuritic chest pain worsening when supine
• Pericardial friction rub on auscultation
• New widespread ST-elevation or PR depression on ECG
• New or worsening pericardial effusion on echocardiography

Immediate evaluation should include: 2

• ECG within 10 minutes to identify characteristic changes
• Transthoracic echocardiography to detect effusion and evaluate for tamponade
• Inflammatory markers and troponin levels