Pericarditis

Pericarditis is defined as inflammation of the pericardium. It is normally found in association with cardiac, thoracic or wider systemic pathology and it is unusual to manifest on its own.

Clinical presentation

Classically, patients present with abrupt, pleuritic, positional left precordial chest pain after a viral prodrome. The pain is relieved in the sitting position when leaning forward and exacerbated when supine. Tuberculous pericarditis may present with constitutional symptoms, including fever, night sweats, anorexia, and weight loss. The physical exam may demonstrate:

• a pericardial friction rub
  • classically triphasic, two components in diastole and one in systole
  • may be transient
• signs of tamponade
  • classically Beck's triad, with jugular venous distension, hypotension, and muffled heart sounds

ECG

• diffuse ST-segment elevation (STE)
  • with upward concavity
  • the STE in lead II > lead III
  • absence of reciprocal changes or Q waves
• lead aVR demonstrates ST-segment depression
  • this lead also may demonstrate PR segment elevation
• diffuse PR segment depression
  • excluding the aforementioned (lead aVR)
• later, T wave inversions may develop

Pathology

In general, infection is the most common cause of pericarditis. Infection accounts for two-thirds of cases while noninfectious causes account for the remaining one-third ⁹.

Pericarditis can be divided into subtypes according to morphology:

Acute forms

• serous pericarditis
• suppurative (purulent) pericarditis
• tuberculous (caseous) pericarditis
• fibrinous pericarditis
• hemorrhagic pericarditis

Established forms

• constrictive pericarditis
• adhesive pericarditis

Radiographic features

Plain radiograph

There may be an increased cardiothoracic ratio with a globular or 'flask-shaped' outline if there is co-existing pericardial effusion. Manifestations of cardiogenic pulmonary edema may also be present.

Ultrasound

Echocardiography is recommended when the pericardial disease is suspected and may demonstrate ¹¹: 

• pericardial thickening
• pericardial effusion
  • indication for hospitalization when new and large
• cardiac tamponade
• elevated filling pressures

Patients who have a preserved ejection fraction but symptomatic heart failure may (with a suggestive clinical history) be examined for occult constrictive pericarditis, features of which include:

• right and left atrial enlargement
• mitral/tricuspid inflow pulsus paradoxus
  • in the absence of an effusion
• annulus paraxodus
  • elevated filling pressures with a preserved mitral septal annular velocity (septal e')
• annulus reversus
  • tissue Doppler of the mitral annuli reveals a septal e' > lateral e'
  • the lateral e' is normally always higher than the septal e'

CT

At contrast-enhanced CT, enhancement of the thickened pericardium generally indicates inflammation ¹.

PET/CT

Focal FDG uptake may be demonstrated in some cases. 

MRI

Usually, GRE cine, T1, T2 black-blood/STIR and IR GRE sequences are performed. In the setting of suspected pericardial constriction, real-time cine sequences should be acquired ^12,13. The presence of an arrhythmia may induce artifacts. For specific features please refer to subtype articles.   

The normal pericardial thickness is considered 2 mm while a thickness of over 4 mm suggests a pericarditis ^1,2. 

Edema of the visceral and parietal pericardium, depicted in T2 black-blood/STIR images, and enhancement usually assessed with late gadolinium enhancement (LGE) images are additional specific MRI features ^12-14.

In addition, cardiac MRI has the ability to assess the myocardium in regard to concomitant myocarditis and viability in a post-myocardial infarction setting or to detect myocardial infarction, if previously unknown.

See also

• pericardial effusion