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.

Epidemiology

Associations

• camptodactyly arthropathy coxa vara pericarditis syndrome

Diagnosis

The diagnosis of pericarditis is based on clinical criteria and supplemental imaging information ¹.

Diagnostic criteria

According to the 2015 European Society of Cardiology (ESC) Guidelines for the diagnosis and management of pericardial diseases the diagnosis can be made if ≥2 of the following four criteria are met ¹:

• pericarditic chest pain
• pericardial rubs
• new widespread ST elevation and/or PR depression (ECG)
• new or worsening pericardial effusion

Supporting findings include the following:

• elevated inflammatory markers (CRP, ESR, WBC)
• imaging findings on cardiac CT or cardiac MRI suggesting pericardial inflammation

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 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.

Classification

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 (CTR) 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 paradoxus
  • 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.

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 artefacts. 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 ^2,3. 

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.

Nuclear medicine

PET

Focal FDG uptake may be demonstrated in some cases. 

See also

• pericardial effusion