Pericardial friction rub

# Overview
The pericardial friction rub, also pericardial rub, is a sign on the precordial exam, detected by auscultation, that suggests irritation of the pericardium and the diagnosis of pericarditis. Inflammation of the pericardial sac causes the parietal and visceral surfaces of the roughened pericardium to rub against each other. This produces an extra cardiac sound of to-and-fro character with both systolic and diastolic components. One, two, or three components of a pericardial friction rub may be audible. A three-component rub indicates the presence of pericarditis and serves to distinguish a pericardial rub from a pleural friction rub, which ordinarily has two components. It resembles the sound of squeaky leather and is often described as grating, scratching, or rasping. The sound is often loud and may even mask the other heart sounds. Friction rubs are usually best heard between the apex and sternum but may be widespread. The sound has three parts: two diastolic, and one systolic, more specifically: atrial systole, rapid-filling phase of the ventricle and ventricular systole. A one-component rub, usually during ventricular systole, is suggestive of myopericarditis following transmural myocardial infarction.

# Causes

## Life Threatening Causes
Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.
- Cardiac tamponade
- Myocardial infarction

## Common Causes
- Amyloidosis
- Cardiac tamponade
- Collagen vascular disease
- Dressler's syndrome
- Familial mediterranean fever
- HIV
- Leukemic infiltration
- Mediastinal  radiation
- Mediastinal emphysema
- Myocardial infarction
- Myocarditis
- Neoplasm
- Parasitic infection
- Pleuropericardial rub
- Pericarditis
- Rheumatic fever
- Sarcoidosis
- Sail sound of ebstein's anomaly
- Thyrotoxicosis
- Toxoplasmosis
- Trauma
- Tuberculosis
- Uremia
- Viral

## Causes by Organ System

## Causes in Alphabetical Order

# Diagnosis

## History and Symptoms
History includes:
- Recent bacterial infection
- Tuberculosis
- Recent viral exposure
- Autoimmune disease
- Fever
- Myocardial infarction
- Pericardiotomy
- Uremia
- Trauma

## Physical Examination
Considering that several causes, mentioned above, can be responsible for the presence of a pericardial rub on auscultation, a full physical exam should be performed, in order to gather every sign, for appropriate differential diagnosis.
A careful exam should be conducted to evaluate the patient for signs of life-threatening situations, such as cardiac tamponade.
Pericardial rubs are best heard with the diaphragm of the stethoscope, and can be described according to:
- Location: although variable, it is usually best heard in the 3rd interspace to the left of the sternum;
- Radiation: little;
- Intensity: although variable, it may increase with the patient leaning forward, when exhaling or holding breath (contrast with pleural rub);
- Quality: scratching and grating;
- Pitch: high
The pericardial rub sound usually varies in intensity over time, therefore auscultation should be performed at several occasions.
Below is the video demonstrating Pericardial friction rub:

## Laboratory Findings
- Labs include:
- Cardiac enzymes
- CBC w/ differential
- ESR
- ANA
- rheumatoid factor
- BUN / creatinine
- PPD
- viral titers
- ASO titers

## Electrocardiogram
ECG for potential MI, pericarditis or other cardiac problems

## Chest X Ray
Depending upon the underlying cause and if an effusion is present, the chest x-ray may show signs of cardiomegaly

## Echocardiography or Ultrasound
If there is a clinical suspicion of cardiac tamponade, and echocardiogram should be performed to assess the size of the effusion, to guide pericardiocentesis.

## Cardiac Computed Tomography and Cardiac Magnetic Resonance
Cardiac Computed Tomography and Cardiac Magnetic Resonance are gaining more importance in the diagnosis of pericarditis. Both are very sensitive methods in diagnosing effusions, as well as in determining pericardial thickness.

# Treatment
- Hemodynamic stability is intact
- Supplemental oxygen

## Acute Pharmacotherapies
- Pericarditis: NSAIDs

## Indications for Surgery
An emergency pericardiocentesis is indicated in the presence of cardiac tamponade, a large symptomatic pericardial effusion, or to establish the diagnosis in a case of suspected malignant or tuberculous pericarditis.