Friction rub

A superficial, grating, or creaking auscultatory sound produced when inflamed serosal or tendon surfaces rub against each other during cardiac cycles, respiration, or movement, typically indicating friction between normally smooth surfaces.

Causes

• Pleural causes

  • Pleuritis

  • Pneumonia

  • Pulmonary embolism

  • Lung cancer

  • Rib fracture causing pleural irritation

• Cardiac causes

  • Pericarditis

  • Myocardial infarction

  • Dressler's syndrome (post-myocardial infarction pericarditis)

• Inflammation of serosal or synovial surfaces

  • Rheumatoid arthritis

  • Systemic lupus erythematosus (SLE)

  • Other serosal inflammatory conditions

• Radiotherapy-induced serosal inflammation

• Tendon sheath inflammation (tenosynovitis)