Pericarditis Flashcards
What is pericarditis?
Acute inflammation of the pericardium, characterised by a triad of chest pain, pericardial friction rub and serial electrocardiographic changes.
What is the aetiology of pericarditis? (x12)
- Idiopathic
- Infective (commonly coxasckie B, echovirus, mumps virus, streptococci, fungi, staphylococci, TB). Viral is most common, though can be bacterial, fungal or parasitic.
- Connective tissue disease e.g., sarcoid, SLE, scleroderma
- Systemic autoimmune disorders e.g., rheumatoid arthritis, systemic sclerosis, IBD
- Post-myocardial infarction (24-72 hour) in up to 20% of patients
- Dressler’s syndrome (weeks to months after acute MI)
- Malignancy
- Metabolic such as myxoedema or uraemia
- Radiotherapy
- Thoracic surgery
- Trauma (blood fills pericardium)
- Drugs such as hydralazine, isoniazid
What is the structure of the pericardium?
2 layers – inner layer called serous pericardium, and outer layer made of strong connective tissue called fibrous pericardium. Inner layer is adherent to myocardium and has a microvillous surface that secretes pericardial fluid. Outer layer is made of collagen and elastin.
How is the pericardium perfused?
Internal mammary arteries
How is the pericardium innervated?
Phrenic nerve
What is the pathophysiology of pericarditis? (x2 points)
(1) Inflammation of the pericardial tissue leads to formation of the effusion. Normal pericardium is permeable to water and electrolytes, so the pericardial fluid is in dynamic equilibrium with the blood serum. Effusion presents because inflammation impairs the equilibrium. (2) Production of inflammatory mediators produces exudate from visceral pericardium in effusive pericarditis, which can be purulent, serous, haemorrhagic, fibrinous, and caseous.
What is the classification of pericarditis according to the fluid that accumulates?
- Serous: serum = blood plasma without clotting factors, platelets, RBCs or WBCs
- Purulent: contains dead leukocytes (mostly neutrophils) produced from infection
- Fibrinous: (AKA uremic pericarditis) consisting of fibrin and leukocytes – occurs in 10% of kidney failure patients, hence why it is called ‘uremic’ pericarditis
- Caseous: from caseous necrosis e.g., in TB infections and certain fungi
- Haemorrhagic: blood exudate
How much can the pericardium tolerate? (x2)
Can tolerate 1L if filled long-term e.g., TB. However, even 20-30ml QUICKLY can cause cardiac tamponade.
What is the clinical classification of pericarditis?
- Acute – less than 4-6 weeks
- Subacute
- Chronic
What is the epidemiology of pericarditis: Age? Gender? How common?
Presents between 20 and 50. More in men. Uncommon.
What are the symptoms of pericarditis? (x4)
- Chest pain – sharp, pleuritis and can mimic STEMI pain. May also have trapezius ridge pain (this is more specific for pericardial pain). Pain RELIEVED by sitting or leaning forward. WORSE on lying down.
- Pericardial friction rub: high-pitched or squeaky sound heard best at the left sternal edge with the patient leaning forward at end-expiration.
- Fever if infectious aetiology
- Myalgia in some acute presentations
How may pericarditis present on examination?
Reduced heart sounds from effusion.
What does an ECG show in pericarditis?
ST segments elevations that are upwardly concave (called J-point). PR segment depressions in most leads. There is converse J point depression and PR elevation in leads aVR and V1.
What are the other investigations for pericarditis? (x8)
- Serum troponin mildly elevated, correlative with extent of ST segment elevation
- Pericardial fluid if infective aetiology – indicated as treatment pericardiocentesis anyway if there is a suspicion of cardiac tamponade, purulent pericarditis, or if the effusion is large or symptomatic.
- Blood culture positive if infective aetiology
- ESR and CRP elevated because of inflammatory state
- Serum urea: elevated if uraemic cause (fibrinous pericarditis)
- FBC: may show raised WCC if infective aetiology
- CXR: may show water bottle-shaped enlarged cardiac silhouette
- Echocardiography: especially when cardiac tamponade is suspected. May show pericardial effusion
How is pericarditis managed? (x4)
- ACUTE: pericardiocentesis if cardiac tamponade of purulent pericarditis to remove fluid from the pericardium
- MEDICAL: treat underlying cause, NSAIDs for pain, inflammation and fever, PPI due to high doses of NSAID
- Exercise restriction (my guess is that you don’t want extra pressure on heart as it would require greater filling and therefore predispose tamponade-like symptoms)
- RECURRENT: low dose-steroids, colchicine, or immunosuppressants
