Cardiology - Pericardial disease Flashcards
What is pericarditis?
Pericarditis refers to inflammation of the pericardium that can either be acute or chronic.
Primary acute pericarditis is rare. Most cases are due to direct involvement from myocardial or endocardial disease, or by extension from neighbouring tissues - e.g. lungs
What is the aetiology of acute pericarditis?
1) Bacterial - e.g. staph, strep, pneumococcus, septicaemic or pyaemic, TB
2) Viral - acute, benign viral pericarditis: virus infections are probably the most common cause now of acute pericarditis, and follow URTI or mumps, infectious mononucleosis and Coxsackie virus (especially in young patients)
3) Aseptic - uraemic, secondary to myocardial infarction (Dressler’s syndrome), tumour infiltration, SLE (Leibmann Sacks)
Name the 4 main types of acute pericarditis?
1) Serous
2) Sero-fibrinous or fibrinous
3) Purulent or suppurative
4) Haemorrhagic
What is serous pericarditis and what causes it?
This type of pericarditis occurs particularly with non-bacterial inflammations. The fluid is clear, straw coloured, protein rich and has a relative density of 1.020 or more with small numbers of polymorphs, lymphocytes and shed mesothelial cells.
The volume of serous fluid is usually small, and if formed slowly produces little effect on cardiac function. If the underlying cause resolves then the fluid is resorbed with little adhesion formation.
What is fibrinous pericarditis?
This is the most frequent type and occurs with rheumatic fever, myocardial infarction and in uraemia. There is an abundant, fibrin rich exudate with variable amounts of fluid and the “bread and butter” appearance on separating the parietal and visceral layers.
If the underlying disease remits there is:
i) Resolution with digestion of the fibrin
ii) Organisation with variable obliteration of the pericardial sac which may result in an adherent pericardium
What causes suppurative pericarditis?
The cause of this type of pericarditis is almost always pyogenic bacterial infection. This could be from:
i) Direct extension from neighbouring inflammations - e.g. empyema, pneumonia
ii) Blood spread from other sites in septicaemia or pyaemia
iii) Lymphatic spread from neighbouring sites, including subdiaphragmatic inflammation - e.g. subdiaphragmatic or hepatic abscess
There may be large volumes of watery turbid fluid or thick creamy pus from which organisms can be cultured. Inflammatory process may extend into the myocardium. Death may occur, but in survivors complete resolution is unusual. More commonly, organisation and an adherent pericardium occur.
What is haemorrhagic pericarditis?
This is blood mixed with inflammatory exudate and has to be differentiated from haemopericardium. It is usually due to invasion by tumour, but sometimes occurs in fulminating bacterial infections. When due to a tumour, malignant cells may be identified in aspirated fluid.
What are the clinical features of acute pericarditis?
Pleuritic chest pain, often positional, is classically relieved by sitting forwards. Many patients also experience a dull central ache without any specific features.
A pericardial rub may be heard, often only in one position or on inspiration. There may also be a fever or systemic features. Look for evidence of tamponade.
What investigations are needed in acute pericarditis?
ECG shows characteristic changes of ST segment elevation which is concave upwards, not just in one territory as in myocardial infarction but multiple and sometimes globally.
Echocardiography may show a small pericardial effusion. Specific tests may demonstrate the cause.
Bloods - FBC, U&E, cardiac enzymes, viral serology, blood cultures, autoantibodies (if indicated)
Cardiomegaly on CXR may suggest pericardial effusion.
How is acute pericarditis treated?
Analgesia - e.g. ibuprofen - can help relieve the pain and inflammation.
Treat the cause.
Consider colchicine BEFORE steroids if relapse/ continuing symptoms. 15-40% of cases recur and steroids increase the likelihood of recurrence.
What are sources of tuberculous pericarditis?
1) Miliary spread - i.e. blood-borne
2) Extension from pulmonary disease or from mediastinal lymph nodes
What is the appearance of tuberculous pericarditis?
There is a fibrinous exudate with granulation tissue covering the pericardial surfaces, visible tubercles and sometimes areas of caseation. It may occassionally be haemorrhagic with copious amounts of blood.
Normal histological TB features are seen microscopically.
What are the effects of tuberculous pericarditis?
Resolution does not occur and the process heals by gross fibrosis often followed by calcification. Not only is the pericardial sac obliterated, but the dense fibrous tissue layer contracts and restricts filling of the heart in diastole - constrictive pericarditis.
What is constrictive pericarditis?
(Pick’s disease) This is where the heart is encased in a rigid pericardium. Most cases are due to healed tuberculous pericarditis, others can be due to suppurative bacterial disease or connective tissue disease.
What is the appearance of constrictive pericarditis?
There is a thick, firm layer of fibrous tissue obliterating the pericardium and completely ensheathing the heart. The tissue frequently contains plaques of calcification and may be firmly adherent internally to the myocardium and externally to the lung, anterior chest wall or diaphragm. There is often a particularly dense fibrous area around the orifices of the inferior and superior vena cava as they enter the right atrium.
