Diseases of the Pericardium Flashcards
How many layers does the pericardium have?
The pericardium consists of two layers: a parietal layer and a visceral layer. The parietal layer is fibrous, protecting the heart with a potential space between it and the visceral layer.
A small amount of serous fluid can be found in between the parietal and visceral layers.
What is the pathophysiology of acute pericarditis?
Inflammation of the pericardium can be due to a number of causes:
- most common is Coxsackie viral infection which can occur in epidemics
- post-myocardial infarction (Dressler’s syndrome)
- uraemia
- connective tissue disease (autoimmune rheumatic diseases)
- postpericardiotomy
- myocardial infarction
- trauma
- tuberculosis
- uraemia
All forms of pericarditis can lead to formation of a pericardial effusion - this can be haemorrhagic, serous,, fibrinous or purulent
Does the nature of the pericardial effusion give any clues as to the underlying cause for pericarditis?
Sometimes.
Fibrinous exudates may eventually lead to adhesion formation. Serous pericarditis often produces large effusions of turbid, straw coloured fluid with a high protein content.
Haemorrhagic effusion is often due to malignant disease, particularly carcinoma of the breast, bronchus and lymphoma.
Purulent pericarditis is rare, and may occur as a complication of sepsis, by direct spread from an intrathoracic infection, or from a penetrating injury.
What are the clinical features of acute pericarditis?
Retrosternal pain radiating to the shoulders and neck and aggravated by deep breathing, movement, a change in position, exercise or swallowing (classically the pain of pericarditis is relieved by leaning forwards).
Pericardial friction rub (high pitched superficial scratching or crunching noise produced by movement of the inflamed pericardium and is diagnostic); usually heard in systole but may also be audible in diastole.
How should suspected pericarditis be investigated?
ECH shows ST elevation with upward concavity over the affected area, which may be widespread.
PR interval depression is a very specific indicator of acute pericarditis.
Later there may be T wave inversion especially if myocarditis is also present.
All patients with confirmed pericarditis should get a transthoracic echo.
How is pericarditis managed?
NSAIDs and colchicine are now used first-line for pain relief in patients with acute pericarditis.
Steroids may suppress symptoms but there is no evidence that they accelerate cure.
In viral pericarditis, recovery usually occurs within a few days or weeks, but there may be recurrences (chronic relapsing pericarditis). Purulent pericarditis requires treatment with antimicrobials, pericardiocentesis +/- surgical drainage.
What are the clinical features of a pericardial effusion?
Retrosternal oppression is sometimes a feature if an effusion develops. They are difficult to detect clinically.
Heart sounds may be quieter, and a pericardial friction rub may persist but is rarely heard because the fluid separates the visceral and parietal pericardium.
QRS voltages on the ECG are often reduced in the presence of a large effusion. Complexes can alternate in amplitude due to a to-and-fro motion of the heat within the fluid filled pericardial sac (electrical alternans).
Serial chest X rays show a rapid increase in the size of the cardiac shadow over days or even hours. A large effusion gives the heart a globular or pear shape.
Echo is definitive.
Give some causes of a pericardial effusion
Viral pericarditis Tuberculosis Uraemia Myxoedema Neoplasia Myocardial infarction Aortic dissection Radiotherapy Perforation during cardiac catheterization
What is cardiac tamponade?
This is a term used to describe acute heart failure due to compression of the heart by a large or rapidly developing effusion.
The effusion can be small and is sometimes <100mL. Sudden deterioration may be due to bleeding into the pericardial space.
Tamponade can complicate any form of pericarditis but can also be due to malignant disease. Other causes include trauma and rupture of the free wall of the myocardium.
Treated with pericardiocentesis.
How is suspected cardiac tamponade investigated?
May show features of the underlying disease, such as pericarditis or acute MI. When there is a large effusion, the ECG complexes are small and there may be electrical alternans.
A chest X ray shows an enlarged globular heart, but can appear normal.
Echo is the best way to confirm the diagnosis and helps to identify the best site for aspiration.
What are the clinical features of cardiac tamponade?
Dyspnoea
Collapse
Tachycardia
Hypotension
Gross elevation of the JVP
Soft heart sounds with an early third sound
Pulsus paradoxus (a large fall in BP during inspiration when the pulse may be impalpable)
Kussmaul’s sign (a paradoxical rise in the JVP during inspiration)
What are the indications for pericardial aspiration?
Diagnostic purposes
Treatment of tamponade
Few millilitres of fluid aspirated through the needle may be sufficient for diagnostic purposes but a drai is needed for symptomatic relief.
What are the complications of pericardiocentesis?
Arrhythmias
Damage to coronary arteries
Bleeding with exacerbation of tamponade as a result of injury to the RV
When tamponade is due to cardiac rupture or aortic dissection, pericardial aspiration may precipitate further potentially fatal bleeding and in these situations, emergency surgery is the treatment of choice.
How does tuberculous pericarditis present?
Tuberculous pericarditis may complicate pulmonary TB but may also be the first manifestation of the infection. In Africa, tubcerulous pericardial effusion is a common features of AIDs.
Typically presents with chronic malaise, weight loss and a low grade fever. An effusion usually develops and the pericardium may become thick and unyielding, leading to pericardial constriction or tamponade. An associated pleural effusion is often present.
How is tuberculous pericarditis treated?
The diagnosis can be confirmed by aspiration of the fluid and direct examination or culture for tubercle bacilli.
Treatment requires specific anti-tuberculous chemotherapy, plus a 3 month course of prednisolone which improves outcome (tappering dose)
