Diseases of the Pericardium

Question 1

What is the function of the pericardium?

Answer 1

• The normal pericardium lubricates the surface of the heart, prevents sudden deformation or dislocation of the heart, and acts as a barrier to the spread of infection.
• It normally contains up to 50mL of serous fluid.

Question 2

What are the 3 common presentations of pericardial disease?

Answer 2

• Acute pericarditis
• Pericardial effusion
• Constrictive pericarditis

Question 3

What is acute pericarditis?

Answer 3

• < 6 weeks
• Coxsackie disease and echovirus are the most common causes of acute pericarditis in the UK.
• Initially dry and fibrinous. However, almost all aetiologies of this condition also induce the formation of pericardial effusion.

Question 4

What are the main causes of acute pericarditis?

Answer 4

• Viral
• Post-MI
• Uraemic / dialysis-related
• Bacterial
• TB
• Fungal
• Malignant
• Autoimmune

Question 5

Describe viral acute pericarditis.

Answer 5

• Often sudden onset. Tends to afect young adults.
• Usually illness only lasts a few weeks and prognosis is good.
  
  • However, recurrences and sudden death can occur.
• HIV should be excluded in young patients with large pericardial effusions, co-existent pulmonary infiltrates and fever.
• Serial serological tests are helpful in diagnosing a viral aetiology of acute pericarditis.

Question 6

Describe post-MI acute pericarditis.

Answer 6

• Occurs in ~20% of patients within the first few days post.
• Likelihood of this is higher in patients with anterior MI, Q-wave MI and high serum cardiac enzymes.
• Typical features:
  
  • Pericardial friction rub
  • Recurrence of chest pain
  • Fever
• ECG findings:
  
  • Persistent positive T waves
  • Reversal of negative T waves
• Usually fibrinous and rarely causes haemodynamic compromise.
• Thrombolysis may reduce risk of post-MI pericarditis.
• NSAIDs other than aspirin and corticosteroids should be used cautiously as they may increase risk of myocardial rupture.
• Dressler’s syndrome occurs a month to one year later.

Question 7

Describe bacterial acute pericarditis.

Answer 7

• Purulent pericarditis may rarely occur with septicaemia or pneumonia.
  
  • May stem from early post-op infection after thoracic surgery or trauma or may complicate endocarditis.
• Common features:
  
  • Swinging fever
  • Dyspnoea
  • Substantial leucocytosis with a marked leftward shift
• Most common causative organisms:
  
  • Staphylococcus
  • Haemophilus influenza
  • Staph aureus is a common cause of purulent pericarditis in HIV patients
• ABx are the mainstay of treatment. Surgical drainage may be indicated.
• Diagnosis is based on serological testing of pericardial fluid and identification of organisms in pericardial or myocardial biopsies.

Question 8

What are the clinical features of acute pericarditis?

Answer 8

• Pericardial inflammation gives rise to chest pain that is substernal and sharp.
• Relieved by sitting forward; made worse by sitting / lying down. Aggravated by the movement of respiration.
• May be referred to neck / shoulders.
• The cardinal clinical sign is pericardial friction rub.
  
  • A leathery triphasic sound heard best at the lower left sternal edge with the patient leaning forward.
• Large pericardial effusion may compress adjacent bronchi and may cause dyspnoea.
• There is usually fever when pericarditis is due to viral or bacterial infection, rheumatic fever or MI.

Question 9

Describe the investigations used in ?acute pericarditis.

Answer 9

• ECG is diagnostic.
  
  • During the first week there is ST segment elevation in all leads facing the epicardial surface (anterior, lateral and inferior).
  • Later, ST segment normalises and T wave inversion may be seen without a decrease in R wave amplitude or the appearance of pathological Q waves.
  • As the illness improves the T waves become normal but occasionally may persist in patients with chronic pericarditis.
• Sinus tachycardia is a common finding in acute pericarditis and may be due to dever or haemodynamic embarrassment.
• Rhythm and conduction abnormalities are not typical unless the myocardium is involved.
• Leucocytosis is common at early stages but later may be replaced by lymphocytosis.
• Cardiac enzymes may be elevated if there is associated myocarditis.

Question 10

Describe the management of acute pericarditis.

Answer 10

• Treat the cause if possible.
• Rx = anti-inflammatory drugs and rest.
• Aspirin is given at high doses (600-900mg every 6 hours).
• Indometacin (25-100mg every 4 hours) or ibuprofen (400mg every 6 hours) can be used for symptoms relief (not post-MI).
• If severe or recurrent, corticosteroids may be necessary.
  
  • Prednisolone 20-80mg daily, followed by gradual decrease in dose in 5-7 days after clinical signs are resolved.
  • If resistant to corticosteroids, azathioprine 50-100mg daily or colchicine 1-2mg/dL may be effective.

Question 11

Describe the aetiology of pericardial effusion.

Answer 11

• The effusion collects in the closed pericardium, and when the pericardium can distend no further this producesmechanical embarrassment to the circulation by preventing ventricular filling.
• This is called cardiac tamponade.

Question 12

What are the clinical features of pericardial effusion?

Answer 12

• Effusion obscures the apex beat and the heart sounds are soft and distant.
• Although a friction rub may be heard in the early stages, it may be quieter once the fluid accumulates, as this separates the visceral and parietal pericardia.
• Features of cardiac tamponade include:
  
  • Raised JVP with a sharp diastolic collapse
  • y descent (Friedreich’s sign)
  • A paradoxical pulse
  • Increased neck vein distension during inspiration (Kussmaul’s sign)
  • Reduced CO
• Pericardial effusion may compress the base of the left lung, and an area of dullness can be detected by percussion below the angle of the left scapula.

Question 13

Describe the investigation of ?pericardial effusion.

Answer 13

• ECG shows low voltages.
• CXR may demonstrate a large globular or pear-shaped heart with sharp outlines.
• Typically, the pulmonary veins are not distended.
• ECHO is most useful for demonstrating effusion and right ventricular collapse during late diastole.
• Doppler may show increased flow through tricuspid and pulmonary valves and decreased mitral flow during inspiration.
• MRI may help detect haemopericardium or loculated pericardial effusion.

Question 14

Describe the treatment of pericardial effusion.

Answer 14

• Cardiac tamponade is a medical emergency and the effusion must be tapped.
• Pericardiocentesis is indicated when a malignant, TB or a purulent pericarditis is suspected.

Question 15

What is cardiac tamponade?

Answer 15

Cardiac tamponade is a clinical syndrome caused by the accumulation of fluid in the pericardial space, resulting in reduced ventricular filling and subsequent hemodynamic compromise.

Question 16

Describe the aetiology of constrictive pericarditis.

Answer 16

• Following certain forms of pericarditis (TB effusion, haemopericardium, bacterial infection or rheumatic heart disease), the pericardium may become thick, fibrous and calcified.
• The heart is then encased in a solid shell and cannot fill properly.
• Myocardial contractility is usually preserved but is impaired at late stages owing to fibrosis, atrophy and calcification of subepicardial layers of myocardium.
• Constrictive pericarditis also develops later after open heart surgery.

Question 17

Describe the clinical features of constrictive pericarditis.

Answer 17

• Typical signs are of systemic venous congestion - ascites, dependent oedema, hepatomegaly and jugular venous distension, without much breathlessness or pulmonary venous distension.
• There are signs of impaired ventricular filling (Kussmaul’s sign), Friedreich’s sign and pulse paradoxicus.
• Fatigue and exercise intolerance are common symptoms.
• Sinus tachycardia often occurs to compensate for low CO.
• AF is common (30%), and a loud 3rd heart sound (a pericardial knock) due to rapid ventricular filling may be heard. This is an early 3rd heart sound.
• Other causes of ascites must be excluded.
• Restrictive cardiomyopathy is a close mimic.

Question 18

Describe the investigation of ?constrictive pericarditis.

Answer 18

• CXR
  
  • Shows a relatively small heart with obvious calcification seen on a lateral film.
• ECG
  
  • May show low QRS voltages and T wave inversion.
• ECHO
  
  • May demonstrate the thickened pericardium with calcification predominantly over the right heart and relative immobility of the heart.
  • Typically, the ventricular cavities are small with normal wall thickness and dilated atria.
  • An abnormal septal motion often present.
  • Pericardial effusion is usually absent.
• Cardiac catheterisation and MRI scan
  
  • May be useful in difficult cases.

Question 19

Describe the management of constrictive pericarditis.

Answer 19

• Surgical resection of a substantial portion of the thickened pericardium provides a cure in about half of cases.
• In others, persistent constriction, AF and myocardial fibrosis prevent full recovery.