Myocarditis and Pericarditis Flashcards
What is myocarditis?
Myocarditis is an inflammatory disease of the myocardium resulting from infectious and non-infectious causes.
What may myocarditis be accompanied by?
Pericarditis
What is the most common cause of myocarditis?
Viral
What are the three phases of the pathogenesis of myocarditis?
- Acute Phase
- Subacute Phase
- Chronic Phase
What occurs in the acute phase of myocarditis?
VIRUS REPLICATION
(lasts a few days)
Viral entry into myocytes - necrosis - exposure to the immune system
What occurs in the subacute phase of myocarditis?
IMMUNE RESPONSE
Immune activation leads to impairment of cardiac muscle with effect on ventricular function.
What occurs in the chronic phase of myocarditis?
DILATED CARDIOMYOPATHY
Viral genome +/- fibrosis, dilation, contractile dysfunction
How is diagnosis of myocarditis made?
CANNOT BE MADE ON CLINICAL BASIS ALONE
Combination of clinical evaluation and established histological, immunological and immuno-histochemical criteria
How is definitive diagnosis of myocarditis made?
ENDOMYOCARDIAL BIOPSY
Dallas Criteria used in evaluating lymphocyte infiltration and myonecrosis.
Which biomarkers are used in the diagnosis of myocarditis?
Biomarkers are not specific but can be used to help confirm diagnosis.
- troponin is more frequently evaluated than creatine kinase
- leukocytes and CRP may be elevated
What is important about the diagnosis of infective causes of myocarditis?
May be difficult to pick up - there is often a delay in presentation.
- Appropriate viral serology or PCR indicated
What are the clinical features of myocarditis?
Ranges from asymptomatic to symptoms resembling a myocardial infarction to cardiogenic shock
What are some of the signs and symptoms of myocarditis?
- chest pain
- arrhythmias
- acute / chronic cardiac failure can occur
- pericardial rub
- Diagnosis can be made on clinical basis alone
What will be seen on ECG in myocarditis?
- can have non-specific changes
- changes may mimic other conditions e.g. MI
What is the use of Echocardiogram
Aids in determining chamber size, wall thickness and systolic and diastolic function.
What is the use of a cardiac MRI in myocarditis?
This is more utilized now:
- detects areas of inflammation
- helps suggest viral etiology (different viruses affect different parts of the heart)
- helps to differentiate between MI and myocarditis
- can help determine if myocarditis is chronic or acute
How is myocarditis treated?
- Treat the cause (if found)
- Limit physical activity
- Mainly supportive management in stable patients
- Treat the complications
What are the 3 most common complications of myocarditis?
- Dilated cardiomyopathy (most common)
- Arrhythmias
- CCF
Outcomes of myocarditis:
Most cases resolve without sequelae, however dilated cardiomyopathy is a common complication when patients are followed-up.
What makes up the pericardium?
2 layers - composed of fibrous tissue
- Inner visceral layer attached to epicardium
- Outer parietal layer
What are the 4 functions of the pericardium?
- Limits the hearts motion (stabilizes the heart within the thoracic cavity)
- Protects the heart from mechanical trauma and infection
- Pericardial fluid acts as a lubricant and decreases the friction of cardiac surfaces
- Prevention of excessive dilation of the heart, especially during a sudden rise in intra-cardiac volume
What are the three ways in which pericarditis may present?
- As a primary site of disease
- Involved in other disease processes that affect the heart (e.g. autoimmune conditions)
- Affected by other diseases or adjacent tissues (e.g. from lung: TB / invasive malignancy)
What are the three primary presentations of pericarditis?
- Acute pericarditis
- Pericardial effusion - cardiac tamponade
- Constrictive pericarditis
How does pericarditis present as acute pericarditis?
Inflamed pericardial layers
How does pericarditis present as pericardial effusion (potentially progressing to cardiac tamponade)?
Accumulation of pericardial fluid exerts pressure on cardiac chambers
How does pericarditis present as constrictive pericarditis?
Thickened +/- calcified pericardium restricts cardiac filling
What are the 3 steps in the pathogenesis of pericarditis?
- Vasodilation
- transudation of fluid - Increased vascular permeability
- leakage of protein - Leukocyte exudation
- neutrophils and mononuclear cells
What does the inflammatory response depend on (in pericarditis)?
Depends on the underlying cause and severity of inflammation.
What types of inflammatory response are seen in pericarditis?
- Serous pericarditis (often viral)
- Serofibrinous pericarditis (often viral)
- Suppurative (purulent) pericarditis (often bacterial)
- Haemorrhagic pericarditis (often malignancy)
- Chylous (lymph pericarditis) = obstruction to lymphatics
What are some of the causes of pericarditis?
- Infectious
- Autoimmune disorders
- Neoplasms
- Radiation pericarditis
- Renal failure (uremia)
- Traumatic cardiac injury
- Idiopathic
What is the most common cause of pericarditis?
Infectious, specifically VIRAL!
What viruses cause pericarditis?
- Coxsackie A & B
- Influenza
- Adenovirus
- HIV
etc.
What are the clinical features of pericarditis?
- Chest pain (sharp-dull ache; tends to refer to the left shoulder or arm)
- Low grade fever
- Dyspnoea
- Palpitations may also occur
- Pericardial friction rub
How is pericarditis diagnosed?
Pericarditis is a CLINICAL DIAGNOSIS!
What other investigations may support the diagnosis of pericarditis?
- Echocardiogram: pleural effusion (NB: absence does not rule out pericarditis)
- Blood tests: PPD, RF, ANA
- Viral serology or PCR
- Look for malignancy
What is the definition of a pericardial effusion?
Abnormal accumulation of fluid n the pericardial cavity increasing intrapericardial pressure & negatively impacting on heart function.
What can cause a pericardial effusion?
- Inflammation from infection
- Trauma causing bleeding in the pericardial space
- Other non-infectious conditions:
- increase in pulmonary hydrostatic pressure e.g. congestive heart failure
- increase in capillary permeability e.g. hypothyroidism
- decrease in plasma oncotic pressure e.g. cirrhosis - Decreased drainage of pericardial fluid due to obstruction of thoracic duct as a result of malignancy or damage during surgery.
What types of pericardial effusions may be seen?
- serous
- serofibrinous
- suppurative
- chylous
- hemorrhagic
(depending on etiology)
What type of effusions are usually seen due to viral causes?
Usually serous or serofibrinous
What type of effusions are usually seen due to malignant causes?
Usually hemorrhagic
How should a pericarditis be treated?
- Bed rest and pain relief (analgesics and anti-inflammatory agents: NSAIDs)
- Steroids for recurring pericarditis
- Treat the causative agent
- Drainage for purulent pericarditis
- Treat any underlying issue
What are some of the complications that can occur due to pericarditis?
- Pericardial effusion - cardiac tamponade
2. Constrictive pericarditis - CCF
What are the clinical features of a pericardial effusion?
- Pericardium relatively stiff
- Symptoms of cardiac compression
- Similar to pericarditis
What are the symptoms of cardiac compression dependent on?
- Volume of fluid
- Rate of fluid accumulation
- Compliance characteristics of the pericardium
What do small pericardial effusions not produce?
Small effusions do not produce hemodynamic abnormalities
What do large pericardial effusions cause?
Large effusions, in addition to hemodynamic compromise, may lead to compression of adjoining structures and produce symptoms of:
- Dysphagia (compression of oesophagus)
- Hoarseness (recurrent laryngeal nerve compression)
- Hiccups (diaphragmatic stimulation)
- Dyspnoea (pleural inflammation / effusion)
What are the clinical features (signs) of pericardial effusion?
- Pulsus paradoxus
- Muffled heart sounds
- Pericardial friction rub
- Ewart’s sign
- Beck’s triad
What is Ewart’s sign?
Compression of the lung in the left infrascapular region (atelectasis, detected as dullness to percussion)
What is Beck’s triad?
(Cardiac tamponade):
- Hypotension
- Muffled heart sounds
- Jugular venous distention
How is pericardial effusion treated?
- Pericardiocentesis done = sent for MC+S & cytology
- low diagnostic yield
- done therapeutically
How is constrictive pericarditis treated?
Surgery (no other alternative)
What is constrictive pericarditis?
= late complication of pericardial disease
- fibrous scar formation
- fusion of pericardial layers
- calcification further stiffens pericardium
What are some of the etiologies of constrictive pericarditis?
- any cause of pericarditis
- idiopathic
- post-surgery
- TB
- radiation
- neoplasms
