Pericarditis, Myocarditis and Endocarditis Flashcards
What is myocarditis? What are the main causes?
Myocarditis is an inflammatory disease of the myocardium diagnosed by specific histological, immunological and immunohistochemical criteria. Based on the WHO an endomyocardial biopsy is the key diagnostic tool.
The main causes are infections, immune mediated and toxin mediated. The immune mediated type is currently recognized as the primary cause.
Infectious agents—> bacteria such as Staphylococcus and streptococcus, fungal such as aspergillus, protozoan such as trypanosoma cruzi and viral such as coxsackie and influenza virus.
Immune mediated—> RA, SLE, Kawasaki, inflammatory bowel disease.
Toxin—> drugs like amphetamines and cocaine, heavy metals such as copper and iron, and physical agents such as radiation.
What are some immunohistochemical criteria to diagnose myocarditis?
> 14 leukocytes mm^2, > 4 monocytes mm^2, > 7 CD3+ T cells mm^2.
If any of these markers are positive then you can diagnose active phase myocarditis.
What is the Dallas criteria?
You look for any type of inflammatory infiltrate in the myocardium on the H&E assay. If there is damage or cardiac myocytes, it is very important to identify signs of necrosis.
What are the different types of histotypes of myocarditis?
Lymphocytic : most common, 90%, with H&E stain we can observe cluster of lymphocytes.
Eosinophilic : Not very common but associated with some other autoimmune disorder and with some tumors.
Granulomatous : causes SCD, arrhythmias and AV blocks. The sarcoid form is associated with systemic or cardiac isolated sarcoidosis and the giant cell form is characterized by the presence of numerous cells, particularly macrophages.
How can myocarditis evolve in a patient over time?
It can either heal completely, transform into chronic myocarditis or auto reactive myocarditis in which there is activation of auto reactive T cells and induction of autoantibodies.
Even when healed a scar can still cause disease at a later stage. Many scars can cause reentry circuit and vulnerability to arrhythmias.
Some patients even have recurring myocarditis due to genetic factors being involved.
What are the main differences between acute myocarditis and chronic inflammatory cardiomyopathy?
Acute myocarditis : onset of symptoms < 30 days, inflammatory infiltrate, release of cardiac biomarkers, potential fulminant presentation in need of hemodynamic support, LV normal or slightly dilated, necrosis but not much fibrosis.
Chronic : onset of symtoms > 30 days, fibrosis symptoms may be present or absent, LV dilated, hypertrophy, EF is typically reduced, not much infiltrate, slight elevation of biomarkers such as troponin.
What is the most common clinical presentation of myocarditis?
ACD-like presentation is the most common which includes acute chest pain, with absence of actual angiographic CAD, ST and T ECG changes, with or without increased troponins.
What is fulminant myocarditis?
Fulminant myocarditis, rather than being a distinct form of myocarditis, is instead a peculiar clinical presentation of the disease. It is characterized by sudden death from cardiogenic shock, ventricular arrhythmias or multi organ failure.
The main conclusion of is fulminant myocarditis may be due to different histotypes and aetiologies that can be diagnosed only by endomyocardial biopsy and managed by aetiology-directed treatment.
How do ECGs differ for different stages of myocarditis?
During active myocarditis there will be prevalence of irregular and polymorphic rhythms.
In a post inflammatory setting with mostly fibrosis and not much inflammation the ECG will be regular and monomorphic.
How is myocarditis treated?
Hemodynamically unstable patients should be treated according to current guidelines for HF.
In hemodynamically stable patients treatement varies depending on biopsy results. They may be treated with diuretics, ACEi and ARBs, immunosuppressive therapy, anti viral treatments and immunomodulatory treatments.
What is pericardial effusion?
A normal pericardial sac contains 10 to 50 ml of pericardial fluid which acts as a lubricant between the pericardial layers. Any condition increasing the amount of fluid around the heart is considered pericardial effusion. This fluid may be transudative, exudative, or sanguineous and may contain infectious organisms or malignant cells. It may be due to infection, inflammation, neoplasms, trauma, vascular injury and others.
What is the difference between transudates and exudates?
Transudates are clear, colorless, have less than 3 g/dL of proteins and less than 1000 uL cell count, and are common of CHF. Exudates are yellow, turbid and bloody with more than 3 g/dL, more than 1000 uL cell count and typical of infections and malignancies.
How is pericardial effusion classified?
Onset : acute, subacute or chronic (>3 months).
Size : mid <10mm, moderate 10-20mm, large >20mm.
Distribution : circumferential or loculated.
Composition : transudate or exudate.
What is the epidemiology of pericardial inflammatory syndromes?
They are the most common disease of the pericardium. Frequently benign disease, 5% of ER admissions, more frequent in males age 16-65 yr. Inhospital mortality is up to 1% often due to a systemic disease rather than the pericarditis itself. QoL of patient may be affected.
What are the main causes of pericarditis?
Viral such as enteroviruses (most common), bacterial such as mycobacterium tuberculosis (not common), autoimmune diseases (SLE or RA), neoplastic such as pericardial mesothelioma and secondary metastatic tumors, metabolic (myxoedema, anorexia nervosa), traumatic and iatrogenic (lesion).
