6. Acute pericarditis Flashcards
Acute pericarditis definition?
Acute pericarditis is most often of idiopathic origin,
meaning that the actual cause is unknown. However, serologic studies have demonstrated that many
such episodes are actually caused by viral infection.
Viruses that can cause pericarditis?
Other viruses known to cause pericarditis include those responsible for influenza, varicella, mumps,
hepatitis B, and infectious mononucleosis.
Manifestation of pericarditis?
Pericarditis is the most common manifestation of
cardiovascular disease in patients with AIDS, arising from HIV infection itself or from superimposed
tuberculous or other bacterial infections in this immunocompromised population.
Tuberculous Pericarditis?
Tuberculous pericarditis arises from reactivation of the organism in mediastinal lymph nodes, with
spread into the pericardium. It can also extend directly from a site of tuberculosis within the lungs, or
the organism can arrive at the pericardium by hematogenous dissemination.
Nontuberculous Bacterial Pericarditis (Purulent Pericarditis)?
Bacterial pericarditis is a fulminant
illness but is rare in otherwise healthy persons; it is most likely to occur in immunocompromised
patients, including those with severe burns and malignancies. Pneumococci and staphylococci are
responsible most frequently, whereas gram-negative infection occurs less often. Mechanisms by
which bacterial invasion of the pericardium develops include (1) perforating trauma to the chest
(e.g., stab wound);
(2) contamination during chest surgery;
3) extension of an intracardiac infection
(i.e., infective endocarditis);
(4) extension of pneumonia or a subdiaphragmatic infection; and
(5)
hematogenous spread from a remote infection.
Noninfectious Pericarditis Following Myocardial Infarction?
There are two forms of pericarditis
associated with acute myocardial infarction (MI). The early type occurs within the first few days after
an MI. It likely results from inflammation extending from the epicardial surface of the injured
myocardium to the adjacent pericardium; therefore, it is more common in patients with transmural
(as opposed to subendocardial) infarctions.
The second form of post-MI pericarditis is known as Dressler syndrome, which can develop 2 weeks
to several months following an acute infarction. Its cause is unknown, but it is thought to be of
autoimmune origin, possibly directed against antigens released from necrotic myocardial cells. A
clinically similar form of pericarditis may occur weeks to months following heart surgery.
Uremic Pericarditis?
Pericarditis is a serious complication of chronic renal failure, but its pathogenesis
in this setting is unknown. Studies have shown no correlation between the plasma level of nitrogen
waste products and the incidence of pericarditis, and it may even develop in patients during the first
few months of dialysis therapy.
Neoplastic Pericarditis?
Tumor involvement of the pericardium most commonly results from
metastatic spread or local invasion by cancer of the lung, breast, or lymphoma. Neoplastic effusions are usually large and hemorrhagic and frequently lead
to cardiac tamponade, a life threatening complication.
Radiation-Induced Pericarditis?
Pericarditis may complicate radiation therapy to the thorax (e.g.,
administered for the treatment of certain tumors), especially if the cumulative dose has exceeded
4,000 centigray. Radiation-induced damage causes a local inflammatory response that can result in pericardial effusions and ultimately fibrosis. Cytologic examination of the pericardial fluid helps to
distinguish radiation-induced pericardial damage from that of tumor invasion.
Pericarditis Associated with Connective Tissue Diseases?
Pericardial involvement is common in many
connective tissue diseases, including systemic lupus erythematosus (SLE), rheumatoid arthritis, and
progressive systemic sclerosis. For example, 20% to 40% of patients with SLE experience clinically
detectable pericarditis during the course of the disease.
Drug-Induced Pericarditis?
Several pharmaceutical agents have been reported to cause pericarditis as
a side effect, often by inducing a systemic lupus-like syndrome. These drugs include the
antiarrhythmic procainamide and the vasodilator hydralazine. Drug-induced pericarditis usually
abates when the causative agent is discontinued.
Pathogenesis?
Pericarditis is characterized by three stages:
(1) local
vasodilation with transudation of protein-poor, cell-free fluid into the pericardial space;
(2) increased
vascular permeability, with leak of protein into the pericardial space; and
(3) leukocyte exudation,
initially by neutrophils, followed later by mononuclear cells. The leukocytes are of critical importance
because they help contain or eliminate the offending infectious or autoimmune agent. However,
metabolic products released by these cells may prolong infl ammation, cause pain and local cellular
damage, and mediate somatic symptoms such as fever
