Endocarditis pathophysiology

Jump to navigation Jump to search

Endocarditis Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Infective Endocarditis from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications & Prognosis

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

X-ray

Echocardiography and Ultrasound

CT scan

MRI

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease

Diagnosis and Follow-up

Medical Therapy

Intervention

Case Studies

Case #1

Endocarditis pathophysiology On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Endocarditis pathophysiology

CDC onEndocarditis pathophysiology

Endocarditis pathophysiology in the news

Blogs on Endocarditis pathophysiology

to Hospitals Treating Endocarditis pathophysiology

Risk calculators and risk factors for Endocarditis pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Altered blood flow around the valves is a risk factor for the development of endocarditis. The valves may be damaged congenitally, from surgery, by auto-immune mechanisms, or simply as a consequence of old age. The damaged part of a heart valve becomes covered with a blood clot, a condition known as non-bacterial thrombotic endocarditis (NBTE).

Bacteremia

In a healthy individual, a bacteremia (where bacteria get into the blood stream through a minor cut or wound) would normally be cleared quickly with no adverse consequences. If a heart valve is damaged and covered with thrombus, these structures can provide a nidus for bacteria to attach themselves and an infection can be established.

Pathogens

The predominant pathogens in infective endocarditis include the following three gram-positive cocci:

  1. Viridans group streptococci, although the incidence is decreasing
  2. Staphylococcus species incidence is increasing
  3. Enterococcus species

Among the streptococcal viridans group the following are the most common:

  • Species: sanguis, oralis (mitis), salivarius, mutans
  • Anginosus (milleri) group: intermedius, anginosus, constellatus
  • Gemella species: morbillorum, bergeriae,sanguinis, hemolysans, Abiotrophia defectiva
  • Granulicatella species: elegans,

Causes of Bacteremia

Dental Procedures

The bacteremia is often caused by dental procedures, such as a cleaning or extraction of a tooth. It is important that a dentist or a dental hygienist therefore be told of any heart problems before beginning the procedure. Prophylactic antibiotics are administered to patients with certain heart conditions as a precaution.

Entrance of Bacteria Into the Bloodstream

Another cause of infective endocarditis is a scenario in which an excess number of bacteria enter the bloodstream. Colorectal cancer, serious urinary tract infections, and IV drug use can all introduce large numbers of such bacteria. When a large burden of bacteria are introduced, a normal heart valve may be infected. A more virulent organism (such as Staphylococcus aureus, but see below for others) is often responsible for infecting a normal valve.

Intravenous Drug Use

Infections of the tricuspid valve and less frequently the pulmonic valve tend to occur in intravenous drug users given the high pathogen burden from their introduction in the vein. The diseased valve is most commonly affected when there is a pre-existing disease. In rheumatic heart disease this is the aortic valve and the mitral valves, on the left side of the heart.

Complications of Endocarditis

Complications of endocarditis can occur as a result of the locally destructive effects of the infection. These complications include perforation of valve leaflets, perforation of fistula between blood vessels or cardiac chambers, abscesses, embolization and disruption of conduction system.

pathology

Image courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology

References

Template:WH Template:WS