ENDOCARDITIS

Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves.Endocarditis is characterized by a prototypic lesion, the vegetation, which is a mass of platelets, fibrin, microcolonies of microorganisms, and scant inflammatory cells.There are multiple ways to classify endocarditis. The simplest classification is based on etiology: either infective or non-infective, depending on whether a microorganism is the source of the inflammation or not. 

People with poor dental hygiene, heart valve abnormalities, congenital heart disease, and weakened immune systems are at higher risk for endocarditis.

Endocarditis can cause direct damage to the heart, or damage to other organs from bacterial emboli, or pieces of bacteria that “break free” from the heart.

Endocarditis is diagnosed by blood tests and ultrasound pictures of the heart.

Most cases of endocarditis can be treated with intravenous antibiotics, although a few serious cases require open-heart surgery.

The best method of preventing endocarditis is maintaining good oral and general health.  People with heart valve abnormalities, congenital heart disease, or who have had endocarditis previously may benefit from preventive antibiotics prior to dental or surgical procedures. 

RISK FACTORS FOR ENDOCARDITIS

Because endocarditis is usually caused by bacteria entering the bloodstream and accumulating on the valves of the heart, people at risk for the condition include those with a tendency for bloodstream infection and those with abnormalities of their heart that allow for accumulation of the bacteria.

Conditions increasing the risk of bloodstream infection:

• Poor dental hygiene
• Intravenous drug use
• Surgeries or procedures, especially those involving the mouth or the gastrointestinal system
• Medical conditions that can weaken the immune system (e.g. diabetes, severe kidney disease, HIV/AIDS, cancer)
• Elderly age
• Prolonged use of intravenous catheters (e.g. in hospitalized patients, patients receiving home intravenous therapy, or patients receiving hemodialysis for kidney failure)
• People recently hospitalized

Conditions increasing the risk of accumulation of bacteria in the heart:

1. Abnormalities of one or more of the heart valves (e.g. malformed valves, leaky valves, rheumatic heart disease)
2. Congenital heart abnormalities (e.g. “holes” in the heart)
3. 1. Artificial heart devices (e.g. mechanical heart valves, pacemakers, defibrillators)

COMPLICATIONS OF ENDOCARDITIS

Endocarditis can cause two types of complications:  complications to the heart from direct damage by the bacteria, and/or complications to other organs from bacterial emboli, or pieces of bacteria that break free from the heart.

• Valve damage – When the bacteria gather on the valve leaflets, they can prevent proper opening and closing of the valve.  Even after the bacteria have been treated with antibiotics, the damage to the valve can be permanent.  If the damage is sufficiently severe, it may require surgical replacement of the valve.  In addition, the damaged valve is at higher risk for developing endocarditis in the future.
• Congestive heart failure – If the bacterial accumulation is sufficiently large, the valve can fail and result in weakening of the pumping action of the heart, a condition known as congestive heart failure.  This is a serious complication, and usually requires immediate surgery to replace the valve.
• Slow heart beats – If the bacterial infection affects the “wiring” of the heart, then the heart may skip beats or beat very slowly.  If this condition results in dizziness or passing out, then a pacemaker may be needed.

Complications from bacterial emboli:

In approximately 11%-25% of patients with endocarditis, small pieces of bacteria, or emboli, break off from the main area of infection in the heart and travel through the bloodstream. As they travel, they may lodge in a blood vessel, block it, and damage the organ that the blood vessel supplies.  Common organs that are affected include:

• Brain – Bacterial emboli can travel from the heart to the brain and cause a stroke.
• Kidney – Bacterial emboli can travel from the heart to the kidney and cause kidney damage or failure.
• Musculoskeletal system – Bacterial emboli can cause inflammation of the muscles and joints.
• Other organs – Emboli can affect the eyes, spleen, liver, lungs, or intestines.

Symptoms of endocarditis usually begin within 2 weeks after infection of the blood.
Common symptoms include:

• Fever
• Chills
• Fatigue
• Excessive sweating, especially at night
• Loss of appetite
• Unexplained weight loss
• Back or joint pain Blood in the urine
• New rashes (especially red, painless skin spots on the palms and soles) Red, painful nodes on the pads of the fingers and toes
• Shortness of breath with activity
• Fluid buildup in arms or legs (swelling of feet, legs, or abdomen)
• Sudden weakness in the face or extremities suggestive of a stroke  

TREATMENT

Treatment of endocarditis requires antibiotic therapy and, in rare and serious cases, open-heart surgery.

Antibiotics - If endocarditis is detected early and the bacterial accumulation (known as a “vegetation”) covers only a small area (less than 10 mm), intravenous antibiotic therapy for 2 to 6 weeks is often the only treatment necessary. Once antibiotic therapy is started, most patients quickly improve, with less fatigue, improved appetite, and a disappearance of fevers and chills. However, this does NOT mean the infection is gone. Treatment should be continued as prescribed because it usually takes the full 2 to 6 week course of antibiotics to kill the last of the infecting organisms.  Stopping this treatment early can cause the infection to re-occur.

Open-heart surgery – Higher risk infections, such as vegetations larger than 20 mm or infections causing congestive heart failure, may require open-heart surgery to remove infected tissue, correct pre-existing heart disease, or repair the heart valve damage. Typical indications for surgery are heart failure due to damaged valves, uncontrolled infection into the heart (abscess formation), recurrent emboli, and relapse after appropriate medical therapy.

by

AKSHAYA SRIKANTH

Pharm.D Intern

INDIA