Infective Endocarditis: Symptoms, Causes, Treatment

What are the symptoms of infective endocarditis?

Infective endocarditis is an infection of the inner lining of the heart chambers and valves. The symptoms can vary widely, but common signs and symptoms include:

1. Fever and Chills: Persistent fever is one of the most common symptoms.
2. Heart Murmur: New or changed heart murmur (an unusual sound heard during a heartbeat).
3. Fatigue: Severe tiredness and weakness.
4. Aching Joints and Muscles: Pain in joints and muscles.
5. Night Sweats: Profuse sweating during the night.
6. Shortness of Breath: Difficulty breathing, especially with activity.
7. Swelling: Swelling in the feet, legs, or abdomen.
8. Persistent Cough: A cough that doesn’t go away.
9. Skin Changes:

• Petechiae: Small, red or purple spots on the skin, inside the mouth, or on the whites of the eyes.
• Osler’s Nodes: Painful, red or purple, raised lesions found on the hands and feet.
• Janeway Lesions: Painless, flat, red spots on the palms and soles.
• Roth Spots: Retinal hemorrhages with white or pale centers, seen in the eyes.

1. Unexplained Weight Loss: Loss of weight without trying.
2. Blood in Urine: Blood or cloudy appearance in urine.
3. Splinter Hemorrhages: Tiny blood spots under the fingernails or toenails.

If infective endocarditis is suspected, it is important to seek medical attention promptly, as it can lead to serious complications if left untreated. Diagnosis typically involves blood tests, echocardiography, and other imaging studies to confirm the presence of infection and its effects on the heart. Treatment usually requires prolonged courses of intravenous antibiotics and, in some cases, surgical intervention to repair or replace damaged heart valves.

What are the causes of infective endocarditis?

Infective endocarditis is caused by the invasion of the inner lining of the heart chambers and valves by microorganisms, most commonly bacteria. The primary causes include:

1. Bacterial Infection:

• Streptococci: Especially viridans group streptococci, which are often found in the mouth.
• Staphylococci: Especially Staphylococcus aureus, which can enter the bloodstream through skin infections or intravenous drug use.
• Enterococci: Often originating from the gastrointestinal or genitourinary tract.
• Other Bacteria: Including those from the HACEK group (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella).

1. Fungal Infection: Less common but can be caused by fungi like Candida or Aspergillus, especially in immunocompromised individuals or those with prosthetic heart valves.
2. Risk Factors and Predisposing Conditions:

• Heart Valve Damage or Disease: Pre-existing heart valve abnormalities, such as those caused by rheumatic heart disease or congenital heart defects.
• Prosthetic Heart Valves: Artificial valves are more susceptible to infection.
• Intravenous Drug Use: Sharing needles can introduce bacteria directly into the bloodstream.
• Recent Dental or Medical Procedures: Procedures that involve the gums, teeth, or respiratory tract can introduce bacteria into the bloodstream.
• Intravascular Devices: Use of catheters, pacemakers, or other devices that can become infected.
• Poor Oral Hygiene: Gum disease or dental infections can provide a source of bacteria.
• Weakened Immune System: Conditions like HIV/AIDS, cancer, or diabetes can increase susceptibility.
• Chronic Conditions: Such as chronic kidney disease, which often requires hemodialysis.

The pathogenesis of infective endocarditis generally involves the bacteria entering the bloodstream, adhering to damaged heart tissue or prosthetic material, and forming vegetations (masses of microorganisms and cellular debris) that can cause further damage to the heart valves and spread to other parts of the body.

How is the diagnosis of infective endocarditis made?

The diagnosis of infective endocarditis (IE) is a complex process that involves a combination of clinical evaluation, laboratory tests, and imaging studies. Here are the typical steps involved in making a diagnosis of IE:

1. Clinical evaluation: The patient’s medical history, physical examination, and symptoms are assessed. Common symptoms of IE include:
   • Fever
   • Fatigue
   • Chills
   • Malaise
   • Weight loss
   • Chest pain or palpitations
2. Physical examination: A thorough physical examination is performed to look for signs of endocarditis, such as:
   • Heart murmur (a abnormal sound heard through a stethoscope)
   • Cardiac arrhythmias (abnormal heart rhythms)
   • Jugular venous distension (swelling in the neck veins)
   • Hepatomegaly (enlarged liver)
3. Laboratory tests:
   • Complete Blood Count (CBC): to evaluate for anemia, leukocytosis (elevated white blood cell count), and thrombocytopenia (low platelet count)
   • Blood cultures: to detect bacteria in the bloodstream
   • Erythrocyte Sedimentation Rate (ESR) and C-reactive Protein (CRP): to assess inflammation
   • Blood chemistry tests: to evaluate kidney and liver function
4. Imaging studies:
   • Transthoracic echocardiogram (TTE): a non-invasive ultrasound test to evaluate the heart valves and detect vegetations or damage
   • Transesophageal echocardiogram (TEE): a more detailed ultrasound test that uses a probe inserted through the mouth or nose to evaluate the heart valves and detect vegetations or damage
   • Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) scans: to evaluate the extent of infection and damage to surrounding tissues
5. Duke Criteria: The Duke Criteria are a set of clinical criteria used to diagnose IE based on the presence of two major criteria or one major and three minor criteria.
6. Blood cultures: Repeat blood cultures are taken after 1-2 weeks of antibiotic therapy to confirm clearance of the infection.
7. Valve vegetation size and mobility: The size and mobility of the valve vegetation are assessed using echocardiography to determine the severity of the infection.
8. Serology tests: Serology tests, such as antibodies against specific bacteria, may be performed to confirm the diagnosis.

A diagnosis of IE is typically made by a cardiologist or an infectious disease specialist after considering all these factors. Treatment usually involves antibiotics, and in some cases, surgery may be necessary to remove damaged tissue or replace affected heart valves.

What is the treatment for infective endocarditis?

The treatment for infective endocarditis (IE) typically involves a combination of antibiotics, supportive care, and in some cases, surgical intervention. The goal of treatment is to eradicate the infection, prevent further complications, and preserve the integrity of the heart valves. Here are the general treatment strategies for IE:

Antibiotics:

1. Empiric therapy: Initial antibiotic treatment is usually started before the results of blood cultures are available. The choice of antibiotics is based on the likely causative organism and the patient’s clinical presentation.
2. Targeted therapy: Once the results of blood cultures are available, targeted antibiotics are used to treat the specific bacterial strain causing the infection.
3. Duration: The duration of antibiotic therapy typically ranges from 4-6 weeks for native valve endocarditis and 6-8 weeks for prosthetic valve endocarditis.

Supportive care:

1. Fever control: Fever control measures such as antipyretics, cooling blankets, and intravenous fluids are used to manage high temperatures.
2. Pain management: Pain management strategies such as analgesics and sedatives are used to alleviate chest pain, headache, and other symptoms.
3. Cardiac support: Cardiac support measures such as vasodilators, inotropes, and diuretics may be used to manage heart failure or decreased cardiac function.

Surgical intervention:

1. Valve replacement: In severe cases of IE, surgery may be necessary to replace damaged or infected heart valves with artificial ones.
2. Debridement: In cases of extensive vegetation or abscesses, surgical debridement (removal of infected tissue) may be necessary to remove infected material and reduce the risk of further complications.
3. Endarterectomy: Endarterectomy is a surgical procedure that removes infected or damaged arterial tissue to restore blood flow to affected areas.

Other considerations:

1. Close monitoring: Patients with IE require close monitoring for signs of complications such as heart failure, arrhythmias, or embolism.
2. Anticoagulation therapy: Anticoagulation therapy may be necessary to prevent thrombus formation or embolization in patients with prosthetic valves or those at high risk of thrombotic events.
3. Dental care: Good oral hygiene and regular dental check-ups are essential to prevent reinfection or secondary infections.

It’s essential to consult with a cardiologist or an infectious disease specialist for personalized guidance on treating infective endocarditis.