What is Endocarditis
Endocarditis is an inflammation of the inner lining of the heart (endocardium) and heart valves.
- In most cases, this condition is caused by an infection, while on other occasions it recognizes a non-infectious etiopathogenesis.
- Infective endocarditis is more commonly of bacterial origin, but other pathogens can also determine the onset of inflammation.
Under normal conditions, the immune system recognizes and defends the body from infectious agents, which - even if they could reach the heart - would be harmless, crossing it without causing an infection. However, if the cardiac structures are damaged, as a result of rheumatic fever, birth defects or other diseases, they can be attacked by microorganisms. Under these conditions, for bacteria penetrated into the body through the bloodstream it is easier to take root in the inner lining of the heart, overcoming the normal immune response to infections. When the ideal situation occurs, infectious agents can organize themselves forming masses called "vegetations" (lesions characteristic of bacterial endocarditis) at the site of infection, be it a heart valve or other structures of the heart, including implanted devices. There is a risk that these cell masses act similarly to blood clots, blocking the blood supply to the organs and inducing heart failure or triggering a stroke. On microscopic analysis, these vegetations show the presence of microcolonies of infecting microorganisms, incorporated in a reticulum of platelets, fibrin and a few inflammatory cells.
If endocarditis is neglected, inflammation can damage or destroy endocardial tissues or heart valves and lead to life-threatening complications. If you have a heart defect, special medical procedures can create transient bacteremia that is potentially responsible for endocarditis: tonsillectomy, adenoidectomy, bowel and respiratory surgery, cystoscopy, bronchoscopy, colonoscopy, etc. The risk of endocarditis also exists when the patient undergoes some dental procedures.
Endocarditis is a serious disease, capable of inducing very serious medical complications and can even be potentially fatal. The diagnostic confirmation is based on the identification of the clinical and microbiological characteristics, with echocardiogram, radiological investigations and blood culture aimed at demonstrating the possible presence of microorganisms. Bacterial endocarditis treatments include the administration of antibiotics and, in severe cases, a surgical procedure.
How the bacteria reach the heart
If the heart is healthy, the ideal conditions for the onset of bacterial endocarditis are unlikely to develop. Furthermore, most heart disease (heart disease) also does not increase the risk of the disease occurring.
The interaction between predisposing factors in the host and the inability of the immune system to eradicate the infectious agent from the endocardium, makes the patient susceptible to infection.
Bacterial endocarditis occurs when infectious agents enter the bloodstream and "attach" to heart tissue, then multiply at the level of damaged or surgically implanted heart valves. This tissue damaged in the endocardium guarantees infectious agents the ideal place to settle: the cardiac surface provides them with the support they need to adhere and proliferate. Not all bacteria that enter the bloodstream can cause endocarditis. Only infectious agents that present tropism for valvular structures and endocardial tissues - that is, that are able to interact with the surface of the lining of the heart and abnormal valves - can potentially determine the clinical picture of endocarditis.
Bacteria are responsible for the onset of most cases, but also fungi or other microorganisms can be responsible. Sometimes the culprit is one of the many common bacteria that live in the mouth, throat or other parts of the body. The offending organism can enter the blood through:
- Daily activities . Brushing your teeth, chewing food and other activities that affect the oral cavity can allow bacteria to enter the bloodstream. The risk increases if the teeth and gums are in poor condition, as they can represent the entry doors for the bacteria.
- Infections or other medical conditions. Microorganisms can spread from the site of a pre-existing infection (eg gingival or cutaneous) to the blood, and from there to the heart. Bacteria can also result from a sexually transmitted disease, such as chlamydia or gonorrhea. Even certain intestinal disorders can give bacteria the opportunity to enter the bloodstream.
- Dental and medical procedures. Any medical act that involves placing an instrument inside the body involves a small risk of introducing bacteria into the bloodstream (example: interventions in the intestinal tract, genital, urinary tract or removal of the tonsils or adenoids). The same applies to some dental procedures that can cause bleeding (avulsions, implantation).
- Bladder catheterization and invasive maneuvers. Bacteria can enter the body through a catheter, a thin tube that is used to empty the bladder (if bladder), for the perfusion of a medical solution or for the drainage of liquids. The laparoscope is also an instrument that can potentially be associated with infection (it is a small flexible tube that has a light source and a camera at one end, used to diagnose and treat a wide range of clinical conditions). Bacteria that can cause endocarditis can also access the bloodstream through needles used for a tattoo or piercing. Contaminated syringes are a potential source of infection for people who use intravenous drugs.
Who is at risk
Several factors can make the heart more vulnerable to infection, increasing the likelihood of developing bacterial endocarditis:
- Valve prostheses. Artificial heart valves (biological or homograft prostheses) are used to replace structures damaged by a heart condition. Bacteria can settle around the valve prostheses, occasionally triggering endocarditis.
- Congenital heart defects. A congenital heart disease, present from birth, can make the heart more susceptible to infections. Some congenital heart defects (for example: ventricular septal defects, atrial septal defect or ductus arteriosus) can be surgically repaired and the possibility of endocarditis arising is reduced.
- Valvular heart disease and other medical conditions. Rheumatic fever, valvulopathies, atherosclerotic aortic stenosis, prolapse mitral insufficiency, senile degeneration and other cardiopathies can reduce cardiac efficiency and alter valve function.
- Previous infective endocarditis. A previous episode of endocarditis can damage the tissues of the heart and the valves, increasing the risk of re-infection.
- Intravenous drug use. Regular users of heroin or methamphetamine have a three times higher risk of developing endocarditis than the general population. This condition is mainly caused by repeated injections and the use of non-sterile needles, often contaminated with bacteria that can cause endocarditis.
Endocarditis is more common in elderly people and in patients with congenital heart disease (male / female ratio 2: 1).
Heart diseases associated with bacterial endocarditis
Two types of heart disease in particular can increase the risk of endocarditis:
- Valvular stenosis : narrowing of the valve lumen, with reduction in cardiac efficiency;
- Valve regurgitation : heart valves do not close properly, allowing blood to flow back into the heart.
Fungal endocarditis
Endocarditis caused by a fungal infection is rarer and is usually associated with a more severe clinical picture.
The risk of fungal endocarditis increases, in the event of:
- Surgery;
- Central venous catheter, which consists of a small tube connected to a vein in the neck, groin or thorax, used to supply medicines and / or fluids to seriously ill people;
- Weakened immune system, as a result of an immunosuppressive condition (such as HIV) or as a side effect of some types of treatment, such as chemotherapy.
Symptoms
For further information: Symptoms of infective endocarditis - Symptoms of non-infectious endocarditis
Symptoms of presentation of infective endocarditis are highly variable and the extent of the disease may be mild or severe. The clinical features with which the disease occurs can be highly indicative, but the symptoms are often non-specific. In almost all cases of bacterial endocarditis, an increase in body temperature is found. The combination of some symptoms with particular objective signs, such as a recent onset heart murmur, will allow the doctor to consider endocarditis as the source of the problem. Subsequent diagnostic investigations will allow us to assess the health conditions of the heart and to identify the responsible infectious agent.
There are two ways in which endocarditis symptoms can begin:
- Over the course of a couple of days, rapidly deteriorating (acute endocarditis);
- Slowly, over a couple of weeks or maybe months (subacute endocarditis).
Subacute endocarditis is more common in people with congenital heart disease. The initial symptoms of bacterial endocarditis are flu-like and may be the only signs that arise. These include:
- Fever (> 38 ° C);
- Asthenia;
- Chills;
- Loss of appetite;
- Headache;
- Joint and muscle pains;
Less common symptoms of endocarditis are:
- Night sweats;
- Shortness of breath;
- Unexplained weight loss;
- Pallor;
- Persistent cough;
- Heart murmur and heart rhythm alteration;
- Septic embolism (30% of cases) in skin, palate and conjunctiva, with characteristic signs such as Janeway lesions (painless bleeding skin lesions on the palms of the hands and soles of the feet) and petechiae;
- Edema localized in hands, legs or feet;
- splenomegaly;
- Anemia and leukocytosis;
- Blood in the urine;
- Mental confusion;
- Thromboembolic problems: stroke in the parietal lobe or gangrene of the fingers, intracranial hemorrhage, conjunctival haemorrhage, embolic renal infarcts or splenic infarcts;
- Immune complex disorders: focal or diffuse glomerulonephritis, Osler nodules (painful periungual lesions), Roth retina stains, positive rheumatoid factor etc.
When to see a doctor
Even if less severe pathological conditions can cause similar manifestations, it is always advisable to consult a doctor immediately, especially if there are risk factors for this serious infection (heart defect or previous case of endocarditis). If not treated properly, the infection can progress and damage the heart structures, with serious repercussions on normal circulatory conditions. This triggers a series of life-threatening complications, such as heart failure, in which the heart cannot deliver the adequate amount of blood compared to the body's actual demand.
Complications
The most severe complications arise from the formation of blood clots on damaged surfaces. These clots then break and enter the circulation as emboli, representing potential causes of stroke, myocardial infarction and kidney failure.
If left untreated, bacterial endocarditis can also induce:
- Heart failure;
- Valve dysfunction;
- Cardiac abscesses;
- Extension of infection (abscess formation in other parts of the body, such as the brain, kidneys, spleen or liver);
- Systemic embolisms.
If bacterial endocarditis progresses and is not adequately treated, it is usually fatal.
Continue: Bacterial Endocarditis - Diagnosis and Therapy »
