Infective endocarditis

Endocarditis is inflammation of the inner lining of the heart, and it almost always settles on a valve. Neither cold weather nor exertion brings it on: it is caused by microbes that have reached the bloodstream and taken hold there. The illness is uncommon but deceptive in its own particular way, because for weeks it can pass for a cold that will not clear or for ordinary tiredness while the valve is quietly being destroyed. That disguise is the reason to know about it in advance if your heart is already different in some way from the average one.

Why the microbe settles on a valve

Bacteria get into the blood far more often than people imagine: while chewing and brushing the teeth, from an inflamed gum, from a graze on the skin, during any medical procedure. In a healthy person they die within minutes, and the smooth surface of a valve gives them nothing to cling to. Everything changes if that surface has been altered by scarring, a defect present from birth, calcium deposits or the artificial material of a replacement valve. A microscopic clot forms there, the microbes become trapped in it and coat themselves in layers of fibrin. The result is a vegetation: a soft outgrowth that neither immune cells nor medicines penetrate well. Two problems follow at once:

• the leaflet is eaten away, the valve stops holding back the blood, and the heart fails rapidly;
• pieces of the outgrowth break off and travel in the bloodstream, blocking arteries in the brain, the spleen, a kidney, an arm or a leg.

That is why the treatment is long and given into a vein: tablets simply do not reach the microbes living inside a vegetation.

Who is most at risk

Three groups carry the highest risk: people with a replacement valve of any kind, including tissue valves and those fitted through a catheter; people who have already had endocarditis; and some patients with heart defects present from birth. The risk is also above average with:

• acquired valve disease, after rheumatic fever or from the narrowing of the aortic valve that comes with age;
• hypertrophic cardiomyopathy;
• an implanted pacemaker or defibrillator, since the leads run right into the chambers of the heart;
• injecting drug use, where the right side of the heart is usually affected and the fragments travel to the lungs;
• a long-term venous catheter, an implanted port or regular haemodialysis;
• a weakened immune system and the period after chemotherapy.

Men are affected roughly twice as often as women. The paradox is that cases are becoming more common precisely because of medical progress: every year more people live with replacement valves and implanted devices, and they live longer.

How it shows itself

The pace varies, and it decides how easily the beginning is missed. The acute form unfolds over a few days with a high temperature and violent shivering; the person feels frankly ill and takes themselves to hospital. The subacute form drags on for weeks or months, the temperature stays low, and it gets blamed on a virus, on overwork, on age.

The usual complaints are:

• fever and chills, night sweats heavy enough to need a change of bedding;
• tiredness that rest does not repair;
• loss of appetite and weight without dieting;
• aching muscles and joints;
• breathlessness on exertion and sometimes a cough;
• an earthy pallor.

There are also uncommon signs that mean little on their own but tell a doctor a great deal alongside a fever: tiny reddish-brown spots on the skin, inside the mouth and on the whites of the eyes, fine lines of bleeding under the nails, tender nodules on the fingertips, painless marks on the palms and soles, blood in the urine, an enlarged spleen. On brown and black skin these marks are harder to see, so look at the mucous membranes and the nails.

The main practical rule: a temperature lasting more than a week with no clear cause, in someone with a replacement valve, a heart defect, a pacemaker or a previous episode of endocarditis, calls for blood cultures rather than for waiting. And the other half of the same rule: do not start an antibiotic on your own initiative. A drug taken at random will not cure endocarditis, but it will leave the cultures sterile, and the treatment then has to be given blind and for longer. If you have already taken one, say so.

Signs that mean calling an ambulance

The complications of endocarditis arrive abruptly and need emergency care rather than an ordinary appointment. Call an ambulance (in Europe the single number 112 works) if there is:

• a drooping face, weakness in an arm or a leg, slurred speech or sudden confusion, in other words the signs of a stroke, the commonest serious complication;
• sudden severe breathlessness, an inability to lie flat, bubbling breathing, pink frothy sputum;
• sharp chest pain;
• sudden severe pain in the side, the lower back or the abdomen, which is how a blocked artery to the spleen or a kidney announces itself;
• an arm or a leg that has suddenly turned pale, cold and painful;
• abrupt loss of vision in one eye;
• an overwhelming headache, a fit, or loss of consciousness.

How the diagnosis is confirmed

The diagnosis rests on three pillars, and none of them works alone.

• Blood cultures. Several sets are taken from different veins, always before the first dose of antibiotic. This is the only way to identify the organism and match the treatment to it.
• Echocardiography. First through the chest wall and then, as a rule, through the oesophagus, which lies directly behind the heart: vegetations, abscesses and a leaking valve show up incomparably better that way. Where there is a replacement valve, a cardiac CT scan or a PET-CT scan is sometimes added.
• Blood tests and examination. Inflammatory markers, a full blood count, a urine test and listening to the heart: a murmur that was not there before, heard during a fever, puts a doctor firmly on alert.

A chapter of its own belongs to the cases where the picture fits perfectly and the cultures stay empty. Besides antibiotics already taken, the explanation is usually an organism that will not grow in ordinary culture media, and those are common in southern Europe: the cause of Q fever, picked up from sheep, goats and cattle; bartonella, which comes from cats; brucella, from unpasteurised milk and cheese. Tell the doctor about the village, the farm animals, the homemade cheese, the cats and the travelling, because it changes the whole direction of the search.

One more detail patients rarely know about: if the intestinal group of streptococci or an enterococcus grows from the blood, the cardiologist will arrange a colonoscopy even when the bowel is causing no trouble. These microbes have a well-known link with polyps and bowel cancer, and what is found at that point can be life-saving.

How it is treated

Treatment begins in hospital and always with antibiotics into a vein: the course runs from two to six weeks and longer when a replacement valve is infected. The drugs are chosen by organism and sensitivity, often combining two classes; fungal endocarditis needs antifungal drugs and nearly always surgery. Once the situation is stable and the organism is responding well, part of the course is sometimes completed outside hospital with frequent blood tests.

Around half of patients need heart surgery. It is considered when:

• the destroyed valve has caused heart failure, which is the commonest and most urgent reason;
• the infection will not retreat: the fever persists, the cultures stay positive, an abscess or a fistula has formed around the valve;
• the vegetation is large and has already thrown off an embolus;
• the organism is a fungus or resistant to drugs;
• the replacement valve or the leads of a device are infected, in which case the whole system is removed.

Alongside this the teeth are put in order, and after discharge a repeat echocardiogram establishes the "new normal" for the valve. Having had endocarditis places a person in the highest-risk group for life, and that is spelled out separately.

How to lower the risk

Prevention here is dull but genuinely effective, and it rests on the two gateways for infection: the mouth and the skin.

• Brush twice a day, clean between the teeth as well, see a dentist regularly and do not put off treatment for bleeding gums or a dental abscess. For anyone with a replacement valve, the dental check-up is part of the cardiac treatment.
• Wash cuts and grazes and do not neglect boils. Spreading redness, pain, pus and a fever are a reason to be seen rather than to reach for whichever ointment is at hand.
• Give up piercings and tattoos.
• Anyone injecting drugs should never share needles and should seek help: this form of the illness runs the hardest course and recurs most often.
• Follow the care instructions for a venous catheter or an implanted port.

The antibiotic before dental work is a separate question. It is not needed by everyone and does more harm than good when used indiscriminately. European recommendations offer a single dose only to the highest-risk group and only before procedures that disturb the gum and the root of the tooth. The wording differs from country to country, so settle your own case with the cardiologist and always tell the dentist about your heart condition. Many people find it useful to carry the discharge summary or a card naming the defect and the replacement valve: away from home it saves time.

Online consultation

A remote appointment is at its best where the point is to suspect in time and to direct correctly. If you have a heart defect, a replacement valve or a pacemaker and an unexplained temperature is now into its second week, the doctor will go through the circumstances and explain which blood cultures need taking and why no antibiotic should be swallowed beforehand. Online is also a convenient way to prepare for a dental visit, to make sense of a discharge summary and to discuss what should worry you over the coming months. The emergency signs listed above are not assessed remotely: with those you call an ambulance straight away.

This material is for information only and does not replace medical advice.