Endocarditis is a serious infection affecting the inner lining of the heart, known as the endocardium. This infection typically involves the heart valves, which are responsible for regulating blood flow. When the endocardium becomes inflamed and infected, it can lead to vegetations—growths composed of bacteria, platelets, and fibrin. These vegetations can cause substantial damage to heart tissue and, if left untreated, endocarditis can be life-threatening.
The Link to IV Drug Use
Intravenous (IV) drug use is a major risk factor for endocarditis. Direct injection of substances into the bloodstream introduces bacteria from sources like uncleaned skin, contaminated needles, or impure drug solutions. Repeated injections also damage heart valves, making them more susceptible to bacterial adherence and vegetation formation.
The most common bacterium in endocarditis among IV drug users is Staphylococcus aureus, accounting for 60-70% of cases. This bacterium resides on the skin; non-sterile injection practices introduce it into the bloodstream, contributing to infection. While left-sided heart valves can be affected, endocarditis in IV drug users often impacts the tricuspid valve on the right side of the heart, as it is the first valve encountered by blood returning from the body.
Recognizing the Symptoms
The symptoms of endocarditis can vary and develop slowly, making diagnosis challenging. Individuals, particularly those with a history of IV drug use, should be aware of these signs. General symptoms often resemble the flu, including persistent fever, chills, fatigue, body aches, and night sweats.
More specific indications include a new or changed heart murmur, an unusual sound heard when listening to the heart. Other signs include shortness of breath, swelling in the legs or abdomen, and small, painful red spots on the skin, fingers, or toes. Tiny red spots can also appear under the fingernails or in the whites of the eyes.
Diagnosis and Treatment
Diagnosing endocarditis, particularly in individuals with a history of IV drug use, involves a combination of tests. Blood cultures are a primary diagnostic tool to identify the specific bacteria causing infection and determine their susceptibility to antibiotics. A complete blood count can also reveal an elevated white blood cell count, indicating infection, or anemia, a symptom of endocarditis.
Echocardiograms are important for visualizing the heart’s structures and detecting vegetations or damage to the heart valves. A transthoracic echocardiogram (TTE) is often the initial imaging method, with a probe moved across the chest. If clearer images are needed or TTE is inconclusive, a transesophageal echocardiogram (TEE) may be performed, using a probe guided down the throat for detailed heart views from behind. Other imaging techniques, such as CT scans or MRI, may identify abscesses or infection spread to other organs like the brain or lungs.
Treatment for endocarditis involves prolonged courses of intravenous antibiotics, administered for 2 to 6 weeks. These antibiotics are often given through a drip in the arm, initially in a hospital, and may continue at home with monitoring. The antibiotic regimen is determined by the bacteria identified in blood cultures and its susceptibility.
Surgical intervention is necessary in situations like severe valve damage leading to heart failure, persistent infection despite antibiotic therapy, or abscess formation around heart valves. Surgery may involve debridement to remove infected tissue, valve repair, or valve replacement. Early diagnosis and treatment are important to prevent complications and improve outcomes.
Potential Complications
Endocarditis can lead to complications, especially if untreated or severe. One risk is the formation of systemic emboli, where pieces of vegetations break off and travel through the bloodstream. These emboli can block blood vessels in organs, potentially leading to a stroke if they reach the brain or a pulmonary embolism if they lodge in the lungs.
Severe valve damage can result in heart failure, where the heart cannot pump enough blood. Other complications include kidney damage, such as glomerulonephritis, and abscesses in the heart muscle or other organs. The ongoing infection can also lead to sepsis, a widespread inflammatory response that can result in multi-organ dysfunction.
Prevention
Preventing endocarditis in individuals who use IV drugs focuses on harm reduction strategies. Using sterile needles and equipment for each injection reduces the introduction of bacteria into the bloodstream. Proper skin preparation before injection, such as cleaning the site with an alcohol swab or soap and water, can also lower the risk of infection.
Avoiding the sharing of drug paraphernalia, including needles, syringes, and cookers, minimizes the spread of bacteria and other infections. Some programs offer sterile supplies and education on safe injection practices. Seeking help for substance use disorder through treatment programs, such as opioid maintenance therapy, and having regular medical check-ups are also important steps to reduce endocarditis risk and associated complications.