Actinomycosis is a chronic infection caused mainly by the anaerobic bacteria Actinomyces israelii. This species of bacteria normally resides in the crevices between the teeth and gums, on the tonsils, and sometimes on mucus membranes lining the intestines and vagina.
Infection occurs only when tissue is injured or inflamed, enabling the bacteria to enter deeper tissues.
Abscesses form in various areas, such as the intestine or face, causing pain, fever, and other symptoms.
Symptoms suggest the diagnosis, and doctors confirm it by identifying the bacteria in a sample of infected tissue.
Abscesses are drained, fistulas are surgically removed, and antibiotics are given.
With prompt diagnosis and appropriate treatment, most people recover fully.
Actinomyces bacteria are anaerobes and do not require oxygen to live.
Actinomyces bacteria cause infection only when the surface of the tissue on which they reside is broken, enabling them to enter other, deeper tissues, which have no defenses against them. As the infection spreads, scar tissue and abnormal channels called fistulas (or tracts) form. After months to years, fistulas may eventually break through the skin and allow pus to drain. Pockets of pus (abscesses) may develop in the chest, abdomen, face, or neck.
Men are affected most often.
Symptoms of Actinomycosis
Actinomycosis has several forms. All cause abscesses, scar tissue, and fistulas.
Abdominal actinomycosis
Actinomyces bacteria infect the intestine, usually the area near the appendix, and the lining of the abdominal cavity (peritoneum).
Chronic abdominal pain, fever, vomiting, diarrhea or constipation, and severe weight loss are common symptoms.
Fistulas may form from the interior of the abdomen to the skin above it and between the intestine and other organs.
Pelvic actinomycosis
The bacteria spread to the uterus, usually from an intrauterine device (IUD).
Symptoms include chronic abdominal or pelvic pain, fever, weight loss, and vaginal discharge.
Abscesses and scar tissue may form in the fallopian tubes, ovaries, and nearby organs such as the bladder and ureters. Fistulas may form between these organs.
Cervicofacial actinomycosis
Usually, small, hard, sometimes painful swellings develop in the mouth and on the face, neck, or skin below the jaw (called lumpy jaw). These swellings may soften and discharge pus that contains small, round, yellowish granules.
The infection may extend to the cheek, tongue, throat, salivary glands, skull, bones of the neck (cervical vertebrae) and face, brain, or the space within the tissues covering the brain (meninges).
Thoracic actinomycosis
This form affects the chest (thorax). People have chronic chest pain and fever. They lose weight and cough, sometimes bringing up sputum. People probably become infected when they inhale into their lungs fluids that contain bacteria.
The infection may spread extensively before it causes any symptoms. Symptoms include chest pain, fever, and a productive cough.
Abscesses may form in the lungs and eventually spread to the membrane between the lungs and chest wall (pleura). There, abscesses cause irritation (pleuritis), and infected fluid collects (called an empyema). Fistulas may form, enabling the infection to spread to the ribs, skin of the chest, and spine.
Generalized actinomycosis
Rarely, the bacteria are carried in the bloodstream to infect other organs, such as the brain, spine, lungs, liver, kidneys, and heart valves. In women, the reproductive organs may be infected.
Symptoms vary depending on which organs are affected. For example, people may have a headache, back pain, or abdominal pain.
Diagnosis of Actinomycosis
Examination and culture of a sample of sputum, pus, or tissue
Sometimes imaging tests
Doctors suspect actinomycosis in people who have abscesses, scar tissue, and fistulas.
Doctors obtain samples of sputum, pus, or tissue to check for various species of Actinomyces, such as Actinomyces israelii. Often, doctors use ultrasound to help them guide a needle through the skin to take a sample from an abscess or infected tissue. Samples may also be obtained during endoscopy, a procedure where doctors place a flexible viewing tube (endoscope) into the airway to view the internal structures. Sometimes surgery is necessary to remove a sample. The sample is examined under a microscope and is sent to a laboratory where bacteria, if present, can be grown (cultured).
Identification of the bacteria in the sample of sputum, pus, or tissue confirms the diagnosis.
Sometimes imaging tests (x-rays or CT scans) are done to determine the number, size, and exact location of abscesses.
Treatment of Actinomycosis
Antibiotics
Sometimes drainage of abscesses and surgical removal of fistulas
High doses of antibiotics such as penicillin or tetracycline must be taken for at least 2 months and may be needed for more than 12 months.High doses of antibiotics such as penicillin or tetracycline must be taken for at least 2 months and may be needed for more than 12 months.
Sometimes small abscesses can be drained with a needle that is inserted through the skin (aspiration). Large abscesses are drained, and fistulas are surgically removed. Sometimes other surgeries may be needed, particularly if the infection affects critical areas such as the spine.
Women with an IUD who have pelvic actinomycosis have it removed and are given penicillin. An extensive pelvic infection may require drainage of abscesses. Sometimes the uterus, fallopian tubes, and ovaries need to be removed.
Prognosis for Actinomycosis
If actinomycosis is diagnosed early and treated appropriately, most people recover fully.
Prognosis is related to which form a person has and which parts of the body are affected. The prognosis is best for the cervicofacial form and is worse for the thoracic, abdominal, and generalized forms, especially if the brain and spinal cord are affected.
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