Nocardia infection, also known as nocardiosis, is a rare condition caused by the bacterium Nocardia asteroides. According to the Centers for Disease Control and Prevention, several different types of this condition can occur. In 80 percent of cases, this condition affects the lungs. In 20 percent of cases, it will cause cellulitis—a bacterial infection of the skin. The less common disseminated nocardiosis can infect the brain or other organs (CDC).
As Nocardia infection tends to occur most often in people with compromised immune systems, and because Nocardia is slow to respond to treatment, it can be fatal, especially if diagnosis and treatment is delayed.
Though the infection usually begins in the lungs, it can spread to other areas, such as:
- gastrointestinal system
- other organs
Nocardia bacteria can be found in the soil of all regions of the world. In the United States, around 500 to 1,000 cases of nocardiosis occur each year. In around 60 percent of these cases, the infection is related to a compromised immune system, according to the Centers of Disease Control and Prevention (CDC).
The disease is contracted through the inhalation of contaminated dust or when Nocardia bacteria enter an open wound. Though healthy people may become infected, you are most at risk if you suffer from a chronic lung disease or if your immune system is compromised. You are also at greater risk of infection if:
- you are using long-term steroid medication
- you have bone marrow or organ transplants
- you suffer from cancer
- you have HIV or AIDS
The type of symptoms you experience will depend on the area of your body that is affected. Some people who are infected do not experience any symptoms. Symptoms will vary depending on the area of the body that has become infected.
This is the most commonly affected area of the body. Symptoms of Nocardia lung infection may include:
- sporadic fever
- night sweats
This is the second most commonly affected area. Symptoms of cellulitis due to Nocardia may include:
- open, seeping sores
- swollen lymph nodes
Though less common, Nocardia infection can infect other part of the body and cause varying symptoms, such as:
Gastrointestinal system infection:
- swelling of the liver and spleen
- sudden weight loss
You might also suffer muscle pain and/or joint pain or stiffness.
Your doctor may order certain tests to determine if you are suffering from Nocardia infection. These tests detect the presence of the infectious bacteria within a given tissue sample. Tests include:
- bronchoscopy—an examination of the interior of the lungs
- brain biopsy—an examination of abnormal brain tissue
- lung biopsy—an examination of abnormal lung tissue
- skin biopsy—an examination of abnormal skin cells
- sputum culture—a test for the presence of bacteria in the lungs
- chest X-ray—an examination of the cavity of the chest
- CT scan—an imaging procedure to examine the lungs
Regardless of which area of your body is infected, your doctor will treat Nocardia infection with long-term antibiotics known as sulfonamides. The treatment period can extend from six months to a year, or sometimes longer depending on the part of the body affected.
Often, long-term and low-dose antibiotics may be prescribed.
If you develop an abscess due to Nocardia infection, your doctor may recommend surgery to drain it.
Your long-term outlook will largely depend on which area of your body is infected. The risk of death is significant if more than one area of your body becomes infected at the same time. According to the Centers for Disease Control and Prevention, about 10 percent of Nocardia infections involving uncomplicated pneumonia are fatal. In general, 60 percent of Nocardia infections are in people with compromised immune systems. The health and stability of your immune system will also play a role in how easily your symptoms can be treated (CDC).
A number of complications can arise from nocardiosis; these too will depend on the location of the infection. Complications may include:
- long-term shortness of breath
- scar tissue on the lung
- impairment or loss of brain functions
If you are taking corticosteroids, try to use them as sparingly as possible; take the lowest effective dose for the shortest period of time. Long-term use of corticosteroids has been identified as a risk factor in Nocardia infection.
If your immune system is severely compromised, your doctor may recommend antibiotics over long stretches of time to prevent Nocardia infection. Nocardiosis is a rare condition seen most commonly in patients with compromised immune systems, such as HIV patients and organ transplant patients.