nocardiosis (redirected from Nocardia infections)

Nocardiosis 

Definition

Nocardiosis is a serious infection caused by a fungus-like bacterium that begins in the lungs and can spread to the brain.

Description

Nocardiosis is found throughout the world among people of all ages, although it is most common in older people and males. While people with poor immunity are vulnerable to this infection, it sometimes strikes individuals with no history of other diseases. Nocardiosis is rare in AIDS patients. It is not transmitted by person-to-person contact.

Causes and symptoms

Nocardiosis is caused by a bacterium of the Nocardia species—usually N. asteroides, an organism that is normally found in the soil. The incubation period is not known, but is probably several weeks.

The bacteria can enter the human body when a person inhales contaminated dust. Less often, people can pick up the bacteria in contaminated puncture wounds or cuts.

Symptoms

The infection causes a cough similar to pneumonia or tuberculosis, producing thick, sometimes bloody, sputum. Other symptoms include chills, night sweats, chest pain, weakness, loss of appetite and weight loss. Nocardiosis does not, however, respond to short-term antibiotics.

Complications

In about one-third of patients, the infection spreads from the blood into the brain, causing brain abscesses. This complication can trigger a range of symptoms including severe headache, confusion, disorientation, dizziness, nausea and seizures, and problems in walking. If a brain abscess ruptures, it can lead to meningitis.

About a third of patients with nocardiosis also have abscesses in the skin or directly underneath the skin. They may also have lesions in other organs, such as the kidneys, liver, or bones.

Diagnosis

Nocardia is not easily identified from cultures of sputum or discharge. A doctor can diagnose the condition using special staining techniques and taking a thorough medical history. Lung biopsies or x rays also may be required. Up to 40% of the time, however, a diagnosis can't be made until an autopsy is done.

Treatment

Treatment of nocardiosis includes bed rest and high doses of medication for a period of 12 to 18 months, including sulfonamide drugs or a combination of trimethoprim-sulfamethoxazole (Bactrim, Septra). If the patient doesn't respond to these drugs, antibiotics such as ampicillin (Amcill, Principen) or erythromycin (E-Mycin, Eryc) may be tried.

The abscesses may need to be drained and dead tissue cut away. Other symptoms are treated as necessary.

Prognosis

Nocardiosis is a serious disease with a high mortality rate. If it has been diagnosed early and caught before spreading to the brain, the prognosis is better. Even with appropriate treatment, however, the death rate is still 50%. Once the infection reaches the brain, the death rate is above 80%. This outcome is most commonly seen in patients with a weakened immune system.

Key terms

Abscess — A localized area of infection in a body tissue. Abscesses in the brain or skin are possible complications of nocardiosis.

Meningitis — An infection of the outer covering of the brain (meninges) that can be caused by either bacteria or a virus.

Resources

Books

Orris, June, editor. Handbook of Diseases. Springhouse, PA: Springhouse Corp., 1996.

---

nocardiosis /no·car·di·o·sis/ (-de-o´sis) infection with Nocardia.

---

no·car·di·o·sis (n-kärd-ss)

n.

A generalized disease in humans that is caused by Nocardia asteroides or occasionally by N. farcinica and that is characterized by pulmonary lesions that may be subclinical or chronic and may spread to other organs of the body, especially the brain.

---

nocardiosis

[nōkär′dē·ō′sis]

Etymology: Edmund I. E. Nocard; Gk, osis, condition

infection with Nocardia species, most often N. asteroides, an aerobic gram-positive species of actinomycetes. It can cause pneumonia, often with cavitation, and chronic abscesses in the brain and subcutaneous tissues, and it can cause cutaneous disease through wounds contaminated with soil. The organism enters via the respiratory tract and spreads by the bloodstream, especially in those who are immunocompromised because of such conditions as HIV infection, organ transplantation, and Cushing's syndrome. Surgical drainage of abscesses and sulfonamide therapy for 12 to 18 months cures between 50% and 60% of the cases treated. Combination antibiotic therapy may be required.

---

nocardiosis (nōkär´dēō´sis),

n any of the pathologic entities that may follow infection with the bacterium
Nocardia.

---

nocardiosis

infection with Nocardia spp. See also bovine farcy.

---

cutaneous nocardiosis

caused by N. asteroides and manifested by the formation of pyogranulomas and the drainage to the surface of pus which may contain sulfur granules.

systemic nocardiosis

lesions may be in any organ; the disease rarely is disseminated, but most commonly causes pyogranulomatous pleurisy and pneumonia producing a voluminous effusion and a resulting dyspnea. In fish the most common lesion is a granulomatous disease. Nocardiosis of Pacific oysters is almost indistinguishable grossly from Denman Island disease caused by Mikrocytos machini.

---

nocardiosis

Infectious disease Infection with Nocardia spp, in particular, N asteroides, which usually presents as a suppurative abscessing lesion of skin and lungs; dissemination to the brain is usually fatal