A localized or disseminated infection caused by the actinomycete Nocardia species.
Typically occurs in immunocompromised patients with subacute or chronic pulmonary disease. More prevalent in patients with deficient cell-mediated immunity (e.g., post-transplant, with AIDS, on corticosteroid therapy, or with malignancies).
Disseminated forms (lungs, skin, subcutaneous tissues, and central nervous system [CNS]) frequently occur.
Treatment of immunocompromised patients with disseminated or severe disease consists of intravenous therapy with two or more antibiotics.
High tendency to recur. Maintenance therapy should be continued until the immunocompromised state can be reversed or improved.
Surgical treatment may be needed in some cases (e.g., CNS abscesses with poor response to antimicrobial treatment).
Nocardiosis is a localized or disseminated infection caused by the actinomycete Nocardia species that usually affects immunocompromised patients. It has been reported more frequently in patients with deficient cell-mediated immunity, such as organ transplant recipients and patients with AIDS. Clinical presentation can be acute, subacute, or, more frequently, chronic. Nocardiosis has a high mortality rate and a tendency to recur. Immunocompetent patients usually develop localized cutaneous lesions, cellulitis, abscesses, or sporotrichoid forms.
History and exam
Key diagnostic factors
- cough with purulent sputum
Other diagnostic factors
- male gender
- nausea and vomiting
- depressed consciousness
- cutaneous ulcers or abscesses
- solid organ and hematopoietic stem cell transplant recipients
- HIV-positive and low CD4 T-cell count (<100 cells/mm³)
- structural pulmonary disease
- malignancy and chemotherapy
- male gender
- agricultural work
1st investigations to order
- Gram and acid-fast stains
- chest x-ray
Investigations to consider
- biochemical species typing
- thoracic CT scan
- CT head
- MRI head
- 16S rRNA sequencing and other polymerase chain reaction (PCR)-based techniques
- identification and typing according to gyrB and rpoB genes
- matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS)
severe nocardiosis: disseminated disease, CNS involvement, cavitary pulmonary lesions, or immunocompromise
nonsevere nocardiosis: immunocompetent, nondisseminated, no CNS involvement, no pulmonary cavitary lesions
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