II. Pathophysiology
- Filamentous gram-positive Bacteria
- Actinomycetes (Bacteria with fungal-like growth)
- Causes Nodular Lymphangitis
- Nocardia brasiliensis most common organism
- NOT normal flora in humans
- Respiratory Exposure risks
- Inhalation
-
Nodular Lymphangitis Exposure
- Soil or plant debris (e.g. gardening)
- Splinters
III. Risk Factors
- Nocardiosis
- Immunocompromised State
- Corticosteroid use
-
Nodular Lymphangitis
- Gardening
- Splinter-related Skin Injury
IV. Findings: Nocardiosis (80% of presentations)
- Respiratory infection (Pneumonia, Lung Abscess, cavitary lesions)
- CNS Infection (including Brain Abscess)
- Disseminated Nocardiosis
- Systemic symptoms and focal symptoms variable based on abscess location
V. Findings: Nodular Lymphangitis (20% of presentations are primary cutaneous or Lymphocutaneous Nocardiosis)
VI. Differential Diagnosis
- See Nodular Lymphangitis
- Pneumonia
- Malignancy
- Kaposi Sarcoma
- Non-Hodgkin Lymphoma
- Glioblastoma
VII. Labs
- Microscopic examination
- Weakly Gram Positive Bacteria
- Branching-thin filaments are acid-fast
- Culture (slow growth may require several weeks)
- Routine fluid culture
- Culture of biopsied tissue
VIII. Management
- Treatment Duration: 3 months (6 months if Immunocompromised)
-
TMP-SMZ DS (Septra DS or Bactrim DS): preferred
- Dose: 5-10 mg/kg/day up to 2 DS tablets orally three times daily for three months
- Complete Blood Count weekly (lower dose if cytopenia)
- Alternative Antibiotics (based on sensitivity)
- Minocycline 100-200 mg orally twice dailyfor three months
- Other Antibiotics that have been used: Amikacin, CarbapenemAntibiotics, Quinolone Antibiotics, Linezolid
IX. Prognosis
- Mortality from Nocardiosis Pneumonia may be as high as 10% even in uncomplicated cases
X. Resources
- Nocardiosis (CDC)
- Nocardiosis (Stat Pearls)