Updated: 7/20/2020

Nocardia

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
2
0
0
Topic
Snapshot
  • A 25-year-old woman with a history of HIV presents to the emergency room for months of fever, night sweats, and cough. She has not had any treatments for her HIV-positive status. On physical exam, she is dyspneic with bilateral rhonchi. A PPD test is negative for tuberculosis. Chest radiograph reveals bilateral pulmonary cavitary lesions. Sputum analysis shows partially acid-fast gram + filamentous rods.
Introduction
  • Classification
    • Nocardia
      • an aerobic gram + bacteria with branching filaments
      • weakly acid fast
      • urease + and catalase +
    • transmission
      • inhalation
      • direct contact with skin break
  • Epidemiology
    • demographics
      • mainly in immunocompromised patients
    • location
      • pulmonary (most common)
      • may spread to central nervous system
    • risk factors
      • immunocompromised status
      • chronic steroid use
      • HIV infection
      • trauma
  • Pathogenesis
    • Nocardia can inhibit phagolysosome fusion
    • immunocompromised patients, especially those with defective cell-mediated immunity, are at higher risk
  • Associated conditions
    • pulmonary nocardiosis
      • in immunocompromised patients
    • cutaneous nocardiosis
      • can happen in immunocompetent patients
Presentation
  • Symptoms
    • constitutional symptoms
      • weight loss
      • night sweats
  • Physical exam
    • fever
    • pulmonary nocardiosis
      • cough
      • dyspnea
      • sputum production
      • chest pain
      • pleural effusion
    • neurologic nocardiosis
      • focal neurologic defects based on location of abscess
      • altered mental status
    • cutaneous nocardiosis
      • nodular lymphangitis
        • painful lymphadenopathy with drainage
      • cellulitis
Imaging
  • Chest radiography
    • indication
      • pulmonary nocardiosis
    • findings
      • multifocal consolidation
      • cavitary lesions
  • Computed tomography (CT) of the brain
    • indication
      • suspected central nervous system involvement
    • findings
      • abscesses appear as rim-enhancing lesions
Studies
  • Labs
    • gram + staining with multi-branching beaded filamentous bacteria
    • Ziehl-Neelsen stain 
      • weakly acid fast
    • culture
  • Making the diagnosis
    • based on clinical presentation and isolation of organism
Differential
  • Actinomyces infection
    • distinguishing factors
      • although Actinomyces is also gram + and forms branching filaments, it is not acid fast and causes oral/facial abscesses associated with dental procedures
      • SNAP treatment
        • Sulfa for Nocardia; Actinomyces uses Penicillin
  • Tuberculosis
    • distinguishing factor
      • negative PPD
Treatment
  • Medical
    • trimethoprim-sulfamethoxazole (TMP-SMX)
      • indication
        • all patients
    • carbapenems
      • indication
        • patients contraindicated to TMP-SMX
Complications
  • Disseminated infection

Please rate topic.

Average 4.1 of 8 Ratings

Questions (2)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
EXPERT COMMENTS (0)
Private Note