Updated: 7/20/2020

Nocardia

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
1 1
0
0
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 (1)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Topic COMMENTS (0)
Private Note