ID-CNS Infections #2 Flashcards
(47 cards)
Two ways that brain abscesses occur
1-Hematogenous: typically multifocal brain abscesses in this scenario
2-Contiguous: infection from anatomic structures in close proximity
3-No source: 20-40%
Do you perform a lumbar puncture for a known or suspected brain abscess?
NO! This could cause brain herniation due to an increase in intracranial pressure.
Ways to diagnose a brain abscess
MRI is more sensitive, but CT is usually sufficient. CT-guided aspiration can be performed but is invasive and gets a microbiological diagnosis, but oftentimes you just treat without doing this
Treatment/Management of a brain abscess
- If it is suspected, empiric treatment are based on predisposing conditions and causative agents.
- If >2.5 cm then it should be surgically excised or drained stereotactically
- If not drained, follow-up CNS imaging should occur within several days to assess for worsening cerebral edema. Repeat CNS imaging urgently if there are any mental status or neurological changes.
- Add glucocorticoids if there is evidence of cerebral edema
- Duration: 4-8 weeks
Empiric antibiotic choice for bacterial brain abscess? What are the expected/most common organisms?
Source: Otitis Media or Mastoiditis
Streptococci (aerobic or anaerobic)
Bacteroides
Prevotella
Enterobacteriaceae
*Metronidazole plus a third-generation cephalosporin (ceftriaxone or cefotaxime)
Empiric antibiotic choice for bacterial brain abscess? What are the expected/most common organisms?
Source: Sinusitis
Streptococci Bacteroides Enterobacteriaceae Staphylococcus aureus Haemophilus species
*Metronidazole plus a third-generation cephalosporin (ceftriaxone or cefotaxime)
Empiric antibiotic choice for bacterial brain abscess? What are the expected/most common organisms?
Source: Dental sepsis
Streptococci
Bacteroides
Prevotella
Fusobacterium
*Penicillin plus metronidazole
Empiric antibiotic choice for bacterial brain abscess? What are the expected/most common organisms?
Source: Penetrating trauma after neurosurgery
Staphylococcus aureus
Streptococci
Enterobacteriaceae
Clostridium species
*Vancomycin plus third generation cephalosporin (ceftriaxone or cefotaxime) or fourth generation cephalosporin (cefepime, ceftazidime) or even meropenem
Empiric antibiotic choice for bacterial brain abscess? What are the expected/most common organisms?
Source: Lung abscess, empyema, bronchiectasis
Fusobacterium Actinomyces Bacteroides Prevotella Streptococci Nocardia
*Penicillin plus metronidazole plus a sulfa (TMP-SMX for Nocardia)
Empiric antibiotic choice for bacterial brain abscess? What are the expected/most common organisms?
Source: Endocarditis
Staphylococcus aureus
Streptococci
*Vancomycin plus gentamicin
Hematogenous spread from pelvic, intra-abdominal, or gynecological infections
Enteric gram-negative bacteria, anaerobic bacteria
*Metronidazole plus a third-generation or fourth generation cephalosporin
Immunocompromised patients
HIV-infected patients
Listeria species
Fungal organisms (Cryptococcus neoformans)
Parasitic or Protozoal organisms (Toxoplasma gondii)
Aspergillus
Coccidioides
Nocardia
*Metronidazole plus a third-generation cephalosporin; antifungal or anti-parasitic agent
How do spinal epidural abscesses occur?
-Contiguous spread from infected vertebrae or intervertebral body disc spaces or hematogenous dissemination from a distant site
Risk factors for an epidural abscess
Prolonged epidural catheter placement Paraspinal glucocorticoid or analgesic injections Diabetes mellitus HIV infection Trauma IVDU Tattooing Alcoholism Acupuncture
Most common organisms causing a spinal epidural abscess
Staphylococcus aureus Gram negative bacilli Streptococci anaerobic organisms rarely fungi
How to diagnose spinal epidural abscess
Clinical: difficult to diagnose because symptoms can be mild or nonspecific and fever is not always present
Diagnostic: MRI, always get two sets of blood cultures, CT guided aspiration for microbiology
Treatment of a spinal epidural abscess
Combination of antimicrobial therapy and surgical drainage; follow-up MRI every 4-6 weeks or with signs of clinical deterioration. Antibiotic choice must have good CNS penetration.
Duration: usually 6-8 weeks or until resolution on follow-up MRI
What is a cranial subdural empyema?
A focal infection or abscess that occurs between the dura mater and arachnoid mater.
What is the management of a cranial subdural empyema?
It is a medical emergency warranting immediate neurosurgical intervention.
What are the inciting factors that can cause a cranial subdural empyema?
Sinusitis, otitis media, mastoiditis
What pathogens are the most common causes of a cranial subdural empyema?
S. pneumoniae, H. influenzae, aerobic and anaerobic Strep species, Staph species (Coag positive and Coag negative), gram negative bacilli, anaerobic species.
Clinical presentation of a cranial subdural empyema?
fever, headache, nausea and vomiting, mental status changes, with history of preceding sinusitis, otitis, meningitis, mastoiditis, or recent neurosurgical procedures or sinus surgeries
Diagnosis of cranial subdural empyema?
MRI, can use CT contrast as an alternative
LP is CONTRAINDICATED if there is a concern for increased intracranial pressure
Treatment of cranial subdural empyema
vancomycin
flagyl
ceftriaxone (penetrates CNS well)
Ultimately a medical emergency that requires immediate evaluation and neurosurgical evaluation
