Brain abscess: Difference between revisions

Revision as of 13:40, 13 August 2020

Background

Microbiology

Direct spread
- Nose/sinuses: Streptococcus species (especially S. milleri), Haemophilus species, Bacteroides species, Fusobacterium species
- Teeth: Streptococcus species, Bacteroides species, Prevotella species, Fusobacterium species, Haemophilus species
- Ears: Enterobacteriaceae, Streptococcus species, Pseudomonas aeruginosa, Bacteroides species
- Penetrating head trauma: Staphylococcus aureus, Enterobacter species, Clostridium species
- Neurosurgery: Staphylococcus species, Streptococcus species, Pseudomonas aeruginosa, Enterobacter species
Hematogenous spread
- Lungs: Streptococcus species, Fusobacterium species, Actinomyces species
- Urinary tract: Pseudomonas aeruginosa, Enterobacter species
- Endocarditis: Viridans group streptococci, Staphylococcus aureus
- Congenital cardiac malformations (especially right-to-left shunts): Streptococcus species
Immunocompromised patient
- HIV: Toxoplasma gondii, Nocardia species, non-tuberculous mycobacteria, Listeria monocytogenes, Cryptococcus neoformans
- Neutropenia: Gram-negative bacilli, Aspergillus species, mucormycosis, Candida species, Scedosporium species
- Transplantation: Aspergillus species, Candida species, mucormycosis, Scedosporium species, Enterobacteriaceae, Nocardia species, Toxoplasma gondii, and Mycobacterium tuberculosis
Plus anaerobes, which are common

Pathophysiology

Either from contiguous spread from a head and neck infection, hematogenous spread from bacteremia or endocarditis, traumatic inoculation, or post-neurosurgery
Microbiology (above) depends on mechanism of infection

Investigations

MRI
- Temporal lobe or cerebellum suggests contiguous spread from chronic otitis or mastoiditis
- Frontal lobe suggests contiguous spread from frontal or ethmoid sinusitis
- Multiple abscesses in a middle cerebral artery distribution suggests bacteremia

Management

Empiric therapy is directed at the likely organisms based on etiology (direct vs. hematogenous spread)
For likely oral, ear, or sinus source, treated with ceftriaxone and metronidazole at CNS doses
For likely hematogenous spread, treated with vancomycin
For uncertain etiology, combination of ceftriaxone, metronidazole, and vancomycin
For neurosurgical patients, vancomycin plus a broad-spectrum antipseudomonal antibiotic such as ceftazidime, cefepime, or meropenem

@@ Line 1: / Line 1: @@
-== Background ==
+==Background==
 ===Microbiology===
@@ Line 20: / Line 20: @@
 *Plus '''[[anaerobes]]''', which are common
-== Investigations ==
+=== Pathophysiology ===
+* Either from contiguous spread from a [[:Category:Head and neck infections|head and neck infection]], hematogenous spread from [[bacteremia]] or [[endocarditis]], traumatic inoculation, or post-neurosurgery
-* MRI
+* Microbiology (above) depends on mechanism of infection
-** Temporal lobe or cerebellum suggests contiguous spread from chronic otitis or mastoiditis
-** Frontal lobe suggests contiguous spread from frontal or ethmoid sinusitis
-** Multiple abscesses in a middle cerebral artery distribution suggests bacteremia
-== Management ==
+==Investigations==
+*MRI
-* Empiric therapy is directed at the likely organisms based on etiology (direct vs. hematogenous spread)
+**Temporal lobe or cerebellum suggests contiguous spread from chronic otitis or mastoiditis
-* For likely oral, ear, or sinus source, treated with [[Is treated by::ceftriaxone]] and [[Is treated by::metronidazole]] at CNS doses
+**Frontal lobe suggests contiguous spread from frontal or ethmoid sinusitis
-* For likely hematogenous spread, treated with [[Is treated by::vancomycin]]
+**Multiple abscesses in a middle cerebral artery distribution suggests bacteremia
-* For uncertain etiology, combination of [[ceftriaxone]], [[metronidazole]], and [[vancomycin]]
-* For neurosurgical patients, [[Is treated by::vancomycin]] plus a broad-spectrum [[Antipseudomonal antibiotics|antipseudomonal antibiotic]] such as [[Is treated by::ceftazidime]], [[Is treated by::cefepime]], or [[Is treated by::meropenem]]
+==Management==
+*Empiric therapy is directed at the likely organisms based on etiology (direct vs. hematogenous spread)
+*For likely oral, ear, or sinus source, treated with [[Is treated by::ceftriaxone]] and [[Is treated by::metronidazole]] at CNS doses
+*For likely hematogenous spread, treated with [[Is treated by::vancomycin]]
+*For uncertain etiology, combination of [[ceftriaxone]], [[metronidazole]], and [[vancomycin]]
+*For neurosurgical patients, [[Is treated by::vancomycin]] plus a broad-spectrum [[Antipseudomonal antibiotics|antipseudomonal antibiotic]] such as [[Is treated by::ceftazidime]], [[Is treated by::cefepime]], or [[Is treated by::meropenem]]
 ==Further Reading==