II. Epidemiology
- Peak Incidence in children: Ages 4 to 7 years old
III. Pathophysiology
- Frontal, temporal, and Parietal Lobes are most commonly affected
IV. Causes: Source
- Unknown primary source of abscess in 20-40% of cases
- Direct Spread
- Subdural Abscess (Subdural Empyema) is spread of Sinusitis or Mastoiditis in 60-90% of cases
- Mastoiditis (due to Chronic Otitis Media)
- Frontal Sinusitis or Ethmoid Sinusitis
- Most common in children who have highly vascular sinuses
- Dental Infection
- Retained Foreign Body such as bullet fragments (abscess development may be years later)
- Neurosurgery (abscess development may be >1 year later)
- Epidural Abscess (rare)
- Subdural Abscess (Subdural Empyema) is spread of Sinusitis or Mastoiditis in 60-90% of cases
- Hematogenous spread
- Lung Abscess or empyema in host with chronic lung disease (e.g. Cystic Fibrosis, Bronchiectasis)
- Esophageal procedures (e.g. esophageal dilation, Varices management)
- Cyanotic Congenital Heart Disease
- Bacterial Endocarditis
- Pulmonary AV Malformation with right to left shunt
- Skin Infections
- Intraabdominal and pelvic infections
- Dental Infection
V. Causes: Organisms
- Strepotococcus esp. viridans (60-70%), as well as pneumococcus
- Staphylococcus, esp. Staphylococcus aureus (10-14%)
- Other source site-specific organisms (in addition to Staphylococcus and Streptococcus species)
- Actinomyces (lung)
- Bacteroides (sinus, dental, ear) in up to 20-40% of cases
- Clostridium (penetrating Head Trauma)
- Enterobacteriaciae, Gram Negative Rods (ear) in up to 25-33% of cases
- Enterobacter (urine, penetrating Head Trauma, neurosurgery)
- Fusobacterium (sinus, dental, lung)
- HaemophilusInfluenzae (sinus, dental)
- Pseudomonas (ear, urine, neurosurgery)
-
Immunocompromised patients
- See Brain Lesion in HIV
- Aspergillus
- Coccidioides
- Cryptococcus
- Listeria
- Nocardia
- Toxoplasma gondii
- Other fungus (e.g. Candida)
-
Immigrants
- Cysticercosis (most common)
- Entamoeba histolytica
- Schistosoma
VI. Symptoms
- Often initially subacute (results in delayed diagnosis typically >1 week)
- However, Subdural Empyema may rapidly progress
- Headache (69%), typically unilateral in the region of abscess
- Neck Stiffness (15%), associated with posterior abscess (e.g. occiput)
- Vomiting (suggests Increased Intracranial Pressure)
VII. Signs
- Fever (45%)
- Focal neurologic deficit (50%)
- Often a delayed finding (>1 week after Headache onset)
- Oculomotor findings (CN 3 or CN 6) suggests Increased Intracranial Pressure
- Seizure (25%)
- Altered Level of Consciousness (associated with significant brain edema and with worse prognosis)
IX. Differential Diagnosis
X. Diagnostics
-
Lumbar Puncture
- Contraindicated in focal symptoms/signs, CNS mass, Increased Intracranial Pressure (risk of Herniation)
- Obtain CNS imaging prior to Lumbar Puncture
XI. Labs
-
Serology
- Blood anti-Toxoplasma IgG
- CSF anti-cysticercal Antibody
- CT-guided or neurosurgery obtained fluid
- Gram Stain
- Acid-fast stain and modified acid fast (Mycobacteria, Nocardia)
- Fungal stains
- Aeorbic and Anaerobic Bacterial cultures
- Mycobacterial culture
- Fungal Culture
XII. Management
- See Toxoplasmosis
-
Bacterial cause (initial empiric therapy, including for Subdural Empyema)
- Overall Antibiotic course of 4-6 weeks is typical
- Cefotaxime 2 g IV q4 hours OR Ceftriaxone 2 g IV every 12 hours (or Pen G 3-4 MU q4h) AND
- Metronidazole 7.5 mg/kg every 6 hours
- Add Vancomycin for suspected Staphylococcus aureus
- Nocardia initial empiric therapy
- Post-Trauma or Post-Surgical
- Vancomycin 15-20 mg/kg every 8-12 hours (or Linzeolid 600 mg q12h) AND
- Cefepime 2 g IV every 8 hours (or Meropenem 2 g IV every 8 hours)
XIII. References
- (2016) Sanford Guide, accessed 4/9/2016
- Southwick in Calderwood (2016) UpToDate, accessed 4/9/2016
- Brouwer (2014) N Engl J Med 371:447 [PubMed]