Brain Abscess
Brain Abscess: Excerpt from The 5-Minute Pediatric Consult
Jeffrey P. Louie, MD
Brain Abscess - BASICS
Brain Abscess - description
- Suppurative infection involving the brain parenchyma
- May be a single or multiple lesion
Brain Abscess - general prevention
- During recreational activities, wearing helmets may prevent penetrating head trauma.
- Preventive medicine: Dentistry and otorhinolaryngology
Brain Abscess - epidemiology
- Males are affected more than females (2:1 male-to-female predominance)
- Average age of presentation is ~7 years of age
Brain Abscess - incidence
~1,500–2,500 cases (adults and pediatric combined) occur per year.
Brain Abscess - prevalence
2%–4% of children with cyanotic congenital heart disease will develop a brain abscess (Tetralogy of Fallot being the most common).
Brain Abscess - risk factors
- Cyanotic congenital heart disease
- Otorhinolaryngologic infections such as sinusitis, mastoiditis, and chronic otitis media
- Meningitis (especially with neonates)
- Penetrating head trauma
- Surgical manipulation of the brain (ventriculoperitoneal shunts, tumor removal)
- Esophageal manipulation (sclerotherapy or dilation)
- Cystic fibrosis
- Dental infections
- Lung infections
- Any site of infection (osteomyelitis, orbital, cellulitis, urinary tract infections)
- Patients who have traveled to endemic areas with neurocysticercosis (Latin America, parts of Africa, Asia, and the Indian subcontinent)
- Congenital or acquired immunocompromised patients
- No definitive etiology occurs in 30% of patients.
Brain Abscess - pathophysiology
- Micro-organisms enter the brain parenchyma by contiguous or hematogenous (metastasis) pathways.
- Location of brain abscesses:
- Cyanotic congenital heart disease patients tend to have abscesses within the middle meningeal artery distribution: Frontal, parietal, and temporal lobes.
- Frontal abscesses are commonly seen with sinus and dental infections.
- Temporal, parietal, or cerebellar abscesses tend to occur with mastoid or otitis media infections.
- Brain abscesses can occur anywhere in the brain parenchyma, regardless of a predisposing risk factor, secondary to hematogenous metastasis.
Brain Abscess - etiology
- Bacteria are the most common causes.
- Streptococcus spp. and Staphylococcus spp. are the most commonly cultured microorganisms.
- Neonates may develop abscesses after a Gram-negative meningitis (Proteus, Citrobacter, and Enterobacter).
- A single organism is found in ~70% of patients.
- Anaerobic organisms are being found with increasing incidence with improved laboratory and culture techniques. Common pathogens are Bacteroides, Peptostreptococcus, Fusobacterium, Propionibacterium, Actinomyces, Veillonella, and Prevotella.
- No growth of a pathogen occurs in 30% of specimens.
- Parasitic infections are often caused by Taenia solium (neurocysticercosis).
- Fungi and protozoa are commonly found in immunocompromised patients.
Brain Abscess - DIAGNOSIS
Brain Abscess - signs & symptoms
Brain Abscess - history
The location of the brain abscess or abscesses will often influence the history of presentation and physical exam.
- Fever, headache and vomiting each occur ~60–70% of cases.
- Classic triad of fever, headache, and focal neurologic findings occurs in <30% of cases.
- Headache is the most common complaint.
- Average duration of symptoms prior to diagnosis is ∼4 weeks.
- Vomiting and mental-status changes can often be the presenting chief complaints.
- Neonates will often have a history of meningitis before developing a brain abscess.
- Questions should focus on acute or chronic otolaryngologic infections such as sinusitis, chronic otitis media, and mastoiditis, as well as a history of cholesteatomas.
- Cyanotic congenital heart disease should be determined, as well as partially repaired cyanotic congenital heart disease.
Brain Abscess - physical exam
- Neonates may present with a full fontanel, increasing head circumference, seizures, or vomiting.
- Older children may have signs of a focal neurologic deficit, hemiparesis, or even papilledema.
- Meningeal symptoms occur in ~30% of patients.
- Ataxia may be found with cerebellar lesions.
Brain Abscess - tests
Brain Abscess - lab
- CBC may be mildly elevated, and <10% will show a left shift.
- ESR is a poor indicator of brain abscesses.
- Electrolytes may show low sodium, indicating syndrome of inappropriate secretion of diuretic hormone.
- A lumbar puncture is contraindicated if any intracranial mass lesion is suspected, but if CSF is obtained:
- It may show a mild to moderate pleocytosis (20% of patients may have normal values).
- Opening pressure is always elevated.
- Glucose may be decreased in 30% of patients.
- Protein is elevated in 70% of cases.
- Only 10% of cultures are positive, unless the abscess ruptures into the ventricles.
Brain Abscess - imaging
- CT and MRI scans are the studies of choice in diagnosing brain abscesses.
- Cranial ultrasound may be useful in premature neonatal cases.
- Not all patients with brain abscesses have fevers.
- Pitfalls:
- Failing to consider a brain abscess in a child with altered mental status, fevers, and meningismus
- Performing a lumbar puncture
- Failing to use contrast with the CT scan
Brain Abscess - differencial diagnosis
- Infectious:
- Meningitis
- Encephalitis
- Subdural empyema
- Epidural abscess
- Vascular:
- Venous sinus thrombosis
- Migraine
- Cerebral infarct
- Cerebral hemorrhage
- Miscellaneous:
- Primary or secondary tumor
- Pseudotumor cerebri
- Hydrocephalus
Brain Abscess - TREATMENT
- Broad-spectrum antibiotics should be started at the time of diagnosis, until identification of the micro-organism is determined. At that time, the antibiotics can be tailored to the offending micro-organism.
- Most brain abscesses are removed surgically. A few may require CT-guided aspiration.
- MRI or CT guided stereostatic aspiration is encouraged.
- When multiple abscesses are found on CT scan, 1 lesion should be aspirated to identify the micro-organism.
- Some patients are managed successfully with antibiotics alone.
- Antiparasitic medications are controversial in the treatment of neurocysticercosis.
- Antifungals should be considered for immunocompromised patients.
- The use of steroids is controversial.
- If a patient is manifesting signs and symptoms of increased intracranial pressure (Cushing triad: Bradycardia, hypertension, and abnormal respirations) or if the patient is comatose and is unable to protect his or her airway, the patient should be intubated, hyperventilated, and given mannitol.
- Patients with unknown predisposing factors should be evaluated by cardiology, dental, and otorhinolaryngology. Immunology should be considered in children with significant medical histories of chronic infections.
Brain Abscess - FOLLOW UP
- A high index of suspicion is required to diagnose a brain abscess. A delay in diagnosis or performing a lumbar puncture for suspected meningitis increases mortality and morbidity.
- With the advent of CT and MRI scans, the mortality rate has dropped from ~30% to <14%.
- Multiple abscesses, coma on presentation, <2 years of age, performance of a lumbar puncture, and rupture of abscess into the ventricle carry a higher mortality rate. 30–40% of patients have some morbidity. This ranges from seizures, hemiparesis, focal neurologic deficits, or hydrocephalus to cognitive/behavior problems.
Brain Abscess - complications
- Arise from the location, size, and number of intracranial abscesses
- Can vary from syndrome of inappropriate secretion of diuretic hormone or seizures to focal neurologic deficits
Brain Abscess - patient monitoring
- Neonates and older patients may be discharged with home physical therapy and home nursing for IV antibiotics
- Patients will need IV antibiotics for a total of 3–4 weeks. Some may require longer courses of antibiotics.
- Some children will need follow-up CT or MRI scans.
- Follow-up with neurosurgical, rehabilitation, and neurology clinics is usually required.
Brain Abscess - bibliography
- Calfee DP, Wispelwey B. Brain abscess. Semin Neurol. 2000;20:353–360.
- Cochrane DD. Brain abscess. Pediatr Rev. 1999;20:209–214.
- Jadavji T, Humphreys RP, Prober CG. Brain abscesses in infants and children. Pediatr Infect Dis J. 1985;4:394–398.
- Kaplan K. Brain abscess. Med Clin North Amer. 1985;69(special issue):345–360.
- Mitchell WG. Neurocysticercosis and acquired cerebral toxoplasmosis in children. Semin Pediatr Neurol. 1999;6:267–277.
- Renier D, Flandin C, Hirsch E, et al. Brain abscesses in neonates. J Neurosurg. 1988;69:877–882.
- Rennels MB, Woodward CL, Robinson WL, et al. Medical cure of apparent brain abscesses. Pediatrics. 1983;72:220–224.
- Saez-Llorens X. Brain abscess in children. Semin Pediatr Infect Dis. 2003;14:108–114.
- Saez-Llorens XJ, Umana MA, Odio CM, et al. Brain abscess in infants and children. Pediatr Infect Dis J. 1989;8:449–458.
- Sidaras D, Mallucci C, et al. Neonatal brain abscess-potential pitfalls of CT scanning. Childs Nerv Syst. 2003;19:57–59.
- Yogev R, Bar-Meir M. Management of brain abscess in children. Pediatr Infect Dis J. 2004;23:157–160.
Brain Abscess - CODES
Brain Abscess - icd9
324.0 Intracranial abscess
Brain Abscess - FAQ
- Q: Do all brain abscesses require surgery?
- A: No. Some will regress with antibiotics and follow-up with MRI.
- Q: What is the best way to diagnose brain abscess?
- A: MRI.
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Book Source Details
- Book Title: The 5-Minute Pediatric Consult
- Author(s): M. William Schwartz MD; et al.
- Year of Publication: 2008
- Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: The 5-Minute Pediatric Consult
Authors: M. William Schwartz MD; et al.
Publisher: Lippincott Williams & Wilkins
Copyright: 2008
ISBN: 0-7817-7577-9
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