Brain Abscess in Children

Brain Abscess in Children — Santa J. Bartholomew, M.D.

Brain abscess is an infection pocket in the brain itself. It is very uncommon in both children and adults, and has become even more rare in recent years because of the better imaging techniques currently available. Overall brain abscess occurs in 1 per 100,000 people and about 25% of these cases are in children between four (4) and 10 years old with a small predilection towards boys.

Reduction in risk factors like sinusitis, middle ear infections, poor dental hygiene, un-repaired blue congenital heart disease, injuries with sharp objects (toys, pencils, chopsticks), immunosuppression (HIV, immunosuppression with organ transplant and hereditary diseases), and complications of brain surgery are the reason for the declining incidence of brain abscess; however, in children who do suffer from this infection the consequences of the disease are significant and the death rate equally as high.

How Does this Happen?

The location of the brain abscess depends in general on the location of the primary (or original) abscess. The most frequent site is the frontal lobe of the brain as it is just below the frontal or ethmoid sinus and right near the upper teeth. Parietal or temporal abscesses are more common in chronic ear infections and sphenoid sinusitis. The lower part of the brain (cerebellum and brainstem) are infrequent locations usually seen with spread of infection through the bloodstream. The infection in these primary sites breaks through the bony barrier to the brain causing infection within the brain. More rarely does the abscess form by bacteria traveling in the bloodstream to the brain.

Parietal or temporal abscesses are more common in chronic ear infections and sphenoid sinusitis.

Most common organisms
  • 36%: Streptococcus
  • 18% Staphylococcus
  • 16% Gram Negative bacteria (Klebsiella, E.coli, Enterobacteriae)
  • Remaining: a mix of other bacteria and fungi
Symptoms

Symptoms are dependent upon the site and size of the abscess, the involvement of other areas of the brain and swelling surrounding the area of abscess.

  • Fever occurs in 30-70% children – new onset headache typically associated with vomiting.
  • Seizures occur in up to 70% of children with as many as 50% experiencing ongoing long-term seizures.
  • Stroke-like symptoms such as hemiplegia, palsy of the cranial nerves and altered consciousness.
  • Infants may have bulging fontanelles.

Unfortunately, the clinical triad (as shown below) only occurs in a small group of children.

Brain Abscess Triad
STAGE OF DISEASEDAYS OF DISEASEPATHOLOGY OF DISEASE
Early cerebritis1-3Poorly defined lesion, edema, vasodilation of blood vessels to brain
Late cerebritis4-9Peripheral ring of white cells around pus with central area of necrosis
Early capsule formation10-14Beginning of capsule formation
Late capsule formation>14 Well-formed thick capsule with pus in the center
How do we find the abscess?
  • Level of suspicion based on history.
  • CT scan : 95-99% sensitive in spotting the lesion but hard to determine by CT if the lesion is an abscess, a tumor or vascular lesion.
  • MRI: Better at demonstrating what the lesion is, can also give more information about swelling of brain and look for smaller abscess in the brain.
  • High white count, sed rate and CRP are found in most children with brain abscess but are not specific to disease.
Treatment
  • Surgery to drain abscess.
  • Intravenous antibiotics.
  • Repair of the underlying problem that caused the abscess.
  • Treat side effects of abscess: brain swelling, seizures, bacteria in the blood.
Prognosis: 4-12% death rate
  • Children that present with multiple abscesses or a very large deep abscess tend towards worse outcomes.
  • Children with rupture of abscess into the intraventricular space have worse outcome.
  • 50% of children have ongoing seizures.
  • Poorer intellectual outcomes in younger children.
  • Delay in diagnosis also alters long-term outcome.
Figure 1: Computed tomography brain without contrast: hypodense right frontal temporal subdural hematoma extending along the anterior falx measuring 8 mm in greatest dimensions and causing right to left midline shift measuring 7 mm (red arrows). (A) Transverse view showing dilatation of the left lateral ventricle including the temporal horn concerning for mild entrapment (blue arrow). (B) More caudal transverse view showing midline shift (red arrow). (C) Coronal view showing midline shift (red arrow); there was also bilateral ethmoid sinusitis (red arrowheads).*
Figure 1: Computed tomography brain without contrast: hypodense right frontal temporal subdural hematoma extending along the anterior falx measuring 8 mm in greatest dimensions and causing right to left midline shift measuring 7 mm (red arrows). (A) Transverse view showing dilatation of the left lateral ventricle including the temporal horn concerning for mild entrapment (blue arrow). (B) More caudal transverse view showing midline shift (red arrow). (C) Coronal view showing midline shift (red arrow); there was also bilateral ethmoid sinusitis (red arrowheads).*

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