Symptoms may be due to mass of abscess (symptoms of raised ICP, focal neurologic signs and seizures), clinical features of the source of infection (symptoms of sinusitis, otitis media, bacteremia, etc.) and systemic toxicity (fever, malaise, hypotension).
- Classic triad of headache, fever, and focal signs: Fever, headache, seizures, and emesis are reported as the predominant symptoms in children with brain abscesses (70, 74, 75, 103). However, the classic triad may be incomplete at the time of presentation (5, 31, 58). In one review it was demonstrated in only 9–28% of pediatric cases (12).
- Fever in 30–70%: Fever is an early indicator of this infectious process in 30–70% of children (74, 103). The absence of fever does not exclude a brain abscess in children, as it is present in only 50% of children with brain abscesses (55).
- Symptoms due to mass of lesion: Larger abscesses may be associated with a significant mass effect and vasogenic edema. This may cause symptoms related to increased ICP, impending herniation, and/or neurological deficits from deleterious effects on adjacent eloquent cortex. Papilledema has been reported in 41–70% of cases (70, 103). An altered level of consciousness may be present.
- Hemiparesis more common in children: The incidence of hemiparesis is higher in children than in adults. This was demonstrated to be the result of a higher frequency of metastatic abscesses seeding eloquent areas of brain (30).
- Infants show signs of increased ICP, seizures, and systemic signs infections: Neonates frequently present with signs of infection and increased ICP, seizures, and increased head circumference with bulging fontanelles (33, 125).
- Intraventricular rupture – decrease in LOC and worsening headache: Intraventricular rupture of the abscess or herniation may be indicated by exacerbation of a headache or a decline in the child’s Glascow Coma Scale score, particularly in the context of meningeal signs (3, 102).
- Change in personality, hemiparesis – frontal lobe: Frontal lobe abscesses may be silent until quite large, and they may result in personality change, frontal release signs, and hemiparesis (31).
- Dysphasia, upper quadrantanopia – temporal lobe: With abscesses in the temporal lobe, dysphasias may be present when the abscess is located in the dominant hemisphere, and visual field deficits ranging from contralateral upper-quadrant field cuts to complete homonymous hemianopia may be observed (31).
- Dyspraxia, special neglect, inferior quadrantanopia – parietal lobe: With parietal lobe abscesses, there may be visual field cuts ranging from an inferior quadrantanopia to homonymous hemianopia; dysphasias when the abscess is located in the dominant hemisphere; or dyspraxia and spatial neglect when the abscess involves the nondominant hemisphere (31).
- Ataxia, abnormal eye movement – cerebellum: Cerebellar abscesses can produce appendicular and gait ataxias and eye movement abnormalities (31).
- Cranial neuropathy, paresis – brainstem: Children with brainstem abscesses typically present with fever and headache early in the infectious course, and paresis and cranial nerve palsies subsequently develop, especially involving GNs III, VI, and VII (62). Classic brainstem syndromes are not frequently observed in children with brainstem abscesses because brainstem abscesses are more likely to elongate into the brainstem than expand laterally (25, 62, 87, 123). Most brainstem abscesses are in the pons or mesencephalon and rarely occur in the medulla (53).
Patterns of evolution
- Dependent on location abscess: The clinical signs and symptoms in children with brain abscesses are contingent on the location and size of the lesion, presence of surrounding edema, virulence of the infectious microorganisms, and signs of infection (51).
Time for evolution
- Most develop symptoms within 2–4 weeks: The clinical features develop over 2–4 weeks, although a slower progression is not unusual. Although the symptoms of brain abscess are largely indistinguishable from those of any other space-occupying lesion, the tempo of progression tends to be more rapid, with 75% of patients having symptoms for less than 2 weeks (118).
- Slower in immunocompromised: Symptoms may present more insidiously in immunocompromised patients (118).
Evaluation at Presentation
- See EVALUATION
- Standard for neurological distress: Standard measures are taken to ameliorate any signs of elevation in ICP. Although steroids blunt the immune response, the benefits from dampening an elevation in ICP due to inflammation may warrant their use.
- Obtain specimen for culture: If the abscess or the seed site responsible for it is easily accessible, a specimen should be obtained early for identification of the infectious agent.
- Initiate antibiotics: Broad-spectrum antibiotics tailored to cover infectious agents common to the presumed source are started as soon as a specimen for culture has been obtained.
Preparation for definitive intervention, nonemergent
- Laboratory analysis for baseline: A CBC, C-reactive protein, and ESR are obtained at the time of presentation to establish baseline values that can be used as the treatment ensues.
- Cultures for source: Cultures from potentially infectious sources (blood, urine, sputum) are obtained unless the source is known.
- Antibiotics started: As soon as cultures have been obtained, antibiotics are started. Typically antibiotics will result in an improvement in the presenting symptoms within 36 hours, and their use will resist spread of the infection at the time of surgery.
Preparation for definitive intervention, emergent
- Steroids: A child seriously ill from an intracranial abscess is suffering from an elevation in ICP due to the inflammatory response within the brain surrounding the abscess. Steroids will blunt this response to some degree, resulting in some brain relaxation.
- Diuretics: A diuretic will remove some of the edema surrounding the abscess, thereby affording a transient drop in the ICP. This effect will not last long, so a diuretic should be used as a tool to protect the brain only as the acutely ill child is being moved to the operating room.
- Imaging: Good imaging will assist in minimizing the invasiveness of treatment of an abscess. Many mature abscesses can be managed with bur hole aspiration, a procedure that is better tolerated by an acutely ill child. Active participation by the surgeon in the imaging process will insure that the appropriate studies are done for any potential treatment option.
- Routine orders: Standard admission orders are given.
- Infectious disease consultation: An infectious disease consultation can be helpful in determining the probable source for the infection and the best antibiotic regimen to use until the infectious organism is identified.
- Broad-spectrum intravenous antibiotics: Begin intravenous antibiotics per the recommendations of the infectious disease consultant.