Specific Management: Intracranial Infection

Seven causes are outlined briefly here.

Bacterial meningitis

Diagnosing meningitis may be difficult particularly in children <2 years. Classical symptoms such as decreased consciousness, neck pain/stiffness, vomiting and rash may be seen in the older child. Children, especially those <12 months old, may present as a fit with a fever. Clinical post-fit recovery may be delayed arousing suspicion of a non-benign cause.

Treatment with broad spectrum antibiotics is needed until a definitive diagnosis can be made.

Treating with steroids (dexamethasone 0.15 mg/kg prior to first dose of antibiotics) reduces profound hearing loss if the causative agent is Haemophilus influenza type B (HIB) and less so in cases of meningococcal or streptococcal infection. [17]

Herpes simplex encephalitis

Herpes simplex encephalitis should be suspected in a child with a decreased consciousness and focal neurological signs, fluctuating consciousness, contact with herpetic lesions or no obvious alternative cause. [18]

The diagnosis of herpes simplex encephalitis can be made with positive cerebrospinal fluid (CSF) for herpes simplex virus DNA in PCR of CSF. A positive PCR of CSF is highly sensitive and specific.

A magnetic resonance image scan and an abnormal EEG can strengthen the diagnosis. Nevertheless, waiting to perform a lumbar puncture should not delay treatment with intravenous acyclovir (see the British National Formulary (BNF) for body surface area dose calculation).

Intracranial abscess

A history of recent antibiotic use, neurosurgery or cyanotic congenital heart disease is relevant. [19]

Clinical signs may include a reduced consciousness, focal neurological signs, signs of sepsis and raised intracranial pressure.  Diagnosis is with a CT scan of the head. [19]

Treatment is with broad spectrum antibiotics and neurosurgical referral.

Tuberculous meningitis

Tuberculous meningitis should be suspected if the child has had contact with pulmonary tuberculosis.

Diagnosis is with a positive CSF PCR for TB DNA.

Further management should be guided by microbiology.

Raised intracranial pressure

A child with decreased consciousness and raised intracranial pressure may have complaints of a headache, display altered behaviour and vomiting. Signs include unilateral or bilateral dilated pupils or unreactive pupils, abnormal posture, papilloedema, a relative bradycardia for age and hypertension.

Manage the patient with the head in the midline, raised 20 degrees and aim to maintain normal physiology, which may require intubation and ventilation.  Consider mannitol or hypertonic saline.

Hypertensive encephalopathy

Headache, nausea, vomiting, visual disturbances and focal neurological deficits and seizures may occur.

Hypertension is defined as the systolic blood pressure >95th centile for age.

Further management should be guided by a paediatric nephrologist or intensivist.

Prolonged convulsion/post convulsive state

Convulsions lasting more than 10 minutes need treating as per the APLS guidelines. [5] In infants, in addition to the core investigations calcium and magnesium should be requested at presentation.

Post-convulsive state should last for less than one hour; if this is prolonged and the blood glucose is normal, the core investigations should be performed.