27.3 Pediatric CNS Disorders: Febrile Seizures, Epilepsy Syndromes, Status Epilepticus, Meningitis and Encephalitis in Children, Cerebral Palsy, Hydrocephalus & Neural Tube Defects, Headache and Migraine, and Brain Tumors

Why this area matters

The TOS CNS competencies are to:

• relate the burden of these disorders to the nation's health;
• distinguish conditions with similar signs;
• prioritize tests and interpret them;
• recognize emergencies and complications;
• apply management and create a wellness program for the family.

Seizures are among the most common pediatric emergencies. CNS infections (bacterial meningitis, TB meningitis, Japanese encephalitis, rabies) still cause death and disability in Filipino children. Cerebral palsy and epilepsy need lifelong family support.

Febrile Seizures

Occur between 6 months and 5 years of age (peak incidence at 18 months), associated with fever $> 38.0^\circ\text{C}$ in the absence of central nervous system infection or electrolyte imbalance.

• Simple Febrile Seizure (Benign): Generalized tonic-clonic motor activity, duration $< 15\text{ minutes}$, occurs only once within a 24-hour period, with complete recovery of baseline mental status and no post-ictal focal neurologic deficit (no Todd's paresis). Risk of subsequent epilepsy is $< 2\%$ (equal to general population). Management: reassure parents, antipyretics for comfort (does not prevent recurrent seizures); no maintenance anticonvulsants needed.
• Complex Febrile Seizure: Demonstrates focal features, lasts $\ge 15\text{ minutes}$, or recurs more than once within 24 hours. Associated with increased risk of subsequent unprovoked epilepsy. Requires thorough investigation (EEG, neuroimaging).

Additional points on febrile seizures:

• Look for the source of fever.
• A lumbar puncture is considered in infants under 12 months who are not fully immunized against Hib and pneumococcus, in children pretreated with antibiotics, and whenever meningeal signs are present.
• About one-third recur, especially when the first seizure occurred before 18 months or at a low temperature, or with a family history.
• Teach parents seizure first aid:
  • lie the child on the side;
  • nothing in the mouth;
  • time the seizure;
  • rescue buccal or intranasal midazolam, or rectal diazepam, for seizures lasting 5 minutes or more.

Epilepsy and status epilepticus

• Epilepsy: two or more unprovoked seizures more than 24 hours apart, or one with a high risk of recurrence.

• Convulsive status epilepticus:
  • a seizure lasting 5 minutes or more, or repeated seizures without recovery;
  • start with airway, breathing, oxygen and a glucose check;
  • first-line (5 to 10 minutes): a benzodiazepine (IV lorazepam or diazepam, or buccal, intranasal or IM midazolam without IV access), repeated once;
  • second-line (10 to 30 minutes): phenytoin or fosphenytoin, levetiracetam, valproate or phenobarbital;
  • refractory status: ICU anesthesia with midazolam infusion, propofol or thiopental;
  • treat the cause: hypoglycemia, hyponatremia, hypocalcemia, infection, trauma or poisoning such as isoniazid, which needs pyridoxine.

Meningitis and encephalitis in children

• Organisms by age are covered in Microbiology:
  • neonates: GBS, E. coli, Listeria;
  • older children: pneumococcus, meningococcus, Hib in the unvaccinated.
• Infants show nonspecific signs: fever or hypothermia, irritability, poor feeding, bulging fontanel and seizures. Neck stiffness is often absent under 18 months.
• Treatment:
  • ceftriaxone (plus vancomycin where resistance is a concern) beyond the neonatal period;
  • dexamethasone before or with the first antibiotic dose in Hib and pneumococcal meningitis reduces hearing loss.
• Complications:
  • SIADH;
  • subdural effusion;
  • hydrocephalus;
  • sensorineural hearing loss, so every survivor gets a hearing test;
  • seizures and developmental delay.
• TB meningitis has a subacute course over weeks, with cranial nerve palsies, hydrocephalus and basal enhancement, often in an unvaccinated child with a TB contact.
• Encephalitis brings fever with altered behavior or consciousness and seizures. Causes are Japanese encephalitis, HSV (IV acyclovir), dengue, enteroviruses, measles and rabies.

Cerebral palsy, hydrocephalus and neural tube defects

• Cerebral palsy:
  • a non-progressive disorder of movement and posture caused by injury to the developing brain (prenatal, perinatal or postnatal);
  • risk factors are prematurity (periventricular leukomalacia gives spastic diplegia), hypoxic-ischemic encephalopathy, kernicterus (dyskinetic CP), infections and stroke;
  • types: spastic (most common: hemiplegia, diplegia or quadriplegia), dyskinetic, ataxic and mixed;
  • associated problems are epilepsy, intellectual disability, visual and hearing impairment, feeding problems and contractures;
  • management is multidisciplinary: physiotherapy, occupational and speech therapy, spasticity treatment (baclofen, botulinum toxin), orthoses and family support.
• Hydrocephalus:
  • obstructive (non-communicating): aqueductal stenosis, posterior fossa tumors, Dandy-Walker malformation;
  • communicating: after meningitis or hemorrhage;
  • in infants it causes a rapidly enlarging head, bulging fontanel, split sutures, "sunset eyes" and irritability; in older children, headache, vomiting and papilledema;
  • treated with a ventriculoperitoneal shunt or endoscopic third ventriculostomy.
• Neural tube defects:
  • myelomeningocele with Chiari II malformation and hydrocephalus, causing leg weakness and a neurogenic bladder and bowel;
  • prevented by periconceptional folic acid.

Headache, migraine and brain tumors

• Migraine in children:
  • attacks are shorter (from 2 hours) and often bilateral, with nausea, photophobia and phonophobia;
  • there is often a family history;
  • abdominal migraine and cyclic vomiting are childhood equivalents;
  • treat with ibuprofen or paracetamol early in the attack and identify triggers. Preventive therapy is used for frequent attacks.
• Headache red flags:
  • morning headache with vomiting;
  • headache that wakes the child;
  • worsening pattern;
  • focal neurologic signs, ataxia, papilledema;
  • change in personality or school performance;
  • head growth in infants;
  • age under 3.
• Brain tumors:
  • the most common solid tumors of childhood;
  • most are infratentorial in children aged 1 to 10: medulloblastoma (midline cerebellum, can seed the spinal canal), pilocytic astrocytoma (cystic cerebellar tumor with a mural nodule and a good prognosis) and ependymoma (fourth ventricle);
  • diffuse midline (brainstem) glioma causes cranial nerve palsies and long-tract signs with a poor prognosis;
  • craniopharyngioma causes bitemporal hemianopia, growth failure and diabetes insipidus.