Pediatrics: Hydrocephalus Diagnosis

Study Notes

Definition and Physiology

Hydrocephalus is an abnormal accumulation of CSF within the head due to impaired circulation and absorption, or rarely from increased production by choroid plexus papilloma.
Obstructive or non-communicating hydrocephalus occurs when there is an obstruction within the ventricular system.
Non-obstructive or communicating hydrocephalus occurs when there is obliteration of subarachnoid cisterns or malfunction of arachnoid villi.

Causes of Obstructive or Non-Communicating Hydrocephalus

Congenital causes:
- Aqueductal stenosis
- Malformation of vein of Galen
- Dandy-Walker syndrome: cystic dilatation of the 4th ventricle with atrophy of the cerebellum
- Chiari malformation type II: elongation of the 4th ventricle with kinking of the brain stem
Acquired causes:
- Neonatal meningitis or intracranial hemorrhage
- Lesions of the posterior fossa (e.g., tumor, abscess)

Causes of Non-Obstructive or Communicating Hydrocephalus

Subarachnoid hemorrhage, especially in prematures
Meningitis (pneumococcal and tuberculous)
Intrauterine intracranial infections (e.g., toxoplasmosis, CMV)
Leukemic infiltration

Clinical Manifestations

Before closure of fontanels: 50% are asymptomatic
Progressive increase in head size
Separation of sutures
Fontanels are widely open, tense, and persistent
Dilated scalp veins
Stretched scalp skin
Macewen sign: cracked pot percussion note of the skull due to separation of sutures
Audible bruit in cases of malformation of vein of Galen
Eyes: sun set appearance and progressive optic nerve damage
Pyramidal tract lesion with brisk tendon reflex, spasticity, clonus, and Babinski sign
Mental retardation occurs late when extensive cerebral cortex atrophy

Diagnosis

History: familial cases in aqueductal stenosis, prematurity, meningitis, or encephalitis
Examination: head circumference recorded and compared with previous measurements
Fundus examination: may show papilledema or optic atrophy
Transillmination of the skull: is positive
Plain X-ray of the skull: large head, separated sutures, wide sella turcica
Serology for TORCH
CT scan and MRI: for specific cause as tumors

Differential Diagnosis

Megaloencephaly: large-sized head due to increased glial tissue
Subdural hematoma: chronic
CNS degenerative and metabolic brain disorders
Brain tumors

Treatment

Depends largely on the cause
Medical: to reduce rate of CSF production using acetazolamide or furosemide
Extracranial shunt: VP shunt allows CSF to flow from lateral ventricle to the peritoneal cavity.

Description

This quiz covers the diagnosis of hydrocephalus in children, including signs and symptoms, medical history, and examination methods. It discusses the differences in presentation between younger and older children.