Definition: enlargement of the cerebral ventricular system.
Subdivisable into obstructive and non-obstructive, or communicating and non-communicating.
Aetiology/ risk factors:
-Abnormal accumulation of CSF in the ventricles, leading to raised intracranial pressure, caused by:
Impaired outflow of CSF from the ventricular system (obstructive/ non-communicating):
-lesions of the third ventricle, fourth ventricle, cerebral aqueduct (inc. TB, neurocysticercosis)
-posterior fossa lesions (tumour, blood) compressing fourth ventricle
-cerebral aqueduct stenosis
Impaired CSF resorption in the subarachnoid villi (non-obstructive/communicating):
–Normal Pressure Hydrocephalus (NPH) = idiopathic chronic ventricular enlargement, long white matter tracts (corona radiate, anterior commissure) are damaged causing gait and cognitive decline
Bimodal age distribution.
Congenital malformations and tumours in the young, and tumours and strokes in the elderly.
-Acute drop in conscious level
-Diplopia (double vision)
-Headache (worse on waking, lying down, bending forward, or coughing)
-Subtle personality change e.g. irritability
NPH = Chronic cognitive decline, falls, urinary incontinence
= wet, wacky, wobbly triad
-impaired GCS (conscious level measure)- drowsiness, listlessness, irritability, coma
-papilloedema, decreased visual acuity, peripheral field loss
-VI nerve palsy (abducens nerve which abducts the eye, this is a ‘false localising’ feature of raised ICP)
-pupil changes (constriction first and later dilation = due to raised ICP)
-head circumference may enlarge (because babies are super stretchy)
-sunset sign = downward conjugate (both) deviation of eyes
NPH = cognitive impairment, gait apraxia (shuffling), hyperreflexia
CT- First line investigation to detect hydrocephalus. May also detect cause e.g. tumour.
–Lumbar puncture- contraindicated in obstructive hydrocephalus as it can cause tonsillar herniation and death.
May be necessary in normal pressure hydrocephalus as a therapeutic trial.
CSF- from puncture, or from ventricular drains- may indicate underlying pathology e.g. TB
-ABC (airway, breathing, circulation)
-protect and secure airway if impaired consciousness
–external ventricular drain = catheter into lateral ventricle to bypass obstruction
–ventriculoperitoneal shunting = ventricular catheter into one/both lateral ventricles connected to subcutaneous drain connected to peritoneal cavity
–lumboperitoneal shunting = alternative shunt, may be suitable for communicating/ non-obstructive hydrocephalus
–advanced neurosurgery: endoscopic ventriculostomy and aqueductoplasty
-surgical excision of tumours causing obstruction
-cerebral herniation ⇒ coning ⇒ death
-shunt infection, block or malfunction
-Obstructive hydrocephalus often fatal if untreated.
-Cognitive and gait decline in NPH can improve with shunting.