HYDROCEPHALUS

• Increase in the volume of CSF occupying the cerebral ventricle due to disturbance in absorption, flow, and production of CSF.

• Increase of CSF ventricular dilatation later, CSF diffuse through the ependymal lining into the periventricular white matter.

• This results white matter damage and gliotic scarring left untreated death

• Occult hydrocephalus : symptoms of increase ICP is not apparent

• Active hydrocephalus : disease is progressive and symptoms of increase ICP is clear

• Arrested hydrocephalus : ICP returns to normal, despite the ventricles remain dilated. CSF production is balanced. In infant, normal development resumes but pre-existing damage remains.

CLASSIFICATION• Non-communicating/obstructive - Flow of CSF is obstructed within the ventricles or

between ventricles and the subarachnoid space.• Communicating - There is communication between the ventricles

and the subarachnoid space - problem lies outside the ventricular system

(reduced absorption/blockage of the venous drainage system)

- Also due to increased CSF production

Other terms related • Normal pressure hydrocephalus - CSF pressure remain normal or only

intermittently raised. - Triad manifestation : cognitive impairment,

gait change and urinary incontinence • Hydrocephalus ex vacuo- Ventricular expansion secondary to brain

atrophy and shrinkage (alzheimer’s disease)- No increase CSF pressure

AETIOLOGY

• Obstructive congenital- Bickers-Adams syndrome - Dandy-Walker malformation- Arnold-Chiari malformation- Agenensis of foramen of Monro- Congenital toxoplasmosis

• Obstructive acquired- Acquired aqueduct stenosis- Supratentorial masses causing tentorial

herniation- Intraventricular hematoma- tumors

• Communicating - Any thickening of the leptomeninges- Any increase in CSF viscosity - Excessive CSF production • Acquired causes in infants and children- Mass lesion- Intraventricular hemorrhage- Infections - Increased venous sinus pressure- Idiopathic

PRESENTATION

• Depend on age, disease progression and individual differences in tolerance to CSF pressure changes

• Features in infants depend on acute or gradual onset

- Early sign : irritability, vomiting and impaired conscious level

- Later : failure to thrive and developmental delays- Other signs : rapid increase in head circumference dysjunction of sutures, dilated scalp veins, tense

fontanelle setting sun sign macewen’s sign Increased limb tone

• Feature in older children and adults- Acute onset : headache and vomiting Papilloedema and impaired upward gaze- Gradual onset : unsteady gait due to spasticity in the legs Large head unilateral or bilateral sixth nerve palsy

• Other features specific to adults- Cognitive deterioration- Neck pain- Nausea and vomiting- Blurred and double vision- incontinence

INVESTIGATIONS• Skull x-ray : basilar invagination (top of the second

vertebra moves upward)• Neuroradiology- CT scan : pattern of ventricular enlargement helps to

determine the cause- Dilated lateral + 3rd ventricle : with normal 4th ventricle – aqueduct stenosis with abnormal 4th ventricle – posterior fossa mass- Generalised ventricular dilatation – communicating

hydrocephalus • Ultrasound : scans through the anterior fontanelle are

occasionally used in infants to demonstrate ventricular elargement .

MANAGEMENT• Pharmalogical - Medical helps to hold back the surgery to

stabilise the patient - Medical treatment alone unsuccessful in

long-term control of ICP- Furosemide and acetazolamide inhibit

secretion of CSF by the choroid plexus.- Isosorbide promotes reabsorption.

• Neurosurgery - Insertion of an external ventricular drain

temporary drainage of the CSF into external collecting system.

- Insertion of a shunt a ventricular catheter drains the CSF through a small reservoir down to either the right atrium of the heart (VA shunt) or into peritoneal cavity (VP shunt) . Can also drain distal CSF in the lumbar are into the peritoneum (LP shunt)

- Other surgical procedures endoscopic fenestration of the floor of the 3rd ventricle may be effective in non-communicating hydrocephalus but its contraindicated in communicating hydrocephalus

COMPLICATIONS• Hydrocephalus- Untreated congenital HC often fatal in first

four years.- Epilepsy, learning and developmental difficulties common complication

• Shunt surgery - Infection - Subdural hematoma- Shunt obstruction- Low pressure state

PREVENTION

• Some can be diagnosed antenatally and managed in early life to avoid complications.

• Prevent trauma in high risk occupations or sports.

• Most cannot be anticipated early detection and rapid intervention