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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