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Related Subjects: |Brain tumour s |Astrocytomas |Brain Metastases |Tuberous sclerosis |Turcot's syndrome |Lhermitte Duclos Disease |Oligodendroglioma |Acute Hydrocephalus |Intracranial Hypertension |Primary CNS Lymphoma (PCNSL)

Neurological and Neurosurgical emergency

Aetiology

• Normal volume of CSF is 200 mls which is produced by the choroid plexus mainly of the lateral ventricles
• Approximately 500 mls is produced daily in total which works out at about 20 mls per hour
• Produced in the two Lateral ventricles and passes into the IIIrd ventricle and then the IVth ventricle and via the foramen of luschka and Magendie into the subarachnoid space
• CSF is absorbed by the arachnoid granulations which are in the walls of the major venous sinuses.
• Hydrocephalus is defined as the accumulation of excessive CSF in and around the brain The excessive cerebrospinal fluid dilates the ventricles and compresses the normal brain
• The incidence of hydrocephalus is 1-2/1000 live births. Can be split into Communicating and Obstructive types.

Diagram of Ventricles

Types of Hydrocephalus

• Communicating type - Free flow of CSF from the choroid plexus in the ventricles to the subarachnoid space The problems lies beyond this affecting function of the arachnoid granulations e.g. SAH, Meningitis, carcinomatous meningitis
• Obstructive type - This means that there is some obstruction in the pathway of flow of the CSF between the ventricles and the subarachnoid space e.g Bleeding from SAH or ICH into the ventricles, infection, midbrain tumour , Colloid cyst of IIIrd ventricle, tumour s, Chiari type 1 malformation, congenital aqueductal stenosis, Dandy walker malformation

Clinical

• May present as acute or subacute/chronic headache associated with signs of raised ICP.
• In young children there is a rapid enlargement of the head as the fontanelles have not closed The child will be irritable, poor head control, skin over the head will be very thin and shiny, sun setting sign in the eyes (the eye cannot move up due to pressure on tectum of the midbrain), copper beaten skull on X-ray, tense fontanelles There may be difficulty in breathing The head circumference is usually more for the age of the patient There will be cognitive impairment and delayed developmental milestones.
• Adults - Severe headache, nausea, vomiting, difficulty in walking and blurring of vision with papilloedema
• Symptoms occur earlier as there is a rapid increase in ICP
• Impaired upward gaze from enlarged IIIrd ventricle compressing midbrain
• Pituitary dysfunction, IIIrd nerve lesion, Gait abnormalities and UMN signs False localising VI palsy

Investigations

• CT scan, MRI scan of the head are helpful in accurate diagnosis all of which show dilated lateral, IIIrd and IVth ventricles proximal to the obstruction There is compression of the brain and may identify a cause e.g tumour , haematoma obstructing the system With a communicating hydrocephalus ventricular dilation is symmetrical.

Classical Imaging signs

• expansion of the temporal horns
• convexity of the third ventricular walls
• rounding of the frontal horns
• effacement of sulci
• enlargement of ventricles out of proportion to sulcal dilatation

Management

• Treatment for acute hydrocephalus is mainly surgical and may be life-saving
• However in the waiting period for surgery drugs like acetazolamide and furosemide are helpful whilst emergency referral to neurosurgeons is made in those with evidence of raised ICP In some rare cases where it is chronic with long-standing compensation the hydrocephalus may be managed conservatively.
• The main purpose of surgery is to divert the excess fluid in the brain outside to either the abdominal cavity or the pleural space by a one-way catheter The procedure commonly performed is called a ventriculoperitoneal shunt.
• Complications of surgery include Infection and bacterial colonisation of the shunt, subdural haematoma, ventriculitis, obstruction and malfunction of the shunt tube and breakage of the shunt tube.