Hydrocephalus Flashcards
Define Hydrocephalus?
Enlargement of the cerebral ventricular system
How can Hydrocephalus be divided?
Into obstructive and non-obstructive
AKA communicating and non-communicating
What is Hydrocephalus ex vacuo?
Apparent enlargement of the ventricles as a compensatory change due to brain atrophy
What is the aetiology of Hydrocephalus?
Abnormal accumulation of CST in the ventricles
What is the aetiology of Obstructive Hydrocephalus?
Impaired outflow of the CSF from the ventricular system
Lesions of the 3rd and 4th ventricle or cerebral aqueduct
Posterior fossa lesions (e.g tumour) compressing the 4th ventricle
Cerebral aqueduct stenosis
What is the aetiology of Non-Obstructive Hydrocephalus?
Impaired CSF reabsorption into the subarachnoid villi
Tumours
Meningitis
What is Normal Pressure Hydrocephalus?
Idiopathic chronic ventricular enlargement
The long white matter tracts are damaged leading to gait and cognitive decline
What is the epidemiology of Hydrocephalus?
Bimodal age distribution:
- Young (congenital malformations and brain tumours)
- Elderly (strokes and tumours)
What are the presenting symptoms of Obstructive Hydrocephalus?
Acute drop in conscious level
Diplopia
What are the presenting symptoms of Normal Pressure Hydrocephalus?
Triad of Symptoms:
- Dementia
- Gait disturbance
- Urinary incontinence
What are the signs of Obstructive Hydrocephalus in adults?
Low GCS
Papilloedema
6th nerve palsy
Why is the 6th nerve affected in Hydrocephalus?
It has the longest intracranial path of all the cranial nerves and so is the most susceptible to palsy due to raised ICP
What are the signs of Obstructive Hydrocephalus in Neonates?
Increased head circumference
Sunset Sign
What is the Sunset Sign?
Downward conjugate deviation of the eyes
What are the signs of Normal Pressure Hydrocephalus on physical examination?
Cognitive Impairment
Gait apraxia (shuffling)
Hyperreflexia
