Normal Pressure Hydrocephalus Flashcards
Definition
Rare condition = When the ventricles of the brain become enlarged due to an increase in cerebrospinal fluid (CSF) in the brainspace, without a concomitant increase in the CSF opening pressure on a lumbar puncture
Typical presentation
Rapidly progressive dementia-like picture, associated with levodopa-unreponsive gait disturbance and urinary or faecal incontinence. Unlike many other types of dementia, it is potentially reversible
Aetiology
- Subarachnoid haemorrhage
- Intracerebral haemorrhage
- Severe meningitis
- Brain tumour
- Head trauma
Epidemiology
- Advancing age (+60)
- Vascular disease
- Diabetes Mellitus
Signs
- Bladder incontinence
- Faecal incontinence
- Shuffling gait
- ‘Magnetic gait’, where the person’s feet appear stuck to the floor
- Dementia symptoms
Symptoms
Symptoms develop quickly over months
- Poor concentration
- Poor memory, particularly short-term
- Poor insight into deficits
- Increasing confusion
Hakim’s classical triad of NPH (3 W’s)
- Mental impairment = WACKY
- Urinary incontinence = WET
- Gait disturbance = WOBBLY
Diagnosis
- CT head:
= ventriculomegaly;
= absence of macroscopic obstruction to CSF flow;
= narrowing of the sulci and subarachnoid spaces;
= enlarged Sylvian fissures - MRI head: similar findings
- Levodopa challenge
- LP:
= measure opening pressure = normal in NPH
= large volume (50ml) CSF tap mimicks effect of shunting procedure. Px then assessed for transient cognitive, gait and sphincter function improvements.
Management
FIRST LINE: Ventriculo-peritoneal shunting (VPS): permenant CSF diversion from ventricular system to peritoneum
SECOND LINE: Torkildsen procedure = passing ventricular catheter to bridge the lateral ventricle and the cervical subarachnoid space at the foramen magnum.
Complications
Most complications occur within the first year after shunt insertion:
- CNS infection
- Subdural haemorrhage
- Shunt malfunction: kinking, infection, migration of catheter, debris occlusion
