CSF And Hydrocephalus Flashcards
What are the 2 types of hydrocephalus and what causes the CSF to build up?
Communicating hydrocephalus - problem with resorption of CSF
Non-communicating hydrocephalus - obstruction of the normal flow of CSF
What’s the aetiology of communicating hydrocephalus?
Infection (after meningitis)
Subarachnoid haemorrhage
Post operative
Head trauma
How can subarachnoid haemorrhage cause hydrocephalus? And what type of hydrocephalus is this?
Can cause communicating hydrocephalus
The blood causes scarring of the arachnoid villi therefore aren’t able to resorb the CSF as efficiently
What are the signs and symptoms of communicating hydrocephalus in a child/infant?
Failure to thrive
Paranoids sign - eyes will look down the way, sun setting eyes
Disproportional increase in head circumference (due to cranial sutures not be fused yet)
What are the signs and symptoms of communicating hydrocephalus in an adult / adolescence?
Symptoms of raised ICP;
- headache - worse in the morning, when leaning forward, when lying down
- nausea and vomiting
- pappiloedema
- abducens nerve palsy
- gait disturbance
What nerve palsy can you get with raised ICP and why?
Abducens (CN VI) palsy because it has the longest course through CSF so it most likely to get damaged
Communicating hydroceaphlus can also be caused by an increase in production of CSF, in which condition can this occur in?
Choroid plexus papilloma can present this way but it is very rare
What is the aetiology of non-communicating hydrocephalus?
Aqueductal stenosis Tumours/cancer/masses Cysts Infection Haemorrhage/haematoma Congenital malformations/conditions
Give an example of a cyst that could cause non communicating hydrocephalus.
Cholloid cysts in the 3rd ventricle
In a CT or MRI what is the first sign of hydrocephalus?
Dilatation of lateral ventricle horns
3rd ventricle will become ballooned
Because everyone has different sizes of ventricles, how would you distinguish between normal and pathologically large ventricles?
Evans ration >30% in hydrocephalus
Ventricular index >50% in hydrocephalus
What is the treatment for communicating hydrocephalus?
External ventricular drain EVD
Shunt
What is the treatment for non-communicating hydrocephalus?
Treat by removing the source of the obstruction
Ventriculostomy with VP shunt is also an option
What is the disadvantage of pacing a shunt in?
They have a high failure rate of 40% within first year, 50% within 5 years and it goes up 5% each year
What causes the failure of the ventricular shunts?
Mechanical failure from occlusion/disconnection Migration Over or under drainage Infection Skin erosion
What is normal pressure hydrocephalus?
Commonly a preventable and/or curable cause of dementia
What are the symptoms/signs of normal pressure hydrocephalus?
Wet, wobbly, wacky
Urinary incontinence
Gait disturbance
Rapidly progression dementia
What is the typical gait of someone with normal pressure hydrocephalus?
Short steps
Shuffling feet
Wide stance
What investigations would you carry out for investigating suspected normal pressure hydrocephalus?
Lumbar puncture (normal opening pressure) CT / MRI
what is the treatment for normal pressure HYDROCEPHALUS?
Programmable VP shunt
Programmable because they are often sensitive to pressure changes
What symptoms improve in normal pressure hydrocephalus?
Most likely to improve is gait > incontinence > dementia
CSF exits the 4 th ventricle through what?
Foramen lushaka (2 lateral foramina) Foramen magendie (1 medial formina)
What is the resorption of CSF by arachnoid villi driven by?
Resorption is driven by the pressure gradient between the intracranial space and the venous system
The production of CSF independent on what ion being pumped into where?
Is this an active or passive process?
CSF production is dependant on Na being actively pumped into the subarachnoid space so water follows (CSF)
What conditions would you require a lumbar puncture for diagnosis and/or treatment?
Meningitis Meningoencephalitis Subarachnoid haemorrhage Malignancy Idiopathic inter cranial hypertension Infusion of drugs or contrast
What are the contraindications for performing a LP?
Unstable patient with CVS or respiratory instability
Localised skin/tissue infection
Evidence of unstable bleeding disorder i.e. on warfarin, clotting deficiency, platelets <50,000
Increased ICP
Chiari malformations (low lying cerebellar tonsils)
Why is a manometer attached when you attain the CSF in a lumbar puncture?
To obtain the opening pressure
How is the CSF obtained from an LP interpreted to aid with diagnosis?
Tube 1 - culture and gram stain
Tube 2 - glucose & protein
Tube 3 - cell count and differentiation
What are the complications from a lumbar puncture?
Spinal headache Apnea Back pain Bleeding or fluid lead around spinal cord Subarachnoid epidermis cyst Nerve trauma Brainstem herniation Infection, pain, haematoma
What are the risk factors for a spinal headache post LP?
Female
18-30 years
Lower BMI
History of spinal headache
What si the treatment for a spinal headache post LP?
Supine position for 2 hours
Hydrate
Caffeine
Epidural blood patch
How do you prevent a spinal headache from an LP?
Pass the needle bevel parallel to the longitudinal nerve fibres of the dura
Replace stylet before removing the needle
Use smaller diameter needle
Use traumatic needle
How does an epidermal inclusion cyst occur as a complication from an LP?
When a core of skin is driven into spinal or paraspinal space with hollow needle
What are the symptoms of nerve root trauma from an LP?
Dysaethesias, electric shocks
Back pain
If herniation occurred as a complication from an LP, how would you treat?
Supine position to improve venous return from the brain
Intubate or ventilate
What is the normal opening pressure range for LP?
6-16mm/H20
