Hydrocephalus Flashcards
What is CSF
ultra filtrate of plasma Fluid found in ventricles and subarachnoid space.
75ml in cranial and 75 in spinal canal
What produced CSF
produced in brain by modified ependymal cells that form choroid plexus
What produces CSF
Produced in brain by modified ependymal cells that form choroid plexus primarily in the lateral ventricles , but in other ventricles too . 10-30 pls produced an hour, replaced 4 times a day.
What does the CSF consist of
Sodium , chloride , bicarbonate , magnesium , potassium , calcium , glucose , protein , pCO2 , pO2 , pH , white cells
If you are suspecting bacterial meningitis what component of CSF will be different
Glucose will be less than 50% of serum level rather than the normal 60%
Should there be any white cells in the CSF
Anything more than 5 then be suspicious of infection
Explain how CSF is produced
Choroid plexus is responsible for 70 - 90% of CSF. Choroid plexus found in lateral ventricles , third ventricle and fourth ventricle. Highly vascular and produces CSF by active ATP dependent process.
What medication can reduce CSF production
Acetazolamide ( carbonic anhydrase inhibitor ), remifentanil and noradrenaline
What can increase CSF production
Volatile anesthetic agents , nitric oxide and hypercapnoea
Where does the CSF drain out of
Foramina in 4th ventricle. Drains into the dural venous sinus via subarachnoid space
Where does the CSF drain out of
Foramen in 4th ventricle
Flow of CSF is dependent on what
Pressure
Raised venous pressure results in what happening to the CSF
Reduced absorption which will cause back flow of CSF from the sinuses
What is Hydrocephalus
Increase in CSF in head to point where brain can not properly function with raised pressure.
More common in children than adults
If hydrocephalus left untreated what could happen
Developmental delay , neurological deficits , cognitive disorders and death
What is the cause of Hydrocephalus
1- Communicating : blockage to CSF reabsorption in arachnoid granulations usually due to overproduction or defective absorption ( CSF can still flow between the ventricles but not into spinal canal)
2- Non-communicating : blockage within the CSF pathway ( can’t flow between ventricles )
3- Congenital : spina bifida , stenosis
4- acquired : infection , tumour ,SAH
What is the cause of Hydrocephalus
Overproduction of CSF or CSF pathway obstruction
What could cause non- communicating hydrocephalus
1- Colloid cyst
2- Pineal tumour
3- Wth ventricular tumour
Presentation of patient with hydrocephalus
Infants 1- Macrocrania 2- recurring committing / poor feeding 3- sunsetting eyes or gaze 4- abnormal cry 5- recurrent apnoea / pneumonia or stridor 6- bradycardia
Older children / adults 1- Headache 2- vomiting 3- confusion / reduced consciousness 4- Diplopia / cranial nerve palsies ( 3 , 4, 6 ) 5- ataxia 6- urinary incontinence 7- dementia 8- bradycardia 9- hypertension
Presentation of patient with hydrocephalus
Infants 1- Macrocrania 2- recurring committing / poor feeding 3- sunsetting eyes or gaze 4- abnormal cry 5- recurrent apnoea / pneumonia or stridor 6- bradycardia
Older children / adults 1- Headache 2- vomiting 3- confusion / reduced consciousness 4- Diplopia / cranial nerve palsies 5- ataxia 6- urinary incontinence 7- dementia 8- bradycardia 9- hypertension
What is macro crania
abnormal increase in skull size = making facial area disproportionately small
What hydrocephalus sign can a fundoscopy show
Papilloedema
What is investigations are required for hydrocephalus
CT or MRI scans
What will you see in a CT scan for hydrocephalus
A lot of dark black fluid in the scan , enlarging the ventricles. ependymal of ventricles is being stretched and CSF is leaking out.
Why does CSF leak out
Blockage will cause ependymal of ventricles to be stretched and thus CSF will leak out
Does big ventricles always mean hydrocephalus
No , could just be CSF taking up space of brain atrophy ( happens as everyone ages )
What is idiopathic intracranial hypertension
Disease effecting young , usually females that are overweight.
High pressure around brain that is associated with sight loss and damage to optic nerve
How to manage Hydrocephalus
1- Ventricular shunt
2- Bypass blockage
3- Endoscopic third ventriculostomy
Explain the use of ventricular shunts to treat hydrocephalus , and where they are usually located
Mechanical device (catheter) to divert CSF from brain by draining the ventricle and then drains fluid outside
1- external drains : for temporary hydrocephalus ( if condition causing hydrocephalus will improve )
Will put into
1- Peritoneum ( most popular )
2- Atria/SVC
3- Pleural space
What are the side effect of the ventricular shunts
They might get blocked and could cause problems in the locations they drain into
What is a Endoscopic Third Ventriculostomy
Endoscope is passed in through the lateral or third ventricle and a thin membrane is used to create a stoma or small opening is done at both of third ventricle for CSF bypass the blockage and drain into spinal cord .
Risk : risk that could damage basilar artery and cause stroke
