Hydrocephalus Flashcards
What is hydrocephalus
Excess CSF in the intracranial and intraventricular spaces causing dilatation of the ventricles (ventriculomegaly) superior to obstruction
Due to imbalance between absorption and production
What causes absorption of CSF
Passive process by conc gradient so if raised ICP it is disrupted by arachnoid granulations in venous sinus
What causes CSF production
Metabolically active process produced by ependymal cells in choroid plexus
What affects CSF production
Acidosis
Altitude
Carbonic anhydrase inhibitor drugs
What are the non-obstructive / communicating causes of hydrocephalus
Production > resorption Choroid plexus papilloma = very rare Arnold chiairi malformation Tiny trauma blocks granulations Infection - meningitis SAH Post-op Trauma Drugs
What are the obstructive causes of hydrocephalus
Aqueduct stenosis (children) Tumours - gradual onset Cysts Infection Haemorrhage Spina-bifida
What are the symptoms in children
Increase in head circumference Bulging / tense anterior fontanelle Failure to thrive Frontal bottling Venous scalp distention Parinaud syndrome - can't look up Bradycardia Seizure
What are the symptoms in adults
Raised ICP Headache - worse lying down / Valsalva N+V Papilloedema Gait disturbance 6th nerve palsy Up gaze difficulty Coma if severe
How do you Dx hydrocephalus
CT head = 1st line
MRI to look in more detail
LP = therepatuic and diagnostic as will reduce pressure
When is LP CI
In obstructing hydrocephalus as difference in brain and spinal pressure will cause herniation
How do you treat communicating hydrocephalus
Shunt
Ventriculo-peritoneal most common
Ventriculo-atrial if peritoneal failure
How do you treat NCH
Remove obstructing lesion
Shunt
What are causes shunt malfunction
Skin erosion
Infection
Mecahincal failure
50% will fail in 5 years
How do you treat acute hydrocephalus and where
EMERGENCY
External ventricular drain into R lateral ventricle
Huge infection risk
What are symptoms of shunt malfunction
Return of original symptoms
How much CSF is produced by choroid plexus
500ml
What is the approx volume in brain
150ml
What is the composition
Glucose - look for this to make sure CSF
Protein
WCC
How does CSF circulate
Lateral ventricle Through foramen of munro 3rd ventricle Through cerebral aqueduct 4th formane Through foramen of Magendie / Luscka Into Subarachnoid space Reabsorbed
What are Arnold chair malformation
Congenital
Acquired through trauma
Cause downward displacement of herniation of cerebellar tonsil through Forman magnum
What are the symptoms
NCH
Headache
Synringomyelia (fluid filled cyst within spinal cord)
What causes normal pressure hydrocephalus
Secondary to reduced reabsorption at arachnoid villi
Head injury
SAH
Meningitis
What are the Sx of normal pressure hydrocephalus
Urinary incontinence
Gait disturbance - wide stance / short shuffle
Quickly progressive dementia
How do you Dx
CT / MRI
LP
Gait assessment / MMSE
How do you Rx
Programmable VP shunt to change pressure
Gait improves the most then incontinence then memory
Complications of shunt
Infection
Haemorrhage
Seizure
What should CSF be on removal
Clear
Colourless
Opening pressure
Glucose, protein and WCC within normal levels
Infection
Low glucose
GBS
High protein
Inflammation
High WCC
Bacterial Menignitis
High opening
High neutrophil
Low glucose
Encephalitis / viral
High opening
High WCC
Normal glucose
Lyme’s / syphillis
High WCC
How do you do LP
Cleanse iodine
Anaethetize area
22 gauge needle
Pop indicates punctured dura
Where do you inset needle
L3/4
What position of patient
Lateral debiscus
Where does CSF lie
Space between Pia and arachnoid matter
What are each tubes for
1 = gram stain and culture 2 = glucose and protein 3 = cell count and differential
What do you do if procedure fails
USS guided
What are indications
Meningitis
SAH
Malignancy
Intracranial hypertension
What are CI
Unstable SKin infection Bleeding disorder Increased ICP Chiairi malformation
What are complications
Spinal headache Apnoea Back pain Infection Cyst Haemorrhage Nerve root trauma
What are symptoms of spinal headache
Bilateral
Improves supine
Typically young female with low BMI
How do you treat
IV saline
IV caffieine
Epidural blood patch
What are the symptoms of nerve root trauma
Electric shock Back pain Altered mental status CN abnormality Cushings - Brady / hypertension / irregular breathing
How do you treat
Immediately remove needle Raise head to increase venous return Mannitol Intubate Corticosteroid Nerve conduction study
