Hydrocephalus Flashcards
What is mean CSF pressure?
10 mmHg
A pressure value of _____ is abnormal
15 mmHg
What kind of rhythm is CSF secretion?
CIRCADIAN
Where is most CFS produced?
Choroid plexus
The production of CSF increases as you get older
FALSE - decreases
What drug reduces the secretion of CSF by 50%?
Acetazolamide
Resistance to outflow =
arachnoid granulations + sagittal sinus pressure
What drives CSF absorption?
ICP
Where is CSF absorbed?
Arachnoid granulations
What are the 2 main functions of CSF?
Buoyancy
Mediator of compliance
Describe buoyancy of CSF.
Reduces weight of brain by 95%
Describe the role of ‘mediator of compliance’.
Accommodates physiological changes in vascular volumes in the head by being displaced into the spinal canal
What are the 4 different classifications of hydrocephalus.
- Infantile
- Adult (acute/chronic)
- Obstructive
- Comminicating
I feel like this lecture is really annoying me?
Pie it off
Describe the signs of a blocked shunt in ADULTS
- Headache + Vomiting
- Lack of up-gaze
- Blurred vision
What is the blurred vision in someone with a blocked shunt due to?
Papilloedema
What can the papilloedema result in suddenly?
BLINDNESS
Describe the signs of a blocked shunt in CHILDREN.
Sunsetting (infants eyes only look downward)
What will a CT of the head show in someone with a blocked shunt?
Hydrocephalus
What should be done urgently in someone with a blocked shunt?
Surgery to replace the shunt
Describe who gets ‘normal pressure hydrocephalus’,
ELDERY
What is the triad of symptoms in ‘normal pressure hydrocephalus’?
- ATAXIA
- MEMORY DECLINE
- INCONTINENCE
What should you always do in someone who presents with the triad of symptoms of: ataxia, memory decline and incontinence?
CT
What time of the day is most CSF produced?
2am
What time of day is least CSF produced?
6pm
ON average, how much CSF is produced a day?
500 mrs
When does production of CSF decrease?
As we get older
Plexus secretion is __________ to CSF
Hypertonic
What is the main drug treatment for hydrocephalus?
Acetazolamide
What kind of process is CSF absorption?
Passive
What 2 things does CSF absorption rely on?
- Intracranial pressure being greater than the pressure in the sagittal sinus
- Resistance to outflow of CSF across the arachnoid granulations
What is CSF absortion diven by?
ICP
Raised ICP means you absorb more CSF
TRUE
Resistance to outflow =
arachnoid granulation + sagittal sinus pressure
Give examples of vitamins that CSF provides.
Vitamin C and thyroxine
Why can CSF cause dementia in old age?
As you get older your CSF doesn’t circulate as much, thus there is a build up of waste products in the brain, which could attribute to dementia
What 4 ways can hydrocephalus be classified?
- Infantile
- Adult – acute/chronic
- Obstructive
- Communicating
Describe the appearance of a baby with hydrocephalus.
- Thin, shiny scalp with visible veins
- Bulging fontanelle
- Downward looking eyes – due to pressure of CSF on tectal plate
- BIG HEAD
What do babies with hydrocephalus need?
A shunt
Outline some issues that congenital hydrocephalus of a baby can cause.
- Poor feeding
- Irritability
- Vomiting
- Sleepiness
- Muscle stiffness + spasm in babies’ lower limbs
What kind of gaze do adults with hydrocephalus not have?
Upwards gaze
Why do adults with hydrocephalus not have an upwards gaze?
Due to pressure on the tectal plate
Describe prostitute sign.
Eyes accommodate to light but do not react
- Seen in adults with hydrocephalus
List the various different options of valves which can be used in hydrocephalus
- Fixed differential pressure
- Adjustable
- Antisyphon
- Switch able
- Constant flow
After insertion of a valve, what percentage of people are satisfied?
80%
What % of shunts are no longer functioning after 12 years?
80%
List some common complications of shuts.
- Overdrainage – acute subdural haematoma (SDH), slit ventricles (very small ventricles)
- Under-drainage – blockage, displaced/disconnected catheter
- Infection – use antibiotics or silver impregnanted shunts (use iodine)
List some rare complications of shunts.
- Intracerebral haemorrhage
- Seizures
- Craniosynostosis (premature ossification of sutures in a baby’s skull)
- Dissemination of tumour cells
- Umbilical fistula
- Erosion into abdominal viscera
- Ascites, hydrocele, inguinal hernia
- Silicone allergies
What can be used to prevents infections in a shunt?
- Antibiotics
- Silver impregnated shunts
- Iodine
What can happen if you get overdrainage of CSF from a shunt?
- Actue subdural haematoma
* Slit ventricles (very small ventricles)
Why might you get under-drainage from a CSF shunt?
- Blockage
* Displaced or disconnected ventricle
What should you ALWAYS ask a patient about if they present with symptoms of hydrocephalus?
Blurred vision
What should be your management in someone with a suspected blocked shunt?
Do CT in someone with a blocked shunt, then call neurosurgery to replace the shunt
What should you always ask someone with a suspected blocked shunt?
Have you had any blurred vision?
Why is blurred vision worrying?
It is caused by papilloedema which can cause irreversible blindness
List some signs + symptoms of someone with a blocked shunt.
- Headache
- Vomiting
- Sunsetting in infants
- Lack of upwards gaze in adults
- BLURRED VISION
If someone has a shunt, how can you check for infection?
Tap the shunt and send a sample to microbiology
Describe ETV.
A surgical treatment for hydrocephalus
An opening is made in the floor of the 3rd ventricle using an endoscope and a burr hole
What is a good alternative to a shunt?
ETV
What is the difference between hydrocephalus and normal pressure hydrocephalus?
Normal pressure hydrocephalus develops much more slowly over time
Describe ICP in normal pressure hydrocephalus
Normal or intermittently raised
What is the triad of symptoms in normal pressure hydrocephalus?
- Ataxia
- Memory decline
- Incontinence
What Ix should you do in suspected normal pressure hydrocephalus?
CT scan
Who usually gets normal pressure hydrocephalus?
Elderly people
Why is it important to diagnose normal pressure hydrocephalus?
Because it is a reversible cause of dementia
What are the 2 main causes of NPH?
- Idiopathic
* Post-inflammatory – SAH, meningitis, trauma, craniotomy
Describe dementia caused by NPH.
- Delay in answering questions
- Loss of spontaneity
- May progress to akinetic mutism (someone that doesn’t move or speak)
- Fluctuates in severity
- Urinary incontinence
Describe ataxia caused by NPH.
- This proceeds all other symptoms
- Difficulty rising from a chair
- Tendency to fall backwards
- Difficulty initiating gait
- Broad based, shuffling gait
Outline the Ix’s of NPH.
- Clinical + CT
- MRI
- Tracer diffusion studies
- ICP measurement
- LP tap test
- Lumbar drainage tests
- Infusion studies
What are the 2 different options for CSF diversion?
- ‘Tap test’ LP
* Lumbar drain
What should always be done with CSF diversion?
Measure NPH triad pre and post CSF drainage
The treatment of NPH is via valves. Outline some of the various valves which can be used.
- Anti syphon
- Adjustable pressure
- Combined
Who typically gets IIH?
Young, obese, females
Describe IIH.
Normal sized ventricles but raised ICP
What are the 2 characteristic symptoms of IIH?
Headaches + visual loss
What are the 3 characteristic signs of IIH?
- Papilloedema
- Constriction of visual fields
- Loss of visual acuity
What must you do if someone is going blind?
Shunt them
Outline the Ix’s and results for IIH.
- LP pressure > 25cm CSF
- Normal CSF chemistry + cytology
- Normal CT + MRI findings
- No evidence of venous sinus thrombosis
What is the no.1 treatment of IIH?
Weight loss
What are the other treatment options for IIH?
- Diuretics
- Lumbar puncture
- Lumbo- / ventriculo- peritoneal shunt
- Optic nerve sheath fenestration
- Subtemporal decompression
- Venous stents
List some complications of LP shunts.
- Blockage
- Infection
- Nerve root irritation
- Low pressure headaches
- Subdural haemorrhage
- Arachnoiditis
- Tonsillar herniation
What is spontaneous intracranial hypotension?
The amount of pressure inside the skull is lower than normal and thus CSF levels are lower too
Outline symptoms of spontaneous intracranial hypotension.
- Orthostatic headaches – headache that gets worse when you stand up
- Neck pain
- Diplopia /visual field defects
- Dizziness
- Muffled hearing
- Galactorrhoea – due to hyperaemia in the pituitary
- Impaired sphincter control
- Symptomatic subdural haematomas
Outline the 4 main causes of spontaneous intracranial hypotension.
- Idiopathic
- Collagen disorders
- Dural diverticula
- Trauma
What are the 2 main Ix’s for spontaneous intracranial hypotension?
MRI of brain and LP
What would an MRI of the head of someone with spontaneous intracranial hypotension show?
- Meningeal enhancement
- Chronic subdural haematomas
- Hindbrain herniation
What would an LP of someone with spontaneous intracranial hypotension show?
- Low pressure
- Pleocytosis
- Raised protein
- Xanthochromia
Outline the treatment of spontaneous intracranial hypotension.
- Conservative – bed rest, fluids, analgesics
- Epidural blood patches
- Surgical repair
What is Syringomyelia?
A chronic progressive disease in which longitudinal cavities form in the cervical region of the spinal cord
This characteristically results in wasting of the muscles in the hands and a loss of sensation
What is the characteristic morphological appearance of syringomyelia?
- Dilated central canals
- Spindles
- Holocord – entire spinal cord
- Tethered conus
What are the 3 classifications of syringomyelia?
- Craniovertebral junction
- Spinal canal
- Idiopathic
Outline the typical presentation of someone with syringomyelia.
- Dissociated sensory loss
- Cuts + burns on hands (loss of STT)
- Small muscle wasting
- Clawed hands
- Loss of upper limb reflexes
- Increased lower limb reflexes
- Hyperhidrosis
Why is the STT affected in syringomyelia?
STT fibres are found anterolaterally in the spinal cord but there is medial crossing of fibres
What is hyperhidrosis?
This is abnormal sweating
It is a feature of early stage syringomyelia
Indicates hyperactivity in pre-ganglionic
What is often a presenting feature of syringomyelia?
Involuntary movements - due to the excitability of spinal neurones
What sleep disturbance is also seen in syringomyelia?
Sleep apnoea
72% of people with craniovertebral junction abnormalities have sleep apnoea
True
Outline the treatment of syringomyelia.
- Open up obstructed CSF channels
- Drain syrinx cavity
- Lower overall CSF pressure
- Conservative management
What is collapse of the syrinx cavity in syringomyelia related to?
Collapse of the syrinx cavity is related to the extent of arachnoid adhesions and fibroids
What type of patient is only suitable for conservative management in syringomyelia?
- Spindles
- Dilated central canals
- Clinically stable cavities
- Extensive fibrosis
- Medically unfit
What are a large proportion of syrinxes associated with?
Hindbrain hernia
People with a hindbrain hernia will get a headache after …
- Coughing
- Sneezing
- Straining
- Laughing
- Bending forward
List symptoms of hindbrain hernia.
- Visual disturbances
- Dizziness
- Deafness
- Tinnitus
- Dysarthria
- Dysphagia
- Somatic sensory disturbances
Why do people with syringomyelia present with cuts and burns on their hands?
Due to loss of STT
This usually sits anterolateral in the spinal cord but fires cross medially
Do patients with syringomyelia present with unilateral or bilateral pain and temperature loss?
BILATERAL - as this is a central cord lesion
Where in the spinal cord does a syrinx usually occur?
Cervical to upper thoracic
Loss of pain and temperature in syringomyelia is usually in what type of distribution?
‘Cape like’ distribution
Why do patients with syringomyelia get muscle atrophy and weakness?
If anterior motor horns are involved
A syrinx usually starts small and centrally and expands out
True
