Disorders of Intracranial Pressure Flashcards
What level of ICP (mmHg) would be classed as abnormally high?
15
How much CSF do we produced each day?
1 pint
Which medication can reduce the amount of CSF we produce per day by 50%?
Acetazolamide
CSF is produced by the ____ and absorbed by ____
Choroid plexus
Arachnoid granulations
What factors create a resistance to CSF outflow?
Arachnoid granulations
Sagittal sinus pressure
What are the main functions of CSF?
Allow buoyancy of the brain
Adapt to changes in vascular volumes
Provide micronutrients and take away waste
What are the clinical signs of hydrocephalus from birth?
Large head Thin and shiny scalp with visible veins Bulging or tense fontanelle Downward looking eyes (sunsetting) Macewan sign (cracked pot on head percussion)
How is hydrocephalus diagnosed in newborns?
US
Which symptoms in a newborn, can occur as a result of hydrocephalus?
Poor feeding Irritability Vomiting Sleepiness Muscle stiffness and spasms in lower limbs
What is the main management option for hydrocephalus?
VP shunt
A VP shunt, once inserted, lasts a lifetime. True/ False?
False
Most need revising in 10 years time
What are some complications of VP shunts?
OVERDRAINAGE: Acute subdural haematoma
Slit ventricles
UNDERDRAINAGE: Blockage
Displaced catheter
INFECTION
What are the classifications of hydrocephalus?
Communicating: occurs when the flow of CSF is blocked after it exits the ventricles.
Obstructive: occurs when the flow of CSF is blocked along one or more of the narrow passages connecting the ventricles.
What are the common causes of paediatric hydrocephalus?
CONGENITAL ACQUIRED Trauma Infection (post-meningitis) Tumour Haemorrhage
What signs in a patient would be suggestive of a blocked shunt?
Headache Vomiting Sunsetting in children Lack of upgaze in adults Blurred vision (PAPILLOEDEMA - PRESSURE ON CN2)
What investigation MUST be carried out if a blocked shunt is suspected?
CT head to indicate hydrocephalus
Which surgical procedure can be used as an alternative to VP shunt?
Endoscopic 3rd ventriculostomy (bypasses blockage)
What is normal pressure hydrocephalus?
Enlarged cerebral ventricles with normal ICP
Who is most likely to get normal pressure hydrocephalus?
Elderly people
What is the triad of signs found in normal pressure hydrocephalus?
Ataxia (shuffling gait)
Memory decline (dementia)
Urinary incontinence
How is NPH diagnosed?
CT/MRI Tracer diffusion studies ICP measurement LP 'tap test' Lumar drainage tests Infusion studies
What is the aetiology of NPH?
Idiopathic
Post-inlfammatory - subarachnoid haemorrhage, meningitis, trauma, craniotomy
What differential diagnoses should be considered in NPH?
Dementia - alzheimers, vascular
Ataxia - cerebellar, myopathy
What is benign intracranial hypertension?
Normal sized ventricles with increased ICP (‘Slit-like ventricles’)
Which conditions are associated with benign intracranial hypertension?
Obesity (especially in young females) Sleep apnoea Hypothyroidism Addison's disease SLE Steroid withdrawal
What clinical signs would you look for in benign intracranial hypertension?
Papilloedema
Constriction of visual fields
Loss of visual acuity
What symptoms would you look for in benign intracranial hypertension?
Headaches
Visual losses
How is benign intracranial hypertension diagnosed?
LP showed increased CSF pressure
Normal CT/MRI
What are the main management options for benign intracranial hypertension? What is first line?
Acetazolamide Diuretics LP VP shunt WEIGHT LOSS - 1ST LINE
What is the main side effect of acetazolamide?
Tingling in peripheries
What is spontaneous intracranial hypotension?
Low pressure in brain cavity due to CSF leak
What are the symptoms of spontaneous intracranial hypotension?
Orthostatic headaches (relieved when horizontal) Neck/arm pain Diplopia/VF defects Dizziness Muffed hearing Galactorrhea Impaired sphincter control
How is spontaneous intracranial hypotension diagnosed?
MRI
Spinal MRI
LP (low pressure)
CT/ isotope myelography
How is spontaneous intracranial hypotension managed?
Conservative - bed rest, fluids, analgesics
Epidural blood patches
Surgical repair
What is the aetiology of spontaneous intracranial hypotension?
Idiopathic
Collagen disorders
Dural diverticula
Trauma
What sign would you look for on MRI, that would suggest spontaneous intracranial hypotension?
Meningeal enhancement
What is syringomyelia?
Cyst in spinal cord (syrinx) expands over time to compress/ damage spinal cord
What are the classifications of syringomyelia?
Craniovertebral junction
Spinal canal
Idiopathic
What are the clinical signs of syringomyelia?
Dissociated sensory loss Cuts and burns on hands Small muscle wasting Clawed hands Loss of UL reflexes and increased LL reflexes
What classical signs would suggest there is a hindbrain hernia present, in association with a syrinx?
Headache following valsalva Visual disturbances Dizziness Hearing loss/ tinnitus Dysarthria/ dysphasia SOmatic sensory disturbances
Which clinical condition is associated with syrinx at the craniovertebral junction?
Sleep apnoea
What is the management options for syringomyelia?
Open up obstructed CSF channels (decompression, laminectomy, duroplasty)
Drain syrinx cavity
Lower CSF pressure
Conservative management
What is papilloedema?
Optic disc swelling due to raised ICP
What are the clinical features of papilloedema and how does it look on fundoscopy?
Symptoms of raised ICP (morning headache, N+V, tinnitus, reduced consciousness)
Transient LOV (only a few seconds)
Increased blind spot
Hyperaemic blurred disc
What are the main clinical signs of acquired hydrocephalus?
Morning headache Vomiting Diplopia Impaired upgaze Papilloedema Drowsy Incontinent Gait abnormality
