Disorders of CSF circulation Flashcards
Where is CSF formed?
In the choroid plexus of the ventricles
CSF is continuously produced. True or false?
True
CSF production rates increase in the elderly. True or false?
False
- decrease
What drug reduces the production of CSF?
Acetazolamide
What are the functions of CSF
Buoyancy
Provides micronutrients to cerebral tissue
Accommodates physiological changes in vascular volumes in the head by being displaced into the spinal canal
Why do we get rising ICP
If the brain enlarges, some blood must escape from the cranial vault to avoid the rise in pressure. Once this process is exhausted, the venous sinuses are flattened and there is little or no CSF
Causes of raised ICP
Hydrocephalus
Space occupying lesion
Oedema
Hydrocephalus - definition
Accumulation of excessive CSF within the ventricular system of the brain resulting in increased ICP.
What are the 2 classifications of hydrocephalus
Communicating
Non-communicating
Communicating hydrocephalus
Obstruction to flow of CSF outside of the ventricular system
- eg in subarachnoid space or arachnoid granulations
Non-communicating hydrocephalus
Obstruction to flow of CSF occurs within the ventricular system so CSF is incapable of exiting the ventricular system
Hydrocephalus - pathophysiology
Obstruction to flow of CSF
Over-production of CSF
Decreased absorption of CSF
Cranial enlargement occurs if hydrocephalus is present BEFORE/AFTER the closure of cranial sutures ?
Before
Expansion of the ventricles and increase in ICP occurs if hydrocephalus is present BEFORE/AFTER the closure of cranial sutures ?
After
Hydrocephalus - clinical features (congenital)
Unusually large head Thin, shiny scalp Bulging/tense fontanelle Downward looking eyes (sunsetting) Poor feeding Vomiting Sleepiness
Hydrocephalus - what are the 2 management options
Surgical shunt
Endoscopic ventriculostomy
Hydrocephalus - surgical shunt
Shunt is implanted in the brain ventricles allowing excess CSF in the brain to flow to a different part of the body
Complications of surgical shunts
Over drainage
Under drainage
Blocked shunt
Infection
Hydrocephalus - endoscopic ventriculostomy
Make a hole in the floor of the brain to allow trapped CSF to escape to the brain surface where it can be absorbed
Normal pressure hydrocephalus - definition
Enlarged cerebral ventricles but other areas are normal
Normal ICP
Normal pressure hydrocephalus is most common in which age group?
Elderly
Normal pressure hydrocephalus - clinical features
Ataxia
Memory decline
Incontinence
Idiopathic intracranial hypertension - who gets it
Obese
Young females
Idiopathic intracranial hypertension - clinical features
Headaches
Visual losses
Idiopathic intracranial hypertension - clinical signs
Papilloedema
Constriction of visual fields
Loss of visual acuity
Idiopathic intracranial hypertension - investigations
Lumbar puncture - over 25cm CSF CT - normal MRI - normal
Idiopathic intracranial hypertension - management
Weight loss
Hydrocephalus ex vacuo - definition
Because of a loss of brain parenchyma, the ventricles expand - as does the CSF - to accommodate the change in intracranial volume
Hydrocephalus ex vacuo - name a disease that this occurs in
Alzheimers
Can occur in any disease that causes atrophy
Syringomyelia - definition
Accumulation of water in the spinal cord
Syringomyelia - clinical features
Clawed hands
Hyperhidrosis (abnormal sweating)
Involuntary movements
Syringomyelia - which investigation confirms the diagnosis ?
MRI scan
