hydrocephalus / ventricular system Flashcards
Hydrocephalus - types
- Communicating (nonobstructive)
- Noncommunicating (obstructive)
- Hydrocephalus mimics
- normal pressure hydrocephalus (a particular form of communicating hydrocephalus)
Hydrocephalus mimics –>
Ex vacuo ventriculomegaly –> appearance of increased CSF on imaging, due to decreased brain tissue (neuronal atrophy)
(TRIAD IS NOT SEEN)
Ex vacuo ventriculomegaly –>
appearance of increased CSF on imaging, due to decreased brain tissue (neuronal atrophy)
Ex vacuo ventriculomegaly is the appearance of increased CSF on imaging, due to
decreased brain tissue (neuronal atrophy)
causes of Ex vacuo ventriculomegaly
- Alzheimer disease
- advanced HIV
- Pick disease
- Huntington disease
Ex vacuo ventriculomegaly - ICP?
normal
Noncommunicating hydrocephalus is caused by
structural blockage of CSF circulation WITHIN ventricular system
Noncommunicating hydrocephalus is caused by structural blockage of CSF circulation with ventricular system - examples?
- stenosis of aqueduct of Sylvius
2. colloid cyst blocking foramen of Monro
Communicating (nonobstructive) hydrocephalus - types
- communicating hydrocephalus
2. normal pressure hydrocephalus
communicating hydrocephalus - mechanism
- decreased CSF absorption by arachnoid granulations
2. increased CSF production.
communicating hydrocephalus - clinical findings
- increased ICP
- papilledema
- herniation
communicating hydrocephalus - example of a cause
arachnoid scaring post-miningitis
Normal pressure hydrocephalus - affects the
elderly
causes of Normal pressure hydrocephalus
idiopathic
Normal pressure hydrocephalus - CSF pressure?
elevated only episodically
Normal pressure hydrocephalus do not result in
increased subarachnoid space volume
Normal pressure hydrocephalus causes (and mechanism)
expansion of ventricles distorts the fibers of the corona radiata –> triad of 1. urinary incontinence 2. ataxia
3. cognitive dysfunction (sometimes reversible)
(Does not results in increased subarachnoid space volume)
normal pressure hydrocephalus - symptoms
triad of 1. urinary incontinence 2. ataxia
3. cognitive dysfunction (sometimes reversible)
normal pressure hydrocephalus - mechanism of triad
expansion of ventricles distorts the fibers of the corona radiata
hydrocephalus - definition?
increase in CSF volume –> ventricular dilation +/- increased ICP
triad of 1. urinary incontinence 2. ataxia
3. cognitive dysfunction - diagnosis?
normal pressure hydrocephalus
brain tumor that can cause hydrocephalus
- Ependymoma
- meduloblastoma
- Pinelioma
CSF is made by
ependymal cells of choroid plexus
CSF is made by ependymal cells of
choroid plexus
CSF is reabsorbed by
arachnoid granulation
CSF after arachnoid granulations mediated reabsorption
drains into dural venous sinuses
ventricular system - direction
Lateral ventricle –> 3rd ventricle via right and left interventricular foramina of Monro –> 3rd ventricle –> 4th ventricle via cerebral aqueduct (of Sylvius) –> 4th ventricle –> subarachnoid space via:
- Foramina of Luschka (lateral)
- foramina of Mangendie (Medial)
ventricular system - lateral ventricle to 3rd ventricle via
interventricular foramina of Monro
ventricular system - 3rd ventricle –> 4th ventricle via
cerebral aqueduct (of Sylvius)
ventricular system - 4th ventricle –> subarachnoid space via
- Foramina of Luschka (lateral)
- Foramina of Mangendie (Medial)
ventricular system - 4th ventricle –> subarachnoid space - lateral foramina
Foramina of Luschka
ventricular system - 4th ventricle –> subarachnoid space - medial foramina
Foramina of Mangendie
idiopathic intracranial hypertension is AKA
pseudotumor cerebri
idiopathic intracranial hypertension (pseudotumor cerebri) - definition
increased ICP with no apparent cause on imaging
idiopathic intracranial hypertension (pseudotumor cerebri) - symptoms and signs
- headache
- diplopia
- papilledema
- no mental status alternations
idiopathic intracranial hypertension (pseudotumor cerebri) - mental status
normal
idiopathic intracranial hypertension (pseudotumor cerebri) - mechanism of diplopia
usually from CN VI palsy
idiopathic intracranial hypertension (pseudotumor cerebri) - clinical examination
papiledema
idiopathic intracranial hypertension (pseudotumor cerebri) - LP
increased opening pressure
headache relief
idiopathic intracranial hypertension - induced headache is relief by
LP
idiopathic intracranial hypertension (pseudotumor cerebri) - RISK FACTORS
- being woman on childbirth age
- vitamin A excess
- danazol
- tetracyclines
idiopathic intracranial hypertension (pseudotumor cerebri) - treatment
- weight loss
- acetazolamide
- topiramate
- invasive procedure for refractory cases
idiopathic intracranial hypertension (pseudotumor cerebri) - drugs
- acetazolamide
2. topiramate
idiopathic intracranial hypertension (pseudotumor cerebri) - invasive procedure for refractory cases
- repeat LP
- CSF shunt placement
- optic nerve fenestration surgery
idiopathic intracranial hypertension (pseudotumor cerebri) - treatment
- weight loss
- acetazolamide, topiramate
- topiramate
- invasive procedure for refractory cases