CSF and Hydrocephalus Flashcards
What does CSF bathe?
Brain and spinal cord
Where is CSF found?
Subarachnoid space
What is the main role of CSF?
Shock absorber
Describe the ventricular anatomy
Lateral ventricles Interventricular foramen 3rd ventricle Cerebral aqueduct 4th Ventricle
Where is the choroid plexus found?
Mostly on floor of lateral ventricles
Some in roof of 3rd and 4th
Describe the flow of CSF
- Lateral ventricles
- Foramina of Munro
- 3rd Ventricle
- Aqueduct of Sylvius
- 4th Ventricle
- Foramen of Magendie (medial, x1) & Foramen of Luschka (lateral, x2)
- Subarachnoid spaces
- Arachnoid granulations (reabsorbed here)
- Dural venous sinuses
Is CSF production passive or active?
Active
Is CSF reabsorption passive or active?
Passive
What is hydrocephalus?
General condition whereby there is excess CSF within the intracranial space
Is normal CSF production or absorption usually affected in hydrocephalus?
Absorption
What is the result of abnormal CSF absorption?
Ventricular system dilatation
Raised ICP
What are potential causes of congenital hydrocephalus?
Chiari malformation
Aqueductal stenosis
Dandy-Walker malformation
What are causes of acquired hydrocephalus?
Meningitis Post-haemorrhagic Neoplasm: benign or malignant Post op Cerebellar stroke Post traumatic
What are signs and symptoms of hydrocephalus in infants?
Cranial enlargement Splaying of cranial sutures Irritable Poor feeding Frontanelles full and bulging Engorged scalp veins (venous scalp distension) Abducens palsy Perinauds syndrome (upwards glaze, convergent nystagmus, eyelid retraction) Exaggerated reflexes Respiratory problems
Are there any RBC in the CSF?
No
What are some other roles of CSF?
Fills in the gaps between the brain and the skull
Immunological role
Removal of some waste products
CSF distribution between brain and spinal cord
50:50
Where is CSF produced?
In the choroid plexus
Is there commonly an overproduction of CSF?
No commonly a problem with the reabsorption of CSF
What are the signs and symptoms of hydrocephalus in older children and adults?
May be asymptomatic Increased ICP - measured with a monitor Headaches - worse in the morning or on coughing Papilloedema Visual disturbances Gait abnormality Loss of upgaze or CN VI palsy Impaired consciousness
What will imaging show in hydrocephalus?
Dilation of the temporal horns of the LV
3rd ventricle will become ballooned
Lateral ventricle size increases
Peripheral sulci effaced (pushing of gyri together)
What is the medical Rx for hydrocephalus?
Acetazolamide
Reduces CSF production from the choroid plexus
What is the surgical Rx for hydrocephalus?
External ventricular drain (EDV)
CSF diversion
Eliminating obstruction
What is a long term solution for hydrocephalus?
Shunts
What is the management for hydrocephalus in an emergency situation?
EVD
What is the most commonly used shunt?
Ventriculo-peritoneal
What are the types of shunts?
¥ Ventriculo-peritoneal (VP shunt) - Most used ¥ Ventriculo-pleural ¥ Ventriculo-atrial - Can be considered in cases of peritoneal failure ¥ Ventriculo-subarachnoid
When can a ventriculo-atrial shunt be considered?
Can be considered in cases of peritoneal failure
What are the potential complications of shunts?
Over drainage Under drainage Blockage Infection Disconnection Seizures Distal end problems
What can over drainage of shunts cause?
Low pressure headaches
subdural haematoma
What is endoscopic 3rd ventriculostomy?
Endoscopic third ventriculostomy (ETV) is a surgical procedure for treatment of hydrocephalus in which an opening is created in the floor of the third ventricle using an endoscope placed within the ventricular system through a burr hole. This allows the cerebrospinal fluid to flow directly to the basal cisterns, bypassing the obstruction.
Where does ETV create a fistula?
Between 3rd ventricle and subarachnoid spaces/ basal cisterns
What does ETV only work for?
non-communicating hydrocephalus
What is communicating hydrocephalus?
Communicating hydrocephalus, also known as non-obstructive hydrocephalus, is caused by impaired cerebrospinal fluid reabsorption in the absence of any CSF-flow obstruction between the ventricles and subarachnoid space.
What is normal pressure hydrocpehalus?
type of brain malfunction caused by expansion of the lateral cerebral ventricles
What is the classic triad in NPH?
Dementia
Gait disturbance
Urinary incontinence
What age is typical for NPH?
> 60
What is the Rx for NPH?
Insertion of a shunt
What is shown in NPH on MRI/CT?
Communicating hydrocephalus
What is idiopathic intracranial hypertension?
Raised ICP without obvious cause
What is the typical patient for idiopathic intracranial hypertension?
Young obese female
What is the typical presentation of idiopathic intracranial hypertension?
Headaches
Visual disturbances
Papilloedema
What will happen to idiopathic intracranial hypertension patients without treatment?
Will go blind
What is the treatment for idiopathic intracranial hypertension?
Loos weight
Medical - Acetazolamide
VP of LP shunt
What are the indications for LP?
¥ Obtain CSF for analysis
¥ Rule out bacterial or viral infection
¥ Measure for blood breakdown products (SAH)
¥ Measure protein load
¥ Measurement of pressure (intracranial pressure (ICP))
¥ CSF drainage for raised pressure
¥ Diagnostic test for Normal Pressure Hydrocephalus
What are the contraindications for LP?
} Unstable patient with cardiovascular or respiratory instability
} Localized skin/soft tissue infection over puncture site
} Evidence of unstable bleeding disorder
◦ Platelets < 50,000 or clotting factor deficiency
What are the pre LP checks?
¥ Awake & conscious patient
¥ No focal neurological deficit (6th nerve palsy)
¥ CT/MRI: rule out intracranial mass lesion
¥ Ensure patient not on anticoagulants
¥ Verbal consent
Describe the positioning for LP
Correct positioning
Fetal position - knees up and neck flexed
Pillow between the knees
Between L4/L5
Describe the technique for LP
Aseptic Local anaesthetic administered Spinal needle angled towards umbilicus Aim for space Going through ligamentum flavum (1st pop) 2nd pop - dura Check for SF Measure pressure Obtain samples Withdraw needle Dress the area
What are the risks of LP?
Bleeding Infection Nerve root injury Retroperitoneal/ intra-abdominal injury Brainstem
What is post-LP care?
Bed rest for 2-4 hours
Warn patients about low pressure headaches
Stop if patient is developing neurological deficit or becoming unconscious
What is typical CSF in meningitis?
Cloudy
Turbid
WBC - mostly polomorphs
When can a bloody CSF sample be a sign of?
Traumatic tap
following SAH
What is a traumatic tap?
When the needle has been inserted into an epidural vein
What causes xanthochromic?
Yellow CSF due to blood breakdown products
When is xanthochromic seen?
In SAH
When is spectrophotometry positive?
After 12 hrs
If it persists for 12 weeks
