Hydrocephalus Lecture

Question 1

where is CSF produced

Answer 1

choroid plexus (60-80%), brain parenchyma (20-30%), arachnoid. 500cc/day

Question 2

outline the circulation of CSF

Answer 2

lateral ventricles → foramen of Monroe→ third ventricle→ aquqduct→ fourth ventricle→ foramen Luschka + Majendieà central canal + around the drain

Question 3

t/f hydrocephalus is buildup of CSF

Answer 3

partially true–> BUT IT NEEDS RAISED ICP AND VENTRICULOMEGALY

Question 4

why does hydrocephalus affect males more often than females?

Answer 4

Epi: 1 in 1000 live births; 85 in 100000. Slightly M>F due to X-linked hydrocephalus in L1 syndrome– causes an aqueductal stenosis picture. In most advanced countries, they are terminated.

Question 5

What is going on here and what locations are affected most?

Answer 5

Communicating Hydrocephalus

Definition: impairment of CSF absorption

Location: arachnoid villi, or the arachnoid membrane.

• Obstruction of basal cisterns
• occlusion/atresia of the arachnoid villi
• Increased sagittal sinus pressure: thrombosis, vein of Galen malformations, achondroplasia, complex syndromic and nonsyndromic craniosynostosis
• Big lateral ventricles (esp the 4th ventricle)

Question 6

general causes of hydrocephalus

Answer 6

meningitis is most common in developing ocuntries

• prematurity
• myelomeningocele
• aqueductal stenosis

Question 7

* if 4th ventricle is big, consider ___ hydrocephalus. if 4th ventricle is small, consider ___ hydrocephalus.

Answer 7

* if 4th ventricle is big, consider communicating hydrocephalus. if 4th ventricle is small, consider obstructive hydrocephalus.

Communicating Hydrocephalus

• Definition: impairment of CSF absorption
• Location: arachnoid villi, or the arachnoid membrane.
• Obstruction of basal cisterns
• occlusion/atresia of the arachnoid villi
• Increased sagittal sinus pressure: thrombosis, vein of Galen malformations, achondroplasia, complex syndromic and nonsyndromic craniosynostosis
• Big lateral ventricles (esp the 4th ventricle)

Obstructive Hydrocephalus

• Definition: impairment of CSF bulk flow.
• Location: can occur at any point along the pathway of CSF flow within the ventricles (foramen of monro, aqueduct of sylvius, outlet foramina of the IV ventricle (Luschka and Magendie)
• May see a “bulge”

Question 8

Management of Hydrocephalus in premature babies

Answer 8

babies bellies/peritoneum can’t handle CSF shunting, so it needs to be in an alternative route

• ventriculosubgaleal shunts
• ventricular resevoirs –> for intracranial hemorrhage

Question 9

T/F you can use ventriculo-subgaleal shunts in premature babies with intracranial hemorrage

Answer 9

false.

only ventricular reservoirs are good for intracranial hemorrhage. it removes bloood products, and can be controlled by MD (as opposted to VSGs which have no MD interventions)

Question 10

disadvanatages to ventricular reservoirs

Answer 10

Disadvantages: over-drainage→ can cause decompression hemorrhages that result in seizures, labor intensive, infection risk

Question 11

ood for acute hydrocephalus from tumour, hemorrhage, severe traumatic brain injury, shunt infection and peri-op hydrocephalus

Answer 11

external ventricular drain

Question 12

EVDs, vent res’s, and VSGFs are all temporary. What is the standard permanent treatment for hydrocephalus

Answer 12

CSF shunt:

SF is sent to the peritoneum, the heart or the pleura.

One way fluid shunts from brain to belly.

Complications: obstruction (see below), infections (about 1.2% within 6months, IV Abx + shunt replacement), over drainage (subdural hematomas acutely, slit- ventricles syndrome: headaches with tiny ventricles. May require valve change or skull expansion)

Endoscopic Third Ventriculostomy (ETV):

permanent treatment as an alternative to CSF shunts. Creates hole in the floor of the third ventricle to bypass the third ventricle. Candidates for ETV are graded, number = chances of success

Advantages: lower infection risk, lower risk of over-drainage

Complications: higher procedural risk (higher bleeding risk), larger ventricle size, risk of sudden deterioration

Complications:

• Valve obstruction: headaches and vomiting

History and P/E: age-dependent, papilledema, similar to previous obstruction

Intracranial imaging: enlarged ventricles

Shunt series: disconnect or fractured shunt

Question 13

What type of hydrocephalus is prevlanet in older people? What is the triad of symptoms?

Answer 13

epi: older patients
symptoms: triad of gait disorder + dementia + urinary incontinence

on ct, you’d see enlarged ventricles (ventriculomegaly)

management is shunt (can reverse dementia, gait and urinary incontinence)

complications: subdural hemorrhage