DeLahunta Chapter 4 - CSF and hydrocephalus Flashcards

1
Q

Where is the CSF produced?

A

1) Choroid plexi
2) ependymal lining of parenchyma
3) capillaries of the parenchma
4) leptomeningeal capillaries of the SAS

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2
Q

What is the proportion of CSF production in the CNS from different sources?

A

42% from the SAS
35% from lateral and 3rd ventricle
23% the 4th ventricle

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3
Q

Which 2 types of cells are lining the ventricular system?

A

-choroid plexus cells (epithelial)
-ependymal cells

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4
Q

What is the difference in electrolytes, glucose, proteins in the CSF compared to plasma?

A

In the CSF (compared to plasma)
-Less K, Ca
-More Cl, Na, Mg
-80% of glucose of the plasma
-Less protein (albumin being the main one)

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5
Q

Within the vertebral canal, the dura is separated from the vertebrae, but has some attachments. One of them is the meningovertebral ligament. How many meningovertebral ligaments are in the vertebral column, where is it more prominent and robust? (Kent et al., 2017, JAVMA)

A

A single MVL was observed in all portions of the vertebral column. It formed a continuous attachment between the ventral aspect of the dura mater and dorsal aspect of the vertebral bodies and IVDs along the midline and was most robust in the cervical portion of the vertebral column, particularly between C3 and C5 or C6.

https://avmajournals.avma.org/view/journals/javma/255/6/javma.255.6.687.xml

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6
Q

Which are the meningeal cell layers in the skull?

A

From out to brain:
1) periosteal dura
2) meningeal dura
3) dural border cells
4) arachnoid barrier cells
5) arachnoid trabeculae (SAS)
6) pia matter
7) basement membrane

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7
Q

What is the effect on the CNS of poor ventilation? What happens with the blood vessels?

A

Hypoventilation –> hypercapnia

Hypercapnia —> cerebral arterial vasodilation –> which increases the volume of intracranial blood –> increases ICP

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8
Q

How can we calculate the cerebral perfusion pressure? What is the physiological value for ICP?

A

CPP=MAP-ICP

ICP=5-12 mmHg - normal (use this as constant in the equation above always)

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9
Q

Which are the types of brain herniation?

A

1) Foramen magnum herniation (caudal positioning of the cerebellar vermis through Foramen Magnum)

2) Caudal trasntentorial herniation (parahyppocampal/occipital cortex herniating caudal to tentorium cerebelli)

3) Rostral transtentorial (rostral herniation of the cerebellum or brainstem rostral towards the tentorium cerebellum)

4) Subfalcine (herniation of the cingulate gyrus under falx cerebri towards the contralateral hemisphere)

5) Transcalvarial (Through calvarial defect)

https://doi.org/10.1016/j.tvjl.2014.04.020

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10
Q

What is the BBB and the Blood-CSF barrier?

A

BBB (between plasma and extracellular fluid):
1) endothelial cells (nonfenestrated, tight junctions)
2) basement membrane
3) astrocytic foot processes

Blood-CSF brrier (between cSF and blood in the ventricles):
1) endothelial cells (fenestrated without tight junctions)
2) basemenet membrane
3) choroid plexus epithelial cells (with tight junctions)
4) meningeal cells interspread amongs the other cells (arachnoid cap cells)

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11
Q

How many lumbar vertebra and sacral segments are in dog, cat, ox and horse? Where the sacral segments and the conus medullaris is located?

A

Lumbar vertebrae:
Dog-cat - L7
Horse-ox - L6
Sacral segments:
Dog-cat S3
Horse-ox S5

Sacral segments located in:
Dog: L5 (Conus meularis L6-7)
Cat: L6 (Conus medularis L7)
Ox: L6 (Conus medularis S1)
Horse: S1-3 at L6, S4-5 at L7 (conus medularis S2)

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12
Q

What is the embryological origin of the meninges?

A

neural crest (part of leptomeninges) with some contribution from mesoderm

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12
Q

In a recent study by Farke et al., 2023, JVIM risk factors of hydrocephalus treatment (ventriculoperitoneal shunting) over shunting were described. What was the percentage of over shunting? What risk factors were associated with this? Which are the clinical signs of overshunting?

A

-18%
-Risk 1: biventricular hydrocephalus compared to tri or tetraventricular
-Risk 2: increased ventricular:brain ratio
indicated a higher risk for overshunting

Signs of overshunting
1) hemispheric collapse
2) subdural hemorrhage
2) peracute deterioration of neurological status

https://onlinelibrary.wiley.com/doi/full/10.1111/jvim.16861

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12
Q

Please describe the morphological criteria for the MRI diagnosis of internal hydrocephalus based on Laubner et al., 2015, BMC VetRes.

A

1) Expansion of the third ventricle (represented by flattening of the interthalamic adhesion and a diminished suprasellar cistern)

2) Disruption of the internal capsule adjacent to the caudate nucleus

3) Periventricular edema (PVE) - T1W hypo and FLAIR hyper

4) Effacement of the cerebral sulci (Narrowing of cerebral sulci and obliteration of the subarachnoid space around the dorsal convexity of the cerebral hemispheres. The absence of a hyperintense subarachnoid space and/or the presence of narrowed cortical sulci were recorded on transverse T2-weighted images at the level of the interthalamic adhesion.)

5) Dilation of the olfactory recess(es).

6) Presence of cerebellar deviation (herniation through formane magnum)

https://link.springer.com/article/10.1186/s12917-015-0479-5

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12
Q

True or False.
1) CSF is produced at a constant flow rate, but it is dependent on increases or decreases of ICP in the ventricular system.
2) CSF production rate is independent on the hydrostatic pressure.
3) CSF production rate is depentent on osmotic pressure of the blood e.g. hypertonic IV reduced the rate of production of CSF

A

1) F. Independent of ICP.
2) T.
3) T.

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12
Q

Which factors were associated with clinically relevant hydrocephalus in dogs based on Laubner et al. 2015?

A

1) increased ventricle:brain index ration

2) elevation of the corpus callosum (p < 0.01)

3) dorsoventral flattening of the interthalamic adhesion (p < 0.0001)

4) periventricular edema (p < 0.0001)

5) dilation of the olfactory recesses (p < 0.0001)

6) thinning of the cortical sulci (p < 0.0001) and/or subarachnoid space (p < 0.0027)

7) disruption of the internal capsule adjacent to the caudate nucleus (p < 0.0001).

https://link.springer.com/article/10.1186/s12917-015-0479-5

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12
Q

What is the role of P-glycoprotein in BBB? Which breeds can have a defect in the coding for P-glycoprotein? What gene mutation has been associated with this defect? Which is the most common intoxication associated with this defect?

A

-P-glycoprotein is a efflux pump which prevents passage of xeniobiotics through the BBB e.g. this even happens in the lipophilic ivermectin which otherwise could pass the BBB as lipophilic
-Expressed in the cappilaries of the brain
-Mutation is ABCB1 gene–> defect in coding the P-glycoprotein
-Breeds are: Colies, border collies, old english sheepdog, australian shelpherd
-Ivermectin intoxciation, but can happen with chemotherapeutics

13
Q

What is the rate of CSF production? How many times is produced/absorbed per day?

A

0.047 ml/min for dog
0.017 ml/min for cat
3-5 times /day

14
Q

What is the communication of ventricular system to the subarachnodi space?

A

1) lateral aprtures
2) conus medullaris (in small animals)

15
Q

What are the arachnoid villi and what their granulations?

A

=prolongation of arachnoid membran & SASinto the lumen of the venous sinus or cerebral veins covered by endothelium of the vessel wall

-collections of them make the granulations
-is where the CSF is mainly absorbed
-act as one way valve: CSF to blood

16
Q

Where is the CSF absorbed?

A

1) arachnoid villi
2) veins and lymphatics around:
–spinal nerve roots
–spinal nerves at intervertebral foramina
–cranial nerves I, II, VII - where they pass through the skull bones
–parenchymal blood vessels

17
Q

What is the function of the CSF?

A

1) protects CNS - modulating pressure changes
2) helps regulating ICP
3) nourishment of the brain (metabolites, nutrients)
4) transport of neurotransmiters and neuroendocrine cells within the parenchyma
5) maintains the ionic balance necesery for neuronal function = chemical buffer for parenchyma

18
Q

Normal CSF TP among species

A

Dog: <25-30 mg/dl
Cat: < 20mg/dl
Cattle: <40mg/dl
Horse <80 mg/dl

19
Q

Why in caudal transtentorial herniation miosis followed by mydriasis occurs?

A

Mibrain compression
Miosis: disinhibition of oculomotor parasympathetic neurons due to loss of influence from forebrain UMN

Mydriasis: complete loss of function of the oculomotor neurons

20
Q

Give me 4 examples of compensatory (ex vacuo) hydrocephalus in animals

A

1) BVD-Cattle – cerebellar hypoplasia
2) Akabane virus-Cattle– cerebral hydranencephaly
3) Ischaemic e.g. thrombosis of vasospasm from Cuterebra migration in cats
4) thiamine deficiency - polioencephalomalacia-in cattle

21
Q

Give me 4 examples of acquired obstructive hydrocephalus in animals

A

1) FIP - mesencephalic aqueduct stenosis (predilation)
2) bacterial meningoencephalitis in farm animals
3) ventriculitis in young dogs
4) vitamin A deficiency in CALVES ->dural fibrosis and arachnoid vili obstruction

22
Q

Why subclinical congenital hydrocephalus (ventriculomegaly) occurs in some dogs?

A

1) mesencephalic aqueduct narrowing during developmetn due to ciliary dyskinesia –> it improves with growth and leaves behind thiner/enarged ventricles

2) immotile ependymal cillia (inadequate flow trhough lateral apertures)

3) malformation of arachoid vili

23
Q

When is congenital hydrocephalus manifested in dogs?

A

Between 3-12 months old
Regardless of the fetal genesis of obstruction

24
Q

Why we may have consciousness deficits and which of them in a forebrain syndrome?

A

lesion in diencephalon (ARAS)
cause stupor or coma

25
Q

Why the dog with congenital hydrocephalus may be blind?

A

Compromise of optic radiation in the centrum semiovale and occipital cortex

26
Q

Why the ‘sunset sign’ occurs in congenital hydrocephalus?

A

Rostolateral expansion of the rostral aspect of the cranial cavity which expands into caudal orbit and ddisplaces the eyes ventrolaterally (mecahnically)

IT IS NOT because of compression of the oculmotor because VOR and PLRs are normal.

27
Q

What is the blood supply of the choroid plexus?

A

Lateral ventricles choroid plexus –> middle cerebral artery

Third ventricle choroid plexus –> caudal cerebral artery

Fourth ventricle choroid plexus–> caudal cerebellar artery

28
Q

Which are the areas of myelographic infusion of contrast agent in dogs and cats?

A

Dogs: cerebellomedulary +L5-6
Cats: cerebellomedulary + L6-7

29
Q

What lesions can be found extramedullary/intradurally in the spinal cord?

A

1) meningioma
2) PNST
3) nephroblastoma (most common of it is intradural)

30
Q

Which are the EEG features of hydrocephalus in dog?

A

Slow-wave pattern with increased amplitude

31
Q

Name at least 3 dog breeds with congenital hydrocephalus?

A

Chihuahua
Pekignese
Maltise
English Bulldog
Yorkie

32
Q

What is the percentage of seizures in dogs with hydrocephalus?

A

1.7 %

https://onlinelibrary.wiley.com/doi/10.1111/jvim.15890

33
Q

Is any singificant difference between oral predisolone vs VPS in clinical/imaging findigns of dogs with congenital hydrocephalus? Which are the rates of success of VPS?

A

No statistical significne.

Of 26 surgically treated dogs with data available, 14 (54%) improved, 1 (4%) stabilized, and 11 (42%) deteriorated; 4 (15%) had known postoperative complications.

https://pubmed.ncbi.nlm.nih.gov/30888275/

34
Q

Which are the postoperative complications of VPS in dogs (De stefani paper)?

A

1) ventricular catheter migration
2) infection
3) shunt under-drainage
4) kinking of the peritoneal catheter
5) valve fracture
6)abdominal skin necrosis.

https://onlinelibrary.wiley.com/doi/full/10.1111/j.1532-950X.2010.00764.x?casa_token=YVhvTOShhvkAAAAA%3AWdjfnRdp7JJnwwh3XJtQ34oOd1sFN_lWqGXm9ynAYrHFNUUbNEZj45u5GuDhz695tHIZEr83Gh2vsHyn

35
Q

Which are the postoperative complications of VPS in dogs and cats (Systematic review of Dupre 2019)

A

DOGS
1) shunt obstruction (10%)
2) pain (5.5%)
3) shunt infection (4.1%)
4) disconnection (4.1%)
5) excessive shunting (2.7%)
6)kinking (1.6%).

CATS
1) coiling of the shunt in the SC tissue (15.4%)
2) kinking (7.7%)
3) shunt obstruction (7.7%).

Complications were most likely during the first 6 months after shunt placement.

https://onlinelibrary.wiley.com/doi/full/10.1111/jvim.15422

36
Q

What is the factor postoperatively (VPS) that has been associated with resolution of >or= 1 preoperative clinical sign in dogs with internal hydrocephalus? (Schmitd et al. 2019)

A

Decreased volume of cerebral ventricles was associated with resolution of ≥1 preoperative clinical sign (P < .003).

The percentage decrease in ventricular size was associated with resolution of ataxia (P = .008) and obtundation (P = .011).

https://onlinelibrary.wiley.com/doi/full/10.1111/jvim.15468