DeLahunta Chapter 4 - CSF and hydrocephalus Flashcards
Where is the CSF produced?
1) Choroid plexi
2) ependymal lining of parenchyma
3) capillaries of the parenchma
4) leptomeningeal capillaries of the SAS
What is the proportion of CSF production in the CNS from different sources?
42% from the SAS
35% from lateral and 3rd ventricle
23% the 4th ventricle
Which 2 types of cells are lining the ventricular system?
-choroid plexus cells (epithelial)
-ependymal cells
What is the difference in electrolytes, glucose, proteins in the CSF compared to plasma?
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)
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 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
Which are the meningeal cell layers in the skull?
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
What is the effect on the CNS of poor ventilation? What happens with the blood vessels?
Hypoventilation –> hypercapnia
Hypercapnia —> cerebral arterial vasodilation –> which increases the volume of intracranial blood –> increases ICP
How can we calculate the cerebral perfusion pressure? What is the physiological value for ICP?
CPP=MAP-ICP
ICP=5-12 mmHg - normal (use this as constant in the equation above always)
Which are the types of brain herniation?
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
What is the BBB and the Blood-CSF barrier?
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)
How many lumbar vertebra and sacral segments are in dog, cat, ox and horse? Where the sacral segments and the conus medullaris is located?
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)
What is the embryological origin of the meninges?
neural crest (part of leptomeninges) with some contribution from mesoderm
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?
-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
Please describe the morphological criteria for the MRI diagnosis of internal hydrocephalus based on Laubner et al., 2015, BMC VetRes.
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
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
1) F. Independent of ICP.
2) T.
3) T.
Which factors were associated with clinically relevant hydrocephalus in dogs based on Laubner et al. 2015?
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