T or F. CSF taps are often normal cisternal and abnormal limberly with degenerative myelopathy.
True
T or F. CSF taps may reveal lesser abnormalities with lumbar taps than cisternal taps in dogs with GME.
True
Explain how Horner’s syndrome can be seen with IVDD?
Damage to the preganglionic sympathetic cell bodies in the spinal cord segment T1 and T2, or severe damage to the cervical spinal cord due to interruption of the tectotegmental spinal tract.
What vascular disease are hypothyroidism a predisposition of?
Atherosclerosis leading to ischemic infarcts
What other organ dysfunction is seen with vascular injuries to the brain?
Brain-heart syndrome that causes arrhythmias
What vascular disease is seen seasonally in cats?
Idiopathic ischemic encephalopathy - most common in late summer
What are other ddx for vascular injuries?
- Neoplasia
- Abscess
- bherent parasite migration
- Trauma
- GME
What particular protein in CSF is often elevated in vascular events?
Albumin - it can even result in hypoalbuminemia
What does the 1998 Vet path article suggest as the cause of feline ischemic encephalopathy?
Aberrant cuterebral larval migration into the olfactory bulbs and pudencies, optic nerves, and cribriform plate. Suggesting entry from the nasal cavity with subsequent release of toxic material and perhaps infarction.
About the BBB, what are 2 distinguishing features of the endothelial cells compared to those elsewhere in the body?
No endothelial fenestration and inter-endothelial tight junctions
What types of cells are found in close proximity to the endothelial cells of the BBB?
- Pericytes
- Perivascular microglia
- Astrocytes
- The basal lamina
Why is the CNS the first system to be affected by low BG?
Because BG enters the CNS by diffusion (not insulin dependent) and because it is the primary fuel for the brain.
What are 3 causes for increased neutrophils in CSF?
- Bacterial meningitis
- Infarction
- FIP
What are 2 causes of mononuclear pleocytosis in CSF?
- GME
- IVDD
What are the clinical signs of brain stem lesions?
- Depression
- Altered gait
- Postural reaction Paresis (quadra, hemi ipsilateral or contralateral)
- CN lesions ipsilateral to the lesion
How can you differentiate peripheral from central vestibular disease?
Peripheral:
- has nystagmus that does not change with head position
- fast phase to the side of the lesion
- ataxia but no postural deficits
- CN 7 and Horner’s syndrome may be seen
Central:
- postural deficits
- CN 5 & 6 occasionally affected
- Dysconjugate, vertical and positional nystagmus
What are the clinical signs of dicephalic lesions?
- Tetraparesis or hemiparesis with postural deficits on the contralateral side
- Gait is usually okay but can have hemi- or tetra paresis
- CN 2 (3, 4, and 6 if space occupying lesion) may be affected on the ipsilateral side
- Alterations in function of pituitary if hypothalamus is affected
- Large lesions may alter consciousness
What clinical signs might you see in cerebellar lesions?
- Wide based stance
- Dysmetria
- Intention tremors with little weakness
- Decerebellate = acute injuries cause opisthotonos, extensor hypertonus in the forelimbs and flexion in the pelvic limbs
What is an intraarachnoid cyst?
Intraarachnoid Cysts
- Accumulation of CSF anywhere in the CNS. Expansion of the cyst results in cord compression
- Can be congenital, traumatic, secondary to infection, inflammation or hemorrhage
- C/S of a progressive myelopathy of the affected area.
- Seen as intradural-extramedullary pooling of contrast, usu but not always on dorsal midline
What is osteochondromatosis (a.k.a. Multiple Cartilaginous Exostoses)?
Osteochondromatosis
- Aka Multiple Cartilaginous Exostoses- a cartilage capped exostosis arising from bone
- Cats develop them as young adults and growth is progressive. Believed to be viral
- Dogs develop them as puppies - can have malignant transformation
- Can occur anywhere but seen in thoracic and lumbar spine mostly.
- Need myelogram to demonstrate compression
What are the 2 different types of IVDD?
- Type I - degeneration and rupture of the dorsal annulus fibrosis and extrusion of the nucleus pulposis. Degeneration of disk - characterized by increased collagen content of the disk, decrease in water content and change in GAG concentration of the nucleus.
- Type II - bulging of the disk without rupture of the annulus fibrosis
How is CSF produced?
CSF - ultrafiltrate of plasma- almost no protein bc the BBB doesn’t allow16
- Produced by ependymal cells of the ventricular system and choroid plexus.
- Brings nutrients, removes waste and chemically buffers the brain
- Produced at 30 ml/hr in a dog
- Moved via ventricles >> lateral ventricular apertures >> arachnoid granulations>> blood
DEscribe the flow of CSF through the ventricular system
From lateral ventricles, through interventricular foramina, through 3rd ventricle and mesencephalic aqueduct to fourth ventricle into subarachnoid space and bilateral recesses and apertures as well as a small amount into the central canal.
What are some causes of hydrocephalus?
- Obstructive - usually at interventricular foramen (Lat to 3rd) or mesencephalic aqueduct b/c are bottlenecks- due to neoplasia, inflammation, hemorrhage.
- Communicating - no obstruction is present, just dilation of the entire ventricular system.
- Can be from lack of uptake b/c inflammation or neoplasia of meninges
- Congenital
- Compensatory - the brain atrophies and the ventricles become larger to fill the space
