EB.5 Vet Path

What do somatic spinal nerves do?

Transmit sensory and motor information

What cranial nerves are considered to be part of the CNS because they are myelinated by oligodendrocytes rather than schwann cells?

CN1 and CN2

Which part of the enteric nervous system is located in the submucosa and aids in digestion, fluid secretion, absorption, and blood flow?

endoneurium

surrounds individual nerve fibers

perineurium

ensheathe nerve fascicles

epineurium

surrounds groups of fascicles

schwann cells

myelinates PNS axons

trophic support for axons

endoneurium fibroblasts

phagocytic abilities in the endoneurium to remove exonal debris

Satellite glial cells

found in neurons but dont know what they do

Dorsal nerve root

sensory information

Ventral nerve root

Motor information

What are dysautonomias?

failure of the autonomic nervous system

How do dysautonomias present in dogs and cats?

GI upset, urinary incontinence, mydriasis, prolapsed 3rd eyelids, bradycardia

What part of the PNS are affected by peritonitis?

enteric, myenteric and submucosal

edematous nerves and hyperplastic support cells

What breed is most likely to have genetic Congenital Hypomyelinating Polyneuropathy due to a mutation in the myelin protein zero (MPZ) gene?

Golden Retrievers

What cells are most likely affected in young hopping golden retrievers?

Schwann Cells > demyelination disorder

What plant has the toxic substance karwinol A and is found in SW USA where it effects ruminants?

Coyotillo

What cells does karwinol A target?

Schwann cells are targeted by the plant Coyotillo

What endocrine disorders cause a plantigrade stance in cats?

diabetes mellitus and hypothyroidism

How does Vitamin A deficiency cause a peripheral neuropathy in calves and pigs?

Vitamin A deficiency causes continued bone deposition and decreased resorption that results in compression of the optic nerves, wallerian degeneration, and blindness

What vitamin is responsible for Riboflavin deficiency or curled toe paralysis in pountry?

Vitamin B deficiency that causes endoneuronal edema

What does lead cause in the CNS?

neuronal necrosis

What does lead cause in the PNS?

demyelination

What toxins target neuronal cell bodies?

• organomercurial compounds

• doxorubicin

What chemical toxin causes distal axonal degeneration?

Vincristine

neuroparaxia

mild traumatic injury that leaves the axon intact and can result in a temporary conduction block followed by total recovery of function

Axonotmesis 

Severe trauma damage that destroys that axon but spares the connect tissue framework, so regeneration and reinnervation is possible

Neurotmesis

Traumatic severance of the nerve with destruction of the supporting framework

What is neurogenic shock?

When traumatic injury causes immediate vasoconstriction followed by vasodilation causing a loss of blood pressure

What are the three types of nerve sheath neoplasms?

• schwannoma 

• neurofibroma 

• perineurioma

What species can get schwannomas?

DOGS, cats, horses, cows

Where do dogs most commonly get schwannomas?

trigeminal nerve, spinal nerve roots of the brachial plexus, and nerve roots at the thoracic and lumbar areas

What pathology is shown in this image?

Trigeminal nerve schwannoma

What pathology is shown in this image?

Spinal nerve schwannoma

What is colonic aganglionosis?

a lethal disorder involving the development of the enteric division of the PNS that most commonly affects foals with overo markings

What is the mutation associated with colonic aganglionosis? 

autosomal recessive mutation of the endothelin B receptor that is required for the development of the

What age equines are most likely to be affected by equine grass sickness, aka equine dysautonomia?

2-7 yr

What are the predisposing conditions of equine dysautonomia?

pasture grasses stressed by rapid growth or sudden cold weather resulting in reduced concentrations of antioxidants and increased concentrations of glutamate and aspartate

What is the only way to diagnose equine grass sickness antemortem?

full thickness biopsy of the ileum 

What animals are most likely to have recurrent laryngeal paralysis?

2-7 yr old tall, male horses, usually the left side

What equine condition causes urinary incontinence, fecal retention, muscle atrophy over pelvis and hindlimbs due to inflammation on the sacrococcygeal nerves?

Polyneuritis equi

What pathology is shown in this image?

Polyneuritis equi (image)

What canine condition is an acute fulminating polyradiculoneuritis with inflammation in the ventral spinal nerve roots that causes paralysis from a few days to months but recovery is common?

Acute idiopathic polyneuritis aka coonhound paralysis

What pathology is shown in this image?

Sensory neuropathy of english pointers

Where are the lesions of sensory neuropathy of english pointers commonly found?

Dorsal root ganglia and dorsal spinal nerves

At what pH does listeriosis proliferate?

>5.4 in silage

What nerve does listeriosis target in order to perform retrograde axonal transport to the brainstem? Hint: It is tied to the clinical sign of drooling

Trigeminal nerve

What pathology is shown in this image of the brainstem of a cow?

microabcesses with listeriosis

What is one of the key pathogens responsible for meningoencephalitis in cattle?

Histophilus somni

What cattle are most commonly affected by Thrombotic Meningoencephalitis due to Histophilus somni?

6-12 mo old feedlot cattle

After Histophilus somni replicated in the respiratory system, how does it spread to the CNS to induce TME?

Hematogenously 

Which pathogen is associated with vasculitis and vascular necrosis causing randomly scattered irregular foci of hemorrhage and necrosis throughout the cerebrum at the grey-white interface?

Thrombotic meningoencephalitis (description)

What pathogen is shown in this image?

TME (image)

What pathology is shown in this image?

Malignant Catarrhal Fever

• a gammaherpes virus - fatal

Caprine Arteritis Encephalitis is a readily transmissible virus between dam and baby. How do you recognize it grossly?

tan-salmon brain and spinal cord necrosis

White Matter

What age of animal is prone to developing the arthritis portion of the disease?

Adults only

What pathology is shown in this image?

Caprine Arthritis Encephalitis

The bacteria in the rumen digest carbohydrates that release what key amino acid?

Thiamine

Why do we see a thiamine deficiency in young ruminants?

because the rumen has not matured yet

Why do we see thiamine deficiency in adult ruminants?

because grain overload causes an overgrowth of thiaminase producing bacteria

What pathology is described as having a yellow discoloration and softening of the cerebrocortical grey matter and is autofluorescent under UV?

Polioencephalomalacia (description)

What pathology is shown in this image?

Polioencephalomalacia (image)

What are causes of polioencephalomalacia in ruminants?

• thiamine deficiency

• sulfur toxicosis

• lead toxicity

• water deprivation/salt toxicity

What is the congenital form a copper deficiency in small ruminants called?

Swayback

What pathology is shown in this image?

bilateral cerebrocortical lesions in a small ruminant indicating copper deficiency

What kind of lesions are seen in the CNS with infections of Clostrudium perfringens type D, aka overeating disease?

bilaterally symmetric foci of malacia and cavitation, yellow-grey-red, prefers to target white matter

What pathology is shown in this image?

Focal symmetric encephalomalacia associated with Clostridium perfringens 

What are the effects of distemper virus in the CNS?

all cells in the CNS are susceptible to infections that cause encephalomyelitis and demyelination due to the virus targeting oligodendricytes

What breeds are most commonly affected by degenerative myelopathy because of a mutation in the superoxide dismutase 1 gene (SOD1)?

German Shepherds, usually over 8 yr

What part of the CNS does degenerative myelopathy most commonly target?

Thoracic spinal cord, axonal degeneration

What pathology is shown in this image?

Chiari like malformation

What breeds are predisposed to chairi like malformation?

Cavalier King Charles Spaniel

What pathology is shown in this image?

dural ossification

What are the lesions of granulomatous meningoencephalitis like?

polka-dot gelatinous or granular irregular areas of grey-white-red lesions in the white matter of the brainstem

What cells are suspected to be involved in granulomatous meningoencephalitis?

t lymphocytes

What pathology is shown in this image?

granulomatous meningoencephalitis 

What dogs are predisposed for necrotizing meningoencephalitis?

young to middle aged pugs, shih tzu, Chihuahua and Maltese

What part of the CNS does NME specifically target?

Cerebral cortex

What breeds are predisposed for necrotizing meningoencephalitis?

Yorkies

Where are lesions of NLE most commonly found?

Cerebral white matter and brainstem

What pathology is shown in this image?

Necrotizing meningoencephalitis 

What pathology is shown in the image?

Necrotizing leukoencephalitis

What is the actual name of beagle pain syndrome?

Steroid-responsive megingitis-arteritis is also known as beagle pain syndrome

How do dogs with steroid-responsive meningitis-arteritis present?

Severe cervical hyperesthesia, hunched posture, fever, neutrophilia, neutrophilic pleocytosis on CSF, and leptomeningeal hemorrhage in the cervical spinal cord and brainstem

What breeds are predisposed to IVDD due to their collagen deficiency?

Chondrosydtrophic breeds

Type 1 Herniation

more sever, acute, large breed dogs

Type 2 herniation 

chronic, small breed dogs

What pathology is shown in this image?

Myelomalacia of the spinal cord following IVDD, probably a small dog, poor prognosis

What disease is similar to human alzheimers and is associated with abnormal protein deposition in the brain?

Canine Cognitive Dysfunction (CCD)

What pathology is shown in this image?

Leptomeningeal fibrosis, particularly in the sulci 

What causes the CSF to be cloudy in cats with FIP?

fibrin rick exudate within the ventricles

What pathology is shown in this image?

FIP

What condition occurs when a Cuterebra fly larvae enters the brain via the nasal cavity?

Feline Ischemic Encephalitis is because of fly larvae

What pathology is shown in this image?

collapsed cerebral cortex most likely due to necrosis following larval invasion

What pathology is shown in this image?

feline thiamine deficiency

How do cats become thiamine deficient?

ingestion of fish containing thiaminase or dietary deficiency

What domestic species most frequently gets primary neoplasms of the CNS?

Dogs

What are examples of embryonal tumors?

• medulloblastoma

• ependymoblastoma

• neuroblastoma

• primitive neuroectodermal tumors (PNET)

Which embryonal tumor is most common in young animals, arises in the cerebellum and usually does not cause hemorrhage, necrosis or cysts?

medulloblastomas 

What pathology is shown in this image?

medulloblastoma (image)

• well circumscribed, soft, gray - pink mass that compresses the fourth ventricle