Small Ruminant Neurological Diseases

Question 1

What locations are you trying to localize a neurologic region to? What are you assessing to do so?

Answer 1

Cerebral Disease (most)
Cerebellar Disease
Brain Stem and CN
Spinal Cord and Peripheral Nerves

Mentation, Gait, Posture, Spinal Reflexes

Question 2

What is scrapies?

Answer 2

Fatal, progressive neurodegenerative disease of sheep
-Need special tag to say sheep free of it before it can move off farm
-0.1-0.3% prevalence
-Prion PrPSc (lymphoid tissue)
-Noninflammatory vacuar degeneration of grey matter with PrPSC scarpie associate fibrils

Question 3

How are animals infected with Scarpie?

Answer 3

Shed in placental and fetal fluid
-Horizonal common
- Ingestion - intestion, GALT, Lymphoid to nervous

Question 4

What are signs of Scrapie?

Answer 4

Intense wasting, pruritic, behavioral change, gait abnormality

2-5yr

Aggression to people and objects

Hing limb ataxia, poor postural reaction, exagerated gait, hypermetria, bunny hop, wool loss and self trauma

Question 5

Is Scrapies reportable?

Answer 5

YES

Question 6

How do you diagnose scrapie?

Answer 6

Antemortem: PRPSc in lymphoid tissue (tonsil, 3rd eyelig, rectal mucosa)
Postmortem- degenrative change in CNS gray matter

Question 7

What is the treatment for scrapes?

Answer 7

None, cull and not in food chain

Question 8

How do you prevent Scrapie?

Answer 8

Selective breed - Codon 136 (V susceptible) or 171 (QQ highly susceptible)

Question 9

What is polioencephalomalacia?

Answer 9

Disruption of cerebral energy metabolism -> accumulation of sodium and water

Edema, swelling, pressure necrosis or cerebral neurons

Question 10

What causes PEM?

Answer 10

Thiamine Deficiency, Sulfur toxicity, Sodium toxicity or water deprivation and lead toxicity

Question 11

What is the pathophysiology behind the thiamin deficiency?

Answer 11

Ruminant microorganisms make thiamine -> Thiamine phosphate cofactor for transketolase, rate limiting enzyme that provide ATP for brain - less ATP = dysfunction and NA ATP ase so intracellular sodium and water accumulate

Question 12

Can the body store thiamine long term?

Answer 12

No, created by microbes (1.5-3mg/day)

-If pregnant ewe doesn’t eat 1 day, need thiamin

Question 13

What is the most common cause of thiamin deficiency PEM?

Answer 13

Ruminal Acidosis
-Lamb and kid on low roughage, high grain diet
-Plant derived thiaminases - braken fern, horsetail, pig weed
-Amprolium

Question 14

What are clinical signs of PEM?

Answer 14

Bilateral Symmetric
-Wanter aimlessly, recumbent, central blindness (no menace but PLR normal) , opisthotons, muscle tremor, extensor rigidity, tonic-clonic convulsions, nystagmus, head pressing

Question 15

How do you diagnose PEM?

Answer 15

Signs or CSF tap (Mild increase protein and mononuclear cell)

Postmortem: Diffuse cerebral edema, cerebrum out foramen magnm, histo

Question 16

How do you treat PEM from thiamin deficiency?

Answer 16

Thiamine 10mg/kg IM, IV or SQ
Mannitol
Dexamethasone

Question 17

How do you prevent PEM from thiamin?

Answer 17

Good quality roughage and rumen health

Question 18

How can sulfur lead to PEM?

Answer 18

Water source, molasses, distiller grain
-Sulfides detoxify in liver but if overwhelmed they go to brain
-Diet >4000PPM
-Water >1000 PPM

Question 19

How does lead toxicosis lead to PEM?

Answer 19

Herbicine, batteries, paint, gas, shot gun shells

-Damage to capillary endothelial cell with neuronal ATPase function

0.3PPM

Normocytic, normochomic anemia, basophilic stippling

Post mortem: liver, kidney or feed sample

Treat: calcium disodium EDTA - chelation

Question 20

How does salt toxicosis or water deprovation cause PEM?

Answer 20

Too much salt, too litter water, too much electrolyte
Hypernatremia - fluid extracellular and increase CSF
-Brain edema, intravascular hemolysis
Treat - 9 g salt per liter

Question 21

What is a gram positive, facultatively intracellular bacteria that is ubiquitous in the enviroment, causes focal encephalitis, septicemia, abortion, mastitis and ophthalmiitis?

Answer 21

Listeria monocytogenes

Question 22

How is listeria spread?

Answer 22

Milk, feces, tear, nasal secretion, uterine fluid (ZOONOTIC)
- survives for months in soil
(Silage with pH >5.5cause?)

Question 23

How does listeria access the brain?

Answer 23

Crosses mucosal surface resulting in bacteremia, septicemia and infection of placenta and fetus
-Micro-abscesses, focal neuronal necrosis and neurophagia

Question 24

What are signs of listeria?

Answer 24

Unilateral
Fever in early stages
CN V - Facial hypalgesia, dropped jaw, dysphagia
CN VII - Drooped lip, ear, nasal deviation, ptosis
CN VIII - Head tilt, circling, nystagmus
CN IX and X - Pharyngeal paresis, dysphagia
CN XII - Unilateral tongue paresis and dysphagia

Question 25

What is case fatality of listeria is untreated?

Answer 25

100%

Question 26

What do you see on CSF for listeria?

Answer 26

High protien and mononuclear pleocytosis

Question 27

How do you treat listeria?

Answer 27

Antibiotics - Oxytetracyline, PPG, Kpen, Nuflour

Question 28

What is a cerebrospinal nematode, paraleaphostrongylus tenuis that migrated within the spinal cord?

Answer 28

Meningeal Worm

Question 29

What kind of host are the ruminants for this and what the infective stage?

Answer 29

Dead end host
L3 (in snail)
Ingestion

Question 30

What are signs of meningeal worm?

Answer 30

Unilateral to bilateral hind limb paresis and ataxia and recumbency (dog sit)

Question 31

How do you diagnose meningeal worm?

Answer 31

Post mortem - migration of larvae in spinal cord
CSF = EOSINOPHICIL pleocytosis

Question 32

How do you treat meningeal worms and what should you remind the owner?

Answer 32

Antihelmintics and anti-inflammatories
-Fenbendazole, ivermectin, dexamethasone, banamine, meloxicam

may have residual deficits

Prevention - ivermectin every 4-6 weeks in camelids

Question 33

What is a common disease of FPT babies and is when bacteria is spread hematogenously from pneumonia, omphaloplebitis, mastitis and endocardidis?

Answer 33

Bacterial Meningitis

Question 34

What pathogens cause bacterial meningitis?

Answer 34

E.coli, pasturella multocida, strep, staph and T. Pyogenes

Mycoplasma

Question 35

What do you see on CSF of bacterial meningitis?

Answer 35

Increase protein, leukocyte count and neutrophils

Question 36

How do you treat bacterial meningitis?

Answer 36

Ceftiofur sodium and ampicillin

Question 37

How can you help prevent bacterial meningitis?

Answer 37

Colostrum
Disbud correctly (3-5sec)

Question 38

Where should you perform a CSF tap?

Answer 38

Lumbosacral site, sedate recumbency, hind limb flexed forward, 1ml fluid per 5kg