12 Ruminant Neurologic Disease IV: Continuation of Bacterial, and Introduction to Other Causes of Neurologic Disease in Ruminants

VERY POOR without surgical drainage and long term antibiotics

What is the prognosis like for brain abscess?

Trueperella pyogenes

What agent is the typical cause of brain abscess?

Brain abscess

Dehorning, sinusitis, inner ear infections, nasal foreign bodies are all risk factors for WHAT

COMPRESSION

What causes the clinical signs of brain abscesses?

Long term antimicrobial therapy and surgical drainage

What allows for success and survival of ruminant brain abscesses?

Trueperella pyogenes (aka Corynebacterium, Actinobacillus, Arcanobacterium)

What often causes pituitary abscesses in ruminants?

Pituitary abscess

Signs of this problem in cattle are acute and progress rapidly over 7-10 days. The cow will have wide base stance, ataxia, head tilt, dysphagia, ataxia, head and neck extension, with asymmetric CN deficits

Pyogenic infection of the head --> allows agent to reach the pituitary via hematogenous spread

What predisposes a cow to a pituitary abscess?

Rete mirabile next to internal maxillary artery (this vascular network mesh of blood vessels predisposes to pituitary abscess bc of close proximity)

What structure particularly makes it easier for species like ruminants, camelids, and carnivores to get pituitary abscesses?

Pituitary abscess

What is this?

Opens the door for pituitary abscess

What do plant foreign bodies have the ability to cause, when things like fox tail and plant awns get into the right nasal passage and force the animal to open mouth breathe?

Clostridium tetani = gram positive rod

Describe the causative agent of tetanus? Gram positive or gram negative? Shape?

Tetanus

This animal presented with progressive muscular rigidity, airplane ears, hypertonia, lockjaw, and limbs are resistant to passive flexion. Thoughts?

Tetanus

This cow presented with hypertonia, retracted lips and trismus (lockjaw), sawhorse stance, and muscular rigidity that becomes worse with auditory stimuli. Thoughts?

*parturition*, castration, tail docking

What history is common to help diagnose tetanus?

Remove existing and future toxin, tetanus antitoxin (current) and tetanus toxoid (future)

Also rumenostomy, antibiotics, muscle relaxers

How do you treat tetanus?

50,000-100,000 once

How much tetanus antitoxin can you give, that binds free tetanus toxin only?

Rumeonstomy (pictures, to feed directly into rumen due to lockjaw), antibiotics, muscle relaxants

What treatments can you do for tetanus BESIDES tetanus antitoxin and tetanus toxoid

Soil, feces, entry via uterus is common in dairy cattle

How does tetanus spread?

2 weeks to 1 month

What is the incubation period like for tetanus?

Tetanospasmin

Which part of the tetanus virus is the toxin responsible for clinical signs, that inhibits the release of glycine and GABA from renshaw cells to cause hypertonia and muscle spasms?

Tetanolysin

Which part of the tetanus virus promotes the spread by increasing local tissue necrosis to open the door

YES (it is routine in sheep and goats, but NOT cattle)

Does tetanus have a vaccine?

HIGH = 80%

Is the mortality rate *high* or *low* for tetanus in ruminants?

Botulism

This is a progressive muscular hypotonia in cattle that works from rear to front, though it has no effect on the peripheral sensory nerves and CNS

Clostridium botulinum

What is the causative agent of botulism?

Botulism

Which toxin can be ID'd in serum for up to 6 days, GI, or food

Botulism

Which problem in cows has an incubation period of 1-7 days?

Preformed toxin = animal carcasses (type C), spoiled silage (type B), pica aka chewing nonfood material (type D)

What is the only way adult cows can get botulism?

Type C

Which type of botulism do cows get from infected animal carcasses?

Type B

Which type of botulism do cows get from eating spoiled silage?

Type D

Which type of botulism do cows get from chewing nonfood material aka pica?

Botulism

This cow has a flaccid tongue, where you pull the tongue out of its' mouth and it just stays there. The cow has cranial nerve deficits and doesn't blink. Thoughts?

Cleaves SNARE protein

What does the botulism toxin cleave to prevent the fusion of the vesicles of neurotransmitters?

Decay of bound botulism toxin at the nerve

What does cows healing from botulism rely on?

Mycoplasma bovis

What agent causes Otitis media in ruminants?

Contaminated milk and colostrum

What is the source for cows getting infected with Mycoplasma bovis and Otitis media?

Respiratory disease and arthritis

What concurrent signs are typically seen with otitis media in cows?

Otitis media

You see a cow that looks like this. Its' radiographs show opacification of the tympanic bullae. The animal is also experiencing respiratory disease signs. What is your thought?

60%

What amount of cows make a full recovery from otitis media?

NO beta lactams

What can you NOT USE to treat otitis media?

a. florfenicol

c. tulathromycin

Select the medications you CAN use to treat otitis media in cows:

a. florfenicol

b. beta lactams

c. tulathromycin

Lead poisoning

This diffuse cerebral disease leads to aggression, convulsions, *central blindness*, wandering, and head pressing. CBC shows basophilic stippling and nucleated RBCs. Thoughts?

Basophilic stippling and nucleated RBCs

What is the CBC giveaway for lead poisoning in cattle?

Lead poisoning

What abnormality in cattle do you treat with urinary excretion following Ca EDTA or D-Penicillamine plus thiamine and magnesium sulfate laxatives?

Lead = lead poisoning

What is accumulating at the end of the long bones in this cow?

*Car batteries*, lead paint, linoleum

What are some of the most common sources for lead poisoning in cattle?

Other mineral deficiencies = iron, zinc, calcium

What might exacerbate signs of lead poisoning in cattle?

Swainsonine

What is the toxic component of locoweed?

Swainsonine

note: BSE ALSO causes vacuolation of the neurons

Which toxin inhibits alpha mannosidase which leads to an accumulation of material and *vacuolation of the neurons*?

organophosphate

note: basically causes fatal overstimulation by stopping acetylcholinesterase

Which toxin inhibits the recycling of inhibitory acetylcholinesterase?

This is probably organophosphate toxin

A cow presents with rear end weakness and flaccid paralysis. Grease and oil is present in the area. You decide to test acetylcholinesterase activity in the blood and find inhibition. What did you learn?

Organophosphate

Though often unsuccessful, this can be treated with muscarinic receptor blockers like atropine, cathartics, emetics, and cholinesterase reactivators

Pigs

What animal is the posterchild for salt poisoning?

Salt poisoning

This problem occurs as an overload of salt or a lack of water intake, resulting in neurologic signs of cerebral edema

Frozen water, stuck cow (in tree or outside fence), far distance to water

What kind of history might lead you to make a salt poisoning diagnosis?

Salt poisoning (due to lack of access to water)

Histopath of a cow shows brain edema and cerebrocortical necrosis. Serum and CSF sodium was over 160 mEq/L. The weather has been colder than normal recently and the farmer who had the cow did not have water trough heaters. What happened?

SLOWLY offer water and give IV slightly lower osmolar fluids

How do you treat salt poisoning?

Vitamin A deficiency

This spring calf has micropthalamia, reduced feed intake and growth, rough hair coat, blindness, edema, diarrhea and seizures. Late last year, the weather was unseasonably dry. What is this?

Vitamin A deficiency

What problem is characterized by central blindness, which often occurs when pregnant cows recieve drought raised forage?

Vitamin A deficiency

Which problem causes abnormal bone development in calves that constricts the optic nerve leading to central blindness?