Small Ruminants: Neurological Disease of Sheep Flashcards
What specific history should be taken when investigating neurological disease?
What is done after a history?
- Age group
- Number affected
- Speed of onset
- Speed of progression
- Time of year
- Feeding
Full clinical exam
Followed by a neurological exam
What are the common clinical signs of cerbellum disease?
What are the differentials?
- Altered head carriage
- Balance- ataxia, wide stance, dysmetria (high steps)
- Intention tremour- incl nystagmus
- Not common
DDXs- Congenital (cerebellar hypoplasia), border disease (cerebellar hypoplasia), possible abscess
What are the clinical signs of diffuse cerebrum disease?
What are some DDxs?
- Altered mental state- depressed, hyperexitable, disorientated
- Blindness
- Seizures
- Opisthotonos- recumbent, extended front legs, flexed hind legs
DDxs- Bacterial meningitis, cerebrocortical necrosis, pregnancy toxaemia
What are the clinical signs of local cerebrum disease?
What are some DDxs?
- Controlateral blindness
- Circling
- Proprioceptive defecits
DDXs- GID cysts, brain abscess, trauma
What are the clinical signs of vestibular disease?
- Head tilt to affected side
- Loss of balance
- Circling
- Falling/rolling to one side
- Spontaneous nystagmus
- Middle ear infection
- Unulateral facial paralysis (runs close to middle ear)
- What can cause brain stem disease?
- What are the clinical signs?
- Listeriosis
- Depression because of ascending reticular activation system
- Multiple cranial nerve defects- V, VII, VIII
- Ipsilateral hemiparesis
- What are the clinical signs of spinal cord disease?
- What can cause it?
1)
* No signs of central disease
* Depends on spinal cord site: tetraparesis/paraparesis
Proprioception
Pain
Skin sensitisation
Pedal and other spinal reflex
2) Spinal abscess, joint ill, tick pyaemia, wobblers syndrome, trauma, congenital abnormality
What are common neurological diseases of younf lambs <3 months?
- Border disease- tremors, hairy shakers
- Congenital swayback- ataxia, copper deficiency
- Drunken lamb disease and lamb nephrosis- ataxia, depression
- Bacterial meningitis- collapsed
- Tetanus
- Trauma
- Spinal abscess (joint ill)
- Listeriosis- circling, facial nerve paralysis
- Louping ill
How can spinal abscesses (joint ill) be treated in lambs?
1mg/kg dextamethasone, penicillin
5 days at least
- What are the ‘variable signs’ of louping ill?
- What disease is it important in?
- Head pressing, trembling, tremors, nystagmus, lip twitching, louping gait
- Important in grouse- high mortality
Vaccine available- bought in, naive
- What is CCN?
- What causes it?
- How and when does it present?
- What history may predipsose?
- What are the clinical signs?
- Cerebrocortical necrosis
- Vitamin B1 deficiency- thiamine
- Acute onset in growing lambs >3m
- Diet change or worming- thiaminase production in the rumen
- Dull, disorientated, blind, tremors, recumbency, opisthotonos, convulsions
- How is CCN treated?
- How is it diagnosed?
- How is it prevented?
1)
* Vitamin B1 IV slowly 10mg/kg
* Vitamin B1 IM every 12 hours for 3 days
* House quietly
* Vision should return 5-7 days
2) PM of the brain
3) Prevention- diet changes
- What causes listeriosis?
- What is it associated with?
- Why are 18-24 month olds more commonly infected?
- How does it progress?
- Listeria monocytogenes
- Associated with poorly preserved silage- soil contaminated- mold
- Changing molar teeth allowing infection of buccal tissues
- Ascending infection to the brain
- What are the clinical signs of listeriosis?
- How is it diagnosed?
- How is it treated?
- Anorexia, depression, unilateral hemiparesis, trigeminal nerve paralysis, facial nerve paralysis, drooped ear, lowered eyelid, deviated muzzle, loss of blink
- CS, CSF tap, PM
- Supportive care- remove silage
Good if caught early
Gold standard- 75kg ewe, 6g benzylpenicillin, 20ml procaine penicillin, 1mg dexamethasone, 5ml procaine penicillin for 5 days
- What parasite causes Gid?
- How does it present?
- What is the treatment?
- How can it be controlled?
- Taenia multiceps
- Gradual onset- circling, unilateral blindness, head tilt, skull softening
- Surgical precise- cerebral (good prognosis), cerebellar (poor prognosis)
- Worm dogs every 6 weeks with praziquantel- keep away from sheep carcasses