CNS disease of sheep and goats Flashcards
Forebrain pathologies (12)
- Bacterial meningoencephalitis
- Thermal injury (disbudding goats)
- Aujesky’s disease/SHV-1
- Brain abscessation
- Sinusitis
- Gid (sheep)
- Cerebrocortical necrosis (CNN)/Polioencephalomalacia
- Louping ill
- Salt poisoning
- Lead poisoning
- Scrapie
- Atypical scrapie
Cerebellar pathologies (4)
Loss of fine motor control
- Congenital swayback
- Dandy-walker syndrome
- Cerebellar abiotrophy
- Cerebellar hypoplasia
Vestibular system pathologies (1)
- Middle ear infection/otitis media
Mid-brain pathologies (2)
Depression, coma, ophisthotonus, ventrolateral strabismus, loss of PLR, intact vision
- Hepatic encephalopathy
- Basilar empyema
Brainstem pathologies (1)
Signs depend on which cranial nerve nuclei affected: locus coeruleus (dullness), pyramidal system (ipsilateral weakness, contralateral extensor thrust)
- Listeriosis
Spinal cord pathologies (10)
- Hairy shakers/hypomyelinogenesis
- Atlanto-occipital septic arthritis
- Delayed swayback
- Vertebral body osteomyelitis and vertebral empyema
- Sarcocystosis
- ‘Wobbler syndrome’ / compressive cervical myelopathy
- Spinal trauma
- Cauda equine syndrome
- Visna/CAE
- Tetanus
Peripheral nervous system pathologies (3)
- Botulism
- Kangaroo gait
- Peripheral nerve damage
Toxicoses with neurological presentations (10)
- Closantel/rafoxanide
- Levamisole
- Organophosphate
- Lead
- Salt
- Mercury (chronic)
- Urea
- Organochlorides
- Bitter lupins
- Ryegrass staggers
Bacterial meningoencephalitis
Usually in neonates
Dull, dont feed, blind, tremors of the head, odd vocalisations, seizure - comatose - death
Bacteraemia leading to meningeal infection
Treat with broad spectrum antibiotics, NSAIDs
guarded prognosis
Thermal injury (disbudding goats)
Signs depend on degree of injury
Dull, don’t feed, blind, tremors of head, odd vocalisations, seizure - comatose - death
Treat with corticosteroids, broad spec antibiotics
Poor prognosis
Aujesky’s disease/SHV-1
Mad itch extreme - fatal pruritis
Notifiable
No treatment
Brain abscessation
Signs depend on location
Blindness, unilateral, contralateral proprioceptive deficits, head tilt, circling
Often 2-4 months
Euthanise
Sinusitis
Depression, head pressing, unilateral nasal discharge (also brain abscess signs?)
Dehorning/ foreign material / migration of bot fly
Prolonged course of antibiotics
Moderate prognosis unless brain abscess
Gid
Blindness, head tilt, circling
Metacestode of dog tapeworm T. multiceps - coenurus cerebralis cyst
Euthanise or remove surgically
Cerebrocortical necrosis (CCN)/ Polioencephalomalacia (PEM)
Central blindness, high head carriage, hyperaesthesia, seizures, dorsomedial strabismus, dark green diarrhoea, opisthonos, paddling, death
Due to an imbalance of thiaminolytic vs thiaminogenic bacteria - thiamine deficiency
Treat with thiamine
Louping ill
Zoonotic
Incoordination, ataxia, paralysis, convulsions, coma, death
Flavivirus transmission by Ixodes ricinus ticks
Supportive treatment plus oxytet if co infection
Vaccine available
Salt poisoning
More common in pigs and cattle
Unsettled, central blindness, ataxia, head pressing, altered gait, aimless wandering, recumbency, seizures, death
Can try to treat with hypertonic saline IVF or frusemide
Lead poisoning
More common in cattle - rare
Blindness, agression, bruxism, tremors, dullness or frenzy, convulsions, death, colic, constipation, ruminal stasis
Diagnose by testing blood
Treat with IV Calcium sodium edetate
Scrapie
Notifiable
Separation, depression, head tremor, low head carriage, pruritis, weight loss, bruxism, cud-dropping, ataxia, paresis, quadriplegia
Prion disease PrPc to PrPsc leads to protein accumulation in brain
No antemortem diagnosis
Inevitably fatal
Atypical scrapie
Abnormal behavious, absent menace response, no scratch response, no alopecia, circling when blindfolded, incoordination, tremor
PrPsc accumulation but distribution in brain is different, in sheep with scrapie resistant genotypes
Congenital swayback
Small weak lambs, fine head tremor, worsens with activity, more mildly affected lambs are poorly coordinated and struggle to find the teat
In utero copper deficiency leads to faulty myelin production and cavitation of white matter
Euthanise
Dandy-walker syndrome (sheep)
Congenital deformity - cerebellar vermis is deformed
Hypertensive hydrocephalus- domed head, thin skull
Euthanise
Cerebellar abiotrophy
Hereditary problem
Degeneration of the cerebellar Purkinje cells
Dysmetria, ataxia, preserved strength, intention tremors
No treatment
Cerebellar hypoplasia
Typical cerebellar signs, but doesn’t worsen over time
Could be congenital, infectious, bluetongue (notifiable)
No treatment
Middle ear infection/otitis media
Unilateral head tilt towards the lesion
Balance often affected, horizontal nystagmus
(recumbency, facial nerve paralysis, horners syndrome)
Bacterial cause, often Pasteurella, Strep, T. pyogenes
Treat with antibiosis, and sometime puncture the tympanum with a needle and flush of the middle ear
Hepatic encephalopathy
Blindness, agression, tremors, dullness, head pressing, sham eating and drinking
Multiple causes e.g. ragwort poisoning
Treat underlying problem, steroids and B vitamins
Basilar empyema
Usually in cattle but possible
Depression, anorexia, ataxia, head pressing, multiple cranial nerve deficits
Abscessation occurs around pituitary gland
Can try prolonged antibiosis if caught early but poor prognosis
Listeriosis
Usually seen winter-spring when on silage, most common in young adults
Depression, circling, head tilt unilateral facial nerve damage, unilateral hemiparesis, propulsive tendency, develops to recumbency and death
Grows in spoiled silage
Treat with penicillin based antibiotics, short acting steroid to reduce brainstem swelling, NSAIDs
Hairy shakers/hypomyelinogenesis
Sheep
Truncal ataxia and hairy fleece
In utero infection with pestivirus (BVD/BVDV)
Atlanto-occipital septic arthritis
Sheep
Low head carriage, stiff neck, tetraparesis, ataxia in young
Clinical signs, elevated protein levels in CSF, reflexes exaggerated
Treat with single dose of dexamethasone, 7-10 days of procaine penicillin
Delayed swayback
Sheep
Progressive ascending ataxia and weakness, normal at birth then develops at 2-4mo
In utero copper deficiency- demyelination after birth
Can try copper supplementation but guarded prognosis
Vertebral body osteomyelitis and vertebral empyema
Varies depending on location of lesion
Compressive spinal lesions, most common in lambs 6-12 weeks
Bacteraemia is presumed
Treatment usually pointless
Sarcocytosis
Sheep
Affects any age but more common in lambs
BAR, hindlimb ataxia and paresis, sometimes seizure and death
Caused by Sarcocystis spp (other hosts are dogs/foxes)
Poor/guarded prognosis
Supportive treatment
Wobbler syndrome/compressive cervical myelopathy
Ataxia, toe-scuffing, tetraparesis, progressing to tetraplegia
Texels and Beltexs
Fibrous/fatty nodules within the cervical spinal canal
Hopeless prognosis
Spinal trauma
Most common in rams and dairy cattle
Anti-inflammatories, rest, or euthanasia
Cauda-equina syndrome
Tail paralysis, inability to urinate, dilated bladder, passive release of urine, reduce anal tone, absent perineal reflex
Usually due to tail head injury
Anti-inflammatories, rest or euthanasia
Visna/CAE
Sheep: weight loss, unilateral hindlimb paresis and ataxia, progressing to general incoordination, HL paralysis, recumbency, death. Usually in older sheep in flocks heavily affected by Maedi
Goats: Similar to sheep but in kids 1-6mo
Lentiviruses
No treatment - euthanise
Tetanus
Clostridium tetani
Puncture wounds
Prevent by vaccination
Treat with high dose penicillin, anti-toxin, sedation
Poor prognosis
Botulism
Stiffness, incoordination, ataxia, excitibility, salivation, nasal discharge, flaccid paralysis, poor tongue retraction, hyporeflexia, ruminal bloat, death
Toxin interferes with release of ACh at NMJs
Supportive care only, poor prognosis
Kangaroo gait
Sheep
Weakness in forelimbs, hindlimbs preserve strength
Seen in early-mid-lactation in ewes, usually with twin lambs
Supportive care only, good prognosis once ewes recover
Peripheral nerve damage
Acute onset, weakness, reduced/absent reflexes, reduced muscle tone, reduced/absent sensation
Peroneal nerve damage
Hyperflexion of fetlock, overextension of hock, prolonged recumbency in cattle
Tibial nerve damage
Hyperflexion of hock, knuckling of fetlock
Prolonged recumbency or injection into caudal thigh
Facial nerve damage
Facial paralysis
May be damaged by ear infection or prolonged recumbency or trauma to the lateral aspect of the face
Anti-inflammatories, supportive therapy
Better prognosis as they can regrow
Closantel/rafoxanide overdose
Myelin swelling
Most common sign is blindness, also tetraparesis and death
Levamisole toxicity (goats)
Anxiety, hyperaesthesia, increased urination and defaecation, tremors, staggering gait, convulsions
Organophosphate toxicity
Restlessness, ptyalism, dyspnoea, tremors, increased frequency of urination and defaecation, bloat, head pressing, intermittent convulsions, paresis, recumbency
Lead poisoning
Depression, incoordination, hyperexcitability, blindness, convulsions, vocalisations, constipations
Salt poisoning
Tremors, blindness, nystagmus, weakness, weakness, incoordination, head pressing, opisthonotus, convulsions, coma.
Common in pigs
Mercury (chronic) poisoning
Anorexia, ataxia, blindness, convulsions, paresis
Urea poisoning
Salivation, bloating, weakness, staggering, muscle twitching, convulsions
Organochlorines poisoning
Fasciculation’s of the head and neck, spasms, bruxism, snapping of eyelids, bloat, incoordination, aimless wandering/circling, convulsions, coma
Bitter lupin poisoning
Medulla and spinal cord excitation followed by depression, prostration, decreased HR and BP, pupillary dilation
