Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

EQUINE > 27.6.4: Neurological horse - abnormal mentation > Flashcards

27.6.4: Neurological horse - abnormal mentation Flashcards

1
Q

Which of the following conditions are notifiable in the UK?
* Viral encephalitides: EEE/WEE/VE
* Viral encephalimyelitis: West Nile Virus
* Borna virus
* Leukoencephalomalacia

A
  • Viral encephalitides: EEE/WEE/VE
  • Viral encephalimyelitis: West Nile Virus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

General signs of forebrain disease

A
  • Obtundation
  • Head-pressing
  • Odontoprisis (teeth grinding)
  • Hyperstesia (irritability)
  • Blindness (lack of menace response with normal PLRs)
  • Seizures
  • Circling
  • Head turn
  • Ataxia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Depressed

A

animal is aware but not alert to surroundings/ not interested in normal stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Obtunded

A

animal is dull and slow to respond, but will respond appropriately

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Stuporous

A

animal is unresponsive to normal stimuli; can be aroused with strong stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Comatose

A

state of unconscious in which animal cannot be aroused, even with noxious stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Causative agent of Eastern/ Western/ Venezuelan encephalitides

A

Alphaviruses
These are zoonotic and notifiable!
Mainly present in N. and S. America.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Clinical signs of viral encephalitides

A
  • High fever
  • All signs of forebrain disease
  • Head tilt
  • Muscle tremors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Diagnosis of viral encephalitides

A
  • Clinical signs + time of year + location
  • Serology: IgM titres
  • CSF: neutrophilic inflammation (would see >50%, non-degenerate). Would also see high protein (>80 mg/dL)
  • PM: RT-PCR formalin fixed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Prognosis for viral encephalitides

A
  • EEE: high mortality (75-95% die)
  • WEE and VE: 50% death
  • Residual damage is possible: central blindness, head tilt, facial paralysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Causative agent, epidemiology and transmission of West Nile Virus

A

West Nile Virus
* Neuroinvasive flavivirus transmitted by mosquitos (Culex pipiens )
* Seasonal disease first discovered in Africa but found worldwide
* Not in UK - notifiable !

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where is West Nile Virus found?

A
  • Not in UK - Notifiable
  • Recent outbreaks in Europe, evidence of persistent circulation in Mediterranean countries
  • High risk for unvaccinated horses travelling to those areas in spring to autumn
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Incubation period of West Nile Virus

A
  • Incubation period of 7-10 days
  • 60% of horses are asymptomatic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Clinical signs of West Nile Virus

A
  • 60% of horses are asymptomatic
  • Ataxia and limb weakness
  • Muscle twitching esp around muzzle
  • Obtundation
  • Dog-sitting posture
  • Thoracic limb knuckling
  • Recumbency, circling
  • Facial and tongue paralysis, head tilt
  • Mortality around 31% in US studies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Diagnosis of West Nile Virus

A
  • Clinical signs
  • Serology (pay attention to vaccination)
  • PCR on CNS tissue
  • CSF analysis: mild pleocytosis with lymphocytes and macrophages, moderate elevation in protein and sometimes xanthochromia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pleocytosis

A

the presence of an abnormally large number of lymphocytes in the cerebrospinal fluid.

17
Q

Xanthochromia

A

the presence of bilirubin in the cerebrospinal fluid

18
Q

Characteristics and transmission of Borna virus

A
  • Borna disease virus-1: neutrotropic virus
  • Transmitted by contact with white-toothed shrew urine
  • Long incubation period: ~2 months after inhalation of urine droplets
19
Q

Clinical signs of Borna virus

A
  • All of those related to forebrain disease
  • Fever
  • Central blindness
  • Chewing
  • Swallowing deficits
  • High mortality: 80%
20
Q

Diagnosis of Borna virus

A
  • CSF: non-purulent inflammation (T-lymphocytes)
  • IFAT or ELISA on CSF
  • PM: Joest-Degen inclusion bodies on brain samples
21
Q

Treatment and prevention of Borna virus

A
  • No vaccine available
  • Most cases occur in Central Europe (endemic areas)
22
Q

Causative agent and characteristics of rabies

A
  • Notifiable
  • Neutropic virus belonging to genus Lyssavirus
  • Zoonotic and fatal
  • Must PTS and send head to authorised laboratory
23
Q

How does rabies spread through the body?

A
  • Neuroaxonal migration with 2 replications: local at the site of the bite and CNS, then centripetal spread
24
Q

Incubation period of rabies

A

Variable: 10 days to several months

25
Q

Clinical signs of rabies

A

Paralytic rabies in horses (compared to dumb rabies in ruminants)
* Shifting lameness
* Mild colic
* Ataxia
* Loss of spinal reflexes: tail and anal paralysis, priapism, tenesmus
* Intermittent fever

Lethal within 10 days.

26
Q

True/false: there is a vaccine available for Borna virus

A

False
No vaccine currently available

27
Q

General points for control of viral encephalitides

A
  • Vector-control: time-operated insecticide spray system in the barn
  • Mosquitos feed from dusk to dawn: keep horses in stables at night with fly-screen windows
  • Stall window fans -> midges are poor fliers
  • Apply permethrin pour-on or any other fly repellant
  • Rodent control in feeding rooms
28
Q

General supportive care for viral encephalitides

A

For mosquito-born and borna virus:
* IV fluids
* NSAIDs
* Slings
* Padding to avoid pressure sores

29
Q

Clinical signs of hepatic encephalopathy

A
  • Depression
  • Obtundation
  • Head-pressing
  • Compulsive walking
  • Ataxia
  • Seizures
30
Q

Diagnosis of hepatic encephalopathy

A
  • Liver enzyme elevation: SDH, GDH, GGT, AST, bile acids
  • If severe disease: hyperammonaemia, low BUN, prolonged clotting times (PT, APTT)
31
Q

Treatment of hepatic encephalopathy

A
  • Treat liver disease and support neuronal function
  • IV fluids with dextrose -> remember the liver is not functioning
  • Oral lactulose and/or mineral oil -> reduced absorption of ammonia in GI system
  • Sedation of cases with compulsive walking/ head pressing
  • Avoid benzodiazepines as they increase GABA activity unless severe seizures
  • Plasma transfusion if low clotting factors
  • Could consider steroids
32
Q

What diet should you feed a horse with hepatic encephalopathy?

A
  • Low protein, high carbohydrate: sorghum, milo, beet pulp and molasses
33
Q

General principles of management of head trauma

A
  • Establish airway (nasal or frontal fractures)
  • Obtain vascular access: hypotension, administer medication, control seizures
  • Clean and dress wounds, staunch bleeding
  • Antibiotics: prevent meningeal infection
  • Padded helmet: avoid further trauma
  • Control temperature: hyperthermia is possible with hypothalamic damage
  • Control brain swelling: hypertonic saline, mannitol
  • Oxygen, antioxidants (vitamin E, DMSO), steroids, NSAIDs, magnesium sulphate
34
Q

Cause of leukoencephalomalacia

A
  • Fatal intoxication caused by ingestion of fumononisin toxins (mainly but not exclusively found on corn or corn by-products)
35
Q

Clinical signs of leukoencephalomalacia

A
  • Obtundation
  • Ataxia
  • Compulsive walking
  • Head-pressing
  • Blindness
  • Acute onset and death within 7 days
36
Q

PM findings: leukoencephalomalacia

A
  • Liquefactive necrosis and degeneration in subcortical white matter
37
Q

Key points in the approach to the horse with abnormal mentation

A
  • Neurolocalisation is important
  • Most common causes in UK: head trauma, hepatic encephalopathy, (need to be aware of WNV)
  • Initial treatment for all is supportive
  • Initial diagnostics: bloodwork and serology
  • Manage client expectations and give enough time
  • Recommend WNV vaccines for all competition horses travelling to Europe for a summer
  • Remain vigilant for emergent conditions

EQUINE (59 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions