Foal: Nervous System Diseases Flashcards
Why are foals particularly tricky to diagnose/ assess for a neurological disorder?
- Foals naturally have more abrupt, jerky and exaggerated head movements
- Foals don’t always have a menace response- this is a learned response
- Their gait is normally choppy and dysmmetric, and often have a wide-base stance
- Preamture foals often are weak, quiet, sleep more, have a depressed suckle and have floppy ears + lips: this needs to be differentiated from a primary neurological disease
What clinical signs are considered abnormal in the foal?
- Barking, teeth grinding, jaw chomping, protruding tongue
- Loss of affinity for the mare, aimless wandering, excessive sleeping
- Head-pressing, dog-sitting
- Depression, coma, seizures
- Decreased responsiveness to stimuli
What are some of the common neurological disorders in the foal?
- Sepsis
- Prematurity
- Hypoxic-ischemia encephalopathy
- Neonatal isoerythrolysis
- Bacterial meningitis
- Viral meningitis
- Skull/ vertebral trauma
- Botulism (Shaker foal syndrome)
- Tetanus
- Tyzzer’s Disease
- Hydrocephalus
- Cerebellar abiotrophy of Arabian Foals
- Occipito-atlanto-axial malformation (OAAM)
What are some causes for seizures in foals?
- Parturition-asphyxia Syndrome (PAS)
- Trauma: maybe got kicked by the mare
- Sepsis
- Hemorrhage
- Metabolic causes
- Developmental
- Idiopathic
What are you looking out for when you suspect a foal is having a seizure?
- Oral and buccal movements (look like they are chewing gum)
- Facial grimacing, twitching
- Rapid eye movements + repetitive eye blinking
- Paddling, tonic posturing, extensor rigidity
Note: foals have a low seizure threshold, possibly due to cortical immaturity
What is the treatment protocol for seizures in foals?
- Anticonvulsants: Diazepam or Phenobarbital
- Anti-inflammatories: Prednisolone sodium succinate, or NSAIDs
- Supportive care
What are the most commonly identified bacteria in bacterial meningitis in the foal?
How do these bacteria get into the meninges?
- E.coli, Streptococcus spp, Actinobacillus equuli, Klebsiella, Staphylococcus spp
Most commonly get into the meninges through hematogenous spread, thus meningitis is commonly associated with septicemia
Can enter through 5 main routes of entry:
- The gut, the lung, the umbilicus, through a penetrating wound, and across the placenta in utero
What are the clinical signs associated with bacterial meningitis in the foal?
- Depression
- Coma
- Cervical stiffness
- Seizures
How can bacterial meningitis be diagnosed in the foal?
- Physical exam + neurological exam
- Blood work
- CSF analysis + culture
- Blood culture
- Blood gas analysis
How can bacterial meningitis be treated in the foal?
- Long term, broad-spectrum IV antibiotics (4-6 weeks minimum)
- Anti-inflammatories
- Supportive care
What is the etiological agent of viral meningitis in the foal?
Equine Herpesvirus-1
- Infection in utero
This is a rare, fulminant, generalized and rapidly fatal disease
What are the clinical signs associated with viral meningitis?
- Aborted or stillborn
- If born alive, diffuse cerebral neuro signs, icteric (hepatic failure), pneumonia and often die in 24 hours after birth
How can viral meningitis be diagnosed in the foal?
- PM examination
- Serological test on pre-colostral serum for EHV-1
Is there a treatment for viral meningitis in the foal?
How can viral meningitis be prevented in future pregnancies?
No
Prevention: vaccinate the pregnant mare
Prevention is better than trying to treat
What is the cause of Hydrocephalus in the foal?
Unknown causes
Thankfully this rarely occurs
