Chapter 54 - Neurocranium and brain Flashcards
What are the important causes of morbidity and mortality in horses related to neurologic disorders?
Brain, spinal cord, and nerve disorders
What is a crucial cause of death in horses due to neurologic disorders?
Traumatic Brain Injury (TBI)
What type of injury is most common as a result of horses running into fixed objects or being kicked by another horse?
Frontal injury to the head
What is indicated by the presence of spinal fluid in the ear canal in horses?
Temporal bone fracture
Which breed was most represented in a retrospective study of horses with TBI?
Thoroughbreds
What is the most common cause of TBI in horses?
Skull fractures due to trauma
What are common neurologic signs observed in horses with TBI?
Ataxia, altered mentation, vestibular deficits
What risk factors are associated with nonsurvival in horses with TBI?
Persistent recumbency and fracture of the basilar bones
What was a significant finding regarding PCV levels on admission in a study of horses with TBI?
Lower PCV in surviving horses
What percentage of horses discharged after TBI were observed to have persistent neurologic deficits?
19%
What injuries result from trauma to the poll in young horses?
Basilar skull fractures
What brain region is affected when a horse with TBI shows seizures and cortical blindness?
Cerebrothalamic region
How many horses returned to their previous physical activity after being discharged with TBI?
29% of discharged horses
What is the outcome of massive bleeding from injury to the basilar artery in horses?
Bleeding into the guttural pouch and out the nares
Which clinical sign is associated with cerebellar injury in horses with TBI?
Hypermetria
What percentage of horses with TBI were discharged alive in one study?
C) 62%
What are the common brainstem signs observed in horses with severe TBI?
Altered state of consciousness, multiple cranial nerve dysfunctions
What does primary traumatic brain injury (TBI) in horses comprise?
Direct physical injury to the brain such as compression, deformation, displacement
What is concussion in horses classified as in terms of TBI?
A primary injury that is not severe and involves transient loss of consciousness
What does secondary brain injury in horses include?
A series of events like excitotoxicity, ischemia, inflammation, and neuronal cell death
Which disorders contribute to secondary brain injury in horses?
A combination of intracranial and extracranial disorders
What is the impact of increased intracranial pressure (ICP) on cerebral perfusion pressure (CPP) and cerebral blood flow (CBF)?
Increased ICP decreases CPP and CBF
What are key parameters to evaluate the neurologic status of a horse with TBI
Brain function, brainstem reflexes, and spinal cord function
How are severe spinal cord injuries indicated in horses with TBI?
Absence of voluntary motor function
what imaging techniques are used for neuroimaging of the equine head in cases of TBI?
CT and MRI
What does the presence of air in the brain, ventricles, or vertebral canal indicate in horses with TBI?
A) Infection
B) Inflammation
C) Presence of fracture
D) Neurological recovery
Presence of fracture
What can result from a laceration, the most severe primary brain injury in horses?
A) Mild confusion
B) Slight headache
C) Intracranial hemorrhage
D) Temporary dizziness
C) Intracranial hemorrhage
What is a significant effect of hypotension on the brain following TBI?
Increased cerebral blood flow and intracranial pressure
What is the role of astrocytes in the brain following TBI?
They clear the extracellular space of glutamate
What happens to astrocytes in response to a massive release of excitatory neurotransmitters post TBI?
they swell up, resulting in glial swelling
What are the consequences of altered respiratory patterns in patients with severe TBI?
A) It has no impact on brain function
B) It leads to consistent cerebral blood flow
C) It can impact cerebral blood flow, volume, and intracranial pressure
D) It results in immediate recovery of brain function
C) It can impact cerebral blood flow, volume, and intracranial pressure
What does the absence of pain perception indicate in horses with TBI?
Severe spinal cord injury with poor prognosis
What conditions increase morbidity and mortality in humans with TBI and are presumed to be similar in horses?
Hypotension and hypoxemia
Why should CSF sampling be avoided in patients with severe TBI?
High risk of cerebral or cerebellar herniation
What effect does head position have on intracranial pressure (ICP) in patients with brain injury?
Elevated head position reduces ICP
What should be considered in the supportive care of a recumbent horse with TBI?
Hydration, nutrition, urination, defecation, and bedding
Why should ketamine and acepromazine be used cautiously in patients with TBI?
They can increase cerebral metabolic demands and ICP
What has been the observed effect of corticosteroids in humans with TBI?
Increase in risk of death, severe disabilities, infection, and gastrointestinal bleeding
What is the role of hyperosmolar therapy in the treatment of TBI in horses?
To decrease intracranial pressure and cerebral edema
What are the benefits of hypertonic saline solution (HSS) in managing TBI?
A) It increases intracranial volume
B) It decreases intracranial volume and ICPC) It improves renal function
D) It enhances muscle recovery
B) It decreases intracranial volume and ICP
What is the recommended plasma osmolality level when administering hyperosmolar solutions for TBI?
A) Below 320 mOsm/L
B) Above 350 mOsm/L
C) Between 150-200 mOsm/L
D) Between 400-450 mOsm/L
A) Below 320 mOsm/L
What risks are associated with mannitol therapy in horses with TBI?
A) Acute renal failure and electrolyte disturbances
B) Increased blood pressure
C) Decreased heart rate
D) Skin irritation
A) Acute renal failure and electrolyte disturbances
How can prophylactic hypothermia benefit patients with TBI?
A) By reducing cerebral metabolic rate and ICP
B) By increasing cerebral oxygenation
C) By improving digestive function
D) By enhancing physical activity
A) By reducing cerebral metabolic rate and ICP
What is the purpose of antioxidant treatment in TBI cases?
A) To increase blood flow
B) To reduce oxidative stress
C) To enhance bone healing
D) To improve coat conditio
B) To reduce oxidative stress
What is the approach for seizure management in horses with TBI?
A) Use of anticonvulsants like benzodiazepines and phenobarbital
B) Physical therapy
C) Avoiding any medication
D) Immediate surgery
A) Use of anticonvulsants like benzodiazepines and phenobarbital
What therapeutic approach is rarely performed in horses but commonly used in human ICU units for TBI?
A) Decompression craniectomy
B) Physical exercise
C) Homeopathic treatment
D) Dietary changes
A) Decompression craniectomy
What bones form the cranial cavity in horses?
Frontal, parietal, interparietal, basioccipital, basisphenoid, presphenoid, and temporal bones
How are fractures of the bones surrounding the brain in horses classified?
by the degree of fragment displacement and damage to underlying tissues
What type of cranial fractures in horses do not penetrate the underlying dura mater?
A) Type I
B) Type II
C) Type III
D) Type IV
A)Type I
Type I cranial fractures are displaced but do not penetrate the underlying dura mater.
Type II fractures only disrupt the dura mater, while
Type III fractures lacerate the dura mater as well as the brain parenchyma.
Why are surgical approaches to the base of the horse’s skull considered experimental?
A) Due to the procedure being technically easy and low risk
B) Because it is a new method not yet fully researched
C) The procedure is technically difficult, provides limited access, and carries a high risk
D) It is a commonly performed procedure with a high success rate
C) The procedure is technically difficult, provides limited access, and carries a high risk
What surgical interventions might be considered for horses with traumatic brain injury?
A) To manage increased intracranial pressure or to evacuate intracranial hematomas
B) Cosmetic surgeries only
C) Routine spaying and neutering procedures
D) Procedures unrelated to the brain or skull
