Podcast
Questions and Answers
What is the primary focus of a neurological examination on horses?
What is the primary focus of a neurological examination on horses?
Which condition is characterized by an inability to hold up a leg for the farrier?
Which condition is characterized by an inability to hold up a leg for the farrier?
What does obtundation indicate in a horse's mentation assessment?
What does obtundation indicate in a horse's mentation assessment?
What symptom is most commonly associated with vestibular disease in horses?
What symptom is most commonly associated with vestibular disease in horses?
Signup and view all the answers
What does Schiff-Sherrington syndrome indicate?
What does Schiff-Sherrington syndrome indicate?
Signup and view all the answers
How can intention tremors help localize lesions?
How can intention tremors help localize lesions?
Signup and view all the answers
Which cranial nerves are unique in originating from locations other than the brainstem?
Which cranial nerves are unique in originating from locations other than the brainstem?
Signup and view all the answers
What does a base wide stance with knuckling suggest in a horse?
What does a base wide stance with knuckling suggest in a horse?
Signup and view all the answers
Which part of the brain is primarily responsible for mental awareness?
Which part of the brain is primarily responsible for mental awareness?
Signup and view all the answers
What role does the ascending reticular activating system (ARAS) play in neurological function?
What role does the ascending reticular activating system (ARAS) play in neurological function?
Signup and view all the answers
What is the most consistent clinical sign of Horner’s syndrome?
What is the most consistent clinical sign of Horner’s syndrome?
Signup and view all the answers
In lesions affecting the optic nerve, what is the expected change in both vision and pupillary light reflex (PLR)?
In lesions affecting the optic nerve, what is the expected change in both vision and pupillary light reflex (PLR)?
Signup and view all the answers
What will happen during dim light dilation testing if both pupils dilate to equal size?
What will happen during dim light dilation testing if both pupils dilate to equal size?
Signup and view all the answers
Which reflex indicates upper motor neuron involvement when hyper reflexive?
Which reflex indicates upper motor neuron involvement when hyper reflexive?
Signup and view all the answers
If a pupil is smaller due to Horner’s syndrome, what conclusion can be drawn from the dim light dilation test?
If a pupil is smaller due to Horner’s syndrome, what conclusion can be drawn from the dim light dilation test?
Signup and view all the answers
What is a key symptom of lesions causing disruption of the sympathetic trunk in the neck?
What is a key symptom of lesions causing disruption of the sympathetic trunk in the neck?
Signup and view all the answers
Which reflex would be absent if there is a lesion cranial to the test site?
Which reflex would be absent if there is a lesion cranial to the test site?
Signup and view all the answers
What indicates a normal muscle strength evaluation when performing the perianal reflex?
What indicates a normal muscle strength evaluation when performing the perianal reflex?
Signup and view all the answers
Which of the following symptoms is NOT characteristic of Horner’s syndrome?
Which of the following symptoms is NOT characteristic of Horner’s syndrome?
Signup and view all the answers
In the context of reflexes, what does a hypo reflexive response indicate?
In the context of reflexes, what does a hypo reflexive response indicate?
Signup and view all the answers
What is a characteristic of spinal ataxia when assessing gait at higher speeds?
What is a characteristic of spinal ataxia when assessing gait at higher speeds?
Signup and view all the answers
Which gait abnormality is characterized by excessive limb lifting?
Which gait abnormality is characterized by excessive limb lifting?
Signup and view all the answers
What does a Grade 3 spinal ataxia indicate about the horse's condition?
What does a Grade 3 spinal ataxia indicate about the horse's condition?
Signup and view all the answers
What is observed when a horse is cantering in a circle?
What is observed when a horse is cantering in a circle?
Signup and view all the answers
What could a poor response in the tail pull test suggest?
What could a poor response in the tail pull test suggest?
Signup and view all the answers
When observing a horse walking in circles, which sign indicates a potential problem?
When observing a horse walking in circles, which sign indicates a potential problem?
Signup and view all the answers
What is the primary method to assess strength while the horse is walking?
What is the primary method to assess strength while the horse is walking?
Signup and view all the answers
Which gait abnormality suggests weakness and dragging?
Which gait abnormality suggests weakness and dragging?
Signup and view all the answers
What type of tremor is most easily observed when feeding a horse?
What type of tremor is most easily observed when feeding a horse?
Signup and view all the answers
What is the expected behavior of neurologic horses during trotting?
What is the expected behavior of neurologic horses during trotting?
Signup and view all the answers
Study Notes
Equine Nervous System Examination (Neuro 1)
-
Objectives:
- Students will demonstrate competence in performing neurological examinations on horses.
- Focus on localization, personnel safety, and biosecurity.
- Include spinal ataxia and grading schemes.
- Include cranial nerves.
- Knowledge of Horner's syndrome pathophysiology and diagnosis.
When to Perform a Neurological Examination
- Necessity: Is neurological disease present? If so, where is the process localized in the nervous system?
- Evaluation: Use "snapshots" of the disease and repeated examinations to determine progression and prognosis.
- Limitations: Subjective assessments, subtle personality/mentation changes might be undetectable. Consider owner input, normal ranges for age and breed, sedative effects, and alpha 2 agonists.
Information to Gather
- Chief Complaint: Seizures, weakness, won't hold up leg, cross-canters behind, unexplained wounds, or clumsiness.
- Signalment: Species, breed, and age.
- History: Define the clinical course and treatments/diagnostics performed up to this point.
- Physical Examination: Incorporate systemic disease evaluations that may induce neurologic symptoms.
Assessment of Mentation and Behavior
- Observation: Observe animal during history taking or video review. Note fear, anxiety, aggression, dullness, obtundation, stupor, and unconsciousness.
-
Clinical Neuroanatomy:
- Mental awareness is a function of higher brain centers (dullness < lethargy < obtundation < stupor < coma).
- Sensory information reaches consciousness in the cerebral cortex leading to initiated voluntary movements.
- Ascending reticular activating system (ARAS) plays a key role; sensory information travels to the cortex through the ARAS pathways.
Assessment of Posture
- Observation: Examine head/limb positioning in space. Observe for strabismus, nystagmus, and blindness (commonly linked to vestibular diseases).
- Head Tilt: This is a crucial indicator for many types of diseases.
- Head Turn: Cerebral and thalamic lesions typically manifest as head turns towards the affected side.
Assessment of Posture (cont'd)
- Schiff-Sherrington Syndrome: Forelimb extensor rigidity without opisthotonus.
- Opisthotonus: Head and neck in extreme extension.
- Midbrain Disease: Decerebrate rigidity impacting all limbs.
- Cerebellar Disease: Decerebellate rigidity, typically affecting just the forelimbs, often accompanied by intention tremors.
- Spinal Ataxia: Evidence of base wide stance, knuckling, sway, and dog-tracking.
Localizing the Lesion
- Mental Change: Implicates cerebral involvement.
- Intention Tremors: Suggest cerebellar issues.
-
Ataxia without Mental Change: Likely spinal involvement.
- Hind limbs alone indicate thoracolumbar or sacral spinal problems.
- Front and hind limbs (or hind limbs worse than front) indicate cervical or thoracic intumescence.
- No limb reflexes are possible.
- Difficult to differentiate upper and lower motor neuron diseases.
Cranial Nerves
- Number: 12 pairs.
- Innervation: Innervates head structures; ipsilaterally (same side).
- Origination: Many originate in the brainstem, except for CN I and CN II.
- Evaluation: Check your 1604 lecture notes or the Hahn paper.
- Organization: Numerical and functional groupings are helpful.
Localizing Lesions in the Visual Pathway
- Optic Nerve/Primary Eye Issues: Both vision and pupils-light reflexes (PLR) are abnormal.
- Cortical Lesions: Vision is affected, but PLR is normal.
- Efferent Arms Lesions: Vision is normal, but PLR is abnormal.
- Important takeaway: One can be blind but have normal PLR.
Sympathetic Innervation to the Eye
- Function: Responsible for pupil dilation, eyelid retraction, and globe protrusion.
- Horner's Syndrome: Results from disrupted sympathetic innervation to the globe/periorbital area.
- Clinical Signs: Common signs include ptosis, miosis, enophthalmos, and potential third eyelid protrusion, and ipsilateral facial and neck sweating.
Horner's Syndrome (cont'd)
- Guttural Pouch/Cranial Cervical Ganglion Lesions: Cause face and cranial neck sweating.
- Sympathetic Trunk Lesions (Neck): Cause face and neck sweating (C3-C4).
- Thoracic Inlet Lesions: Potential for sweating in areas down to the shoulder.
Anisocoria (Unequal Pupils)
- Evaluation: Darkened room, observe pupil dilation in dim light.
- Normal Response: Equal dilation.
- Abnormal Response: Indicates possible CN III or Horner's syndrome.
- Diagnosis: The pupil that's smaller is abnormal.
Reflexes
- General: Many are limited to recumbent animals, as opposed to standing ones (e.g. patellar reflex).
- Hyperreflexia: Usually suggests an upper motor neuron issue.
- Hyporeflexia: Typically points to a lower motor neuron problem.
- Panniculus/Cutaneous Trunci Reflex: "Fly twitch." Absent with lesions anywhere above the test point in the spinal pathway.
- Other Reflexes: Cervico-facial, lordosis/kyphosis, perianal and anal tone, and lateral thoracic.
Neck Stretching
- Evaluation: Subjective assessment of neck flexibility, stiffness, and potential pain.
Abnormalities of Gait
- Spinal Ataxia: The faster the horse travels, the more normal its gait appears.
- Hypermetria: Excessive limb lifting (upper motor neuron).
- Hypometria: Weakness and dragging of limbs (lower motor neuron).
- Intention Tremors: Easily observed during feeding or other situations. Linked to cerebellar disease.
Spinal Ataxia (Grading)
- Grade 0: Normal.
- Grade 1: Extremely mildly affected; performance limiting needing multiple tests.
- Grade 2: Mildly affected; performance limit; observable to a professional.
- Grade 3: Obvious abnormality to a layman, even at rest.
- Grade 4: Significantly ataxic; may fall during exams. Dangerous.
- Grade 5: Recumbent; unable to stand; extremely dangerous.
Walking/Gait Assessments
- Straight Line: Observe cadence/consistency, foot placement, and limb flight consistency.
- Circles: Observe pivoting, circumduction, limb flight height, toe dragging and other deviations.
- Trotting: Assess cadence/consistency, foot placement, and limb flight consistency.
- Cantering: Observe if the 3-beat gait pattern is maintained (common for faster horses to deviate slightly).
- Racetrack is a helpful comparison for gait norms
Tail Pull Reflex
- Initiation: Stand horse; pull tail to elicit extensor reflex.
- Significance: A poorly executed reflex suggests a lower motor neuron lesion at L3-L5.
- Subjective Assessment: Assess strength and learning during the exercise.
Walking with Head Elevated
- Normal Response: Normal horses continue walking without any alterations.
- Abnormal Response: Abnormal horses may demonstrate cat-walking or try to look. Removes visual compensation affecting the gait.
Placements (Proprioception Assessment)
- Theoretical Test: Places, hops. Use is not prevalent anymore, theoretical tests of proprioception.
- Alternative Tests: These types of tests are not conducted regularly anymore.
Obstacles (Hills/Curbs)
- Proprioception Test: Evaluate how horses navigate hills/curbs; not frequently used in current practice.
- Clumsiness Variation: Some horses are naturally clumsy, making some tests less useful.
Autonomous Zone
- Importance in Uneven Limb Conditions: Importance when only one limb is affected.
- Radial Nerve Specificity: Radial nerve doesn't have a consistently defined zone in all horses.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz assesses students' knowledge and skills in performing neurological examinations on horses. Focus areas include localization, spinal ataxia, cranial nerves, and understanding Horner's syndrome. Prepare to demonstrate competence in identifying neurological diseases and their implications in equine patients.
