Fichas
Equine case
Fichas del conjunto (36)
- 1What is meant by making a noise?A noise that can be heard by the rider or a spectator as a horse is being exercised - not a noise heard with a stethoscope
- 2What is normal 'noise' for a horse?Normal horse inspiratory sounds are quieter than expiratory sounds
- 3What is the breathing like for a horse in walk or trot?They have the choice when to breathe - regulate own breathing pattern
- 4How does a horse breathe during canter and gallop?Respiratory: locomotor coupling
- 5How can you tell whether a horse is in the inspiratory or expiratory phase?In canter or gallop:
Inspiratory phase the front legs are off the ground
Expiratory phase the front legs are on the ground - 6What areas of the clinical examination would be focused on with noise?Respiratory and upper airway
- 7What is the normal breathing rate of horses?8-12 breaths per minute
16 bpm is usually the cut off and anything higher is abnormal - 8What is occurring if a horse is making respiratory noise?Some sort of obstruction between the nostrils and the trachea
- 9What is the most likely region for the obstruction to be? and why?Pharynx or larynx due to muscular effort required to keep open
(tracheal rings and nasal bone) - 10How would the vet locate the lesion?1. Check for facial symmetry, palpate nostrils, submandibular and parotid regions
2. Palpate for symmetry of intrinsic laryngeal musculature
3. Palpate cricoartyenoideus dorsalis muscle to compare left and right - 11What is the innervation, origin and insertion of the CAD muscle?Inner: recurrent laryngeal nerve (axons in vagus nerve)
Ori: Dorsal aspect of cricoid cartilage
Inser: Muscular process of arytenoid cartilage - 12What is the innervation to the cricothyroideus muscle?Cranial laryngeal - only one of the larynx muscles to not be innervated by the recurrent laryngeal
- 13What happens with recurrent laryngeal neuropathy?Atrophy of the cricoarytenoideus dorsalis
- can feel the muscular process (more nobbly) - 14What is atrophy?Decrease in the functional mass or size of a cell/ tissue/ organ
- 15What are the possible diagnostic tests for pharyngeal/laryngeal obstruction?1. Endoscopy at rest
2. Endoscopy at exercise
3. Laryngeal ultrasound can be used to assess muscle size and echogenicity - 16What is the route of the endoscope?1. Nostril
2. Nasal passage (ventral meatus)
3. Nasopharynx
4. Larynx (glottis)
5. Trachea - 17What is the gutteral pouch also known as?Diverticulum of auditory tube
- 18Why is it good that most horses tolerate resting laryngeal endoscopy?Sedation affects the muscular tone and so affecting what's seen
- 19How is laryngeal function scored?1. Graded from 1 to 5 (or 4, depending on system)
2. Based on evaluation of the arytenoid cartilages
- symmetry, synchronicity of movement, whether full abduction can be achieved and maintained
3. 1 is normal, 4/4 or 5/5 is most severe, complete immobility of the arytenoid cartilage and vocal fold - 20What else is needed to may a definitive diagnosis as well as resting endoscopy?Exercise endoscopy
- 21What are the interchangeable terms for recurrent laryngeal neuropathy?1. Arytenoid cartilage collapse (ACC)
2. Recurrent laryngeal neuropathy
3. Laryngeal hemiplegia
4. Laryngeal paralysis - 22What does the clinical significance of ACC depend upon?Degree of obstruction of the rima glottidis and the type of work that the horse is expected to perform
- 23Which side does ACC often affect?Left side of the larynx
- 24Where does the recurrent larygneal nerve run?Left: loop around aorta
Right: loop around right subclavian artery
Both travel back up the neck and supply larynx - 25Why is the left recurrent larygneal nerve more likely to be affected than the right in the horse?Left is 250cm long which is twice the length of any other motor nerve
Right: 31cm - 26What does myelin do?Prevents cation loss between the Nodes of Ranvier
- 27What are the events that happen at the neuromuscular junction?1. Voltage gated calcium channel opened by pre synaptic action potential
2. Influx of calcium ions
3. Calcium dependent exocytosis of acetylcholine (ACh)
4. Ligand gated sodium channel opened by ACh
5. Influx of sodium ions
6. Opening of voltage gated sodium channels - start action potential in muscle fibre - 28What is recurrent laryngeal neuropathy?Distal axonopathy whereby the larger myelinated nerve fibres degenerate from the motor synapse proximally towards the cell body
- 29What does recurrent laryngeal neuropathy cause?Permanent dysnfuction of the muscles innervated by this nerve, the effect on the cricoarytenoideus dorsalis muscle leads to failure to achieve arytenoid abduction. Generating noise in exercise
- 30What can happen when injecting into the jugular vein?If miss and injecting an irritant can cause issue due to the recurrent laryngeal nerve being in jugular groove
- 31What are the treatments for recurrent laryngeal neuropathy?1. Do nothing and only exercise in ability
2. Prosthetic laryngoplasty ('tieback')
3. Ventriculocordectomy (Hobday) - 32What is the tieback operation?Place a permanent suture between the caudal border of the cricoid cartilage and the muscular process of the arytenoid
- Mimics the action of the CAD muscle as if it were in a semi-contracted state - 33What is the hobday operation?Removal of the vocal cords - will reduce noise but small affect on ventilation
- 34What are the potential risks associated with the tieback?1. Anaesthetic
2. Coughing and dysphagia
3. Food in trachea causing inflammation and potential asperation
4. Up to 50% of horses will have complications
5. Lead to other types of obstruction
6. Lose abduction over time - 35Why is an endoscope done 48 hours post tieback surgery?Check for food in trachea and make sure suture is holding and abduction hasn't slipped too far
- 36How common is this disease?- Clinically significant recurrent laryngeal neuropathy thought to affect 2-8% of horses
- More common in large horses
- More significant if high exercise demands
Información
- Descripción
- (Cases) 2. Neurological and associated senses AHS2 Fichas sobre Equine case, creado por Rachael Jones el 13/03/2017.
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- Rachael Jones
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