quizz nvc Flashcards
ddx forebrain
Metabolic-toxic: hepatic, intestinal, equine leukoencephalomalacia (Fumosinin B1)
Neoplasia: cholesterinic granuloma, other
Inflammatory: EPM, WNV, EEE, WEE, VEE, rabies, EHV-1, Borna
Traumatic: pull injury
Vascular: intracarotid injection
What is the normal range for CSF proteins in horses?
0.5 – 1.0 g/L (up to 1.8 g/L in foals)
Remember that neonates of all species may have slightly xanthochromic CSF.
Moreover, with LS tap, we can have small particles swirl indicative of epidural fat and collagenous tissue which can increase CK measurements.
What is the most consistent sign of Horner’s syndrome in horses?
ptosis
Up to which level does sweating extend in case of a lesion
1/ in the region of the guttural pouch and cranial cervical ganglion?
2/ lesion involving the sympathetic trunk?
1/ Sweating of the face (most prominent at the base of the ear) and the cranial neck down to the level of C2
2/ Sweating of the face and neck extending down to the level of C3 to C4
Which are the bacteria, the toxin and the mechanism implicated in the leuko-encephalo-malacia in horses ?
Fusarium verticillioides (moniliforme)
Fumonisin B1 (in moldy corn)
Inhibit sphingolipids synthesis : accumulation of sphingolipids intermediates: increased ICP and oedema: liquefactive necrosis of subcortical WM (affect also liver and heart)
DDx vestibular dysfunction
Peripheral
Otitis media-interna
Temporohyoid osteopathy
Temporal bone fracture
Idiopathic vestibular disease
Central
EPM
Viral (rabies, WN, EHV1, EEV)
Abscess (Streptococcus equi, foals++)
Neoplasm
What is the most common genetic mutation associated with deafness in horses? Breeds? What is the frequency of this mutation in deaf population? What is the mechanism?
Gene: EDNRB, endothelin B receptor (autosomal semi-dominant)= Lethal white foal syndrome: ileocolonic aganglionosis (or aganglionic) megacolon
Frequency: ~91% of deaf and suspected deaf (mostly American Paint horses, Quarter Horse, Miniature horses, and rarely Thorougbred)
Mechanism: melanocytes contribute to the blood vessel-rich stria vascularis of the scala media of the inner ear. It normally regulates the chemical composition of the endolymph of the scala media within which the organ of Corti resides. A** lack of normal melanocytes** can alter the development and function of the stria vascularis, as well as the endolymph. This can lead to degeneration of cochlear hair cells and auditory nerve neurons.
What are the 3 pathophysiological mechanisms that can give rise to neonatal encephalopathy?
1/ Maladaptation to extrauterine life (better outcome, with 85% survival)
2/ Perinatal asphyxia (hypoxic-ischemic encephalopathy, outcome depends on the severity and duration of hypoxia)
-Dystocia
-Umbilical cord abnormalities (torsion, compression)
-Severe maternal disease
-Placental disease
3/ Metabolic derangements (outcome depends on the cause and consequences)
- Sepsis
- Kernicterus
- Electrolyte abnormalities (H/h Na, h Ca)
- Uremic encephalopathy
- Systemic illness
- Hypoglycemia
What is the indication for Madigan squeeze procedure? What is the benefit?
Foals with uncomplicated maladjustment, that is no signs of asphyxia or metabolic derangements, without respiratory depression or rib fracture
No benefit on overall outcome, but faster recovery
The purpose of this procedure is to simulate the pressure induced by parturition, thus resetting the hypopituitaric-pituitary-adrenal axis.
Give 2 non-infectious non-metabolic causes of behavioural changes.
eNAD/EMD: “bad” behavior
Leukoencephalomalacia (fumonisin B1): maniac
What is the major component that induce CNS depression in the fetus?
Allopregnanolone derived from progesterone metabolism
Which disease is associated with kernicterus in foals?
Neonatal isoerythrolysis
Antemortem diagnosis is achieved by the presence of appropriate clinical signs in the presence of total bilirubin concentrations greater than 19 mg/dL.
All reported cases of kernicterus in the veterinary literature are secondary to NI. The odds of developing kernicterus increased by 1.13 for each 1 mg/dL increase in maximum total bilirubin concentration.
Which toxin (and originating plant) can induce bilateral symmetrical vestibulocerebellar ataxia and tremors?
lolitrem B (perennial ryegrass)
At which age appear the normal menace response in horses?
2 weeks
What is the best surgical technique for temporohyoid osteoarthropathy? Why?
Ceratohyoidectomy
Lower rate of complications (22% against 33% for partial stylohyoid ostectomy) and favourable outcome
Complications include hemorrhage, dysphagia, dyspnea, and laryngeal collapse
What is the pathophysiology of THO? Why is CN VII affected?
Bony proliferation at the articulation of the stylohyoid bone with the petrous temporal bone can result from the spread of otitis media/interna or as a primary degenerative joint disease.
Both bone fuse and movement (chewing, opening of the jaw) can break the temporal bone and compress the facial nerve (and vestibulocochlearis), further it can lead to meningitis/encephalitis
Facial nerve is exiting at the stylomastoid foramen in close contact to the stylohyoid-petrous articulation.
Which breed is overrepresented in temporohyoid osteoarthropathy?
Quarterhorse and related breeds (52%)
What is the most common sign in horses with temporohyoid osteo-arthropathy ?
Loss of audition (100%)
50% unilateral (right > left); 50% bilateral
Followed by:
Vestibular and facial nerve dysfunction (83%)
Exposure ulcerative keratitis (71%)
Concurrent left laryngeal hemiparesis (61%)
The outcome for auditory loss is good with THO: true or false?
False
Short- and long-term follow-up revealed persistent auditory loss in all horses based on abnormal response to sound, and further confirmed through a BAER in 8 horses.
What are the most common causes of bilateral auditory loss?
Sensorineural deafness
THO
Multifocal brain disease
What are the most common causes of unilateral auditory loss?
temporo-hyoid osteopathy
otitis
What is the most common causes of BAER abnormalities?
Temporohyoid osteoarthropathy (20/57)
Followed by:
Congenital sensorineural deafness in Paint horses (17/57)
Multifocal brain disease (13/57)
Otitis media/interna (4/57)
Mainly bilateral because CSD are all bilateral.
What are the horse breeds described with cerebellar abiotrophy?
Arabian
Gotland pony
Oldenburg horse breeds
Headshaking is not a seasonal disease: true or false?
Not true
Seasonality of clinical signs is reported in approximately 60% of HSK horses while the remainder exhibit constant or erratic episodes.
In a largely US population of HSK horses, the majority (91%) of horses with seasonal HSK developed signs in the spring and early summer and these ceased in late summer and fall.
The majority (43%) of UK horses with seasonal HSK are symptomatic in spring, summer and autumn, 39% in spring and summer.
Geldings consistently appear to be over-represented in headshaker population: true or false?
true
Increase in exercise intensity is not associated with precipitate clinical signs of idiopathic headshaking: true or false?
False
Increase in exercise intensity frequently precipitates clinical signs.
In which horse breed is known the mutation for cerebellar abiotrophy? What is the mutation?
Arabian
5-20% of Arabian horses are carriers
Also reported in Oldenburg, Gottland pony, and Eriskay pony
SNP in TOE1 gene (CFA 2)
In proximity with MUTYH on the antisense strand
Autosomal recessive
Which plant (and associated toxin) cause nigropallidal encephalomalacia?
Plant: Centaurea solstitialis (yellow star thistle) or Centaurea repens (Russian knapweed)
Neurotoxin: repin
What is the suspected mechanism of pituitary pars intermedia dysfunction?
Degeneration of dopaminergic neurons in the hypothalamus -> release of their inhibitory effect on pars intermedia of pituitary gland -> adenoma or hyperplasia
Which plant, toxin and mechanism cause swaisonine toxicosis ?
Plant: locoweeds (Oxytropis, Astralagus, Swainsona)
Toxin: swainsonine (indolizidine alkaloid)
Mechanism: inhibition of alpha-mannosidase -> lysosomal storage -> neuronal vacuolation and epithelial cells
What are the mechanism/localization of lesions in shivers?
The mechanism is a Purkinje cell (PC) axonal degeneration without a substantial impact on PC soma.
When compared with controls, calretinin-negative, calbindin-positive, glutamic acid decarboxylase-positive spheroids were increased 80-fold in Purkinje cell axons within the deep cerebellar nuclei of horses with shivers.
In horses with shivers, surface EMG (sEMG) show abnormalities only during backward walking: true or false?
False
During backward walking, hindlimb muscle activation patterns show sustained, elevated flexor and extensor muscle activation with loss of the precise agonist and antagonist firing patterns required for a normal gait.
Although a movement disorder was only obvious with backward walking during surface EMG studies, altered and elevated firing patterns were present even during forward walking and trotting.
Thus, signs of shivers arise from a lack of coordinated recruitment of hindlimb flexor and extensor muscles obvious during backward walking but present subclinically during forward walking.
What are the most affected deep cerebellar nuclei in horses with shivers?
Lateral nuclei (dentate and interpositus)
What is the gene associated with hydrocephalus in horse? In which breed?
B3GALNT2 (AR)
Friesian horse (+ 1 case of Belgian foal)
Give 3 treatments for idiopathic headshaking.
Nose nets / face mask
Cyproheptadine (antihistamine with additional anticholinergic, antiserotonergic, calcium channel blocking and local anaesthetic activity)
Carbamazepine (anticonvulsant which stabilises voltage-gated sodium channels)
Electrostimulation
Magnesium
Platinum coil compression
What is the EDX finding associated with headshaking?
Reduced threshold for nerve activation
What is the clinical presentation of shivers?
Shivers in horses is characterized by trembling or shivering of the tail and thigh muscles and a characteristic hindlimb posture initiated by specific movements.
By 7 years of age, walking backward is difficult for Shivers horses because of either fixed hyperflexed abducted hindlimbs or rigid hindlimb extension.
Signs associated with guttural pouch mycosis?
Most common clinical signs:
Non-exercise-associated epistaxis (ICA ± maxillary artery, suberficial temporal artery)
Dysphagia (CN X & IX)
Other clinical signs:
Laryngeal hemiplegia (CN X)
Horner (cranial cervical ganglion or ganglionic axons)
Facial nerve paresis
Tongue paresis (CN XII)
Dorsal displacement of the soft palate (tensor veli palatini, CN V.3; palatopharyngeus, palatinus, levator veli palatini, CN X.pharyngeal branch)
Rarely, vestibular signs (inflammation eroding tympanic cavity)
Rarely, sternocephalicus muscle atrophy (CN XI)
What are the 3 breeds predisposed to narcolepsy?
Shetland pony
American miniature horse
Suffolk draft horse
What is the unusual clinical sign associated with shivers when horses are walking backward?
Facial twitching (17%)
How to differentiate shivers from standing hyperflexion and stringhalt?
1/ Backing and forward walking:
Normal: standing hyperflexion (only present during picking up hoof)
Abnormal: shivers (consistent HE or HF) or stringhalt (consistent or variable HE).
Entrained forward walking (trotting, cantering)
Normal: shivers (walking can be impaired intermittently with shivers-forward hyperflexion)
Hyperflexion: stringhalt
During backward walking, what is the main difference between shivers-hyperflexion and stringhalt?
Shivers: abduction
Stringhalt: adduction
What is the main hypothesis for isolated unilateral trigeminal dysfunction in a horse?
EPM / Sarcocystis neurona
Causes of laryngeal paralysis in horses (9)
Idiopathic
Guttural pouch disease
Iatrogenic (perivascular injection of irritating substances)
Trauma
Organophosphate intoxication (bilateral!)
Lead poisoning
Thiamine deficiency
Toxic plants (chickpeas, Lathyrus)
Infectious : strangles, EPM
Optic fibers decussation at the optic chiasm in human, horses
Humans 50%, Horses 80-90%
Fluphenazine toxicosis and yellow star thistle encephalopathy affect motor/sensory function
motor
Icteric CSF is a normal finding in foals: true or false?
True
Up to 10 days of age
What are the 4 most common causes of facial neuropathy?
Trauma (31%)
CNS disease (25%)
Idiopathic (19%, including 6% of true idiopathic and 13% not investigated)
Temporohyoid osteopathy (16%)
What is the outcome of facial paralysis in horses?
53% had full resolution
25% were euthanized
11% partially improved
11% were unchanged or worse
How many horses with facial paralysis also have ocular pathology?
36%
How many horses with facial paralysis were diagnosed with temporohyoid osteoarthropathy?
16%
Which breeds were overrepresented in concomitant facial paralysis and temporohyoid osteoarthropathy?
Quarter Horses were 8.14 times more likely and Pony breeds were 40.71 times more likely to have a diagnosis of THO than Thoroughbreds
Complex central nervous system malformations in Dutch Warmblood foal is associated with poor prognosis: true or false?
false
What is the cause of stiff horse syndrome?
Antibodies directed against glutamic acid decarboxylase (GAD), which produces the active form of GABA in the central nervous system, have been identified in the CSF of confirmed cases.
EMG has shown increased motor unit firing in the absence of any limb movement, which seems to be due to a decrease in GABA.
Horses show an insidious onset of waxing and waning muscle stiffness progressing to acute painful muscle contractions often initially initiated by startling or touching.
Which breeds seem predisposed for shivers?
Warmblood
Draft horses
What is the pathological findings in stringhalt? What is the suspected mechanism for the clinical signs?
Histo: Wallerian-type distal axonopathy of the tibial, deep, and superficial peroneal as well as recurrent laryngeal nerves accompanied by myofiber atrophy in the muscles supplied by affected nerves.
EMG (hindlimb): increased insertional activity, Fibs, and PSW, consistent with denervation.
Mechanism: disruption of the afferent or efferent fibers supplying muscle spindles and golgi tendon organ. Disruption of these stretch or tension feedback loops could interfere with the muscle’s ability to gauge the number of motor units required for a normal smooth muscle contraction resulting in hypertonicity and hyperreflexia.
What is the plant responsible for plant-associated stringhalt?
Hypochaeris radicata (Australian dandelion)
Taraxacum officinale (European dandelion)
(commonly referred to as catsear, flatweed)
Complex central nervous system malformations in Dutch Warmblood foal is associated with seizures: true or false?
True
Horses have smooth muscles that innervate the eyelid, which dogs do not have. How are these called?
arrector ciliorum m
ptosis of upper eyelid is most probably associated with … in Horse
Most probably associated with Horner syndrome
and equine grass sickness
Epilespy in arabic foal: type of seizure, age of cessation, most common concurrent disease
Seizures are characterized by generalized tonic activity
Cessation of seizures can be expected by 1 year of age
Pneumonia is the most common concurrent disease
What is the muscle implied in eyelash angle?
What is the innervation?
In which species?
Which significant disease is associated with its dysfunction and how to test that?
Arrectores ciliorum
Sympathetic
Horses and cattle (not in humans and dogs)
Equine grass sickness / Horner syndrome
low-dose of topical phenylephrine (alpha-1 agonist, 0.5%)
resolve the upper eyelid ptosis (tarsal smooth muscle) and the lowered angle of the upper eyelashes
Which CN are affected in nigropalladial encephalomalacia?
Ingestion of yellow star thistle (Centaurea solstitialis) or Russian knapweed (Centaurea repens).
CN V
CN VII: hypertonicity of facial and lips muscles, with the upper lips often pulled over the teeth in a grimace
CN XII: tongue lolling and fail to move food into back of the throat but remain capable to withdraw the tongue (different from botulism): may attempt to drink by immersing their head, allowing water to reach pharynx
Magnesium sulfate is associated with decreased head-shaking behaviour: true or false?
True
Administration of MSS IV increased plasma total and ionized magnesium concentrations and significantly decreased head-shaking behavior in horses with trigeminal-mediated headshaking.
In a horse with diffuse prosencephalic signs, hepatic enzyme activities within normal limits, and marked hyperammonaemia, what would be your first hypothesis?
Intestinal encephalopathy
= primary hyperammonemia
Gastrointestinal upset, such as enteritis or colitis, occurs and a shift in intestinal flora results in overproduction of ammonia, potentially due to overgrowth of ** urease-producing bacteria**. This overproduction, frequently coupled **with intestinal inflammation and increased absorption of ammonia, leads to a high level of ammonia in the blood that overwhelms hepatic capacity for metabolism. Ammonia rapidly diffuses into the central nervous system and causes cerebral dysfunction.
In case of intestinal encephalopathy, blood works usually show hypo- or hyperglycemia?
hyper
What are the 3 main causes of hepatic encephalopathy in horses?
Theiler’s disease (virus)
Pyrrolizidine alkaloid toxicosis
Fall panicum hepatotoxicosis
DDx spinal cord
Degenerative: EDM/NAD
Neoplasia: melanoma
Inflammatory: EHV-1 myelopathy, equine protozoal myeloencephalitis (EPM), discospondylitis, WNV, (rabies)
Traumatic: cervical vertebrae stenotic myelopathy (CVSM), OAA malformation in Arabian, external injury
Vascular: FCEM
What should happen when you tap the skin over the brachiocephalic muscle with a closed tip of the hemostat from the cranial end of the neck to the back of the shoulder?
contraction of the brachiocephalicus and cutaneous colli muscles
Twitching of the facial muscles at the commisures of the lips
Mention the 2 most common spinal cord disease in horses
Cervical vertebral compressive myelomathy (CVCM), neuroaxonal dystrophy (NAD)
What are the genes involved in occipitoatlantoaxial malformation and in which breed?
HOXD3 (AR)
Arabian
Where can we see fractures of the neck most often in foals and adult horses?
Foals: fractures of atlas and axis, especially through the physis of the separate center of ossification of the dens
Adult: vertebral body or arch in the mid-neck region (3-6th vertebrae) or APJs of the more caudal vertebrae (5-7)
What is the unusual clinical sign associated with Parelaphostrongylus tenuis infestation in horses?
Acquired scoliosis due to dorsal gray matter segmental myelitis with reduced sensation over the affected side (convex curve)
leads to** loss of sensory afferent information on the affected side. Normal muscle tone requires sensory information; without it, the muscles become abnormally flaccid. Subsequent imbalance in cervical muscle tone (flaccid on affected side**, normal muscle tone on unaffected side) causes curvature of the neck toward the normal side.
What is the treatment of pasture associated stringhalt?
Spontaneous recovery, Phenytoin
Which mutation cause malignant hyperthermia?
+breed, other mut
RYR1 gene (ryanodine receptor), autosomal dominant.
Halter horses
In other species, description of Ca2+ voltage-gated channel mutation
What is the innervation of the thyrohyoideus muscle in horse?
First cervical (C1) nerve branches
What are the 3 causes of stringhalt?
Unipedal stringhalt: idiopathic, but often history of trauma to the dorsal metatarsus or hock
Pasture-associated stringhalt (PSH): grazing drought-affected, poor-quality pastures that contain the plant Hypochaeris radicata (commonly referred to as catsear, flatweed, and false dandelion); mainly affect mature and taller horses
Idiopathic bilateral stringhalt
What is the presentation and outcome of the 3 forms of stringhalt?
1/ Unipedal stringhalt
Unilateral hyperreflexive gait consistently present at a walk and trot
Function as trail horses and have been successful in jumping competitions; guarded after surgery (lateral digital extensor myotenotomy)
2/ Pasture-associated stringhalt (PSH)
Hyperflexion of both hindlimbs with some degree of asymmetry possible. Clinical signs vary in severity. Up to 20% of horses develop laryngeal hemiplegia.
Most horses recover over 6-18 months (spontaneously, or with phenytoin)
3/ Idiopathic bilateral stringhalt
Bilateral hyperflexion at a walk and trot that is not as extreme as that seen with PSH, and horses will back up and lift a hindleg normally
Which vertebral neoplasia has been reported in several horses of different breeds and ages? What would be your differential diagnoses?
Myeloma
Ddx: vertebral osteomyelitis or other primary metastatic neoplasia such as hemangiosarcoma, osteosarcoma, chrondrosarcoma, undifferentiated sarcoma and malignant melanoma.
Slap test can be detected from which age?
2 weeks
Efferent pathway of thoracolaryngeal reflex:
Contralateral vagal nucleus, vagal nerve, recurrent laryngeal nerve, larynx
Which infectious disease may cause nerve root lesions?
Borrelia burgdorferi
Post-anesthetic myelopathy is a condition of horses that affects primarily grey or white matter
grey
What is the minimal intravertebral ratio on horse?
C3-C6: 52%
C7: 56%
What is the minimal intervertebral ratio on horse?
50%
What change can be seen in C6 in normal horses? In which breeds?
Transposition of one or both ventral processes of C6 onto C5 or C7
Warmblood breeds
In a population of 100 horses, 24% had anomalous C6, with either asymmetric or symmetric absence of the ventral lamina of the transverse process.