MNP - cranial nerves Flashcards
The aspect of caudal digastricus muscle is associated with the outcome in facial paralysis: true or false?
True
Muscle atrophy (89%), hyperintensity in T2W (89%), and pre-contrast T1W (79%) images, as well as contrast enhancement of the affected muscle (74%) and affected facial nerve (47%).
There was no statistically significant correlation between atrophy or enhancement of the affected caudal portion of the digastric muscle nor between enhancement of the affected facial nerve and outcome.
Hyperintensity both in T2W images and precontrast T1W images was significantly correlated with a worse prognosis
In dogs with idiopathic, oculomotor neuropathy, what statement IS false?
- Approximately half of all animals improved over time
- Improvement concerned only external ophthalmoparesis
- Improvement was noted both for external and internal ophthalmoparesis
- The majority of cases presented nerve enlargement in MRI
3
DDx dropped jaw
Idiopathic trigeminal neuritis (most common)
Trauma
Rabies
Lymphoma
Neospora caninum
Rickettsial vasculitis
Hypothyroid neuropathy
Idiopathic polyneuritis
DDx trismus
Masticatory muscle myositis
Polymyositis
Extraocular myositis
Muscular dystrophy
Tetanus
Temporomandibular joint luxation
Craniomandibular osteopathy
Retrobulbar abscess
Foreign body
DDx laryngeal paralysis
Degenerative: GOLPP
Anomalous: genetic, polyneuropathy complex
Metabolic: hypothyroidism, hypoadrenocorticism, toxic (Pb, organophosphorus)
Neoplastic: thymoma, lymphoma, thyroid carcinoma
Inflammatory: polymyositis, myasthenia, polyneuritis
Traumatic: surgery (ventral slot), wound
What are the clinical features associated with trigeminal nerve tumor?
Enlarged trigeminal nerves with marked homogeneous contrast enhancement and a mass effect on the brainstem or outside the cranial cavity along the nerve.
Unilateral clinical (also the case for neuritis)
Sensory impairment (also the case for neuritis)
Ipsilateral noninfectious middle ear effusion (only neoplasia, 33%)
Significantly older than dogs with neuritis and ITN.
Contrast enhancement of cranial nerves VII and/or VIII on MRI was associated with a decreased chance of resolution of the clinical signs: true or false?
True
Which ocular abnormalities can we see in optic nerve hypoplasia? Which breed has been associated with this condition?
Lack of neurons in ganglionic layer of the retina and atrophy of the optic nerve, possible retinal dysplasia or retinal detachment -> blind, mydriatic and absent direct PLRs.
Miniature poodle
Which 2 breeds have potentially an inherited form of megaoesophagus?
Miniature schnauzer
Wire-haired fox terrier
How does hyperchylomicronemia in cats result in neuropathy affecting cranial nerves?
deficiency in lipoprotein lipase causes granulomatous masses of lipid and coagulated blood (xanthomas) -> xanthomas in nerve roots and peripheral nerves cause compressive neuropathy with loss of axons and myelin
What is the proportion of hypothyroid dogs among those with acquired laryngeal paralysis?
30%
Toxic causes of megaeosophagous in small animals
lead, organophosphates, snake venom
breeds with congenital megaesophagus
Newfoundland
Parson Russel Terrier
Samoyed
Spinger Spaniel
Smooth Fox Terrier
Sharpei
Siamese
+ GS2 Swedish lapland
+ Laryngeal paral-polyneuropathy in Dalmatian, Leonberg (1-9y), Pyraneam montain dog, Rottweiler (2-6m)
+ demyelinating polyneuropathy in miniat Schnauzer
Breed with aquired form of megaoesophagus <2y
Newfoundland (other breeds 7-15y)
causes of aquired megaoesophagus
idiopathic
43% myathenia gravis
38%, polymyositis
14%, musc dystrophy,
dysautonomia,
storage disease,
hypoadrenocort, hypothyroidism
gastroint (esophagitis, oesophageal obstruction, hiatal hernia, volvulus, pyloric dysfunction in cat)
toxic: lead, organophosphorus, snake venom
% dogs with generalised myasthenia gravis with megaoeso
90%
treatment megaoeso + prognosis indic
DOG: Betanechol, Sildenafil
CAT: cisapride
+sucralfate, anticids
prognosis indic: response to therapy within 7-10d
diagnostic with unilateral mast muscle atrophy
50% trigem nerve sheet tumor
other extraaxial mass 20%
idiopathic 30%
origin of nerve sheat tumor
schwann cells or perineural fibroblast
effect radiotherapy trigem nerve sheat
improve clinical signs, no effect m atrophy/survival time
muscle aspect associated with worse prognosis in idiopath facial neuritis
caudal port digastricus: T2/pre contraste T1 hyper correlated with worse prognosis
inner ear MRI abnomalies in idiopath vestib and median/internal otitis
idiopath vestib: utricule atrophy in T2, contrast enhanc CN VIII/VII, lack suppression inner ear
median/internal otitis: decrease FLAIR suppression
risk factor idiopath vestib compared to others affections in dog/cat
higher age, higher bodyweight,
pathol nystagmus, facial nerve paresis, periferal neuroloc
cat: non purebreed, without history otitis ext
localiasation associated with peripheral vestib
29% periferal lesion
33% meningoencephalit or intracran mass
on central 14% perif lesion
prognosis facial and vestib neuropathy
complete resolution 30%
40% vestib deficit
46% hemifacial contract, 15% facial paral
15% relapse
muscles controling auditory tube
tensor tympani/veli palatini : trigeminal
levator veli palatini/ salphingopharyngeus: vagus
origin of nerve sheat tumors
Schwann cells or perineural fibroblast
more fqt affected nerve : trigeminal
can vestibular idiopath syndrome associated with horner in dog/cat ?
no
risk factor associated with idiopath vest syndrome in dog/cat
dog and cat: improve, not associated with Horner
dog: higher age, higher bodyweight, pathol nystagmus, facial nerve paresis, periferal neuroloc
cat: non purebred, without histoty of otitis ext
% long term deficit/relapse with facial and vestib neuropathy of unknow origin
40% long term deficit (hemifacial contracture 50%)
15% relapse
risk fact aspiration pneumonia after unilat aryt lateralisation
megaoesophagus
opioids
no effect metoclopramide, preexisting asp
18-30% aspi pneumonia betwwen 1-5y
congenital laryngeal paralysis in Alaskan Huskies:
associated with other nerve dysfunction ?
characteristics of most affected dogs
mononeuropathy
blues eyes, white facial marking, oral mucosal tag or tissue band
onset 6m, 40% spontaneous improvement
bacterial cult of larynx of dogs with laryngeal paral maj pure/ mixed colony
maj pure
vestibular peripheral syndrome:
1. % facial paralysis
2. recurrence rate
3. risk factor associated with idiopath
4. factor associated with resolution
- 60%
- 15%
- Increasing age, higher bodyweight, imrpoving signs, nystagmus, facial nerve paresis, absence Horner, periferal local
- higher resol: history of previous vestibular episodes
lower resol: contrast enhancement of cranial nerves VII and/or VIII on MRI
% of idiopath vestibular in dogs with idiopath facial paralysis
70%
facial and vestibulocochlear nerves enter the petrous part of the temporal bone through the internal acoustic meatus and are enclosed in a common dural sheath and have the same blood supply
fact associated with median otitis in vest synd
young
male
horner
history periph otitis
fact associated with ischemic infarct in vest synd
old
peracute
no strabism
central local
CSF vestib disease
MUO lympho
idiopath/ischem: activated macrophages or normal
sensib TNCC for central/perif diff 50/90%, TP 60/40%
cat vestibular syndrome: risk factor for each cause
neoplasia: old, chronic, central local
thiamine: female, waxin/waning, bilat, wide excursion head
idiopath: non purebreed, improvement
polype: Horner
