Chiari-laadne malformatsioon ja süringomüeelia Cavalier King Charles spanjelitel – maailma kogemused ja pilootuuring Eestis
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Kuupäev
2012
Kättesaadav alates
ainult raamatukogus, only in library
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Chiari-laadne malformatsioon ja süringomüeelia (CM/SM) on progresseeruv konditsioon, mis
koosneb kahest eristatavast, kuid omavahel tihedasti seotud patoloogiast. Antud seisundeid esineb
nii koos kui ka eraldi mitmetel koeratõugudel, kuid Cavalier King Charles spanjelitel (CKCS) on
märgatud eelmainitud sündroomi ebatavaliselt kõrget esinemissagedust. Chiari-laadne
malformatsioon on iseloomustatav kolju kuklaosa moodustavate luude arenguhäirete ja väikeaju
kaudoventraalse osa sopistumisega läbi suure kuklamulgu selgrookanalisse. Süringomüeelia korral
on iseloomulikeks muutusteks seljaaju tsentraalkanali laienemine ja/või iseseisvate vedelikuga
täidetud õõnsuste ehk süürinksite tekkimine seljaaju kudede vahele. Peamiseks sümptomiks
CM/SM korral on valu, kuid võib esineda ka teisi neuroloogilisi nähtusid. Sündroomi täpne
tekkemehhanism on veel välja selgitamata, kuid tõendid näivad viitavat, et CM on SM
väljakujunemisel oluliseks põhjuslikuks teguriks. Samasugust tendentsi on täheldatud ka
humaanuuringutes, kus on selgunud, et CM on sagedasim SM väljakujunemise põhjus inimestel.
Uuringud on nii inimestel kui loomadel näidanud CM/SM puhul tugevat pärilikku tausta, mistõttu
võib oletada, et probleem on suure tõenäosusega geneetiliselt edasi kanduv.
2011. aasta kevadest alates on Eesti Maaülikooli väikeloomakliinikus võimalik kasutada
veterinaarseteks menetlusteks mõeldud magnetresonantstomograafi (MRT), samal ajal alustati
kohaliku CKCS populatsiooni uurimist CM/SM esinemise suhtes. Pilootuuringusse kaasati 14
CKCS tõugu koera, kellele teostati Eesti Maaülikooli väikeloomakliikus ajavahemikul 07.03.2011 –
01.11.2011 MRT uuring pea- ja kaelapiirkonnast.
Võimalikke CM/SM sündroomiga seonduvaid kliinilisi sümptomeid kirjeldasid omanikud kolmel
koeral. Chiari-laadse malformatsiooni esinemine tuvastati kõikidel uurimuses osalenud koertel,
seega on vastava muutuse esinemine uuritaval populatsioonil 100%. Süringomüeelia diagnoositi
ühel koeral (7,1% uuritud populatsioonist), samas kergemad muutused seljaaju struktuuris
(tsentraalkanali laienemine) olid täheldatavad veel üheksal koeral (64,3% uuritud koertest).
Lisaks tuvastati uuritavatel koertel lateraalsete ajuvatsakeste ebasümmetriat ja ulatuslikumat
ajuvedelikuga täitumist, samuti primaarsele sekretoorsele keskkõrvapõletikule viitavaid muutusi
trummipõiendites.
Pilootuuringus osalenud koerte arv ei ole kindlasti piisav tegemaks üheseid ja kaugeleulatuvaid
järeldusi CM/SM sündroomi levimuse kohta Eesti CKCS populatsioonis. Sellest hoolimata on
tõestatud antud probleemi esinemine Eestis elavatel koertel, mistõttu peaksid kohalikud kasvatajad
ja omanikud sellele tähelepanu pöörama.
Käesoleva uurimistöö laiemaks eesmärgiks on anda nii CKCS omanikele kui loomaarstidele parem
emakeelne ülevaade CM/CM sündroomi olemusest ja tähtsusest antud tõul. Käsitletud aspektid
võiksid kasvatajatele/omanikele ja neid nõustavatele veterinaaridele mõtteainet pakkuda,
motiveerides tulevikus rohkemaid omanikke oma koeri CM/SM suhtes uurima.
Chiari-like malformation and syringomyelia (CM/SM) is a progressive condition comprised of two distinguishable, but closely related pathologies. Those conditions can either together or separately affect several dog breeds, but an unusually high prevalence has been noted in Cavalier King Charles Spaniels (CKCS). Chiari-like malformation is characterised by developmental defects of bones forming the occipital part of the cranium and by cerebellar herniation through the foramen magnum into the vertebral canal. Characteristic changes in case of SM include dilatation of spinal central canal and/or development of independent fluidfilled cavities or syrinxes between tissues of spinal cord. The main symptom of CM/SM is pain, but other neurological symptoms may occur. The exact mechanism underlying the development of the syndrome is still unclear, but available evidence seems to point to CM being a critical causative factor in the development of SM. Similar tendency has been noted in human studies, where CM has appeared to be the most prevalent cause of developing SM. Both human and animal studies have demonstrated a significant background of heritability in case of CM/SM, which makes genetic transmission extremely likely. Since spring of 2011, a magnet resonance imaging (MRI) device intended for veterinary diagnostics has been in use in the Small Animal Clinic of Estonian University of Life Sciences. The study of prevalence of CM/SM in Estonian CKCS population was begun at the same time. 14 CKCS breed dogs were included in the pilot study and underwent a MRI scan of head and neck region in the Small Animal Clinic of Estonian University of Life Sciences between 07.03.2011 and 01.11.2011. Clinical symptoms possibly related to CM/SM syndrome were described in three dogs by the owners. Chiari-like malformation was identified in all dogs in the study, which makes the prevalence of this condition 100% in the study population. SM was diagnosed in one dog (7,1% of study population), whereas more minor changes in spinal cord structure (slight dilatation of central canal) could be perceived in nine additional dogs (64,3% of imaged dogs). Additionally, dyssymmetry and excessive filling with fluid of lateral ventricles and also changes indicative of primary secretory middle ear inflammation in tympanic bullae were observed in several dogs in the study. The number of dogs included in the pilot study is undoubtedly insufficient to make singular and far-reaching conclusions regarding the prevalence of CM/SM syndrome in the Estonian population of CKCS, but the incidence of the problem in Estonian dogs is proven regardless, underlining the need for local breeders and owners of CKCS breed dogs to pay attention to the problem. This study also carries the wider purpose of giving the veterinarians and CKCS owners a better native-language overview of the essence of CM/SM syndrome and its importance in regards of the health of CKCS breed based on up-to-date information. The aspects covered could provide new fodder for thought for both breeders/owners and veterinarians advising them and possibly motivate more owners to have their dogs investigated for CM/SM.
Chiari-like malformation and syringomyelia (CM/SM) is a progressive condition comprised of two distinguishable, but closely related pathologies. Those conditions can either together or separately affect several dog breeds, but an unusually high prevalence has been noted in Cavalier King Charles Spaniels (CKCS). Chiari-like malformation is characterised by developmental defects of bones forming the occipital part of the cranium and by cerebellar herniation through the foramen magnum into the vertebral canal. Characteristic changes in case of SM include dilatation of spinal central canal and/or development of independent fluidfilled cavities or syrinxes between tissues of spinal cord. The main symptom of CM/SM is pain, but other neurological symptoms may occur. The exact mechanism underlying the development of the syndrome is still unclear, but available evidence seems to point to CM being a critical causative factor in the development of SM. Similar tendency has been noted in human studies, where CM has appeared to be the most prevalent cause of developing SM. Both human and animal studies have demonstrated a significant background of heritability in case of CM/SM, which makes genetic transmission extremely likely. Since spring of 2011, a magnet resonance imaging (MRI) device intended for veterinary diagnostics has been in use in the Small Animal Clinic of Estonian University of Life Sciences. The study of prevalence of CM/SM in Estonian CKCS population was begun at the same time. 14 CKCS breed dogs were included in the pilot study and underwent a MRI scan of head and neck region in the Small Animal Clinic of Estonian University of Life Sciences between 07.03.2011 and 01.11.2011. Clinical symptoms possibly related to CM/SM syndrome were described in three dogs by the owners. Chiari-like malformation was identified in all dogs in the study, which makes the prevalence of this condition 100% in the study population. SM was diagnosed in one dog (7,1% of study population), whereas more minor changes in spinal cord structure (slight dilatation of central canal) could be perceived in nine additional dogs (64,3% of imaged dogs). Additionally, dyssymmetry and excessive filling with fluid of lateral ventricles and also changes indicative of primary secretory middle ear inflammation in tympanic bullae were observed in several dogs in the study. The number of dogs included in the pilot study is undoubtedly insufficient to make singular and far-reaching conclusions regarding the prevalence of CM/SM syndrome in the Estonian population of CKCS, but the incidence of the problem in Estonian dogs is proven regardless, underlining the need for local breeders and owners of CKCS breed dogs to pay attention to the problem. This study also carries the wider purpose of giving the veterinarians and CKCS owners a better native-language overview of the essence of CM/SM syndrome and its importance in regards of the health of CKCS breed based on up-to-date information. The aspects covered could provide new fodder for thought for both breeders/owners and veterinarians advising them and possibly motivate more owners to have their dogs investigated for CM/SM.
Kirjeldus
Märksõnad
Cavalier King Charles spanjel, Chiari-laadne malformatsioon, neuroloogiline valu, magnetresonantstomograafia, oksipitaalne malformatsioonisündroom, süringomüeelia, magistritööd