Title: Canine Chiari-like malformation

{{Short description|Disease in dogs}}'''Chiari-like malformation''' ('''CM''') the most common cause of [[foramen magnum]] obstruction and [[syringomyelia]] in dogs. Syringomyelia (SM) is a disease of the [[spinal cord]] typified by fluid filled cavities, or [[Syrinx (medicine)|syrinxes]], within the spinal cord substance but it can cause pain by disrupting the [[cerebrospinal fluid]] (CSF), in the brain&lt;ref name=&quot;part1&quot;&gt;{{Cite web |last=Rusbridge |first=Clare |date=10 November 2024 |title=Chiari-like Malformation and Syringomyelia – Veterinary Neurologist |url=http://veterinary-neurologist.co.uk/chiari-like-malformation-and-syringomyelia/ |archive-url= |archive-date= |website=NeuroVet.co.uk |publisher=}}&lt;/ref&gt;&lt;ref&gt;{{Cite journal |last=Rusbridge |first=Clare |date=June 5, 2020 |title=New considerations about Chiari-like malformation, syringomyelia and their management |url=https://onlinelibrary.wiley.com/doi/abs/10.1136/inp.m1869 |journal=In Practice |publisher=John Wiley &amp; Sons, Incorporated for the British Veterinary Association |volume=42 |issue=5 |pages=252–267 |doi=10.1136/inp.m1869 |issn=2042-7689|doi-access=free }}&lt;/ref&gt; CM is a condition characterized by the mismatch of size between the brain and the skull.&lt;ref&gt;{{cite journal | vauthors = Knowler SP, Cross C, Griffiths S, McFadyen AK, Jovanovik J, Tauro A, Kibar Z, Driver CJ, La Ragione RM, Rusbridge C | title = Use of Morphometric Mapping to Characterise Symptomatic Chiari-Like Malformation, Secondary Syringomyelia and Associated Brachycephaly in the Cavalier King Charles Spaniel | journal = PLOS ONE | volume = 12 | issue = 1 | article-number = e0170315 | date = 2017-01-25 | pmid = 28122014 | pmc = 5266281 | doi = 10.1371/journal.pone.0170315 | bibcode = 2017PLoSO..1270315K | doi-access = free }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Knowler SP, Galea GL, Rusbridge C | title = Morphogenesis of Canine Chiari Malformation and Secondary Syringomyelia: Disorders of Cerebrospinal Fluid Circulation | language = English | journal = Frontiers in Veterinary Science | volume = 5 | page = 171 | date = 2018 | pmid = 30101146 | pmc = 6074093 | doi = 10.3389/fvets.2018.00171 | doi-access = free }}&lt;/ref&gt; CM is very widespread in many Toy breed dogs and has been studied in the [[Cavalier King Charles Spaniel]] and the [[Griffon Bruxellois]] (Brussels Griffon) and Chihuahua.&lt;ref&gt;{{cite journal | vauthors = Knowler SP, Kiviranta AM, McFadyen AK, Jokinen TS, La Ragione RM, Rusbridge C | title = Craniometric Analysis of the Hindbrain and Craniocervical Junction of Chihuahua, Affenpinscher and Cavalier King Charles Spaniel Dogs With and Without Syringomyelia Secondary to Chiari-Like Malformation | journal = PLOS ONE | volume = 12 | issue = 1 | article-number = e0169898 | date = 2017-01-25 | pmid = 28121988 | pmc = 5266279 | doi = 10.1371/journal.pone.0169898 | bibcode = 2017PLoSO..1269898K | doi-access = free }}&lt;/ref&gt; As many as 95% of Cavalier King Charles Spaniels may have CM.&lt;ref name=&quot;Loughin 2016&quot;&gt;{{cite journal | vauthors = Loughin CA | title = Chiari-like Malformation | journal = The Veterinary Clinics of North America. Small Animal Practice | volume = 46 | issue = 2 | pages = 231–42 | date = March 2016 | pmid = 26631589 | doi = 10.1016/j.cvsm.2015.10.002 }}&lt;/ref&gt; It is worldwide in scope and not limited to any country, breeding line, or kennel, and experts report that it is believed to be inherited &lt;ref&gt;{{cite journal | vauthors = Lemay P, Knowler SP, Bouasker S, Nédélec Y, Platt S, Freeman C, Child G, Barreiro LB, Rouleau GA, Rusbridge C, Kibar Z | title = Quantitative trait loci (QTL) study identifies novel genomic regions associated to Chiari-like malformation in Griffon Bruxellois dogs | journal = PLOS ONE | volume = 9 | issue = 4 | article-number = e89816 | date = 2014-04-16 | pmid = 24740420 | pmc = 3989173 | doi = 10.1371/journal.pone.0089816 | bibcode = 2014PLoSO...989816L | doi-access = free }}&lt;/ref&gt; CM is so widespread in the Cavalier that it may be an inherent part of the CKCS's breed standard.&lt;ref&gt;{{Cite web |title=Canine Chiari Malformation (CM) &amp; Syringomyelia (SM) and the Cavalier King Charles Spaniel |url=https://www.cavalierhealth.org/syringomyelia.htm#IN_DEPTH: |url-status=live |access-date=2025-11-12 |website=www.cavalierhealth.org}}&lt;/ref&gt;

This disease not only affects thousands of dogs, but a similar [[Arnold–Chiari malformation|condition]] affects over three-hundred-thousand children yearly.&lt;ref name=&quot;nyvf&quot;&gt;{{cite web |url=http://www.nyvf.org/index.php/research/current-studies/chiari-screening |title=Chiari-Like Malformation in Dogs Non-invasive Screening Tests |website=www.nyvf.org |archive-url=https://web.archive.org/web/20101012205316/http://nyvf.org/index.php/research/current-studies/chiari-screening |archive-date=2010-10-12}} &lt;/ref&gt; Therefore, canines are an appropriate model for the treatment of the human condition.&lt;ref name=&quot;nyvf&quot; /&gt;

==Symptoms==
Clinical signs for CM include behavioural signs of pain vocalization, head scratching/rubbing, reduced activity, reduced stairs/jumping ability, spinal pain, altered emotional state (behavioural change to more timid, anxious or aggressive), sleep disturbance and touch aversion.&lt;ref name=&quot;Clinical Application of Diagnostic&quot;&gt;{{cite journal | vauthors = Rusbridge C, Stringer F, Knowler SP | title = Clinical Application of Diagnostic Imaging of Chiari-Like Malformation and Syringomyelia | language = English | journal = Frontiers in Veterinary Science | volume = 5 | page = 280 | date = 2018 | pmid = 30547039 | pmc = 6279941 | doi = 10.3389/fvets.2018.00280 | doi-access = free }}&lt;/ref&gt; Common symptoms in human patients include, severe headache and neck pain, dizziness, vertigo, disequilibrium, visual disturbances, ringing in the ears, difficulty swallowing, palpitations, sleep apnea, muscle weakness, impaired fine motor skills, chronic fatigue and painful tingling of the hands and feet, and pruritus.&lt;ref&gt;{{Cite web |title=Chiarians Unite – Chiari Malformation |url=http://www.chiariansunite.org/chiarimalformation.htm#342894460 |archive-url=https://web.archive.org/web/20091121162048/http://www.chiariansunite.org/chiarimalformation.htm#342894460 |archive-date=2009-11-21 |access-date=2011-04-14}}&lt;/ref&gt;

==Diagnosis==
Diagnosis of CM alone is challenging and identified by anatomical characteristics and ruling out other disorders.&lt;ref name=&quot;Clinical Application of Diagnostic&quot;/&gt; Whole spine [[Magnetic resonance imaging|Magnetic Resonance Imaging]] (MRI) may be used to evaluate the extent of syrinx formation (fluid filled cavity within the spinal cord) in CM dogs, developing a thermal camera-based screening test for the disorder and a method of measuring the actual syrinx volume from MR images.&lt;ref name=&quot;T120210&quot;/&gt;

Before the introduction of MRI, the diagnosis of CM and SM were commonly confused with that of allergic skin disorders, [[disk disease]], ear infections and [[epilepsy]].&lt;ref name=&quot;what-is&quot;&gt;{{Cite web |title=Diagnosis |url=http://www.caninechiariinstitute.org/patient-center/what-is-chiari/diagnosis |archive-url=https://web.archive.org/web/20110708051140/http://caninechiariinstitute.org/patient-center/what-is-chiari/diagnosis |archive-date=2011-07-08 |access-date=2011-05-04 |website=CanineChiariInstitute.org |publisher=The Canine Chiari Institute}}&lt;/ref&gt; After CM was reported in human patients, the initial research was provided for the diagnosis of animals.&lt;ref name=&quot;what-is&quot;/&gt; MRI in animals is safe, however, to ensure that the patient remains motionless, light general anesthesia is required.&lt;ref name=&quot;what-is&quot;/&gt;

According to recent studies, [[thermography]] may be a useful tool in the diagnosis of CM and SM.&lt;ref&gt;{{cite journal | vauthors = Infernuso T, Loughin CA, Marino DJ, Umbaugh SE, Solt PS | title = Thermal imaging of normal and cranial cruciate ligament-deficient stifles in dogs | journal = Veterinary Surgery | volume = 39 | issue = 4 | pages = 410–7 | date = June 2010 | pmid = 20459492 | doi = 10.1111/j.1532-950X.2010.00677.x }}&lt;/ref&gt;{{Failed verification|date=August 2017}} [[Thermographic camera|Thermography]] requires no sedation or clipping of hair for a dog to be imaged by the infrared camera. After the image is captured, computer software is used to assess changes in the temperature and color pattern to detect abnormality.&lt;ref name=&quot;what-is&quot;/&gt;

==Treatment==
The type of treatment needed for dogs diagnosed with CM/SM depends on the severity of the condition and the age of the dog. Young dogs with clinical signs should be considered for surgical removal to minimize the progression of the disease as the dog ages. Older dogs with little or no clinical signs may be treated medically, rather than surgically. However, severe cases of CM/SM may require surgery regardless of age. The goal of surgery is syrinx decompression through restoration of normal cerebrospinal fluid circulation.&lt;ref name=&quot;what-is&quot;/&gt;

The surgical treatment of CM in dogs is described as &quot;foramen magnum decompression FMD&quot;.&lt;ref name=&quot;T120210&quot;&gt;{{Cite web |title=Contact Support |url=http://www.todaylongisland.com/CHIARI_ebook_120210.pdf |url-status=dead}}&lt;/ref&gt; Despite an approximately 80% success rate with this surgical technique, there is a 25% to 50% relapse, primarily due to excessive scar tissue formation at the decompression site.&lt;ref name=&quot;T120210&quot;/&gt; A cranioplasty may be performed instead, in which a plate, constructed using titanium mesh and bone cement, is fixed to the back of the skull following a standard FMD procedure. The procedure had been effective in humans. The postoperative relapse rate associated with the titanium cranioplasty procedure is less than 7%.&lt;ref name=&quot;T120210&quot;/&gt;
==History==
The name &quot;Chiari-like&quot; derives from one of the early scientists who diagnosed a similar structural [[Arnold–Chiari malformation|condition]] in children, Dr. [[Hans Chiari]].

== References ==
{{Reflist}}

[[Category:Dog diseases|Chiari-like malformation]]