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| − | {{OpenPagesTop}}
| + | aka Wobblers |
| − | Also Known As: '''''Wobblers — Cervical Vertebral Malformation — Cervical Vertebral Stenosis — CVM — Equine Stenotic Myelopathy'''''
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| | ==Introduction== | | ==Introduction== |
| − | '''Cervical vertebral stenotic myelopathy (CVM)''' is an equine disease common in '''Thoroughbred''' horses between the ages of '''6 months to 3 years'''. It is most typically seen in '''rapidly growing colts'''. It is the most common differential diagnosis in equine ataxia cases.
| + | Cervical vertebral stenotic myelopathy is an equine disease common in Thoroughbred horses between the ages of 6 months to 3 years. It is most typically seen in rapid growing colts. |
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| | ==Pathogenesis== | | ==Pathogenesis== |
| − | A '''narrowing''' of the '''vertebral canal''' due to '''malalignment''' or '''maldevelopment of the [[Spinal Column - Anatomy & Physiology|cervical vertebrae]]''' causes '''progressive compression of the spinal cord'''.
| + | Narrowing of the vertebral canal due to malalignment or maldevelopment of the vertebrae, causing progressive compression of the spinal cord. |
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| | There are two types of the disease: | | There are two types of the disease: |
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| − | '''(1) Type 1 CVM — Dynamic'''
| + | (1) CVM Type 1 - Dynamic |
| − | :This form is more common in '''younger''' horses. Spinal cord compression is caused by excessive movement of the vertebrae during '''flexion''' and '''extension''' of the '''neck''' and is therefore '''dynamic''' in nature. Vertebrae '''C3-C5''' are most commonly affected.
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| − | '''(2) Type 2 CVM — Static'''
| + | This form is more common in younger horses. Spinal cord compression is caused by excessive movement of the vertebrae during flexion and extension of the neck. Vertebrae C3-C5 are most commonly affected. |
| − | :This form is more common in '''older''' horses, as a result of '''osseous change''' in the vertebrae. The spinal cord is constantly compressed. Vertebrae '''C5-C7''' are most commonly affected.
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| − | ==Aetiology==
| + | (2) CVM Type 2 - Static |
| − | The disease produces '''[[Osteochondrosis|OCD]]-like lesions''' on the vertebrae, producing an irregular joint surface. '''Nutrition''' is thought to play a part in the development of disease, with excessive '''protein''' and zinc, copper, calcium and phosphorous imbalances indicated as contributing factors. As horses with cervical vertebral malformation appear to be more likely to develop [[Osteochondrosis|OCD]] lesions in other joints there is thought to be a '''heritable''' component.
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| − | ==Clinical Signs==
| + | This form is more common in older horses, as a result of osseous change in the vertebrae. Vertebrae C5-C7 are most commonly affected. |
| − | '''Hind limb ataxia''', '''spasticity''' and '''weakness''' are the main [[Site of Spinal Lesions Determination - Horse|clinical signs]]. The development of these signs are normally '''insidious''' but may come about suddenly following trauma. Ataxia is normally '''bilateral''' and '''symmetrical'''. Forelimbs may also be affected.
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| − | ==Diagnosis== | + | ==Aetiology== |
| − | '''Standing lateral radiographs of the spine are required for diagnosis'''.
| + | The disease produces OCD (osteochondrosis dessicans)- like lesions on the vertebrae, producing an irregular joint surface. Nutrition is thought to play a part in the development of disease, with excessive protein and zinc, copper, calcium and phosphorous imbalances indicated as contributing factors. As horses with Cervical Vertebral Malformation appear to be more likely to develop OCD lesions in other joints there is thought to be a heritable component. |
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| − | '''Subjective''' radiographic signs:
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| − | * Spinal cord mal-alignment
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| − | * [[Degenerative Joint Disease|Osteoarthritis]] of articular processes
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| − | * Caudal epiphyseal flare aka ski-ramping (a triangle of new bone into the spinal canal)
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| − | '''Objective''' radiographic signs:
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| − | * Intravertebral ratio:
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| − | **Minimum saggital diameter of spinal canal divided by the maximum dorsoventral height of the same vertebral body.
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| − | **<50% is significant
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| − | * Intervertebral ratio:
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| − | **"Caudal aspect of the dorsal lamina of the vertebral arch of the more cranial vertebra to the dorsocranial aspect of the body of the more caudal vertebra, OR from the caudal vertebral body of the more cranial vertebra to the cranial dorsal lamina of the vertebral arch of the more caudal vertebra, whichever is smaller"
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| − | **<48% is significant
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| − | If the radiographs are of a high quality, a combination of these signs should be sufficient to make the diagnosis of CVM.
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| − | Abscesses, tumours, synovial cysts, ligamental hypertrophy and trauma may not show signs radiographically despite producing the clinical signs of CVM.
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| − | '''Myelography''' is gold-standard ante-mortem diagnostic procedure to document location of spinal cord compression.
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| − | *Minimal complications encountered when performed with experienced personnel
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| − | *It is generally only indicated in potential '''surgical''' cases but also essential to create a surgical plan.
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| − | *>50% narrowing of dorsal dye column is considered significant
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| − | ==Differential Diagnosis==
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| − | * [[Equine Herpesvirus 1|Equine Herpes Virus 1]] (EHV-1) myeloencephalitis
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| − | * Equine Degenerative Myeloencephalopathy
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| − | * Trauma
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| − | * Migrating [[strongyles]] - rare now due to ivermectin treatment
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| − | * [[Polyneuritis Equi|Polyneuritis equi]]
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| − | * Ryegrass staggers
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| − | * [[Equine Protozoal Myeloencephalitis|Equine Protozoal Myeloencephalitis]] - in some countried or imported horses
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| − | * Neoplasia
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| − | ==Treatment==
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| − | The mainstays of treatment are '''box rest''' (for several months), '''anti-inflammatories''' ([[NSAIDs|NSAIDS]]), and '''dietary adjustment''' for type 1 (to a low protein diet to slow the growth of the horse, allowing the canal growth to 'catch up').
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| − | '''Surgery''' can be performed. This involves ventral stabilisation of the vertebrae using a steel or titanium implant.
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| − | ==Prognosis==
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| − | Horses with a '''grade 1''' ataxia on the [[Body, Spinal Cord and Limb Neurological Examination - Horse#Gait|Mayhew scale]] may retain '''athletic''' function. Conservative treatment in mildly affected horses normally improves clinical signs and surgery may improve the ataxia score by one or two grades on the Mayhew scale.
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| − | {{Learning
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| − | |flashcards = [[Equine Orthopaedics and Rheumatology Q&A 05]]
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| − | }}
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| − | ==References==
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| − | Hahn, C (2006) '''The wobbly horse: differential diagnose''' ''In Practice 2006 28: 8-1''
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| − | RVC staff (2009) '''Nervous System and Special Senses''' RVC Intergrated BVetMed Course, ''Royal Veterinary College''
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| − | May, SA & McIlwraith, CW (1998) '''Equine Orthopaedics and Rheumatology Self-Assessment Colour Review''' ''Manson Publishing Ltd''
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| − | Robinson N.E. & Sprayberry K.A. (2008) '''Current Therapy in Equine Medicine''' ''Saunders''
| + | ==Clinical signs== |
| | + | Hind limb ataxia, spasticity and weakness are the main clinical signs. The development of these signs are normally insiduous |
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| | + | ===Cervicospinal Arthropathy=== |
| | + | * = "'''Wobbler'''" in horses |
| | + | *Usually presents in first two years of life |
| | + | *Mainly in fast growing thouroughbreds |
| | + | *Most common site is C3-C4, can occur anywhere |
| | + | *Abnormal laxity between the vertebrae + cervical vertebral malformation may be evident |
| | + | *[[Musculoskeletal Terminology - Pathology|Osteophyte formation]] at edges of synovial components of joint |
| | + | *Some due to stenosis of neural canal later in life (1-4 years of age) |
| | + | *Clinical signs: |
| | + | **Ataxia - hindlimbs more affected |
| | + | *Presumed cause is rapid growth |
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| − | {{review}}
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| − | {{OpenPages}}
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| | [[Category:Joints - Degenerative Pathology]] | | [[Category:Joints - Degenerative Pathology]] |
| | [[Category:Bones - Developmental Pathology]] | | [[Category:Bones - Developmental Pathology]] |
| − | [[Category:Musculoskeletal Diseases - Horse]]
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| − | [[Category:Neurological Diseases - Horse]]
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| − | [[Category:Expert Review - Horse]]
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aka Wobblers
Introduction
Cervical vertebral stenotic myelopathy is an equine disease common in Thoroughbred horses between the ages of 6 months to 3 years. It is most typically seen in rapid growing colts.
Pathogenesis
Narrowing of the vertebral canal due to malalignment or maldevelopment of the vertebrae, causing progressive compression of the spinal cord.
There are two types of the disease:
(1) CVM Type 1 - Dynamic
This form is more common in younger horses. Spinal cord compression is caused by excessive movement of the vertebrae during flexion and extension of the neck. Vertebrae C3-C5 are most commonly affected.
(2) CVM Type 2 - Static
This form is more common in older horses, as a result of osseous change in the vertebrae. Vertebrae C5-C7 are most commonly affected.
Aetiology
The disease produces OCD (osteochondrosis dessicans)- like lesions on the vertebrae, producing an irregular joint surface. Nutrition is thought to play a part in the development of disease, with excessive protein and zinc, copper, calcium and phosphorous imbalances indicated as contributing factors. As horses with Cervical Vertebral Malformation appear to be more likely to develop OCD lesions in other joints there is thought to be a heritable component.
Clinical signs
Hind limb ataxia, spasticity and weakness are the main clinical signs. The development of these signs are normally insiduous
Cervicospinal Arthropathy
- = "Wobbler" in horses
- Usually presents in first two years of life
- Mainly in fast growing thouroughbreds
- Most common site is C3-C4, can occur anywhere
- Abnormal laxity between the vertebrae + cervical vertebral malformation may be evident
- Osteophyte formation at edges of synovial components of joint
- Some due to stenosis of neural canal later in life (1-4 years of age)
- Clinical signs:
- Ataxia - hindlimbs more affected
- Presumed cause is rapid growth