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S. Platt1
1College of Veterinary Medicine- University of Georgia, Small Animal Medicine & Surgery, ATHENS, USA
Case Based Approach to Neck Pain
Simon R. Platt BVM&S MRCVS Dipl. ACVIM (Neurology) Dipl.ECVN
University of Georgia, Athens, GA.
Chiari-like malformation and Syringomyelia (CM/SM):
Chiari-like malformation (CM) and syringomyelia
(SM) often occur together, although both may occur independently of the other. Syringomyelia is a condition characterized by the presence of a  uid  lled cavity (syrinx) or cavities within the parenchyma of the spinal cord. SM is secondary to abnormal cerebrospinal  uid movement and is usually associated with Chiari-like malformation, although it may be associated with other conditions such as congenital malformations, trauma, in ammation, and neoplasia. Chiari-like malformation
is de ned as a decreased caudal fossa volume with herniation of the cerebellum and often brainstem into or through the foramen magnum. In people, this condition is referred to as Chiari malformation, which has several types.
The term syringomyelia is accepted to describe  uid accumulation within the spinal cord, whether it be secondary to central canal dilation (hydromyelia) or secondary to  uid accumulation within the spinal cord parenchyma (syringomyelia or syringhydromyelia). It
is dif cult to determine the location of the  uid using Magnetic Resonance Imaging (MRI) and these cavities often communicate with each other. Syringomyelia frequently occurs with Chiari-like malformation in dogs and the terms Chiari-like malformation and syringomyelia (CM/SM) have been adopted to describe the canine condition.
Onset of signs may be acute or chronic in dogs ranging from 6 months to 10 years of age. The most common sign of CM/SM is pain, predominately isolated to the cervical region, occurring in 35% of affected dogs and 80% of people with the similar condition.
These structural abnormalities are best diagnosed with MRI, but they may be clinically silent; therefore, their signi cance must be carefully considered when such abnormalities are discovered.
Treatment may not be necessary in asymptomatic dogs or dogs with mild non-progressive signs. Dogs exhibiting
pain, more severe neurological de cits, or progressive signs can be treated either medically or surgically. Typically, medical therapy is pursued initially involving the use of analgesics and drugs that reduce CSF formation. Furosemide (1-2 mg/kg orally q12h) and prednisone (0.5-1 mg/kg orally 24h, tapering dose) are frequently used. Treatment of neuropathic pain with drugs such as Gabapentin (10 mg/kg PO q 8 h) is also an important aspect of therapy.
Approximately 70% of patients show some improvement, but it is rarely complete. If medical therapy does not alleviate the clinical signs, surgical decompression of
the foramen magnum has been suggested (suboccipital craniectomy) and is the treatment of choice in
people. Foramen magnum decompression has been performed in dogs with a success rates reported at about 80%; however, recurrence is common and neuropathic pain may persist requiring continued medical therapy. Additionally, multiple surgeries may be required if scar tissue develops at the surgical site obstructing CSF  ow; although, cranioplasty may reduce the likelihood of this complication. Improvement may not be a result in the reduction of syrinx size, which usually persists.
Steroid Responsive Meningitis-Arteritis
A severe form of steroid responsive meningitis-arteritis (SRMA) has been reported in Beagles, Bernese Mountain Dogs, Boxers, German Short-Haired Pointers, and sporadically in other breeds. This condition has
a worldwide distribution and represents one of the most important in ammatory diseases of the canine CNS. Beagles, especially but not exclusively those in laboratory-bred colonies, appear at risk. In the Beagles, the condition has been termed Beagle pain syndrome, necrotizing vasculitis, polyarteritis, panarteritis, juvenile polyarteritis syndrome, and primary periarteritis. In other breeds, this condition previously appears under the terms necrotizing vasculitis, corticosteroid-responsive meningitis, aseptic suppurative meningitis, and corticosteroid-responsive meningomyelitis.
Affected animals usually are most commonly young adults between 8 and 18 months of age, although the age range may extend from 4 months to 7 years. The clinical course is typically acute with recurrences. Signs include recurring fever, hyperesthesia, cervical rigidity, and anorexia. There may be a creeping gait, arching of the back with head held down, and crouched posture.
The prognosis is guarded to favourable, especially in dogs with acute disease that are treated promptly using immunosuppressive doses of corticosteroids. Untreated dogs tend to have a remitting and relapsing course. Tipold recommends the following long-term therapy (e.g., for at least 6 months), especially in any dog that
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