Treatment options

 Clare Rusbridge has outlined a range of treatment options in her document Syringomyelia Made Simple, which has since been replaced by her newest version, Canine Chiari-like Malformation and Syringomyelia. However, the list below is a useful, simple introduction and more detailed information can be found in the more current document. Some vets, neurologists and SM cavalier owners also use and recommend a range of holistic and complementary therapies, ranging from acupuncture for pain to herbal treatments.
Below are the latest treatment recommendations from her revised information document (released 8 Sept 2005, provided with permission).
Also, Clare Rusbridge has produced a new treatment diagram which is appended below and can also be downloaded (with her permission) as a pdf file here.
Medical management

Long-term studies of medical management of syringomyelia are not available yet. The drugs used to treat syringomyelia can be divided into 3 types:
1. •analgesics
2. •drugs which reduce CSF production
3. •corticosteroids
Pain in mild cases may be controlled by non steroidal anti-inflammatory drugs (NSAIDs) e.g. Rimadyl and Metacam.  In more severe cases anticonvulsants, which have a neuromodulatory effect on hyperexcitable damaged nervous system, may be useful, for example gabapentin (Neurontin Pfizer; these are not licenced for dogs). Oral opioids, e.g. pethidine or methadone are also an alternative.
Drugs which reduce CSF production
Proton pump inhibitors such as omeprazole (Losec or Prilosec) can inhibit cerebrospinal fluid formation and therefore may be valuable; clinical data on their use and effectiveness for SM is currently lacking. This drug is unlikely to be useful in the long term as therapy longer than 8 weeks duration is not recommended as this may increase the risk for stomach cancer. Carbonic anhydrase inhibitors such as acetazolamide (Diamox; Lederle laboratories) also decrease CSF flow and may also be helpful in treating syringomyelia although adverse effects of abdominal pain, lethargy and weakness may limit long term use). Furosemide also decreases intracranial pressure and therefore could be useful in the treatment of syringomyelia.
Corticosteroids are very effective in reducing both pain and neurological deficits although the exact mechanism is not known. It has been suggested that these drugs reduce CSF pressure however laboratory evidence of this is lacking. They possibly have a direct effect on pain mediators such as substance P. Although corticosteroids may be effective in limiting the signs and progression, most dogs require continuous therapy and subsequently develop the concomitant side effects of immunosuppression, weight gain and skin changes. If there is no alternative then the lowest possible dose that can control signs is used. Alternate day therapy is preferred.

Here is similar but more detailed information from Canine Chiari-like Malformation and Syringomyelia:

There are three main drugs used for treatment of CM/SM: drugs that reduce CSF production; analgesics; and corticosteroids (Fig 3). If the dog’s history suggests postural pain or discomfort relating to obstruction of CSF flow then a trial of a drug which reducing CSF pressure, e.g. furosemide, cimetidine or omeprazole, is appropriate. This can also be very useful if it is difficult to determine if the cause of discomfort is CM versus, for example, ear disease. CSF pressure reducing drugs may be sufficient to control signs in some dogs, but additional analgesics are likely to be necessary for an individual with a wide syrinx. In this circumstance we suggest that non steroidal anti-inflammatory drugs are the medication of first choice partly because there are several licensed products. However, for dogs with signs of neuropathic pain, i.e. allodynia and scratching behaviour (suspected dysesthesia); a drug which is active in the spinal cord dorsal horn is more likely to be effective. Because gabapentin has established use in veterinary medicine we suggest that this is the drug of first choice but amitriptyline or pregabalin may also be suitable. Corticosteroids are an option if pain persists or where available finances prohibit the use of other drugs. Because the mechanisms of development of neuropathic pain are multifactorial, appropriate polypharmacy is likely to be more effective than treatment with single agents. Anecdotally, acupuncture and ultrasonic treatments have been reported to be useful adjunctive therapy in some cases.

Treatment diagram
Dr Rusbridge has prepared this diagram of treatment options, which gives drug choices, recommended dosages, trial periods, and options if a form of treatment is not effective.
You can download a PDF file of this diagram by clicking here.