Pain Management Case of the Month: Harley

An 8-year-old male neutered Tibetan terrier, 17 kg, was presented to the family veterinarian for lethargy and ataxia for the past two days. Harley had previously seen another vet when his owners were at their cottage, who prescribed meloxicam and gabapentin, unknown dosages. His owner reported that Harley had not had a bowel movement in two days.

Multimodal Pain Management for Acute Episode of Suspected Intervertebral Disc Disease

Signalment and History

An 8-year-old male neutered Tibetan terrier, 17 kg, was presented to the family veterinarian for lethargy and ataxia for the past two days. Harley had previously seen another vet when his owners were at their cottage, who prescribed meloxicam and gabapentin, unknown dosages. His owner reported that Harley had not had a bowel movement in two days.

On neurological examination by the referring veterinarian, Harley displayed proprioceptive ataxia in both hind limbs with moderate proprioceptive deficits. Harley yelped and defecated immediately with palpation at the thoracolumbar junction. The family veterinarian gave Harley a presumptive diagnosis of intervertebral disc disease (IVDD) and injected dexamethasone 0.3 mg/kg SQ and dispensed prednisone 0.6 mg/kg q 24 hours, omeprazole 1.18 mg/kg q 24 hours, misoprostol 0.003 mg/kg q 6–8 hours for seven days, and gabapentin 12 mg/kg q 8 hours. Strict rest and rehabilitation were recommended.

Physical Examination and Diagnostics

Harley was presented to me for rehabilitation and assessment one week later. Harley was being crate rested and carried outside for elimination breaks with mild discomfort when posturing for defecation. His owners noted improvement in pain since his initial injury. Harley was ambulatory on four limbs, displaying moderate bilateral paraparesis and ataxia in the hind end, more severe on the right hind than left.

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His gait was rigid with decreased flexion of hips and stifles, and occasional knuckling of the right hind. Moderate kyphosis of the thoracolumbar spine and moderate tucking of the pelvic region was noted during ambulation and a stance position. Pain was scored at a 2/4, using the Colorado State acute pain scale, on palpation of T13-L. No pain was elicited elsewhere in the spine and joints of the long bones.

Myofascial pain was scored 1/4 with palpation of both iliopsoas muscles. Nociception was present in all digits bilaterally, and a crossed extensor reflex was not present. Conscious proprioception reflexes were tested with a dorsal paw placement test and were absent on right hind and moderately delayed in the left hind.

Moderate muscle atrophy was noted in both hind limbs. Harley continued to receive all medications as prescribed by the referring veterinarian. Crate rest was continued with slow leash walks for elimination. Harley was fitted for a Help’em Up Harness to allow the owner to support Harley’s hind end while ambulating.

Further evaluation by a neurologist was declined, and the risks and safety concerns of rehabilitation of an undiagnosed neurologic condition, long-term prognosis, and treatment limitations were discussed with the owners. The owners understood the risks and consented to a treatment plan tailored to an open diagnosis of IVDD.

Treatment Plan

Harley was enrolled into an in-clinic twice-weekly rehabilitation program consisting of laser therapy, neuromuscular electrical stimulation, and acupuncture/electroacupuncture for the first two weeks. Once Harley showed improvement in pain and ataxia, hydrotherapy and gentle strengthening exercises would be added. Photobiomodulation in the form of low-level laser therapy (class 3b) was provided to Harley (Dosage: 810 nm, 4 x 500 mW, continuous wave). Acupuncture was performed for the suspect area simultaneously with laser therapy. Electrical muscle stimulation (ESTIM) was applied with Harley supported over a peanut stability ball and hind paws placed on a proprioceptive disc, to achieve a standing position.

These parameters were used to promote motor activation, muscle strengthening, and proprioceptive neuromuscular facilitation. Harley responded favorably to ESTIM therapy; the owners noticed larger degrees of flexion of the hind limbs immediately after treatment. Harley was prescribed a home exercise program including manual therapies and proprioceptive training exercises.

Clinical Outcome

The owner reported continued favorable results after two weeks of ESTIM and laser and acupuncture treatments. Harley’s pain was scored 1/4 with palpation of T13-L1, mild proprioceptive ataxia was seen bilaterally in the hind limbs, and conscious proprioception reflexes had improved to mildly delay bilaterally. The owners had also reported Harley’s mentation had greatly improved in the home. Hydrotherapy was initiated in week three and consisted of short intervals of slow-pacedfull-buoyancy walking in the underwater treadmill. Intervals of time and speed were increased gradually as tolerated by Harley. Harley responded favorably to aquatic therapy, showing an increase in strength, endurance, and willingness to go on walks. Acupuncture, laser therapy, and hydrotherapy were continued twice weekly. After four weeks of treatment, Harley was weaned off prednisone and omeprazole as directed by the referring veterinarian with no compromise to pain or mobility. At this point in time, the owners discontinued rehabilitation treatments for financial reasons.

On week five of treatment, the owner thought Harley was doing well, so they reduced the gabapentin dose from 200 mg q 8 hours to 100 mg q 12 hours. In the clinic, Harley was scored at 2/4 pain score with gentle palpation of T13-L1. Moderate tension was palpated in thoracolumbar epaxial muscles bilaterally and frequent muscle spasms of the epaxials were elicited with gentle palpation. Harley vocalized with tail jack manipulation; pain was scored at 3/4. Increase in kyphosis at the thoracolumbar junction at a standing position; there was no change in neurological status.

TENS therapy was reinstated, gabapentin was increased back to 200 mg q 8 hours, and methocarbamol (44 mg/kg divided) was prescribed at 250 mg q 8 hours. Harley responded favorably to the increase of gabapentin and addition of TENS and methocarbamol.

Within seven days, Harley was ambulating with mild hind end ataxia and had a pain score of 0/4 with spinal palpation. Harley continued with once-weekly laser therapy, TENS, and hydrotherapy in-clinic. Harley responded favorably to this treatment protocol for the next 2 weeks, maintaining a pain score of 0/4. Harley was decreased to BID dosing for both gabapentin and methocarbamol for 1 week. Pain was scored 0/4. Gabapentin was discontinued, and then methocarbamol the week after. Harley maintained pain score of 0/4, with mild neurological deficits and kyphotic posture.

Harley was weaned to every-other-week in-clinic treatments, then once monthly for maintenance. Harley continues to attend rehab sessions for laser therapy, TENS, and hydrotherapy, as the owner notices an increase in kyphotic posture as treatment time approaches. Harley has maintained a pain score of 0/4, with all medications discontinued.

Discussion

Extrusion or protrusion of intervertebral disc material results in mechanical compression, neuronal damage, and repetitive firing of the afferent nociceptive pathways, which in turn contributes to ischemia and stimulation of the inflammatory cascade. Abnormal processing of pain pathways within the central and peripheral nervous systems results in the development of neuropathic pain.

IVDD treatment options are commonly neuroprotective and neuroregenerative in nature. Treatment options are commonly specific to reducing inflammation, oxidative stress, excitotoxicity, intracellular calcium accumulation, blood spinal cord barrier disruption, extracellular matrix derangement, and caspase activation. Confinement to one room in the house was recommended for four weeks after the injury in an attempt to promote healing and prevent further injury to the nucleus pulposus and reduce pain and inflammation associated with nerve roots and meninges.

When treating IVDD, it is imperative to treat secondary myofascial trigger points and inflammation in the paraspinal muscles. Laser therapy can significantly shorten the time to functional recovery and avoid the need for surgical intervention. Acupuncture modulates the autonomic nervous system and neuroimmune system as well as aids in hormonal regulation.

Thermotherapy provides analgesia via inhibition of motor neurons, thereby breaking the cyclic pain related to muscle spasms. In this case, thermotherapy was used to promote general relaxation of painful muscles in the spine, and decrease muscle tonicity, preventing secondary muscle compensation and pain during ambulation.

Maintaining a steady state of pain management was challenging with Harley, owing to frequent alterations in pharmaceutical dosage and frequency by the owner. Pain management may have been achieved in less time if pharmaceuticals were given consistently and as prescribed.

Conclusion

This case demonstrates how IVDD episodes may be successfully managed conservatively using a multimodal plan consisting of pharmaceutical and modality-based therapies, as well as proper exercise restrictions. 

Maureen Blaney Flietner
Jenna Cook, BSc(hons), RVT, CCRP, CCMT, CVPP, is a registered veterinary technician, certified canine rehabilitation practitioner, certified canine massage therapist, and certified veterinary pain practitioner in Toronto, Canada. Jenna has a strong passion and love for neurologic rehabilitation, geriatric care, and pain management. Jenna loves spending time outside and hiking with her husband and two dogs, Roxie and Olga.

 

Comments from Mike Petty, DVM, CCRT, CVPP, DAAPM

I think that the most important takeaways from this pain case are 1: that not all cases of IVDD need surgery and, 2: treatment should be considered in a multimodal fashion as was done in this case.

In my own treatment of IVDD cases, I do not insist on cage rest, only restricting the dog from using stairs and running after other pets in the household or wildlife outside. Most rehabilitation practitioners feel that an early return to function can be facilitated by normal day-to-day activities.

Comments on medications: Try as I might, I cannot find a canine study that definitively shows that methocarbamol is helpful in cases of IVDD. My own suspicion is that it causes drowsiness and that is sometimes interpreted as pain relief. The original veterinarian on this case put the dog on three medications I have issue with. The first is prednisone, and it seems that most neurologists are in either the corticosteroid camp or the nonsteroidal anti-inflammatory drug (NSAID) camp when it comes to treating pain and inflammation. I generally defer to the NSAID camp because of the reduced side effects compared with a corticosteroid. The second issue I have is with omeprazole. A recent study article in the American Veterinary Medical Association has shown that giving omeprazole with a corticosteroid actually increases the likelihood of a gastric ulcer. And finally I also have an issue with misoprostol, which, while it is excellent at stopping gastric ulcers, can also cause spontaneous abortions if the owner handling the drug is pregnant; in my mind, not worth the risk.

Mike Petty
Michael C. Petty, DVM, CCRT, CVPP, DAAPM, is in private practice in Canton, Michigan. He is a frequent national and international lecturer on topics related to pain management. Petty offers commentary on each Pain Case of the Month (and occasionally writes one himself). He was also a member of the task force for the 2015 AAHA/AAFP Pain Management Guidelines for Dogs and Cats.

 

Photo credits: Photo courtesy of Jenna Cook

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