The painful dog (Proceedings)

The canine patient presented for apparent pain without an obvious cause can be a diagnostic challenge. Thorough examination is an important step in identifying a source of discomfort and determining appropriate diagnostic testing for further evaluation.

Sources to consider include…

     Head/Cervical Pain

     * Cervical vertebral column - e.g. IVD disease, meningitis, A-A instability

          o Brain disease - neoplasia, Chiari-like malformation

          o Middle/inner ear canal - e.g. otitis media/interna

          o Dental disease - e.g. tooth root abscess

          o Esophageal disease - e.g. esophagitis

          o Retropharyngeal disease - e.g. abscess

          o Glandular tissue - e.g. sialoadenitis

          o Temporomandibular joint - e.g. fracture/luxation

          o Muscle - e.g. masticatory myositis

          o Ocular disease - e.g. acute glaucoma (more likely in presence of ocular signs)

     * Thoracic/Abdominal Pain

          o Thoracolumbar vertebral column - e.g. IVD disease, meningitis, discospondylitis

          o Retroperitoneal disease - e.g. ureteral obstruction, pyelonephritis, abscess

          o Abdominal organs - e.g. pancreas, GI tract

          o Aortic thromboembolism (partial)

     * Caudal Body Pain

          o Lumbosacral disease - e.g. IVD protrusion, stenosis

          o Coxofemoral disease

          o Pelvic disorders - e.g. flat bone tumors of the ilium

          o Other orthopedic disease - e.g. iliopsoas, gracillis, semitendinosus muscle injury

          o Prostatic disease - e.g. prostatitis

          o Perineal disease - e.g. perianal fistula, anal gland abscess

     * Poorly Localizable Pain - may be referred from a focal spot or more diffuse or generalized

          o Meningitis ( arteritis/vasculitis)

          o Polyarthritis

          o Discospondylitis

          o Myositis

          o Hypertrophic osteodystrophy

          o Tick borne diseases

          o Behavioral condition?

     * Therapeutic considerations

          o NSAIDs – generally more effective for osteoarthritis vs. pain of neurologic origin

          o Corticosteroids

          o Tramadol – synthetic opioid, generally well tolerated, 1-5mg/kg in dogs, 1-2mg/kg in cats PO up to q6h; should not be used in patients taking serotonin reuptake inhibitors (e.g. fluoxetine) or monoamine oxidase inhibitors (e.g. selegiline)

          o Gabapentin – works to block calcium channels at the level of the CNS, 5-25mg PO TID, dose limiting effect generally sedation

          o Amantidine – oral NMDA receptor antagonist, 3-5mg/kg PO q24h; shown to improve activity level in dogs with osteoarthritis with concurrent NSAID administration

          o Fentanyl dermal patch – short term solution

          o Acupuncture – needles placed in specific locations induce release of neurotransmitters which act to affect sensory input, generally well tolerated

          o Physical rehabilitation

Suggested reading:

Neuropathic Pain, Mathews, KA, Veterinary Clinics of North America: Small Animal Practice, Update on Pain Management, 38(6), 2008