“Back” Dogs: Examination & Diagnosis

1. “Back” Dogs: Examination & Diagnosis Dan Hicks, DVM, MS, DACVIM (Neurology/Neurosurgery) Veterinary Neurology & Neurosurgical Specialists

2. Clinical Neurology: A 1. Clinical features 2. Anatomic localization 3. Differential diagnosis 4. Plan B

3. Localization • Differential Diagnoses: dependent on where, when (acuity), what (signalment) • Exam tells us where not what!

4. Neuroanatomical Localization Supratentorium Infratentorium C1-C5 L3 S1 T3 Peripheral Nervous system/individual nerve

5. Step 1: UMN or LMN

6. Signs of LMN disease • Paresis/Paralysis – hopping is normal (brisk) if voluntary movement remains • Hypo to atonic • Hypo to areflexic • Neurogenic mm atrophy

7. LMN Gait • Ability to support wt decreased • Short stride (step-distance) • Bunny-hopping • Collapsing • Fine mm tremors (orthostatic tremors) • Not ataxic (not proprioceptive disorder)

8. UMN signs • Paresis: delays in gait generation, hopping is particularly slow • Spasticity: release of antigravity mm from inhibition • Hypereflexia/tonia/crossed extensor: release of inhibition • Basis for decrebrate rigidity (lesion b/n rostral and caudal colliculi

11. Now the What… • Signs explained by focal lesion? • Think “structural” problem – compression or inflammation • Generalized lower motor neuron? • Think botulism, tick paralysis, or Coon hound paralysis

13. “Structural” lesions - Imaging CT MRI

14. Imaging modality? • Radiographs: • Osseous lesions • Fracture/luxations • Diskospondylitis • Osteoproliferation/osteolytic diseases • “In-direct” evaluation • Chest films in older dogs? • Screening for metallic objects

16. Myelography • Invasive • Seizures

17. CT vs MRI: Tips for quick ID • On CT, bone is ALWAYS WHITE • Bone is black or dark on MR • In bone window CT, trabecular pattern of bone is evident • In soft tissue window CT, bone is bright white • In a T1-weighted MRI image, fat is WHITE. CSF is dark • In a T2-weighted image, CSF is WHITE

18. Computed Tomography • Great bone detail • Soft-tissue detail: moderate Normal cord Herniated Disk

20. MRI

22. Identical case presentations: Disk rupture Spinal lymphoma

23. Syringohydromyelia (aka: SM)

24. Fungal Myelitis: Cryptococcus

25. Spondylosis:

26. FCE

27. Hemangioma

28. Reality check… • Age of advanced imaging • Advancement in neurosurgery • Great, but… • $$$$ • Concomitant illness

29. Non-surgical therapy • Consider neurologic score • Less severe signs = higher success rate • 50% improve or recovery without surgery • Warning for deep pain negative

30. Treatment • 1.“Pain and Pee” • pain control speeds healing times, improves efficacy of cage rest and rehab • 2. CAGE REST • Allows injury annulus fibrosus to heal and inflammation to subside • Minimizes additional trauma • Minimizes volume of extruded disk material • Try sedative if pet is anxious • Rehab • Focal spinal injections

31. Cage Rest • Length of cage rest not well studied • Traditionally, 4-6 weeks (time for ligamentous healing) • Shorter times may be just as good • Early controlled movement (rehab) may promote healing

32. Nursing care & Rehab • Prevent bed sores • Monitor of UTI • Home rehab exercises • Most owners enjoy participating in pet’s recovery • Profession rehab

33. Pharmacology PAIN BLADDER • Opioids • NSAIDS • Gabapentin • Amantidine • Focal injections • Prazosin • Phenyoxybenzamine • Diazepam **Bladder expression or catheterization may be needed

34. Steroid controversy • Possible benefits: • Reducing inflammation of injured cord • Altering propagation of inflammatory mediators • Side effects: • GI ulceration • Pneumonia • UTI • Longer hospital stays (Levine, 2007)

35. Steroid controversy • One study: Dogs receiving steroids had lower “quality of life” index scores than those not receiving steroids (Levine 2007) • Currently no scientific evidence supporting use in IVDD • True answer still remains