Neurology in a nutshell

• Neurological examination

  Smell

  Conscious vision (menace, visual placing)

  Pupilliary light response (direct and indirect)

  Anisocoria - fixating response, Stabismus.

  Skin sensation (jaw tone), palpebral reflex, corneal reflex.

  Facial Muscle symmetry, lacrimal gland function, nasal gland.

  Hearing

  Nystagmus

  Swallowing (gag reflex)

  Laryngeal function (bark), GI function.

  Neck position/ tone. Tongue position and tone.
• What is the testing for spinal nerves?

  Proprioceptive tests:

  • Knuckling
  • Hopping
  • Paper slide
  • Hemiwalking
  • Wheelbarrow
  • Tactile placing
  • Extensor postural thrust.
• What is the forebrain responsible for?

  Behaviour

  Initiation of movement.

  Perception of sensation, including conscious propioception.
• What does forebrain damage lead to?

  Altered behaviour

  Altered mentation - obtundation or dullness

  Seizures

  Altered perception, including central blindness and altered propioception.

  Inability to initiate movement - paresis/paralysis.

  Head turn

  Circling toward the lesion.
• What is the cerebellum for?

  Fine motor control.
• What does cerebellar dysfunction lead to?

  Hypermetric ataxia

  Intention tremor

  Wide based stance

  (Absent menace response)

  (Some vestibular signs, but uncommon).
• What is the brain stem responsible?

  Cranial nerve nuclei (III-XII)

  Long tracts connecting forebrain to spinal cord (all motor and sensory tracts).
• What does brain stem damage lead to?

  Cranial nerve deficits.

  Long tract signs, i.e. proprioceptive deficits, or if more severe paresis.

  (Obtundation)
• What are the clinical signs of vestibular lesions?

  Vestibular signs can be central or peripheral. Affecting the vestibulocochlear organ (peripheral) or the vestibular nuclei in the brain stem (central) or higher connections in the brain (central).

  May show head tilt, circling and nystagmus (and associated asymmetric ataxia and nausea)
• What will happen if the LMN is damaged?

  Paresis/paralysis.

  Reduced tone or flaccid

  Reduced or absent segmental reflexes.
• What will happen if the UMN is damaged?

  Paresis/paralysis

  Retained or increased tone.

  Retained or increased segmental reflexes.
• Transection of the spinal cord

  Spinal cord transection leads to catastrophic damage. There is currently no possibility for restoration of function with a hopeless prognosis.

  Transection is usually a sequalae to vertebral fracture or luxation.

  
• Spinal cord compression

  Compression of the spinal cord will lead to a degree of dysfunction dependant upon the degree of compression.

  The larger fibres will be damaged more easily, so propioception is lost first and is last to recover following removal of compression.

  Compression of the spinal cord does not necessarily result in irreparable damage, if compression is removed then full function can be acheived. The length of time and severity of compression affect the outcome but the prognosis can be good.

  
• Spinal cord concussion

  Concussive injury to the spinal cord is akin to bruising of the spinal cord. It may lead to local dysfunction of axons and cell bodies at the site of concussion. As with bruising it may get worse over a period of hours after the initial insult to the spinal cord, but will in many cases subside over a period of days to week.

  They will present as sudden onset, with some initial deterioration.

  Very severe cases may progress to ascending myelomalacia, but this is uncommon.

  
• Focal ischaemic lesions of the spinal cord

  Focal ischaemia is seen with FCE, where there is direct emobilisation of arteries within the spinal cord. Presents as sudden onset focal dysfunction.

  There is no Treatment but in many cases there will be good resolution with conservative therapy.

  
• Global ischaemia of the spinal cord

  Is seen with iliac thrombosis. Basically the whole rear end of the animal is ischaemic. Very common in cats, rare in dogs.

  Should be obvious on the clinical examination: pain, pulse less, pale, pare tic hind legs.

  Usually secondary to cardiovascular disease in the cat (Cushing’s or kidney disease in dogs), investigate and treat the cardiovascular disease and prognosis dependant upon that.

  
• Atrophy and degeneration of the spinal cord

  Any long term insult to the spinal cord can result in death or axons or cell bodies. This will present as atrophy (shrinkage of the spinal cord) and progressive spinal cord dysfunction. If the underlying pathology is removed then neurological status may be stable and progressively deteriorate.

  There are some degenerative conditions that will result in primary neuronal death presenting with progressive spinal cord dysfunction.

  
• What is the presentation of intervertebral disc disease extrusion

  Intervertebral disc extrusion is very common in dogs, It can manifest in a wide spectrum of clinical signs from pain to paralysis, and can occur as single episodes or multiple recurrent episodes.

  It is predisposed in the Chondrodystrophic breeds and can affect either the thoracolumbar or cervical spinal cord.
• How to diagnose intervertebral disc disease extrusion?

  Diagnosis can only be made with advanced imaging, ideally MRI. Of the nucleus pulposus has undergone calcification prior to extrusion then CT can be used for diagnosis. Radiography may show evidence for disc degeneration, but will not give an accurate diagnosis.

  Prognosis for recovery of ambulation is generally good. If there is tetra/paraplegia with loss of deep pain sensation in the limbs then the prognosis is poor.
• What are the treatment guidelines for intervertebral disc disease extrusion?

  If there is an acute onset non-ambulatory tetra/paraplegia then referral for advanced imaging and consideration of decompressive surgery should be considered.

  If the clinical signs are progressive then referral for advanced imaging and consideration of decompressive surgery should be considered.

  If there is spinal pain alone then conservative management can be considered in the first instance.

  If financial concerns limit referral then conservative management can be considered in the first instance.
• What does conservative management consist of for intervertebral disc disease extrusion?

  Cage rest

  Analgesia (as needed)

  Bladder management

  Good nursing - including motivational therapy.

  Physiotherapy
• What is the presentation of protruding intervertebral disc disease?

  Intervertebral disc protrusion is very common in dogs and tends to be progressive presentation in older dogs which is associated with inter verbal disc degeneration. It produces clinical signs predominantly by compression of the spinal cord or associated nerve roots. This can occur in the thoracolumbar, cervical or lumbosacral region.
• How do you diagnose protruding intervertebral disc disease?

  Diagnosis can only be made with advanced imaging, ideally MRI. Radiography may show evidence for disc degeneration, but will not give an accurate diagnosis.
• How do you treat protruding intervertebral disc disease?

  Treatment is either by conservative management or surgical decompression. IVDD protrusion is rarely presented as an acute emergency but usually a progressive problem. Acute exacerbation of chronic protrusion by excessive movement of the spine can result in a combination of concussive and compressive pathology, this may respond well to conservative management.
• What is Discospondylitis?

  An infectious inflammation within the nucleus pulposus of the disc, i.e. effectively walling off the abscess.
• How does Discospondylitis present?

  It will present as chronic pain, but can occasionally progress to ataxia or some paresis.
• How do you diagnose Discospondylitis?

  Diagnosis can be made by radiography in chronic cases by demonstrating destruction of the vertebral body endplates, this is usually accompanied by secondary spondyloasis. It can occur at multiple sites along the spine or in a single disc. It is commonly seen at the LS junction. Radiography may be normal in early cases and diagnosis may require advanced imaging such as CT to make a diagnosis.
• What is the treatment for Discospondylitis?

  In the UK most cases are bacterial and treatment can be started with broad spectrum antibiotics. In other countries fungal discospondylitis.
• What is Fibrocartilaginous embolisation?

  FCE is a focal embolus of fibrocartilage within the ascending artery of the spinal cord - microscopic embolus within the spinal cord itself. So it will be sudden onset spinal cord dysfunction, usually non-painful but may be uncomfortable for 24 hours with some initial progression.

  Due to the anatomy of the vessels this predominantly affects the centre of the spinal cord and will often, but not always, be unilateral resulting in mono or hemiplegia (IVDD will never be truly unilateral).
• What is the presentation of Degenerative myelopathy?

  DM, previously known as CDRM (chronic degenerative radiculomyelopathy), is common is the German shepherd dog.

  Usually presents as a chronic progressive hindlimb ataxia. Usually occurs at 6-9 years of age, and usually progresses over 9 months to a stage requiring euthansia on grounds of quality of life. It is not a painful condition.
• What is the diagnosis and treatment of degenerative myelopathy?

  Diagnosis is by exclusion (IVDD protrusion) there are no signs yet identified on MRI.

  There is no effective therapy, physiotherapy has been shown to slow the rate of deterioration but not prevent.
• How does caudal cervical spondylomyelopathy (CCSM) present?

  CCSM presents as progressive neurological deficits in the cervical spinal cord, i.e. Proprioceptive ataxia affecting all 4 limbs progressing to tetraparesis/plegia. It can occur at a wide range of ages dependant upon the underlying pathology. CCSM predominantly affects large to giant breeds.

  
• What is the diagnosis and treatment for caudal cervical spondylomyelopathy (CCSM)?

  DAWS (Disc associated Wobbler syndrome) is a dog with some cervical cord compromise from CCSM that subsequently acquires an IVDD protrusion.

  Diagnosis requires advanced imaging and may require dynamic imaging studies.

  Some cases may respond to conservative therapy id there is a concussive injury to the spinal cord, however there are a range of surgical option including decompression, distraction or stabilisation, dependant upon the underlying aetiology.
• Neoplasia in the spinal cord - meningioma

  Tumour of the meninges resulting in compressive pathology to the adjacent spinal cord.
• Neoplasia in the spinal cord - Glioma

  Tumour of the glial cells arising from within the spinal cord and compressing the adjacent spinal cord.
• Neoplasia in the spinal cord -metastatic disease

  Secondary spread to to affect the spinal cord.
• Neoplasia in the spinal cord - tumour of the vertebrae

  Resulting in compressive pathology to the adjacent spinal cord.
• Neoplasia in the spinal cord - nerve root tumour

  Tumour of the nerve root which may extend along the nerve through the intervertebral foramina to compress the spinal cord.
• Neoplasia in the spinal cord - lymphoproliferative neoplasia

  The commonest manifestation in cats, which may be multifocal.
• How do spinal cord neoplasias present?

  Tumours will usually present with progressive neurological dysfunction with a focal presentation. They may be pain-free or associated with pain.