Neurologic Exam Flashcards
Conditions affecting peripheral nerves result in??
Monoparesis/monoplegia -> partial or complete loss of voluntary motor function
Hyp/anesthesia of dermatones
Monoparesis/plegia with nerve root signs is usually due to??
Stretching or inflammation of nerve roots -eg disc protrusion or pressure from a tumor
What are ‘nerve root signs’?
Lameness from hyperpathia
What is the DDX for nerve root signs
Musculoskeletal disorder
Peripheral nerve condition
Traumatic nerve injuries can result in what three conditions?
Neuropraxia
Axonotmesis
Neurotmesis
What is neuropraxia?
Degeneration of the myelin sheaths but the nerve is intact
What is axonotmesis ?
Degeneration of axons but myelin sheath is intact
What is neurotmesis ?
Complete severed of nerve and degeneration of distal portion and shwaan cell
What are signs of peripheral nerve injuries?
Anesthesia and absence of peripheral reflexes and anesthesia of the skin inervated by the nerve
Knuckling if the carpus indicates?
Radial nerve paralysis
Dropped hock in cats is associated with what disease?
Diabetes mellitus
Glucose binds to protein causing damage to nerves and blood vessels
Dog
HBC non-progressive LMN signs Hypanesthesia Hyporeflexia Hypotonicity Neurogenic muscle atrophy
Peripheral nerve injury
What is the treatment for a peripheral nerve injury?
Glucocorticoids to decrease inflammation
Decompress nerve surgically
Protect- self mutilation
Physio
If no regeneration after 6months- amputate
A brachial plexus avulsion usually results from?
Abduction of the front limb that forces it caudally or cranially
(C6 - T2)
Disruption of nerve roots C8 and T1 leads to denervation of the __________
Extensor and flexors of the elbow andcarpus
Disruption of C6 and C7 will result in denervation of___________
Extensors and flexors of the shoulder
If you have lost the panniculus reflex, what area is damaged?
C8 to T1
-lateral thoracic nerve
Miosis, ptosis, enopthalmos and protrusion of the nicitan membrane are all signs of what? What nerves are damage?
Horners syndrome
T1 ventral nerve roots -> sympathetic ganglion
How can you treat a brachial plexus avulsion ??
Glucocorticoids to decrease inflammation
Protect limb and wait for regeneration. -> 6months
PHYSIO
If no regeneration after 6 months ->amputate
Wha is the prognosis of a brachial plexus avulsion without a deep pain reflex?
Very poor
Where do malignant peripheral nerve sheath tumors most often occur?
Caudal cervical area, associated with brachial plexus
Dog with chronic progressive monoparesis of the forelimb. Has nerve root sign hyperesthesia.
What is the best DDX?
Malignant peripheral nerve sheath tumor
What is the best treatment for a nerve roots/peripheral nerve neoplasia?
Surgical resection -
Results in further loss of function -> requires amputation
What is the prognosis for nerve root/peripheral nerve neoplasia?
High rate of occurrence
Radiation and chemo have limited benefit.
How can you diagnose a nerve sheath tumor?
History- slow progressive monoparesis with nerve root signs
Myelogram -> contrast in epidural space is blocked by tumor (golf T sign)
CT and MRI
Where do fibrocartilaginous emboli originate from?
Nucleus pulposus of intervertebral discs
What type of injury does a fibrocartiaginous emboli cause?
Ischemic myelopathy
Fibrocartilaginous emboli are most common in what dogs?
Large breed gos
Miniature schnauzers
Most 1-7yrs
Large dog
History- sudden onset of paresis in the right forelimb after exercise.
PE- no evidence of pain.
-LMN reflexes -> hyporeflexia
What is your DDX?
Fibrocartilaginous emboli
T/F: fibrocartilaginous emboli are most common at the brachial intumescence in both cats and dogs
False
True for cats
In dogs it is more common in the pelvic intumescence
Large dog
History- sudden onset of paresis in the right forelimb after exercise.
PE- no evidence of pain.
-LMN reflexes -> hyporeflexia
What is your next step in order to diagnose this dog?
Radiographs
Myelography
MRI (esp in non-ambulatory cases)
Myelogram often appears normal in fibrocartilaginous emboli -> diagnosis of exclusion
What is the best treatment of fibrocartilaginous emboli?
Supportive therapy!!
Rest. Clean, turn, PHYSIO
Is a better outcome expected if you see UMN or LMN signs in a case of fibrocartilaginous emboli?
UMN has better prognosis
If your fibrocartilaginous emboli is in the L6-S1 area, what signs would you expect to see?
Normal forelimb
Hindlimb -LMN signs
- hyporeflexia and CP deficits
- No crossed extensor reflex
Bladder -UMN signs
-small tight bladder
What could you do to manage the bladder signs in a dog with a lesion at cranial to S1 ?
UMN bladder
-tight urinary sphincter
A1 antagonists
-phenoxybenzamine -> longhalf life and takes several days to accumulate and take effec
- prazosin -> caution can cause hypotension
- tamsulosin
What could you used to treat bladder signs from a lesion caudal to S1?
LMN bladder
- atonic detrussor muscle and sphincter
Muscarinic agonist
-bethanecol -> detrussor muscle
A1 agonist
-phenopropanolamine -> tighten sphincter
