Peripheral Neuropathies Flashcards
What are some clinical signs of peripheral neuropathy?
Mostly due to dysfunction of the motor nerves
- paresis
- hypotonia
- muscle atrophy
- depressed/ absent segmental spinal reflex
What are some autonomic signs associated with peripheral neuropathy?
- vomiting/ regurgitation
- diarrhea, ileus
- urinary retention, incontinence
- impaired lacrimation/ salivation
- pupillary dysfunction
What are the most useful diagnostics in peripheral neuropaphy?
- electromyograph (EMG)
- motor nerve conduction velocities (MNCV)
- sensory nerve conduction velocities (SNCV)
- muscle biopsy –> gives the specific etiology
What are the usefulness of EMG and MNCV?
together they can
- confirm dysfunction of the neuromuscular system
- differentiate peripheral nerve disease from muscle disease
- distinguish axonal disease for demyelination
What does the F-wave evaluate?
proximal nerve and ventral nerve roots
What does the SNCV evaluate?
sensory nerves an dorsal nerve roots
What are some metabolic disorders causing peripheral neuropathy?
- diabetes mellitus
- hypothyroidism
What are some clinical signs associated with diabetic neuropathy?
- para to tetra paresis
- pelvic limb ataxia
- reduced postural and segmental spinal reflexes
- distal muscle atrophy
- plantigrade stance (esp cats)
- sensory nerve dysfunction
- more of a demyelination disorder
What are some clinical signs associated with hypothyroidism?
- 1 or multiple limb paresis
- facial paresis, vestibular signs, trigeminal nerve dysfunction
- stridor, laryngeal paralysis, megaesophagus
- due to both axonal and demyelination
- CN deficits, megaesophagus and and laryngeal nerve paralysis less likely to improve with treatment
Which cancer has reported paraneoplastic peripheral neuropathy?
insulinoma
- immune-mediated, antigen mimicry
What are some infectious/ inflammatory causes of peripheral neuropathy?
- protozoal polyradiculoneuritis
- acute polyradiculoneuritis
- brachial plexus neuritis
- chronic inflammatory demyelination polyneuropathy
- sensory polyganglioradiculoneuritis
Which organisms are common in protozoal polyradiculoneuritis?
- neospora
- toxoplasma
What are the c/s associated with protozoal polyradiculoneuritis?
- there is predilection for nervous tissues
- can invade peripheral nerves, muscles, and CNS
- paresis 1 or more limbs
- muscle atrophy
- reduced muscle tone
- postural reactions deficits
- reduced/ absent segmental spinal reflexes
How to diagnose protozoal polyradiculoneuritis?
- serology, but watch for patients that were exposed but not necessarily clinical for
- EMG
- PCR
- muscle biopsy
What’s the treatment for protozoal polyradiculoneuritis?
- clindamycin for Toxoplasmosis
- can also be used for neospora, +/- pyrimethamine
- potentiated sulfonamide can also be used for neospora
What’s the clinical sign for acute polyradiculoneuritis?
- aka coonhound paralysis
- acute, rapidly progressive
- severe cases can lead to CN deficits, hypoventilation
- segmental spinal reflexes are reduced to absent
- sensory intact, may be hyperesthetic
ddx: NMJ diseases: tick paralysis, botulism, elapid envenomation, fulminant myasthenia gravis - use EMG to distinguish
What’s the treatment for acute polyradiculoneuritis?
supportive therapy (steroids not beneficial)
patient will spontaneously recover in a few week, but can take up to 6m
What are some c/s of chronic inflammatory demyelinating polyneuropathy?
- insidious, slowly progressive
- start with pelvic limb
- reduced/ absent segmental spinal reflexes
- various degree of paresis,
- exercise intolerance
- muscle atrophy
How is chronic inflammatory demyelinating polyneuropathy diagnosed?
- MNCV
- muscle biopsy
- response to corticosteroids
What are the c/s related to sensory polyganglioradiculoneuritis?
- progressive
- ataxia
- reduced/ absent segmental spinal reflexes and proprioception
- ## muscle tone & mass = normal
How is sensory polyganglioradiculoneuritis diagnosed?
SNCV
nerve biopsy
How is sensory polyganglioradiculoneuritis treated?
immunosuppressive dose of corticosteroids or other immunosuppressants – but has not been successful
What are some common traumatic causes of peripheral neuropathy?
- brachial plexus avulsion
- sciatic nerve injury
- caudal nerves secondary to traction injury of the tail
- femoral nerve dysfunction secondary to iliopsoas muscles in the dog
What are some c/s of traumatic peripheral neuropathy?
- paresis
- diminished/ absent segmental spinal reflexes
- impaired postural reactions
- pain
- impaired sensation
