SA Med - Neuro - Neuro Dz 2

drraythe's version from 2017-10-02 05:03

Botulism, tick paralysis, more lower mm neuro Dzs...

Question Answer
Pathophys of botulism?Ingestion of Clostridium botulinum’s preformed toxin (w/ C. tetani its usually an Infxn w/ the organism). & it ***Blocks ACh release (presynaptic)
CSs of botulism?Ascending diffuse lower motor neuron Dz, Including some cranial nerve deficits (so all floppy & useless - opposite of tetanus which is all spastic bc that toxin inhibits an inhibitory NT, whereas botulism is stopping the release of excitatory NT)
How do you Dx botulism?Rule out other czs of diffuse lower motor neuron Dz. Electrodiagnostics. There are no lesions on necropsy.
How do you Tx botulism? Prog?Only supportive care-- might need ventilator. Prog: guarded.
What are the 3 types of ticks implied in tick paralysis?Dermacentor variabilis & D. andersoni, Ixodes holocyclus
Explain the pathophys of tick paralysis, explain what situation allows tick paralysis to happenToxin is from the gravid female tick. Has to be on the dog for 5-9 days (really engorged). However, the exact MOA is unknown. They think it might interfere w/ ACh release, or interfere w/ propagation of an action potential
What are the CSs of tick paralysis?Rapidly ascending diffuse lower motor neuron signs: Hypo- to areflexia, difficulty breathing
Dx of tick paralysisFind a tick (lol), Rule out other diffuse lower motor neuron Dz (botulism, coonhound paralysis aka polyradiculoneuritis, maybe very bad MG.)
Tx & PTx of tick paralysis?Tx: REMOVE THE TICK (yay simple), prog is EXCELLENT, if the tick can be found & wholly removed
Coonhound paralysis is aka?Acute Idiopathic Polyradiculoneuritis
What does the word Polyradiculoneuritis mean?Inflammation/Dz of spinal ventral nerve roots (& some peripheral nerves i think).
Pathophys of Acute Idiopathic Polyradiculoneuritis (coonhound paralysis)Probably autoimmune? Antigen: raccoon saliva? Vaccine-related?
CSs of Acute Idiopathic Polyradiculoneuritis (coonhound paralysis)?Acutely ascending diffuse lower motor neuron signs... Including respiration (dyspnea) :( Sensorium unaffected (bc ventral nerve roots do motor, dorsal do sensory), SO Can wag tail & urinate/defecate normally
2 ways you can try to Dx Acute Idiopathic Polyradiculoneuritis (coonhound paralysis)?Electrodiagnostics, Cerebrospinal fluid may have elevated protein
Tx & prog of coonhound paralysis?Tx: LONG-TERM intensive supportive care & physical therapy. May require ventilatory support. However, good prog.
Chronic Relapsing Polyneuropathy: Who gets this?Older dogs & cats.
Chronic relapsing polyneuropathy: what is this a Dz of? How does it present? How can you help it/prog?Ascending lower motor neuron paresis, & can have proprioceptive abnormalities. There is an Insidious (proceeding in a gradual, subtle way, but w/ harmful effects) onset. May respond to steroids. Tends to improve but can relapse-- guarded prog
Trigeminal Neuritis- how does this happen? What is this Dz?Idiopathic, it is inflammation of trigeminal nerve (V).
What are the CSs of trigeminal neuritis? Tx?Acute onset of the inability to close the mouth (dropped jaw), Spontaneous remission w/in 2-3 weeks :)!
Tx: Assist in feeding/drinking (might need a gruel), Physical therapy for the jaw (Open & close the mouth x 5 minutes, 3 times per day)
Infectious Neuropathies are czd by what 2 infectious agents? What problem do they cz, in WHO, & what are the CSs?Toxoplasma & neospora. You will see Polyradiculoneuritis, esp in puppies, which will present as Pelvic limb extension/joint contracture
Brachial plexus avulsion- where does it avulse? What are the CSs from this?Severe abduction of the thoracic limb will cz Avulsion at the level of the nerve roots, leading to CSs like: Lower motor neuron atrophy, reflexes+/- Horner’s syndrome (sympathetic nerve damage of ca portion)
Tx & PTx of brachial plexus avulsion?Tx: Physical therapy, time (May require limb amputation). Prog varies.
Tail avulsion in cats might lead to what problem?Incontinence
Injxn trauma- often occurs at the sciatic nerve. How does this look?Can cz Needle puncture, hematoma, drug/product toxicity, or scarring... in younger animal will see less mm mass

Peripheral Nerve Injury, Metabolic Neuropathies, toxic neuropathies, Dysautonomia, Neoplastic Neuropathies

Question Answer
What is Neurapraxia? Prog?Bruising or stretching of nerve-- but nerve will be ok. There will be Transient lack of nerve function but Little or no structural damage to the nerve-- there is Good prognosis for return of function
What is Axonotmesis? Prog?Damage to the axon but connective tissue support remains-- Axons can regrow along the basal lamina/connective tissue scaffold. Guarded to good prognosis for return to function
What is Neurotmesis? Prog?Completely transected nerve :( No ability to regrow. Grave prognosis for return to function.
How can you differentiate Neurapraxia, Axonotmesis, & Neurotmesis?These all look the same (at first) clinically. It takes about 1 week for lower motor neuron atrophy (& associated electrodiagnostic abnormalities) to reveal itself (in class she said: so give them plenty of time-- a week to see how bad it is. 3-6mo to see how much they will recover. )
Who gets DM related metabolic neuropathy more cats or dogs?Cats
Explain pathophys of diabetes related metabolic neuropathy?Pathophysiology unclear (several hypotheses): Microvascular Dz vs. metabolic aberrations vs. immunologic attack of myelin
CSs of DM related metabolic neuropathy?Paraparesis
Plantigrade stance
Lower motor neuron reflexes & atrophy
Tx & PTx of DM related metabolic neuropathy?Tx: Tx the ‘beetus
PTx: Function may or may not return when good diabetes control is achieved
Hypothyroidism czs a metabolic neuropathy but there is Unknown pathophysiology. Association btwn hypothyroidism & polyneuropathy is suspected but is difficult to prove... however you can see what problems/Dzs w/ this Dz?Laryngeal paralysis,
Facial nerve paresis/paralysis
Peripheral vestibular syndrome
Lower motor neuron reflexes & paresis/paralysis
Delayed organophosphate toxicity: who gets this? What is the pathophys? CSs? Dx & Tx?Happens in CATS, due to Chronic exposure, unknown pathophysiology. You will see Paraparesis w/ decreased postural Rxns (Lower motor neuron reflexes). Dx based on signalment, Hx, & cholinesterase activity
TX= 2PAM (aka Pralidoxime (2-pyridine aldoxime methyl chloride,) )
What chemotherapy might cz a toxic neuropathy? How does it present & how to you Tx?Vincristine! Not common tho. You will see Paraparesis w/ decreased postural Rxns, Lower motor neuron reflexes. Resolves w/ drug withdrawal
What is the geographic distribution of Dysautonomia?Kansas, Missouri
What is the signalment like for cats & dogs w/ dysautonomia?CATS: Younger
DOGS: Outdoor, rural/farm
CSs of dysautonomia? Prog?Almost any parasympathetic or sympathetic dysfunction (all the things). Prog guarded to grave
2 drugs you can use to Dx dysautonomia?(1) Pilocarpine (you will see miosis if given) (non-selective muscarinic receptor agonist)
(2) Bethanechol (improved ability to urinate) ( parasympathomimetic choline carbamate that selectively stimulates muscarinic receptors w/o any effect on nicotinic receptors. )
Peripheral nerve sheath tumor tend to happen in what 2 locations?Trigeminal nerve (mandibular branch she said in class) & brachial plexus
What are CSs of peripheral nerve sheath tumor?CSs reflect location of Dz! Can see Lower motor neuron reflexes, atrophy. Often very painful if in brachial plexus. May extend into the brainstem or spinal canal (See associated signs of encephalopathy or myelopathy). Horner’s syndrome (brachial plexus location)
Which tumor can cz a Paraneoplastic syndrome of polyneuropathy?Insulinoma - unknown pathophys (kinda opposite of the DM but still czs neuropathy. needless to say, sugar & insulin are important for the nervous system lol)
What are the most common DDx for Diffuse Lower Motor Neuron Dz? (6)(Myasthenia gravis - acute, fulminant)
Tick paralysis
‘Coonhound’ paralysis
Snake envenomation
Chronic organophosphate toxicity

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