Exam 3 Flashcards
(141 cards)
What is the pattern of a normal muscle biopsy?
- Mosaic Pattern
- -Fiber types are scattered and not grouped in a particular pattern
What do neurogenic diseases involve?
*Involves nerve cell bodies, axons and/or dendrites involved
What is a needle EMG?
- Denervated muscle is spontaneously active at rest (fibrillation potentials)
- Short duration (<3 ms) and low amplitude (<300 µv), fibrillation potentials occur in semi-rhythmical runs (<30/second).
How does regeneration occur?
*through collateral sprouting
What does neuron atrophy cause?
*Causes muscle atrophy of the same muscle fiber type
What occurs with reinnervated muscle fibers?
- since motor neuron type determines muscle fiber type, re-innervated muscle fibers assume histochemical properties of neuron (change fiber type).
- results in muscle fiber type grouping due to re-innervation (as opposed to the mosaic pattern of normal muscle).
What do myogenic/myopathies involve?
*Involve muscle degeneration
What occurs with a myogenic disease needle EMG?
*Low muscle activity at rest
What would occur in a muscle biopsy of a myogenic disease?
- Muscle fiber atrophy in a random fashion
- all muscle fiber types are affected
- retains the mosaic pattern but fewer overall number and size of all types of muscle fibers
What are examples of Neurogenic diseases?
- Compression of nerve roots or peripheral nerves (PTP 565 – Fundamentals class)
- Bell’s Palsy*
- Diabetic polyneuropathy*
- Alcoholic polyneuropathy
- Polio and post-polio syndrome
- Amyotrophic lateral sclerosis (ALS)*
- Guillian-Barre syndrome (GB)*
What is an example of a myogenic disease?
*Muscular dystrophy
What are the fibers in a normal muscle biopsy?
*Muscles may have proportionately more fast-glycolytic (FG) muscles fibers as compared to slow, oxidative (SO) secondary to its function
What is Bell’s Palsy
- Lesion of CN VII
- -demyelination in mild cases
- -demyelination and axonal damage in more severe cases
- Innervation to upper face is bilateral
- Innervation to lower face is unilateral (from opposite hemisphere)
How does Bell’s Palsy typically present?
*Presents as flaccid paralysis on the ipsilateral side of the face, affecting the upper and lower quadrants of the face
What is the Etiology of Bell’s Palsy?
- Unknown in most cases
- May be secondary to viral infection causing swelling in auditory canal (remember that CN VII goes through the auditory canal)
- In a small number of cases, secondary to acoustic neuroma impinging on nerve
What are the motor signs of Bell’s Palsy?
- Flaccidity
- –Mouth droops
- -Nasolabial fold is flattened
- -Eyelid does not close
What are the sensory signs of Bell’s Palsy?
*Decreased taste on ipsilateral tongue
What are the ANS signs of Bell’s Palsy?
*Decreased tearing (dry eye)
What is the incidence of Bell’s Palsy?
- 20/100,000 US each year
* Affects 20,000-100,000 people in US per year
What is the onset of Bell’s Palsy?
- Typical onset is overnight
* Onset more common between 20-40 YO
What populations will have a greater risk of getting Bell’s Palsy?
*Diabetics and pregnant women and people with MS
What is the Medical treatment for Bell’s Palsy?
- High-dose corticosteroids for 5 days followed by a tapered dose for another 5 days
- Antiviral medications, e.g. acyclovir
- –Improves outcomes when paired with corticosteroids
- Eye patch, artificial tears (methylcellulose eye drops every 4 hours)
- Gentle massage and gentle heat occasionally used
- PT for muscle retraining only if problems persist
- –E-stim for facial muscles
- 70% of people completely recover within 2-3 weeks (in simple cases) or 3-6 months (in severe cases)
What is diabetic polyneuropathy?
*Affects PNS axons primarily (some de-myelination
What is the etiology of Diabetic polyneuropathy?
*Disrupted microcirculation