Neuromuscular Flashcards
Fibrillation
Abnormal spontaneous activity
- spontaneous depolarization of single muscle fiber; ACTIVE DENERVATION
- REGULAR
- -> neuropathic disease
- ->some myopathies (inflammatory, dystrophies)
- -> Severe NMJ (Botulism)
Positive sharps
Spontaneous depolarization of single muscle fiber
-ACTIVE DENERVATION
Spontaneous Activity: Muscle fiber and multiple muscle fibers
- Fibrillation
- Positive wave
- Myotonia
- Complex repetitive discharges (CRD); multiple muscle fibers
Myotonia
Spontaneous muscle fiber discharge
- waxing/waning amplitude and frequency
- ->myotonic dystrophy
- ->myotonia congenita
- ->paramyotonia congenita
- ->hyperkalemic periodic paralysis
Complex repetitive discharges
spontaneous depolarization of single muscle fiber, followed by ephaptic spread to adjacent denervated fibers AND reactivation of initial pacemaker fiber (loop)
- -> chronic neuropathy
- -> myopathy with denervation (i.e. necrotic, inflammatory)
Spontaneous Activity: Motor neuron/axon
- Fasiculation
- Myokymia
- Tetany
- Cramp
- Neuromyotonia
Fasciculation
- single, spontaneous, involuntary depolarization/discharge of motor unit
- IRREGULAR
- **doublet/triplet/multiplet: MUAPs fire in groups of 2/3/multiple
- characteristic of tetany from hypoCa
Myokymic
rhythmic, grouped, spontaneous dicharges of same motor unit
- -> radiation injury i.e. brachial plexopathy
- -> GBS
- -> MS
Cramp
high frequency, irregular repetitive discharges of several normal MUAPs.
-benign or associated wtih neuropathic, metabolic, endocrinologic conditions
Neuromyotonic
high frequency, decrementing repetitive discharges of single motor unit
- delayed muscle relaxation
- ->autoimmune VGKC channelopathy
- ->chronic neuropathy (i.e. SMA, polio)
- associated with other findings i.e. fascics, myokymia
MUAP morphology-polyphasia
-measure of synchrony of muscle fibers within motor unit
MUAP morphology-satellite potentials
-seen in early reinnervation (by collateral sprouts from adjacent units)
MUAP morphology-Neuropathic
Acute axonal loss: normal morphology, decreased recruitment
- reinnervation doesnt occur for weeks/months
- loss of motor units (decrease recruitment)
- also see this pattern in demyelinating with conduction block
Chronic axonal loss, partial denervation: large, polyphasic, inc duration and amplitude (reinnervation of denervated muscle fibers occurs via collateral sprouting by adjacent axons–> MUAPs inc duration, inc amplitude
Chronic Axonal loss with complete denervation:
small, polyphasic, small amp, short duration, polyphasic, DECREASED recruitment
-reinnervation occurs via axonal growth (no surviving axons to sprout)
MUAP-myopathic
Acute: short duration, small amplitude, polyphasic, EARLY recruitment
- fewer muscle fibres per motor unit
- polyphasia due to dyssynchronsous firing of muscle fibers
Chronic: small amplitude, LARGE polyphasic units (look up why)