Kapitel 27 - Neurodiagnostics Flashcards
Where are the cell bodies of motoneurons located?
They are located within the central nervous system, either in the cranial nerve nuclei of the brainstem or in the ventral horns of gray matter in the spinal cord.
List the three components of a motor unit
a. Motoneuron
b. Neuromuscular junction
c. Myofibers innervated by the motoneurons
What are the four classifications of neuromuscular disease?
a. Neuropathies (can be central or peripheral) – disorders of the neurons cell body, axons and/or Schwann cells (myelin)
b. Junctionopathies (pre-, synaptic och post synaptic) – disorders of neuromuscular junctions
c. Myopathies – disorders of muscle fibers
d. Neuromyopathies – disorders of both neurons and muscle fibers.
What are the minimum database specific for neuromuscular disease?
a. Serum creatinie kinase
b. Serum electrolytes
c. Blood lactate
d. Urine test for myoglobinuria
e. Thyroid hormone screening
f. Serum assay for acetylcholine receptor antibody
What are the gold standard in diagnosing myasthenia gravis?
Acetylchonline Receptor antibodies
What two tests are specific for neuromuscular pathies?
Electrodiagnostic testing and muscle/nerve biopsy
What are the 4 types of normal spontaneous activity?
a. Insertional Activity
b. Miniature end-plate potentials
c. End-plate spikes
d. Motor unit action potentials
What are the 3 types of abnormal activity
a. Fibs (fibrillation) and sharps (positive sharp waves)
b. Complex repetitive discharge
c. Myotonic potentials
When can you see prolonged and decreased insertional activity
a. Prolonged: Can be the only abnormal finding early in the course of neuromuscular disease
b. Decreased: In muscles with end stage disease
What are Complex repetitive discharge most commonly associated with?
Chronic denervation
What are Myotonic potentials characteristic of?
Myotonia congentia
Which nerves are routinely recorded for sensory nerve conduction velocity?
Fibular, ulnar and radial nerve.
Explain M-wave, F-wave and H-reflex
a. M-wave: A type of compound action potential and are result of orthodromic (impulse that run in its normal direction) action potentials along a nerve, acetylcholine release and myofiber depolarization
b.F-wave: represent a long-latency muscle action potential after supramaximal antidromic motor nerve activation
c. H-reflex: Represent an electrically elicted stretch reflex.
What are the two basic procedures for muscle biopsies?
a. Precutaneous needle (punch) biopsy
b. Open surgical biopsy procedure
What nerve is easy and a good choice for biopsy when generalized neuromuscular disease is suspected?
The common fibular nerve
