Block 2 Flashcards
Trigeminal Motor Nucleus in the rostral pons, the origin of the branchial motor fibers of CN V3, which innervate the muscles of mastication
Solitary nucleus in the rostral medulla; the origin of the special (visceral) sensory fibers of CN VII (gustatory), which innervate the anterior 2/3 of the tongue.
Facial motor nucleus, origin of the branchial motor (special visceral) fibers of CN VII that innervate all the muscles of facial expression, stapedius m., stylohyoid m., and posterior belly of the digastric m.
Cochlear nucleus (CN 8)
Neuronopathy
pathology of sensory and/or motor neurons
Radiculopathy
pathology of nerve roots
plexopathy
pathology of nerve plexus
neuropathy
pathology of nerves
myopathy
pathology of muscles
polyneuropathy
pathology of multiple nerves
axonopathy
polyneuropathy involving the nerve axon
demyelinating neuropathy
polyneuropathy involving nerve myelin
mononeuropathy
pathology involving single nerve
brain lesion
UMN signs; unilateral and contralateral to lesion
cord lesion
UMN signs: bilateral or unilateral, ipsilateral to lesion
motor neuron lesion
UMN and LMN signs: diffuse and asymmetric, ipsilateral to lesion
peripheral nerve lesion
LMN signs: symmetric, progress distal to proximal, ipsilateral to lesion
NMJ lesion
Reflexes preserved. No atrophy at first. Fatiguable weakness. Proximal to distal distribution.
Muscle lesion
Reflexes preserved. May have muscular atrophy. Weakness is not fatiguable. Proximal to distal distribution.
Sxs of UMN lesion
Weakness, increased reflexes and increased tone (no atrophy or fasciculations
Sxs of LMN lesion
Weakness, atrophy, fasciculations, and decreased reflexes & tone
Lambert-Eaton Myasthenic Syndrome
- Sxs: weakness, esp LE, fatiguability, may improve w/ exercise
- automonic sxs: dry eyes, mouth, decreased sweating, constipation, and erectile dysfunction
- bulbar/respiratory sxs are rare
- Pathophys: Ab targeting Presynaptic voltage-gated Ca ch’s (and inhibition of Ca-dep release of ACh)
- Labs: see **incremental **response and facilitation on EMG
- Assoc. w/ small cell lung carcinoma
- Lambert-Eaton Myasthenic Syndrome
- Tx: 3,4 diaminopyridine or guanidine (increase ACh), AChE inhibitor, plasmaphoresis, or immunosuppression
Acquired myasthenia gravis
- clinical sxs: fatiguable weakness (extraocular, ptosis, bulbar, periph), fatigue, respiratory failure
- Pathophys: auto-ab’s to postsynaptic ACh receptor or MuSK
- Labs: **decremental **responseon EMG
- Associated with thymic hyperplasia, thymomoas, and thymic carcinoma
- Tx: AChE inhibitors (pyridostigime bromide), corticosteroids, IVIg, plasmapheresis, thymectomy
Duchenne’s Muscular Dystrophy
Duchenne’s = Deleted Dystrophin
- Onset in early childhood, pelvic-girdle weakness resulting in waddling gait; problems running/climbing, difficult getting up off floor
- Enlarged calf muscles
- Prognosis: stop walking in adolescence, dilated cardiomyopathy common cause of death
- Pathophys: x-linked frameshift mt in dystrophin, a protein that serves as a structural link between cytoskeleton and ECM in skeletal muscle, localized to **sarcolemma membrane. **
- Tx: steroids
Becker Muscular Dystrophy
A less severe form of Duchenne’s MD; also x-linked mt of dystrophin, but usually non-frameshift insertions
Limb Girdle Muscular Dystrophy 2B
proximal > distal weakness, calf-atrophy, onset in 20’s, recessive mt of chrom 2p13.2,
Emery-Dreifuss Muscular Dystrophy
- classic triad: progressive muscle weakness, jt contractures, and cardiac dz
- inheritance: x-linked (emerin, FHL1), AD/ AR (lamin A/C)
- prognosis: most remain ambulatory, need close cardiac f/u
Fascioscapulohumeral muscular dystrophy
- sxs: facial and shoulder girldle weakness; open eyes/mouth, shoulder sloped anteriorly rotated with **scapular winging **(dbl hump:
- inheritance: AD decrease in # of D4Z4 repeats
- prognosis: 20% wheel-chair bound
Myotonic muscular dystrophy
- AD trinucleotide repeat (CTG) leading to myotonia (onset 5-25 y.o), weakness, and myopathic facies
- prognosis: slowly progressive muscular weakness, cardiac conduction defects
My Tonia, My Testicles (atrophy), My Toupee (frontal balding), My Ticker (arrhythmia)
Dermatomyositis
- an inflammatory myopathy with progressive proximal mu. weakness and classic derm signs of periorbital/nasal crease rash (heliotrope), “shawl sign,” grotton papules (edges of fingers)
- Increased CK, increased risk for CA
- Bx: perimysial inflammation (CD4 T cells) and atrophy
- Tx: steroids long term
Polymyositis
- An inflammatory myopathy with progressive symmetric proximal muscle weakness, dysphasia, increased CK, increased risk for CA
- Pathology: endomysial inflammation (CD8 T cells)
- Tx: steroids
Inclusion body myositis
- Asymmetric weakness: quads, wrist/finger extensors, ankle dorsiflexors
- Progressive over 5-20 yrs
- Usually seen in older males
- Pathology: atrophy/hyperstrophy, inflammation (rimmed vacuole within myofibril)
- Tx: none effective
Statin-associated AI myopathy
- toxic myopathy associated with statin-use
- increased CK, myalgias, most resolve with d/c use
- Ab to HMGCR
- Tx with immunosuppression
Metabolic myopathy
Glycogen or lipid metabolism
clinical presentation: prox. muscle weakness, episodic sxs (often with exercise), rhabdomyolysis, muscle cramps
Mitochondrial myopathies
- clinical sxs: prox. muscle weakness, ext. ophthalmoplegia, seizures, ID, hearing loss
- Mutation in DNA or nuclear-encoded mitochondrial enzyme complex component
- Path: see increased mitochondria on bx “ragged-red fibers” on trichrome
