Neuromuscular Jxn and Myopathy Flashcards
Baclofen
GABA B Receptor agonist
Anterior horn cells
Stimulated by Glutamate
Inhibited by GABA and Glycine
Glutamate is broken into GABA
By enzyme:
Glutamate Decorboxylase (GAD)
GAD65 Ab blocks this enzyme in stiff person syndrome
Tetanus
Blocks the release of presynaptic GABA and Glycine
NeuroMyotonia
Voltage gated K+ channel antibodies
Myokymia is charachteristic
(another pathognomonic Myokymia was XRT induced Plexopathy)
Pre-Synaptic Toxins
Magnesium/Mg: Blocks Ca++ Channels
Botulinum: Blocks Ach release
Lathrotoxin (Black Widow): Excessive release of Ach
Tick Paralysis: Blocks Ach realease
Scorpion Venoum: Causes Ach release
B-Bungarotoxin (Snake Venoum): Inhibits Ach release
Post Synaptic Toxins
Curare: Binds nicotinic Ach receptors
Organophosphatase Poisoning
inhibts acetylchilnestrase so there is too much Ach
Leading cause of death:
Bronchospasm and Bronchorrhea
DUMBELLSS:
Diarrhea, Urination, Miosis, Bradycardia, Bronchospasm, Emesis, Lacrimation, Lethargy, Salivation, Seizure
AntiCholinergic symptoms
Usually Drug side effect
(Reduced Ach)
Antihistamines, antipsychotics, antidepressants, antiparkinsonian drugs, Atropin, Benztropin, Scopolamine
Blurry vision, Hallucination/Delirum, Mydriasis, Ileus, Urinary retention, Flushing, Hyperthermia
Blind as a Bat, Mad as a Hatter, Red as a Beet, Hot as a Hade, Dry as a bone
Meds Absolutely Contraindicated in MG
D-Penicillamine
Curare
Botulinum Toxin
Interferon-alpha
Neomycine and Quinine are contraindicated.
Myopathies with Normal CK
Steroid Myopathy
Hyperthyroid Myopathy
Mitochondrial Myopathy
Chanelopathies
Myopathies with Markedly elevated CK
Dystrophionopathies
Myoshi distal myopathy
Rhabdo, malignant hyperthermia and NMS
Polymyositis
X-Linked Myopathies
Men only
Gower’s Maneuver when standing (may show video or pic)
Duchenne’s: Dystrophin is completely absent. Very severe disease. Death by late teens to 20 y.o
Becker’s: Dystrophin very reduced. Death by 30-60’s
Emery-Dreifuss: Emerin Deficiency. Joint contractures; mostly arms and shoulder. Elbow contracture is pathognomonic for ABPN.
Autosomal Dominant Muscular Dystrophies.
FSHD: face and winged scapula. Popeye appearance (Deltoid and Bicep spared). Big wide eyes, pouting mouth.
Oculopharyngeal muscular Dystrophy: French Canadian descent. Ptosis and Dysphagia. No other eye symptoms. If Ptosis and Diplopia think MG
Limb Girdle Muscular Dystrophy (LGMD):
LGMD type 1 is AD
LGMD type 2 is AR
Myotonic Dystrophy (DM1) Type 1: CTG repeat. Long face, Temporal wasting, frontal balding, Myotonia (grabs door handles and can’t let go. CARDIAC COMPLCATIONS
Autosomal Recessive MD’s
LGMD type 2: accounts for 60% of Distal Myopathies
MD2: much less common than MD1. Milder and no cardiac complications