Dougherty Part 10 Flashcards
Limb Girdle Muscular Dystrophy presents where
proximal muscles affected:
shoulder to humerus
thigh
what is seen Limb Girdle Muscular Dystrophy
begin to walk with a waddling gait because of weak hip and leg muscles
trouble getting out of chair or climbing stairs
weakness in shoulder
Limb Girdle Muscular Dystrophy is typically related to what
dystrophyn glycoprotein complex
Facioscapulohumeral Muscular Dystrophy presents where
face
pecks
biceps
Facioscapulohumeral MD presents how
facial weakness
wasting of the upper arms and shoulder muscles
the scapular bones look like wings when the arms are raised
Emery-Dreifuss Muscular Dystrophy presents with what triad
early on humeropperoneal weakness (proximal in the upper limbs and distal in the lower limbs)
prominent contractures, especially elbows and ankles
cardiomyopathy
what muscular dystrophy do you see cardiomyopathy
Emery Dreifuss Muscular Dystrophy
what muscular dystrophy do you see a waddling gait
limb girdle muscular dystrophy
what muscular dystrophy do you see the scapular bones popping out like wings when arms are raised
Facioscapulohumeral MD
what issue can be elicited by percussion of the thenar eminence
myotonic dystophy
what is seen in myotonic dystrophy
facial muscle atrophy and ptosis
myotonia (sustained involuntary contration)- stiffness, difficulty releasing grip
abnormal gait and weak foot dorsiflexion
weakness of intrinsic hand and wrist extension
what is the issue in myotonic dystrophy
AD
Dystrophila myotonia-protien kinase (DMPK)
CTG repeat expansion on 19q
what is anticipation and when is it seen
onset at a younger age in succeeding generations
myotonic dystrophy
hypotonic channelopathies are due to what
potassium:
hypokalemic periodic paralysis
hyperkalemic periodic paralysis
normokalemic periodic paralysis
malignant hyperpyrexia aka malignant hyperthermia is due to what
Calcium channel
Ryanodine Receptor RyR1 (RYR1 gene)
what is seen in malignant hyperpyrexia and what triggers it
sudden hyper metabolic state with tachypnea and general muscle contraction
triggered by anesthesia (halogen containing gases or succinylcholine)
how do you treat malignant hyperthermia
dantrolene
what are the underlying processes occurring in malignant hyperpyresia
lactic acidosis (anaerobic metabolism) rhabdomyolysis hyperkalemia renal failure hyperthermia
congenital myopathies may present as what
“floppy baby” (hypotonia)
arthrogryposis- congenital fixation of a join in an extended or flexed position
a central light center (hole) in an area of type 1 fibers histologically is seen in what
central core disease
central core disease is what and due to what
hypotonia
AD- ryanodine receptor-1 (RYR1) gene defect
central core disease proposes a risk for what
malignant hyperthermia
Nemaline Myopathy presents how
nonprogressive hypotonia, weakness
delayed development in kids
involves proximal limb muscles
what is seen histologically in Nemaline Myopathy
subsarcolemmal spindle-shaped particles from Z-band (alpha-actin) material
look like purple deposits in blue cells (trichrome stain)
Centronuclear (myotubular) myopathy is characterized by what
central nuclei usually confine to type 1 fibers
what is seen in lipid myopathies
lipids accumulare in myocytes
RED DOTS in the cells on lipid stain
lipid myopathies are due to what
defects in carnitine transport
defects in mitochondrial dehydrogenase enzyme system
ragged red fibers are seen in what
mitochondrial myopathies
mitochondrial myopathies are also known as what and is due to what
“oxidative phosphorylation diseases”
defect may be mtDNA or nuclear DNA
what is seen histologically in mitochondrial myopathies aka oxidative phosphorylation diseases
ragged red fibers from aggregated mitochondria
mitochondria “parking lot” paracrystalline inclusions
Dermatomyositis presents how
lilac or heliotrope discoloration of upper eyelids with periorbital edema
scaling erythematous eruption or dusky red patches over knuckles, elbows, knees (Grotten lesions)
muscle weakness +/- myalgias (slow and symmetrical)
what are grotten lesions and when are they seen
seen in dermatomyositis
scaling erythematous eruption or dusky red patches over knuckles, elbows, knees
dermatomyositis is associated with what
up to 25% have caner (paraneoplastic w/ breast and lung) juvenile DM (in addition GI involved causing abdominal pain)
dermatomyositis is due to what
microvasculature being attacked by antibodies and compliment creating ischemia
what is seen on bone X-rays of people with dermatomyositis
calcinosis
what cells mediate Dermatomyositis
CD4 T-cells
B cells
what is seen in dermatomyositis due to microvascular attack
inflammation of perimysial connective tissue NOT muscle
telangiectasias in nail folds, eyelids, and gums
perifasicular atrophy- atrophy prominent at periphery of fascicles
what is polymyositis
systemic inflammatory myopathy
cytotoxic CD8+ T cells in endomysium destroy muscle
what is seen in polymyositis
muscle weakness +/- myalgias (EARLY PROXIMAL muscles, late distal muscles)
autoantibodies against tRNA synthetases
+/- ANA positive
Inclusion Body myositis is seen what patients and presents how
over 50 years old
EARLY DISTAL muscles (loss of quads)
+/- amyloid deposits
inflammation centered on myocytes
what cells mediate inclusion body myositis
CD8+ cytotoxic T cells
what are the intracellular deposits seen in inclusion body myositis
beta-amyloid protein
beta-pleated sheet fibrils
hyperphosphorylated tau protein
what myositis starts with proximal muscles and which one starts distal
polymyositis and dermatomyositis begin proximally
inclusion body myositis begins distally
