anterior horn cell, NMJ, and muscle disorders Flashcards
What are the clinical features of ALS?
1) progressive weakness and wasting 2) spasticity and hyperreflexia 3) initially clinical symptoms may be limited to asymmetric limb weakness and fasciculations 4) foot drop or hand deformity 5) pathologic reflexes (Hoffman, crossed adductor, Babinski) 6) sensory exam is normal 7) speech may be slurred or spastic 8) may have cognitive defects
What are the clinical features of CMT?
There are 3 phenotypes based on age of onset 1) most common. distal weakness and sensory loss develop slowly in the first 2 decades of life. 2) patients are already impaired as infants and experience delayed walking. often leads to confinement to wheelchair 3) adult onset.
What are the clinical features of DN (diabetic neuropathies)?
1) most commonly a distal sensory or sensorimotor polyneuropathy. 2) numbness and burning dysesthesias in their feet which over time spreads up the legs and eventually into the hands. 3) weakness of foot dorsiflexor muscles results in a slapping foot drop gait 4) grip strength and fine hand dexterity may be diminished 5) asymmetric pin sensation loss 6) loss of position, vibration and light touch and decreased reflexes 7) loss of pain and temperature sensation 8) ANS dysfunction (postural hypotension, diarrhea, impotence, urinary retention, increased sweating). 9) lumbosacral plexopathy
What are the clinical features of MG?
1) fluctuating weakness and fatigue in cranial, limb, or turnk musculature. 2) ptosis, diplopia and blurred vision 3) weak facial muscles and speech may become slurred, nasal, and hoarse. 4) trouble chewing and swallowing 5) neck muscle weakness 6) respiratory muscle weakness
What are the clinical features of DMD?
1) clumsy waddling gait 2) lumbar lordosis 3) psuedohypertrophy of calves 4) Gower’s maneuver 5) subnormal intelligence 6) increasing proximal weakness 7) weak respiratory muscles 8) joint contractures and kyphoscoliosis once in a wheelchair.
Differentiate a mononeuropathy from a radiculopathy and plexopathy.
mononeuropathy = affects a single nerve. radiculopathy = one or more nerves are affected and don’t work properly. so problem is at nerve root. plexopathy = affects brachial or lumbosacral plexus.
What are the common genetic defects in CMT?
variety of dominant, recessive, and x-linked forms. most common form is a duplication of the DNA containing the peripheral myelin protein gene PMP22.
What are the common genetic defects in DMD?
X-linked recessive disorders caused by a variety of deletions, duplications and point mutations in the area of the X chromosome coding for the membrane protein dystrophin. 3 most common types of mutations are: deletions, duplications, and point mutations.
Describe the immune-pathogenesis of MG
ACHR antibodies (some have MUSK antibody though which binds to a portion of the postsynaptic membrane).
Describe the treatment of MG
1) temporary symptomatic relief with oral cholinesterase inhibitors (pyridostimine) 2) corticosteroids (prednisone) and other immunosuppressive agents (azathioprine, mycophenoalte mofitil) to suppress immune response 3) temporary dramatic improvement seen with plasma exchange or IV immunoglobulin. 4) thymectomy (to reduce adverse effects of medications)
Describe symptomatic management of difficulty swallowing
swallowing therapy, surgery, feeding tubes
emotional lability (inappropriate laughing and crying) indicates what?
UMN disorder
what is a general characteristic of neuromuscular junction disorders?
rapid onset weakness (hours to days)
what characterizes neuromuscular disorders?
1) insidious, slowly progressive weakness. 2) muscle atrophy is accompanied by striking weakness 3) muscle caramps common 4) pain and tenderness with muscle inflammation 5) skeletal muscle deformities
what is proximal weakness characteristic of?
muscle disorders
