The most common disorder of neuromuscular transmission: Right Ans -
myasthenia gravis
Myasthenia gravis is characterized by...? Right Ans - Fluctuating weakness
and fatiguability of the skeletal muscles
Peak occurrence age for women= Right Ans - 20-30s
Peak occurrence age for men= Right Ans - 50-60s
Ratio of women to men= Right Ans - 3:2
Autoimmune disorder with action at the site of the neuromuscular junction
and motor endplate, lack of Ach: Right Ans - Myasthenia gravis
What are the risk factors for MG? Right Ans - Thymic disorders (thymic
tumor- thymoma), DM an immune disorders such as RA and SLE, menstrual
periods or shortly after pregnancy, familial association
True/false: the most associated risk factor for MG is thymic disorders—
Right Ans - True
~___% of patients die from respiratory failure with ____% mortality within 10
years of diagnosis. Right Ans - 25;50
True/false: deaths from MG is decreasing dramatically with immunotherapy
— Right Ans - True
Where is the fundamental defect located with MG? Right Ans - At the
neuromuscular junction
Autoimmune diseases cause antibodies against postsynaptic proteins at the
neuromuscular junction to block the _____________ receptors and cause MG.
Right Ans - Acetylcholine (decreased number and flattened receptors, so Ach
cannot bind)
, What are the two types of muscular weakness distribution patterns? Right
Ans - Ocular/bulbar and generalized
Cranial muscles, particularly eyelids and extra-ocular eye muscles are the first
to show weakness; diplopia and ptosis are common early signs= Right Ans
- Ocular/bulbar type
Weakness spreads sequentially from the face and next to upper limbs, hands,
and then the lower limbs= Right Ans - Generalized type
What are the cardinal features of MG? Right Ans - Voluntary skeletal
muscle weakness and fatiguability
Repetition of an activity causes _______, and rest restores function. Right Ans
- Fatigue
_______________ of MG may occur before menstrual period, shortly following
pregnancy, stress, and chronic infections. Right Ans - Exacerbation
True/false: other neuro tests like sensory and reflexes are not normal—
Right Ans - False (they are normal- only thing affected is neuromuscular
junction)
What two eye disorders may occur from cranial/bulbar muscle weakness
associated with MG? Right Ans - Diplopia and ptosis (person may tilt head
back to see and weak neck muscles may lead to head bobbing in an
unsupported position)
Chewing causes ________. Right Ans - Fatigue
Difficulty _______ lips. Right Ans - Closing
Speech may be ______. Right Ans - Nasal
Why may a person with MG have difficulty swallowing that may lead to nasal
regurgitation and/or aspiration? Right Ans - Palatal, pharyngeal, and
tongue weakness
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