A 34-year-old woman presents with progressive bilateral ptosis and diplopia that worsen in the evening. She reports difficulty chewing after prolonged meals and denies sensory changes. Vital signs: BP 118/76, HR 82, RR 14, Temp 37°C, SpO2 98%. Neurologic examination confirms fatigable extraocular weakness and bilateral ptosis; reflexes and sensation are intact. Serum acetylcholine receptor antibodies are positive. Which of the following mechanisms best explains this disorder?
- A)Demyelination of peripheral nerves after infection
- B)Mutation in dystrophin causing myofiber necrosis
- C)Antibodies against presynaptic P Q type calcium channels
- D)Degeneration of dopaminergic neurons in the substantia nigra
- E)Antibodies against postsynaptic acetylcholine receptorsGABARITO
Explicação
Antibodies against postsynaptic acetylcholine receptors is correct. Myasthenia gravis causes fatigable skeletal muscle weakness, especially ptosis, diplopia, and bulbar symptoms, with normal sensation and reflexes. The disorder is often associated with thymic ... Ver explicação completa e trilha adaptativa →