A 64-year-old hypertensive diabetic man presents with acute onset diplopia, right ptosis, and right medial rectus weakness. Pupillary responses remain intact. Vital signs show BP 158/92 mmHg, HR 88/min, RR 16/min, temp 37.2°C, SpO2 98% on room air. MRI reveals a small acute infarct in the right midbrain with restricted diffusion on DWI. Extraocular movements are otherwise preserved. Which cranial nerve is most likely affected?
- A)Trochlear nerve (CN IV)
- B)Vestibulocochlear nerve (CN VIII)
- C)Oculomotor nerve (CN III)GABARITO
- D)Facial nerve (CN VII)
- E)Abducens nerve (CN VI)
Explicação
Medial rectus weakness with ptosis indicates CN III palsy. The midbrain location and preserved pupillary reflexes suggest fascicular damage to CN III fibers before they exit the brainstem, sparing parasympathetic fibers in the peripheral portion. Ver explicação completa e trilha adaptativa →