A 45-year-old woman with metastatic breast cancer to the brain presents to the emergency department with a 2-day history of progressive headache, confusion, and nausea. Vital signs show hypertension (160/95 mmHg) and bradycardia (52 bpm). Brain MRI with and without contrast reveals obstructive hydrocephalus with enlargement of the lateral and third ventricles, but the fourth ventricle is normal in size. The obstruction is localized at the aqueduct of Sylvius on axial imaging. Which of the following is the most likely cause of the obstruction at this location?
- A)Metastatic deposit compressing the midbrain and narrowing the aqueductGABARITO
- B)Communicating hydrocephalus secondary to impaired cerebrospinal fluid absorption at the arachnoid granulations
- C)Ependymitis causing thickening of the ependymal lining within the third ventricle
- D)Stenosis of the foramen of Monro preventing flow from the lateral ventricles
- E)Obstruction of the foramen of Luschka and foramen of Magendie
Explicação
Metastatic disease in the midbrain is the most likely cause of obstruction at the aqueduct of Sylvius. The aqueduct is a narrow, midline structure in the midbrain connecting the third and fourth ventricles. External compression from a midbrain lesion (metastas... Ver explicação completa e trilha adaptativa →