Differential Diagnosis
- Single most likely diagnosis
- Ischemic stroke: The patient's symptoms of sudden onset weakness on one side of the body, slurred speech, facial drooping, and homonymous hemianopia are classic for a stroke. The gradual progression over a week could be due to a slowly evolving infarct or a series of small strokes. The brisk reflexes and upgoing plantar response on the affected side further support a central nervous system lesion such as a stroke.
- Other Likely diagnoses
- Brain metastasis: Given the patient's past history of breast cancer, a metastatic lesion to the brain is a strong consideration. The symptoms could be due to a mass effect from the tumor, and the gradual onset could be consistent with a growing tumor.
- Glioma or primary brain tumor: A primary brain tumor could also present with gradual onset of focal neurological deficits, depending on its location and rate of growth.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Cerebral venous sinus thrombosis: Although less common, this condition can present with similar symptoms, especially if there is associated cerebral edema or infarction. It's crucial to consider this diagnosis, especially in patients with a history of cancer or other hypercoagulable states.
- Intracranial hemorrhage: While the gradual onset might be less typical, an intracranial hemorrhage could present with focal neurological deficits and should be ruled out with imaging.
- Rare diagnoses
- Mitochondrial disorders: Conditions like MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) could present with stroke-like symptoms but are much rarer and typically have other systemic manifestations.
- Inflammatory or demyelinating diseases: Conditions such as multiple sclerosis or vasculitis could present with a variety of neurological symptoms, including focal weakness, but the pattern and progression would typically be different from what is described.