What could a 73-year-old with episodic vertigo and weakness be experiencing?

The presentation of episodic vertigo and weakness in a 73-year-old patient raises significant concern for cerebrovascular issues, particularly a transient ischemic attack (TIA). A TIA can manifest with brief episodes of neurological dysfunction due to temporary disruption of blood flow to the brain, which aligns with the patient's symptoms of episodic vertigo and weakness.

Vertigo may arise from vestibular involvement, while weakness could suggest compromised motor function, often seen in vascular events. Given the patient's age and the transient nature of the symptoms, a TIA is a critical condition to consider, as it serves as a warning sign for potential stroke risks.

In contrast, benign paroxysmal positional vertigo primarily causes vertigo related to changes in head position, without significant weakness. Multiple sclerosis, although it can cause vertigo and weakness, typically involves a more chronic pattern along with additional neurological deficits not indicated here. Vestibular neuritis usually manifests with persistent vertigo, often associated with nausea but does not typically cause weakness. Therefore, the combination of episodic vertigo and weakness strongly supports the consideration of a TIA as the most likely diagnosis in this scenario.