What condition is characterized by a sudden severe headache and weakness on one side of the body?

The condition characterized by a sudden severe headache and weakness on one side of the body is indeed hemiplegic migraine. This type of migraine is distinct due to its neurological symptoms, particularly the transient hemiplegia, which is weakness or paralysis affecting one side of the body.

Hemiplegic migraine typically presents with a severe headache, often described as throbbing, accompanied by aura symptoms, which can include visual changes, sensory disturbances, and motor weakness. The unilateral weakness, or hemiplegia, seen in this condition can mimic some acute neurological events, thus differentiating it from other types of headaches.

This condition is significant because it not only has a headache component but also has serious neurological implications. Early recognition is crucial, as it may require different management strategies than more common headaches. This emphasizes the importance of differentiating hemiplegic migraine from other headache types, which do not typically present with such pronounced neurological deficits.

Other choices represent different types of headaches that, while they may feature severe headache as a symptom, lack the specific combination of unilateral weakness and severe headache characteristic of hemiplegic migraine.