Which of the following best describes the condition referred to as idiopathic intracranial hypertension?

Idiopathic intracranial hypertension is characterized primarily by an increase in intracranial pressure without the presence of a mass lesion, which aligns with the correct description. This condition can arise without any identifiable cause, hence the term "idiopathic." The increase in pressure can lead to symptoms such as headaches, visual disturbances, and, in severe cases, can result in permanent vision loss.

The other options do not accurately capture the essence of the condition. It is not a rare genetic disorder affecting blood flow, nor is it an infection of the central nervous system. Additionally, it does not affect only older adults; idiopathic intracranial hypertension can occur in a variety of age groups but is more commonly observed in young women. The correct answer effectively highlights the core characteristic of idiopathic intracranial hypertension, making it a vital understanding within the context of neurology and family medicine.