Understanding Vitamin Toxicity Symptoms

The question describes a 23-year-old experiencing a severe headache and showing papilloedema on fundoscopy, linked to megavitamins therapy. Papilloedema, or swelling of the optic disc, typically indicates increased intracranial pressure.

Analyzing Vitamin Intoxication Effects

We need to identify which vitamin intoxication commonly causes symptoms of increased intracranial pressure like severe headache and papilloedema:

• Vitamin $B_{12}$ intoxication: Generally considered non-toxic even in high doses; toxicity is very rare and not linked to these symptoms.
• Vitamin A intoxication: This condition, known as hypervitaminosis A, is well-documented to cause increased intracranial pressure. Symptoms include severe headache, nausea, vomiting, visual disturbances, and papilloedema. It often results from chronic excessive intake of preformed vitamin A (retinol).
• Vitamin E intoxication: While high doses can interfere with blood clotting (increasing bleeding risk), it doesn't typically cause papilloedema or severe headache related to intracranial pressure.
• Vitamin K intoxication: Toxicity is rare and symptoms are usually related to blood coagulation issues or hemolytic anemia, not neurological symptoms like papilloedema.

Conclusion on Likely Cause

Based on the classic presentation of severe headache and papilloedema associated with megavitamins therapy, Vitamin A intoxication is the most probable diagnosis.