This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Headache And Migraine, Subject name: Medicine
All of the following cause metabolic headache except: 
Select and explain. 
A. Hypoxia, B. Hypercapnia, C. Hyperglycemia, D. Hyponatremia
C: Hyperglycemia
Answer: C: Hyperglycemia 
Explanation: Hypoxia Causes cerebral vasodilation --> headache. Hyperglycemia Hyperglycemia does not present as headache Hypercapnia Cause cerebral vasodilation and stretching of meninges. Hyponatremia Cerebral edema leads to a headache and seizures.