This is a condition where the amount of sugar in the blood stream declines to a low level, which produces symptoms. Relative hypoglycemia occurs in situations where the blood sugar declines from an elevated level to a lower, but not too low, a level at a rate such that the brain reacts to this change. Generally, the blood sugar must fall below 50 for a patient to experience symptoms of hypoglycemia. The brain's two most critical sources of energy are sugar and oxygen. When the sources of these are too low, the brain reacts to try to restore them.
When the blood sugar falls too low or too rapidly, a patient experiences symptoms such as lightheadedness, weakness, headache, sweating, and change in level of consciousness if the condition is severe enough. Hypoglycemia may occur in patients with Diabetes Mellitus or when a patient fasts for a prolonged period of time.
Some patients may have hypoglycemia for other reasons as well. Eating meals at regular intervals, avoiding excessive amounts of simple carbohydrates, and avoiding oversleeping in the morning are important methods to avoid this condition. Some patients need to eat small meals frequently and consume a great proportion of their caloric intake from proteins and fats rather than carbohydrates to fend off hypoglycemic episodes.
Many patients with migraine note that they crave carbohydrates just before or during their migraine attacks and that this can play a role in ending a migraine. Eating multiple small meals daily rather than fewer large meals, can be helpful in maintaining blood sugar levels.
The non-migraine headache associated with hypoglycemia is typically noted to be a dull throbbing headache in the temples. It does not have other symptoms with it that are typical for migraine, but rather resembles the other hypoglycemic symptoms noted previously.