Migraines are not the common headaches that people experience making migraine the most common type of headache that causes people to seek medical consult. Migraine is considered a chronic disorder that involves moderate to severe pain on the head. Unlike other types of headaches, migraine tends to be debilitating in cases the headache attacks and the pain is not readily relieved by over the counter pain relievers.
Other types of headache such as tension type headache and cluster headaches are caused by muscle tension along the cranium leading to a feeling of muscle tightness along the head. However, in the case of migraines, more underlying conditions cause the pain on the head making it a serious condition. Migraine headaches are often associated with symptoms involving the autonomic nervous system.
Before looking into the exact scientific mechanism of migraines, it is essential to look into the various causes of migraine; although, the exact etiology is unknown. Some of the risk factors for migraine headaches include:
Migraine indicates a genetic influence of up to 51% as seen in twins who suffer the condition.
- Psychological disturbances
The presence of anxiety, depression and even bipolar disorder was also seen to be a trigger for migraine.
- Physiologic triggers
Migraine is also triggered by the physiologic effects of fatigue, hunger and stress. Hormonal imbalances as seen during menstruation, pregnancy, use of oral contraceptives and menopause also trigger the development of migraine.
- Environmental triggers
Environmental triggers to migraine may also include poor lighting and indoor air quality.
All of these factors were seen in people with migraine, although they do not constitute the definite cause of migraine. Nevertheless, all of these factors lead to the belief that migraine is due to neurovascular disorders with the role of the trigeminal nerve and blood vessels in the development of pain.
Migraine initially develops as a result of disruption in the ion channels in the brain. Ion channels are present in all cells including the cells in the brain and ion pumps act to move ions across the cells. Since they are responsible for the movement of ions, they have a very important action in the communication in the nervous system. When malfunctions occur, they can trigger the development of migraine headache by triggering cortical spreading depression. This cortical spreading depression or CSD is a burst of neuronal activity in the brain followed by inactivity. When there is a burst in the neuronal activity, the blood supply in the cerebral cortex usually is reduced for up to six hours. This reduction in the blood glow usually sensitizes the nerves around the blood vessels that result in pain.
While the CSD may cause a reduction in blood flow, the CSD may also cause the blood vessels to dilate sooner leading to the leakage of fluid from the blood vessels to the surrounding tissues. This causes swelling and the pressure along the adjacent nerves can also cause pain.
The torture in migraine doesn’t stop there. The CSD can also affect the trigeminal nerves on the face. When the trigeminal nerves are sensitized, it causes pain along the side of the face that can also trigger pain on one side of the head leading to migraines.
The continuous research in migraine headache has led to the discovery of the complicated reasons as to why migraines occur. Until the present time, it is clear how a change in the influx of ions and the flow of neurotransmission in the brain can play a significant part in the development of migraines.