Muscle contraction headache

Tension headaches, which were recently renamed tension-type headaches by the International Headache Society, are the most common type of headaches. The pain can radiate from the neck, back, eyes, or other muscle groups in the body. Tension-type headaches account for nearly 90% of all headaches. Nearly everyone will have at least one tension headache in their lifetime. Approximately 3% of population suffers from chronic-tension type headache.

Frequency and duration
Tension-type headaches can be episodic or chronic. Episodic tension-type headaches are defined as tension headaches occurring less than 15 days a month, whereas chronic tension headaches occur 15 days or more a month for at least 6 months. Tension headaches can last from minutes to days or even months, though a typical tension headache lasts 4-6 hours.

Pain
Tension headache pain is often described as a constant pressure, as if the head were being squeezed in a vice. The pain is frequently bilateral which means it is present on both sides of the head at once. Tension headache pain is typically mild to moderate, but may be severe. In contrast to migraine, the pain does not increase during exercise.

Cause and pathophysiology
The exact cause of tension headaches is still unknown. It has long been believed that they are caused by muscle tension around the head and neck. Although muscle tension may be involved, there are many forms of tension headaches and some scientists now believe there is not one single cause for this type of headache. One of the theories is that the pain may be caused by a malfunctioning pain filter which is located in the brain stem. The view is that the brain misinterprets information, for example from the temporal muscle or other muscles, and interprets this signal as pain. One of the main molecules which is probably involved is serotonin. Evidence for this theory comes from the fact that tension headaches may be successfully treated with certain antidepressants. Another theory says that the main cause for tension type headaches and migraine is teeth clenching which causes a chronic contraction of the temporalis muscle. Patients with chronic tension-type headache have increased muscle and skin pain sensitivity, demonstrated by low mechanical, thermal and electrical pain thresholds. Hyperexcitability of central nociceptive neurons (in trigeminal spinal nucleus, thalamus, and cerebral cortex) is believed to be involved in the pathophysiology of chronic tension-type headache.

Treatment
Episodic tension-type headaches generally respond well to over-the-counter analgesics, such as paracetamol, ibuprofen or aspirin. The effect of the analgesic is boosted if either caffeine (a cup of coffee) or a dose of the sedative antihistamine diphenhydramine (Benadryl, 25mg) is taken at the same time. However, these medications should be avoided in cases of chronic tension headache, due to the risk of medication overuse headaches. Chronic tension-type headaches are more difficult to treat. Suggested therapies include:

Non-pharmacological therapy:
 * Swimming two to three times a week
 * Acupuncture
 * Biofeedback
 * Massage
 * Heat pillow
 * Relaxation techniques like:
 * Jacobson's Progressive Muscle Relaxation
 * Autogenic training
 * The NTI Tension Suppression System

Pharmacological therapy:
 * Amitriptyline
 * Mirtazapine

Tension headaches are exacerbated by states or activities that induce muscle tension, such as stress. Avoiding such states can lessen the frequency of tension headaches. Tension headaches can also be secondary to other conditions, such as an upper respiratory infection or other virus.

Often the best treatment for a mild tension headache that does not impair a person's ability to function is simple endurance. Many tension headache sufferers receive relief from sleep. However, it is always best to see your physician for a full work-up of the headaches.

Prognosis
Tension headaches that do not occur as a symptom of another condition are painful and annoying, but not harmful. It is usually possible to receive relief from treatment. Tension headaches that occur as a symptom of another condition are usually relieved when the underlying condition is treated. Frequent use of pain medications in patients with tension-type headache may lead to the development of medication overuse headache.