Headache

A headache is a condition of pain in the head; sometimes neck or upper back pain may also be interpreted as a headache. It ranks amongst the most common local pain complaints.

Headaches have a wide variety of causes, ranging from eye strain, sinusitis and tension to life-threatening conditions such as encephalitis, meningitis, cerebral aneurysms and brain tumors (although up to 99% of headaches have a benign cause and do not warrant further treatment other than a painkiller). When the headache occurs in conjunction with a head injury the cause is usually quite evident; however, many causes are more unclear. The most common type of headache is a tension headache. Some experience headaches when dehydrated, or suffering from caffeine withdrawal symptoms.

There are five types of headache: vascular, myogenic (muscle tension), cervicogenic, traction, and inflammatory.

• Vascular
      - The most common type of vascular headache is migraine. Migraine headaches are usually characterized by severe pain on one or both sides of the head, an upset stomach, and, at times, disturbed vision. It is more common in women. After migraine, the most common type of vascular headache is the "toxic" headache produced by fever.
      - Other kinds of vascular headaches include cluster headaches, which cause repeated episodes of intense pain, and headaches resulting from high blood pressure (rare).
• Muscular/myogenic headaches appear to involve the tightening or tensing of facial and neck muscles; they may radiate to the forehead. Tension headache is the most common form of myogenic headache.
• Cervicogenic headaches originates from disorders of the neck, including the anatomical structures innervated by the cervical roots C1-C3. Cervical headache is often precipitated by neck movement and/or sustained awkward head positioning. It is often accompained by restricted cervical range of motion, ipsilateral neck, shoulder, or arm pain of a rather vague non-radicular nature or, occasionally, arm pain of a radicular nature.
• Traction and inflammatory headaches are symptoms of other disorders, ranging from stroke to sinus infection.

Like other types of pain, headaches can serve as warning signals of more serious disorders. This is particularly true for headaches caused by inflammation, including those related to meningitis as well as those resulting from diseases of the sinuses, spine, neck, ears and teeth.