[Tension type headache with special reference to muscle abnormality].
Muscle contraction headache (tension-type headache; MCH) usually begins when a patient is looking down or bending their neck. In the case of MCH patients, EMG activity of the posterior neck muscles at a sitting posture is significantly higher than the controls when the orbito-meatal line is horizontal or bending downward. Comparing with the controls, blood flow of the posterior neck muscle decreases sharply when the head is bent downward. Decrease of the muscle blood flow continues if the muscle is passively contracted. However, in the case of active contraction, blood flow recovers reflexly in 30 seconds. This explains why postural muscle contraction is important. When a patient is ordered to bend her neck down at the orbitomeatal line 30 degrees from horizontal, patient complains of a dull feeling at her posterior neck muscles in 30 seconds. In two minutes dull headache appears at the occipital area, soon becoming more intense and spreading to the forehead and temporal area. Once she looks up, muscle contraction of the neck disappears though she still feels headache. After the local anesthesia is applied to the occipital tender point, her headache disappears completely. From this experiment, MCH is a referred pain from occipital tender point which is the insertion point of occipital neck muscles. Patients with poor stability of cervical bone, and relatively heavy head weight compared with their neck are susceptible to MCH. Psychological stress decreases blood flow of the muscle and aggravates ischemic muscle contraction. Other risk factors include hypotension, anemia, and weak muscle power.
Sakuta
M
M
Department Neurology, Japanese Red Cross Medical Center.
D005260:Female; D006801:Humans; D007511:Ischemia / Q000209:etiology; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000098:blood supply; D009333:Neck; D011187:Posture; D012039:Regional Blood Flow; D018781:Tension-Type Headache / Q000209:etiology* / Q000503:physiopathology