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Headache Following a Head Injury

Headache after an injury

A headache is not unusual immediately following a blow to the head. The headaches may come and go but usually resolve within 4 weeks after the injury. As long as the headaches are getting better, they are not likely to represent a serious problem.

Headaches are classified as mild, moderate, or severe.

  • Mild: A mild headache improves or goes away completely with home treatment, medicine, or rest. It may return when the medicine wears off.
  • Moderate: A moderate headache improves with home treatment, medicine, or rest, but it never completely goes away. You are always aware that your headache is present.
  • Severe: A severe headache is incapacitating. Home treatment, medicine, and rest do not relieve this headache.

An ongoing headache that is getting worse after a head injury may be caused by swelling or bleeding within or around the brain or between the brain and the covering of the brain (subdural hematoma). The bleeding may be rapid or slow. Symptoms may develop within minutes, hours, or occasionally weeks after the injury.

Falls occur more frequently in babies, older adults, and people with dementia or alcohol or drug abuse problems. Determining if the person has had a head injury may be difficult or delayed since he or she may not be able to tell you about the fall or injury. A subdural hematoma may develop immediately and cause obvious problems, but if the bleeding is slow, symptoms may not develop for days or even weeks.

A head injury may cause a small amount of bleeding within the skull that does not cause symptoms for days or even weeks after the injury. After a head injury, a small blood clot may form and draw fluid from the tissues around it, which makes the clot slowly get bigger. The increasing size of the clot causes a slow increase in the pressure within the skull and the surrounding brain tissue. Usually the first symptom of the increased pressure is a new, persistent, and increasingly severe headache. Confusion and sleepiness may also be present.

A persistent headache that is accompanied by other symptoms of a concussion, such as drowsiness and personality changes, is more serious. As the pressure increases around the brain, other symptoms may develop quickly, including dilation of a pupil or paralysis on one side of the body.

By Healthwise Staff
Primary Medical Reviewer William H. Blahd, Jr., MD, FACEP - Emergency Medicine
Specialist Medical Reviewer H. Michael O'Connor, MD - Emergency Medicine
Last Revised April 5, 2012

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