Medical Editor: Jay W. Marks, MD
What is a headache?A Headache is defined as a pain in the head or upper neck. It is one of the most common locations of pain in the body and has many causes.
How are headaches classified?Headaches have numerous causes, and in 2007 the International Headache Society agreed upon an updated classification system for headache. Because so many people suffer from headaches and because treatment sometimes is difficult, it is hoped that the new classification system will allow health care practitioners come to a specific diagnosis as to the type of headache and to provide better and more effective treatment.
There are three major categories of headaches:
- primary headaches,
- secondary headaches, and
- cranial neuralgias, facial pain, and other headaches
What are primary headaches?Primary headaches include migraine, tension, and cluster headaches, as well as a variety of other less common types of headache.
- Tension headaches are the most common type of primary headache. Up to 90% of adults have had or will have tension headaches. Tension headaches occur more commonly among women than men.
- Migraine headaches are the second most common type of primary headache. An estimated 28 million people in the United States (about 12% of the population) will experience a migraine headache. Migraine headaches affect children as well as adults. Before puberty, boys and girls are affected equally by migraine headaches, but after puberty, more women than men are affected. It is estimated that 6% of men and up to 18% of women will experience a migraine headache in their lifetime.
- Cluster headaches are a rare type of primary headache affecting 0.1% of the population (1 in a 1,000 people). It more commonly affects men in their late 20s though women and children can also suffer these types of headache.
What are secondary headaches?Secondary headaches are those that are due to an underlying structural problem in the head or neck. There are numerous causes of this type of headache ranging from bleeding in the brain, tumor, or meningitis and encephalitis.
What are cranial neuralgias, facial pain, and other headaches?Neuralgia means nerve pain (neur= nerve + algia=pain). Cranial neuralgia describes a group of headaches that occur because the nerves in the head and upper neck become inflamed and become the source of the pain in the head. Facial pain and a variety of other causes for headache are included in this category.
What causes tension headaches?While tension headaches are the most frequently occurring type of headache, their cause is not known. The most likely cause is contraction of the muscles that cover the skull. When the muscles covering the skull are stressed, they may spasm and cause pain. Common sites include the base of the skull where the trapezius muscles of the neck inserts, the temple where muscles that move the jaw are located, and the forehead.
There is little research to confirm the exact cause of tension headaches. Tension headaches occur because of physical or emotional stress placed on the body. These stressors can cause the muscles surrounding the skull to clench the teeth and go into spasm. Physical stressors include difficult and prolonged manual labor, or sitting at a desk or computer for long periods of time concentrating. Emotional stress may also cause tension headaches by causing the muscles surrounding the skull to contract.
What are the symptoms of tension headaches?The pain symptoms of a tension headache are:
- The pain begins in the back of the head and upper neck and is described as a band-like tightness or pressure.
- Often is described as pressure encircling the head with the most intense pressure over the eyebrows.
- The pain usually is mild (not disabling) and bilateral (affecting both sides of the head).
- The pain is not associated with an aura (see below), nausea, vomiting, or sensitivity to light and sound.
- The pain occurs sporadically (infrequently and without a pattern) but can occur frequently and even daily in some people.
- The pain allows most people to function normally, despite the headache.
How are tension headaches diagnosed?The key to making the diagnosis of any headache is the history given by the patient. The health care practitioner will ask questions to understand when the headache began, learn about the quality, quantity, and duration of the pain, and ask about any associated symptoms. The history of tension headache will include pain that is mild to moderate, located on both sides of the head, described as a tightness that is not throbbing, and not made worse with activity. There will be no associated symptoms like nausea, vomiting, or light sensitivity.
The physical examination, particularly the neurologic portion of the examination, is important in tension headaches because it should be normal to make the diagnosis. The only exception is that there may be some tenderness of the scalp or neck muscles. If the health care practitioner finds an abnormality, then the diagnosis of tension headache would not be considered until the potential for other types of headaches have been investigated.
How are tension headaches treated?Tension headaches are painful, and patients may be upset that the diagnosis is "only" a tension headache. Even though it is not life-threatening, a tension headache can affect the activities of daily life.
Most people successfully treat themselves with over-the�counter (OTC) pain medications to control tension headaches. The following work well for most people:
stress management can all be used as adjuncts to help with control of tension headaches.
It is important to remember that OTC medications, while safe, are medications and may have side effects and potential interactions with prescription medications. It always is wise to ask your health care practitioner or pharmacist if you have questions about OTC medications and their use. This is especially important with OTC pain medications, because patients use them so frequently.
It is important to read the listing of ingredients in OTC pain medications. Often an OTC medication is a combination of ingredients, and the second or third ingredient may have the potential for drug interaction or contraindication with medications a patient is currently taking. For example:
- Some OTC medications include caffeine, which may trigger rapid heartbeats in some patients.
- In night time preparations, diphenhydramine (Benadryl) may be added. This may cause drowsiness, and driving or using heavy machinery may not be appropriate when taking the medication.
- Aspirin should not be used in children and teenagers because of the risk of Reye's Syndrome, a disease where coma, brain damage, and death can occur if there is a viral like illness when the and aspirin is used.
- Aspirin and ibuprofen are irritating to the stomach and may cause bleeding. They should be used with caution in patients who have peptic ulcer disease or who take blood thinners like warfarin (Coumadin) and clopidogrel bisulfate (Plavix).
- Acetaminophen, if used in large amounts, can cause liver damage or failure. It should be used with caution in patients who drink significant amounts of alcohol or who have liver disease.
- One cause of chronic tension headaches is overuse of medications for pain. When pain medications are used for a prolonged period of time, headaches can recur as the effects of the medication wear off. Thus, the headache becomes a symptom of the withdrawal of medication (rebound headache).
What causes cluster headaches?The cause of cluster headaches is uncertain. It may be that certain parts of the brain begin to malfunction for an unknown reason. The hypothalamus, an area located at the base of the brain is responsible for the body's biologic clock and may be the part of the brain that is the source for the headaches. When brain scans are performed on patients who are in the midst of a cluster headache, there is abnormal activity in the hypothalamus.
Cluster headaches also:
- tend to run in families and this suggests that there may be a genetic role;
- may be triggered by changes in sleep patterns;
- may be triggered by medications (for example, nitroglycerin, used for heart disease).
What are the symptoms of cluster headaches?Cluster headaches are headaches that come in groups (clusters) lasting weeks or months, separated by pain-free periods of months or years.
- During the period in which the cluster headaches occur, pain typically occurs once or twice daily, but some patients may experience pain more than twice daily.
- Each episode of pain lasts from 30 to 90 minutes.
- Attacks tend to occur at about the same time every day and often awaken the patient at night from a sound sleep.
- The pain typically is excruciating and located around or behind one eye.
- Some patients describe the pain as feeling like a hot poker in the eye. The affected eye may become red, inflamed, and watery.
- The nose on the affected side may become congested and runny.
How are cluster headaches diagnosed?The diagnosis of cluster headache is made by taking the patient's history. The description of the pain and it's clock-like recurrence is usually enough to make the diagnosis.
If examined in the midst of an attack, the patient usually is in a painful crisis and may have the eye and nose watering as described previously. If the patient is seen when the pain is not present, the physical examination is normal and the diagnosis again depends upon the history.
How are cluster headaches treated?Cluster headaches may be very difficult to treat, and it make take trial and error to find the specific treatment regimen that will work for each patient. Since the headache recurs daily, there are two treatment needs. The pain of the first episode needs to be controlled , and additional headaches need to be prevented.
Initial treatment options may include the following:
- inhalation of high concentrations of oxygen (though this will not work if the headache is well established);
- injection of tryptan medications, for example, sumatriptan (Imitrex), zolmitriptan (Zomig), and rizatriptan (Maxalt) which are commonly used for migraine treatments as well;
- injection of lidocaine, a local anesthetic, into the nostril;
- dihydroergotamine (DHE, Migranal), a medication that causes blood vessels to constrict;
- calcium channel blockers [for example, verapamil (Calan, Verelan, Verelan PM, Isoptin, Covera-HS), diltiazem (Cardizem, Dilacor, Tiazac)]
- prednisone (Deltasone, Liquid Pred)
- antidepressant medications
- lithium (Eskalith, Lithobid)
- valproic acid, divalproex (Depakote, Depakote ER, Depakene, Depacon), and topiramate (Topamax) (often used for seizure control)
Can cluster headaches be prevented?Since cluster headache episodes may be spaced years apart, and since the first headache of a new cluster episode can't be predicted, daily medication may not be warranted.
Lifestyle changes may help minimize the risk of a cluster headache flare. Stopping smoking and minimizing alcohol may prevent future episodes of cluster headache.
What diseases cause secondary headaches?Headache is a symptom associated with many illnesses. While head pain itself is the issue with primary headaches, secondary headaches are due to an underlying disease or injury that needs to be diagnosed and treated. Controlling the headache symptom will need to occur at the same time that diagnostic tests are being considered to diagnose the underlying disease. Some of the causes of secondary headache may be potentially life-threatening and deadly. Early diagnosis and treatment is essential if damage is to be limited.
The International Headache Society lists eight categories of secondary headache. A few examples in each category are noted. (This is not a complete list).
Head and neck trauma
- Injuries to the head may cause bleeding in the spaces between the layers of tissue that surround the brain (subdural, epidural and subarachnoid spaces) or within the brain tissue itself.
- Concussions, where head injury occurs without bleeding
- A symptom of whiplash and neck injury
- Stroke or transient ischemic attack (TIA)
- Arteriovenous malformations (AVM) may cause headache before they leak
- Carotid artery inflammation
- Temporal arteritis (inflammation of the temporal artery)
- Brain tumors, either primary, originating in the brain, or metastatic from a cancer that began in another organ
- Idiopathic intracranial hypertension, once named pseudotumor cerebri, where the pressure is too high in the cerebrospinal fluid within the spinal canal.
How are secondary headaches diagnosed?If there is time, the diagnosis of secondary headache begins with a complete patient history followed by a physical examination and laboratory and radiology tests as appropriate.
However, some patients present in crisis with a decreased level of consciousness or unstable vital signs. In these situations, the health care practitioner may decide to treat a specific cause without waiting for tests to confirm the diagnosis.
For example, a patient with headache, fever, stiff neck, and confusion may have symptoms that suggest meningitis. Since meningitis can be rapidly fatal, antibiotic therapy may be started before blood tests and a lumbar puncture are performed to confirm the diagnosis.
What are the exams and tests for secondary headaches?The patient history and physical examination provide the initial direction for determining the cause of secondary headaches. Therefore, it is extremely important that patients with severe headaches seek medical care and give their health care practitioner an opportunity to assess their condition. Tests that may be useful in making the diagnosis of the underlying disease causing headaches include:
- blood tests,
- computerized tomography (CT Scan),
- magnetic resonance imaging (MRI) scans of the head, and
- lumbar puncture.
Blood tests provide helpful information in association with the history and physical examination in pursuing a diagnosis. For example, an infection or inflammation in the body may cause a rise in the white blood cell count, the erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP). These two tests are very non-specific, that is, they may be abnormal with any infection or inflammation, and abnormalities do not point to a specific diagnosis of the cause of the infection or inflammation.
Blood tests can also assess electrolyte disturbances, and a variety of organ functions like liver, kidney, and thyroid.
Computerized tomography of the head
Computerized tomography (CT scan) is able to detect bleeding, swelling, and tumors. It can also show evidence of previous stroke. With intravenous contrast injection, it can also be used to look at the arteries of the brain.
Magnetic resonance imaging (MRI) of the head
MRI is able to better look at the anatomy of the brain, meninges (the layers that cover the brain and the spinal cord). While it is more precise, the time to perform the scan is significantly longer than for computerized tomography. This type of scan is not available at all hospitals. Moreover, it takes much longer to perform, requires the patient to cooperate by holding still, and requires that the patient have no metal in their body (for example, a heart pacemaker or metal foreign objects in the eye).
Cerebro-spinal fluid, the fluid that surrounds the brain and spinal cord, can be obtained with a needle that is inserted into the spine in the lower back. Examination of the fluid can reveal infection (such as meningitis due to bacteria, a virus, or tuberculosis) or blood from hemorrhage. In almost all cases, computerized tomography is done prior to lumbar puncture to make certain there is no bleeding, swelling, or tumor in the brain. Pressure within the space can be measured when the lumbar puncture needle is inserted. Elevated pressures may make the diagnosis of idiopathic intracranial hypertension in combination with the appropriate circumstances.
When should I seek medical care for a headache?A patient should seek medical care if their headache is:
- The "worst headache of your life." This is the wording often used in textbooks as a cue for medical practitioners to consider the diagnosis of a subarachnoid hemorrhage due to a ruptured cerebral aneurysm. The amount of pain will often be taken in context with the appearance of the patient and other associated signs and symptoms.
- Different than your usual headaches
- Starts suddenly or is aggravated by exertion, coughing, bending over, or sexual activity
- Associated with persistent nausea and vomiting
- Associated with fever or stiff neck
- Associated with seizures
- Associated with recent head trauma or a fall
- Associated with changes in vision, speech, or behavior
- Associated with weakness or change in sensation
- Not responding to treatment and is getting worse
- Requires more than the recommended dose of over-the-counter medications for pain
- Disabling and interfering with work and quality of life
Headache At A Glance
- The head is one of the most common sites of pain in the body.
- The most common types of headache can be classified as 1) primary, 2) secondary, and 3) cranial neuralgias, facial pain, and other headaches.
- The most common types of primary headaches are 1) tension, 2) migraine, and 3) cluster.
- Tension headaches are the most common type of primary headache and usually are treated with over-the-counter medications for pain
- Secondary headaches are a symptom of an injury or an underlying illness.
- Patients should seek medical care for new onset headaches, fever, stiff neck, change in behavior, vomiting, weakness or change in sensation.
References: International Headache Society. The Classification.
Previous contributing author and editor: Dennis Lee, MD and Harley I. Kornblum, MD, PhD
Previous contributing author and editor: Dennis Lee, MD and Harley I. Kornblum, MD, PhD