HEADACHE- BROADER PERSPECTIVES

Introduction

World over, headache is the commonest symptom for which people seek medical advice from doctors. Almost all persons, at some point in their lifetime, irrespective of age and sex would have suffered from headache.  A headache may be defined as pain or  discomfort in the head, scalp, or neck..  Most people worry that their headache could be due to a brain tumor or a stroke, but such serious underlying causes of headache are rare.

Today, due to people leading stressful lifestyles, tension headaches and migraine headaches are the most common types of headache.

What is the mechanism by which we experience pain? 

It is common knowledge that nerve fibers carry pain impulses to the brain. Most nerve fibers in the body are covered with a protective coating of fatty substance called myelin. This protective covering does not cover the nerve endings.  These bare nerve endings are responsible for transmitting pain impulses to the brain. When tissues come in contact with a pain causing agent, it reacts by releasing various chemical substances. These substances, released in a positively charged electrical state, encounter the negatively charged free nerve endings, instantly creating a pain impulse.  The pain impulse thus generated is transmitted electrochemically through the nerve fibers to the spinal cord and then onto a collection of neurons in the deep part of the brain called the thalamus. The thalamus is an area of the brain concerned with receiving and interpreting sensory impulses that reach the brain from different parts of the body.  The pain impulse is then transmitted to the cerebral cortex, the outer layer of the brain where the pain sensation is felt in its entirety. 

Interestingly, the skull bones or the brain itself is not sensitive to pain.  There are six parts of the head that are sensitive to pain:

1.      The skin covering the skull, tissues, muscles, veins and arteries between the skin and skull bones.

2.      The under surface of the dura which is the outer covering of the brain.

3.      The arteries at the base of the brain and those that carry blood to the surface of the brain

4.      The large veins of the brain (venous sinuses).

5.      The 12 cranial nerves, which originate directly from the brain.

6.      The nerves that supply pain-sensitive fibers to eyes, neck, back of head, nose, mouth, and sinuses.

Causes of headache:

There are five major causes of headache. The following events trigger pain reactions;

1.     Muscle Contraction: Tightening of muscles at the back of the neck and head result in tension headache. This tightening results in pressure on the blood vessels and tissues, which in turn releases chemical substances that trigger pain impulses. Leading a stressful life results in this type of tension headache.  Working for long hours on the computer or typewriter especially in a faulty sitting posture causes voluntary or involuntary tensing of facial, head, or neck muscles causing such tension headache.

2.      Traction: When the head is jerked back unexpectedly as in a traffic accident, pain sensitive tissues of the neck are stretched resulting in a headache.

3.      Inflammation: Infections in the head and neck region cause inflammation of the surrounding tissues which release pain causing chemicals resulting in headache. The commonest is infection of the Para nasal sinuses (sinuses are airs filled spaces in the skull). An infected tooth can also produce such a headache.

4.     Changes in the diameter of blood vessels:  One of the most agonizing headaches, popularly known as the migraine headache, is caused by a change in the diameter of certain arteries in the head. Initially, the arteries constrict and then swell.  Pain results when cells of the arterial walls release the chemical substances that stimulate nerve endings. This also triggers other adjacent tissues into releasing pain-producing chemicals.

5.      Direct Pressure: The classic cause of headache produced by direct pressure is the dreaded brain tumor. As the tumor enlarges it may press against a pain sensitive area. Alternatively, a tumor may increase the pressure within the skull causing intense continuous pain.  However, this is often associated with other serious symptoms like convulsions, difficulty in speech, weakness etc.

Classification of headache:

Headaches may be classified in the following order:

1.    Tension Headache: Is the most common type of headache. Tension, stress, or emotional problems produce these types of headache. Muscle contractions of the temporal and occipital muscles in the sides and back of the head can cause tension headache by producing muscle spasm and causing pressure on pain sensitive tissues.

2.    Migraine Headache: This is the second most common type of headache. Migraine headaches are severe, recurrent headaches that are generally accompanied by other symptoms like visual disturbances or nausea. They tend to begin on one side of the head, although the pain may spread to both sides. The headache may be preceded by an “aura" (warning symptoms that start before the headache) and the sufferer usually feels a throbbing, pounding, or pulsating headache.

3.    Cluster Headache: This type of headache appears without warning and go just as suddenly, only to return minutes later and the attacks may continue for several days.

4.     Sinus Headache: Are due to inflammation in the sinus passages that lie behind the cheeks, nose, and eyes. The headache occurs in conjunction with nasal stuffiness, postnasal drip, foul smell and severe tenderness on pressure over the sinus regions. Pain in such cases is often felt in front of the face and head and may range from mild to moderate. It may be more annoying than agonizing.

5.      Neuralgic Headache: Is headache caused due to irritation of a major cranial nerve, like the Trigeminal which produces violent stabbing pains over the face and head on one side.

6.     Headache resulting from infection of the covering of the brain is called meningitis which causes severe headache associated with vomiting and neck stiffness.

7.      Headache due to pressure exerted on tissues inside the head. The causes include brain tumor, brain abscess (collection of pus inside the brain) hydrocephalus (blockage of circulating fluid in the cavities of the brain), collection of blood inside the head (the haematomas), leaking of blood from an abnormal blood vessel like an aneurysm. These headaches are often associated with other symptoms like convulsions, weakness of limbs, deteriorating level of consciousness, difficulty in speech, changes in behavior etc.

8.     Headache due to general health problems likes high blood pressure and spondylotic changes in the bones of the neck.

9.     Headache caused by Eye problems: A number of disorders of the eye can cause headache. Errors of refraction are one of the commonest causes of headache especially in children. A refractory error if not rectified makes the individual to squint in order to focus on an image, which results in muscular contraction triggering a headache. Another eye disorder which can cause headache is glaucoma, a condition in which pressure of fluid within the eyeball rises to harmful levels. This is a serious condition, which if not corrected is likely to cause blindness.

10. Headache caused by dental disorders: The commonest dental problem that causes headache is a tooth abscess. Another dental related problem, temporomandibular joint dysfunction, can cause chronic headache. Malocclusion due to ill fitting dentures or loss of molar teeth on one side with alteration of the normal chewing movements may lead to degenerative changes in the joint and to pain in the ear, radiating to the head.

11. Toxic Headaches:  A number of toxins produced within the body or those that enter the body from outside can cause headache. Most of the viral and bacterial infection that produce endogenous toxins can lead to fever and headache. Exogenous toxins (that originate outside the body) that can cause headache which includes such toxins as auto emissions, industrial fumes and wastes, polluted waters, pesticides, food preservatives, cleaning fluids, and fuels. The lead in cosmetics, gasoline additives, and paint can also cause headaches. 

12. Drugs causing headache: A number of drugs for treating various diseases can also cause headaches. One important example is Nitrates that are given for heart disease. Even drugs like aspirin taken for pain in large amounts can cause headache.

13. Miscellaneous headaches: 

1. Ice Cream Headache: are terms used to describe a form of headache which human beings are known to sometimes experience after consuming cold beverages or foods such as ice creams, often as a result of rapid consumption. In rare instances, neuro-cranial blood vessels can constrict so completely that a temporary blackout can occur.

2. Fast Food Headache: Victims of this complain of a feeling of pressure or tightness in the face, a burning feeling over the trunk, neck, and shoulders, a pressing pain in the chest, and a headache after eating in a Chinese restaurant.  This is caused by monosodium glutamate, which is widely used as a food additive, which dilates blood vessels causing headache.

3. Alcohol Headache: Alcohol is also a dilator of blood vessels. Some wines and other alcoholic beverages also contain a chemical called histamine another potent dilator. Red wine in particular may have a high histamine content and can trigger migraine and cluster headaches in susceptible individuals. The throbbing hangover headache attacks that occur on the morning after a heavy drinking bout is due to acetaldehyde and acetate - breakdown products of alcohol- circulating in the blood and dilating the arteries in the cranium.

4. Fasting Headache: Fasting can lower the blood glucose level and can trigger migraine and a dull headache often accompanies any prolonged fast.

5. Withdrawal or rebound headache: Caffeine, nicotine, and other substances can constrict blood vessels and thus diminish vascular headaches. If either of these substances is continuously introduced into the blood by drinking coffee regularly or by smoking, blood vessels assume a semi constricted state. However, if these substances are withdrawn, suddenly and completely, blood vessels dilate causing considerable headache. That is the reason why on stopping or delaying intake of coffee or tea can cause headache in some individuals.

6. Coital Cephalgia also known as "sex headaches", are a rare type of severe headache that occurs at the base of the skull before orgasm during sexual activity. The pain usually moves from the base of the skull through the head towards the frontal lobes. Extremely severe and sharp pain behind the eyes is also a symptom. The headaches usually have an immediate onset and typically last for a few minutes to a few hours, although it is possible for such headaches to last up to a few days.  More prevalent in men, these headaches appear in roughly 1% of the population. It is important to see a doctor if you have such symptoms in order to rule out a potential brain aneurysm, or tumors. In most cases, these headaches are benign. More serious symptoms include a stiff neck, confusion, and dizziness.

7. Ictal headaches are headaches associated with seizure activity. They may occur either before (pre-ictal), after (post-ictal), or most rarely during a seizure. Many cases of ictal headache may be misdiagnosed as migraine with aura, or even cluster headache. However, while these conditions usually involve just one side of the head (are unilateral), an ictal headache may be centrally situated or cover the entirety of the head.  Severity of ictal headaches can vary from a slight pressure or "cloud" to an intensity far beyond migraine. Some have called it a "suicide headache" in the worst instances. Temporary blindness may also occur in some cases.

8. Headaches may occur if you have a cold, the flu, fever, or premenstrual syndrome.

9.  If you are over age 50 and are experiencing headaches for the first time, a condition called temporal arteritis may prove to be the cause. Symptoms of this condition include impaired vision and pain aggravated by chewing. There is a risk of becoming blind with this condition. Therefore, it must be treated by your doctor right away.

Headache: Home Care

Keep a headache diary, particularly when you first have headaches, to help identify the source or trigger of your symptoms. From that information, you can figure out how to modify your environment or habits to avoid recurrent headaches. When a headache occurs, write down the date and time the headache began, what you ate for the past 24 hours, how long you slept the night before, what you were doing and thinking about just before the headache started, any stress in your life, how long the headache lasts, and what you did to make it stop. After a period of time, you may begin to see a pattern and be able to identify triggers to avoid.  A headache may be relieved by resting with your eyes closed and head supported or by using relaxation techniques. A massage or heat applied to the back of the upper neck can be effective in relieving tension headaches.  Over-the-counter pain medications are often effective headache relievers. If you are using pain medications more than 2 days a week, you may be suffering from rebound headaches. Rebound headaches are caused by a cycle of using pain medications for short-term relief, followed by the headache pain returning for increasingly longer periods of time despite taking more pain medications.

Good health habits can help lessen stress and reduce your likelihood of getting headaches. These include:

• Adequate sleep

• Eating a healthy diet

• Exercising regularly

• Stretching your neck and upper body, especially if your work involves typing or using a computer.

• Learning proper posture

• Quitting smoking

• Learning to relax using meditation, deep breathing, yoga or other valuable techniques

Take the following symptoms very seriously and contact your doctor as soon as possible.

• Your headache comes on suddenly and is explosive or violent.

• You would describe your headache as "your worst ever", even if you are prone to headaches.

• Your headache is associated with slurred speech, change in vision, problems moving any of your arms or legs, loss of balance, confusion, or memory loss.

• Your headache gets progressively worse over a 24-hour time period.

• Your headache is accompanied by fever, stiff neck, nausea, and vomiting.

• Your headache occurs with a head injury.

• Your headache has lasted more than a few days.

• Your headaches are worse in the morning.

• You have a history of headaches but they have changed in pattern or intensity.

• You have headaches frequently, and there is no known cause. Your headache is severe and localized to one eye with redness in that eye.

• You are over age 50 and your headaches just began.

In conclusion, most headaches are not dangerous and life threatening.  Most of the times the headaches are due to the busy and stressful lifestyles most people lead in today’s competitive world. Drugs are not the answer to treat most headaches, which can be brought under control by modifying ones life style and learning relaxation techniques.