What are headaches?
Headaches are pain or discomfort that can be generalized or local affecting any part of the head. There are many causes of headaches, some originating from the head region itself, while others come from the neck and upper back, as well as ophthalmologic origins.
What causes headaches?
In the past, scientists thought that headaches were caused by changes in blood vessels within the brain, however, recent research has led scientists and physicians to believe that the pain originates within the brain itself, involving various nerve pathways and the neurotransmitters within the brain, in addition to the vasodilatory effects.
Cluster headache causes
Cluster headaches are considered to be from the vasodilatation (opening) of the blood vessels in the brain. This causes the acute and severe pain by compressing and irritating the cranial nerve (trigeminal), which innervates the sensory and some motor function of the face.
The etiology of tension headaches are less understood; however, it is thought to be due to neurotransmitter or chemical changes surrounding the brain due to stress and emotional factors.
Another theory is that continued musculoskeletal (myofascial) irritations may cause tension headaches. Examples of continued myofascial irritation or stimulation includes jaw clenching as well as poor posture of the back or neck.
Migraine headache causes
Migraine headaches are thought to be vascular in origin, similar to cluster headaches, and are also associated with a imbalance in the neurotransmitter serotonin. Migraines are also considered to be familial, which means there is a genetic link involved. The theory is that some patients with a family history of migraines have a gene that predisposes them to migraines.
Your physician will diagnose your headache as either “primary” or “secondary.”
Primary headaches are not caused by an underlying pathology or disease. Primary headaches are benign, more common, and can be broken down into three categories: cluster, tension, and migraine headaches.
Secondary headaches are associated with a pre-existing pathology causing the pain, which may be benign or malignant of origin. There are many causes of secondary headaches that should be excluded by a headache specialist before assuming a headache is of primary origin. Some of the more severe causes that require immediate treatment are:
- Intracranial hemorrhages/ hematomas
- Meningeal infections (viral, bacterial, fungal)
- Malignant hypertension
- Malignant tumors (primary or malignant)
- Ophthalmologic (glaucoma, cataract)
Your physician may wish to order radiological studies (MRI, CT scan), neurological exam, blood work, or an eye/vision assessment to help rule out some of the causes of secondary headaches.
There are many different types of headaches, and the symptoms often vary with each:
In cluster headache, men are more commonly affected than women with a peak age of onset around 25 years. Patients will experience severe, unilateral, pulsatile, and periorbital pain that typically lasts anywhere from 20 minutes to three hours. Patients describe the pain associated with cluster headache to be far more severe than is experienced in tension or migraine headaches.
Tensions headaches are considered the most common headache diagnosed in adults. The pain is described as a restrictive, band-like pain that is being wrapped around the patient’s head. Patients describe it as an insidious (slow) onset that can be exacerbated by bright lights, noise, and especially stress.
Migraines are more common in women and affect a significant portion of the population. The pain associated with migraines is described as either unilateral (one-sided) or bilateral (both sides), intense and throbbing that typically lasts over an hour, but less than 24 hours.
Migraines are further classified as “classical” and “common.” In classical migraines the pain is unilateral and is preceded by an aura. A common migraine is often bilateral and has no associated aura or neurological manifestation.
One of the known phenomena of a migraine headache is that many people, although not all, have an associated aura that may occur before, during, or after the onset of the migraine. Some patients describe the aura as scintillating flashes of light, a particular smell, spots of vision loss, as well as numbness of one or both sides of the face, unsteadiness, weakness, or an altered level of consciousness.
Pharmacologic treatment for primary headaches can be classified as abortive or preventive. Abortive therapy and other therapies are directed at terminating the pain immediately.
Although abortive therapies may provide relief from the headache, they do not decrease the frequency or intensity, or prevent the attack from recurring. They also are not equally effective each time and efficacy varies from person to person.
Medications and techniques that are considered preventive therapies are directed at reducing the frequency and severity of the attacks. Unfortunately, most of these medications are unable to terminate an acute episode, so they are typically used in conjunction with abortive therapies during an attack.
Behavioral modifications, including biofeedback training, mind and body relaxation (yoga, acupuncture, and massage), and cognitive behavior therapy, have been identified as successful treatments for migraine headache.
Recently there has been a flood of investigations going on to determine the efficacy of botulinum A toxin (BOTOX®) injections for the treatment of migraines. Some people receiving BOTOX® injections for their facial wrinkles have noted improvement of their headaches. Essentially, BOTOX® is injected in the same or similar locations as is for the treatment of wrinkles in cosmetic practices.
Some of the common preventive medications are: antiseizure medications, antidepressants, antihistamines, and cardiovascular drugs (beta blockers or calcium channel blockers).