In ancient Greece, headaches were considered a severe affliction. The victims prayed for relief from Asclepius, the god of medicine. And if the pain continued, the doctor would perform the most famous remedy - drilling a small hole in the skull to drain the supposedly infected blood. This terrible technique, called preparation, often replaced the headache with a more permanent condition. Fortunately, doctors today do not resort to electric tools to treat headaches. But we still have a lot to learn about this ancient disease. Today we have divided headaches into two camps – primary headaches and secondary headaches.
The former is not a symptom of an underlying disease, injury or condition; are a condition. But we'll come back to them in a moment, because while primary headaches account for 50% of reported cases, we know a lot more about secondary headaches. These are caused by other health problems, with triggers ranging from dehydration and caffeine withdrawal to head and neck injuries and heart disease.
Doctors have classified more than 150 diagnosable types, all with different potential causes, symptoms and treatments. But let's take just one common case—a sinus infection—as an example. The sinuses are a system of cavities that extend behind our foreheads, noses and upper cheeks. When our sinuses are infected, our immune response heats up the area, roasting the bacteria and inflaming the sinuses far beyond their normal size. Congested sinuses put pressure on the cranial arteries and veins, as well as the muscles in the neck and head.
Their pain receptors, called nociceptors, fire in response, prompting the brain to release a flood of neuropeptides that inflame cranial blood vessels, swelling and heating the head. This discomfort, combined with oversensitive head muscles, creates a painful, throbbing headache. Not every headache comes from swelling. Tense muscles and inflamed sensitive nerves cause varying degrees of discomfort with every headache. But all cases are reactions to some cranial irritant. While the cause is clear for secondary headaches, the origin of primary headaches remains unknown. Researchers are still investigating potential triggers for three types of primary headaches: recurrent, long-lasting migraines; intensely painful, fast-burning cluster headaches; and the most common tension headache of all. As the name suggests, tension headaches are known for creating the feeling of a tight band being squeezed around the head. These headaches increase the sensitivity of the pericranial muscles, which then painfully pulse with blood and oxygen. Patients cite stress, dehydration, and hormonal changes as triggers, but these symptoms don't quite match.
For example, in dehydration headaches, the frontal lobe shrinks away from the skull, creating a swelling of the forehead that does not correspond to the pain site of a tension headache. Scientists have theories about what the real cause is, from blood vessel spasms to oversensitive nociceptors, but no one knows for sure.
Meanwhile, most headache research focuses on more severe primary headaches. Migraines are recurring headaches that create a vise-like sensation in the skull that can last from four hours to three days. In 20% of cases, these attacks are intense enough to overload the brain with electrical energy that hyperexcites sensory nerve endings.
This creates hallucinations called auras, which can include seeing flashing lights and geometric patterns and tingling sensations. Cluster headaches, another primary type of headache, cause burning, stabbing bursts of pain behind one eye, resulting in a red eye, a narrowed pupil, and a droopy eyelid. What can be done about these conditions, which dramatically affect the quality of life for many people?
Tension headaches and most secondary cases can be treated with over-the-counter pain relievers, such as anti-inflammatory drugs that reduce swelling in the skull. And many secondary headache triggers,
such as dehydration, eye strain and stress can be proactively avoided. Migraines and cluster headaches are more complex, and we haven't yet discovered a reliable treatment that works for everyone. But fortunately, pharmacologists and neuroscientists are working hard to unravel these pressing mysteries that weigh so heavily on our minds.
