What are Headaches (Cephalalgia)?
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck.
The brain tissue itself is not sensitive to pain as it lacks pain receptors. Rather, the pain is caused by disturbance of the pain-sensitive structures around the brain.
Nine areas of the head and neck have these pain-sensitive structures, which are the cranium (the periosteum of the skull), muscles, nerves, arteries and veins, subcutaneous tissues, eyes, ears, sinuses, and mucous membranes.
There are a number of different classification systems for headaches. The most well-recognized is that of the International Headache Society. Headache is a non-specific symptom, which means that it has many possible causes.
Treatment of a headache depends on the underlying cause but commonly involves pain killers.
There are more than 200 types of headaches. Some are harmless and some are life-threatening. The description of the headache and findings on neurological examination determine whether additional tests are needed and what treatment is best.
Primary vs. secondary headaches
Headaches are broadly classified as "primary" or "secondary".
Primary headaches are benign, recurrent headaches not caused by an underlying disease or structural problems. For example, migraine is a type of primary headache. While primary headaches may cause significant daily pain and disability, they are not dangerous.
Secondary headaches are caused by an underlying disease, like a tumor, brain bleed or infection. Secondary headaches can be harmless or dangerous. Certain "red flags" or warning signs indicate a secondary headache may be dangerous.
90% of all headaches are primary headaches. Primary headaches usually first start when patients are between 20 and 40 years old. The most common types of primary headaches are migraines and tension-type headaches. They have different characteristics.
Migraines typically present with pulsing head pain, nausea, photophobia (sensitivity to light) and phonophobia (sensitivity to sound).
Tension-type headaches usually present with non-pulsing “bandlike” pressure on both sides of the head, not accompanied by other symptoms.
Other very rare types of primary headaches include:
cluster headaches: short episodes (15–180 minutes) of severe pain, usually around one eye, with autonomic symptoms (tearing, red eye, nasal congestion) which occur at the same time every day.
Cluster headaches can be treated with triptans and prevented with prednisone, ergotamine or lithium.
Headaches may be caused by problems elsewhere in the head or neck. Some of these are not harmful, such as Cervicogenic headaches (pain arising from the neck muscles).
Medication overuse headache may occur in those using excessive painkillers for headaches, paradoxically causing worsening headaches.
More serious causes of secondary headaches include:
* meningitis: inflammation of the meninges which presents with fever and meningismus, or stiff neck
* bleeding inside the brain (intracranial hemorrhage)
* subarachnoid hemorrhage (acute, severe headache, stiff neck WITHOUT fever)
* ruptured aneurysm, arteriovenous malformation, intraparenchymal hemorrhage (headache only)
* brain tumor: dull headache, worse with exertion and change in position, accompanied by nausea and vomiting. Often, the patient will have nausea and vomiting for weeks before the headache starts.
* temporal arteritis: inflammatory disease of arteries common in the elderly (average age 70) with fever, headache, weight loss, jaw claudication, tender vessels by the temples, and polymyalgia rheumatica.
* acute closed-angle glaucoma (increased pressure in the eyeball): a headache that starts with eye pain, blurry vision, associated with nausea and vomiting. On physical exam, the patient will have red-eye and a fixed, mid dilated pupil.
A number of characteristics make it more likely that the headache is due to potentially dangerous secondary causes which may be life-threatening or cause long-term damage. These "red flag" symptoms mean that a headache warrants further investigation with neuroimaging and lab tests.
In general, patients complaining of their “first” or “worst” headache warrant imaging and further workup. Patients with progressively worsening headaches also warrant imaging, as they may have a mass or a bleed that is gradually growing, pressing on surrounding structures and causing worsening pain.
Patients with neurological findings on exam, such as weakness, also need further workup.
Migraines are often unilateral, pulsing headaches accompanied by nausea and/or vomiting. There may be an aura (visual symptoms, numbness or tingling) 30–60 minutes before the headache, warning the patient of a headache.