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Primary versus Secondary Headaches

Headache is Common

Headache is a profoundly common symptom. Studies suggest at least 50% of people have headaches during a given year and more than 90% of people have a headache at least at some point in life.How does a person know if it is “just a headache” or the symptom is due to something more serious? While most of the time there is no serious underlying problem, a Neurologist can evaluate if there is any concern for this or need for further testing. If certain features are present, it is important to evaluate for an underlying problem rather than just treat the pain.

What is Meant by Primary versus Secondary Headaches?

When a headache is “just a headache” without another underlying disease or problem, this is termed a “primary headache.” In this situation, a Neurologist can focus on finding triggers for the headache to avoid and – if needed – prescribe medications or other therapies to eliminate the head pain. This can improve quality of life, increase productivity at home or work, and decrease overall pain.When a headache is caused by another underlying condition, this is considered a “secondary headache.” The head pain is “secondary” to another cause. This is less common than primary headache, but the underlying causes can sometimes be concerning and require urgent evaluation and treatment.

Primary Headaches

Primary headache neurox
Primary Headache

Primary headaches involve head pain due to pain generated in the nerves around the skull, blood vessels around the brain or skull, muscles of the head or neck, or chemical or electrical activity in the brain. These can be divided into various categories, based on the presenting symptoms and patterns. An experienced knowledgeable Neurologist can take a detailed history and exam to pinpoint the type of headache, as the manner to treat and prevent various headache types varies. An accurate diagnosis of primary headache is of the utmost importance to having success at treating it. Common examples include:

secondary vs primary headache
  1. Migraine headache. This headache may be unilateral or behind the eyes, involve nausea or vomiting, involve sensitivity to light or sound. This headache is often progressive and worsens over a period of hours. Occasionally, an “aura” may be present, with is an additional symptom that occurs at the start of the migraine. This may involve an ocular aura with flashing or squiggling lights in the vision. However, the aura can also involve difficulties with speech, tingling, or even weakness.

  2. Tension headache. This headache is often described as a tight band around the forehead. This headache is often dull or throbbing.

headache migraine illustration
  1. Cluster headache. This headache is very severe and tends to come in spurts – or clusters – of brief severe headaches every day for weeks or months. The pain may be sharp and on one side of the face. The severity of these headaches can make them profoundly debilitating. A Neurologist will be able to recognize this headache syndrome and offer treatment options to get relief.

  1. Trigeminal autonomic cephalgias. This is an entire category of less common headache types including paroxysmal hemicrania, hemicrania continua, and others. With these headaches, there is also abnormal activity of the autonomic nervous system, which can cause excessive tearing, nasal dripping, a droopy eyelid, red eye, or unequal pupil sizes. The treatment of these headaches is quite different than other headache types, and often includes a trial of a non-steroidal anti-inflammatory medication called Indomethacin.

Secondary Headaches

Secondary headaches involve head pain that is due to another underlying condition. These vary from being benign (not serious), to more dangerous.

Common examples of relatively benign secondary headaches include:

  1. “Ice cream headaches” or “brain freeze.” This is due to excessively cold material having contact with the soft palate of the top of the mouth, which can irritate part of the nervous system called the sphenopalatine ganglion.

  1. Sinus headaches. Due to inflammation or congestion in the sinuses, sinus infectious or allergies can lead to this headache. Treating the underlying infection or allergy leads to relief of the headache.

  1. Medication overuse headaches. Occasionally, frequent use of opiates, acetaminophen, or non-steroidal anti-inflammatory medications (NSAIDs) can lead to rebound headaches. Typically, it is recommended to not take these pain medications more than four times a week to reduce risk of this.

  1. Not taking in enough fluids can cause headache.

  1. Caffeine withdrawal.

  1. Poor sleep. A lack of sleep or untreated obstructive sleep apnea can lead to headache.

  1. Cervicogenic headache. This headache is due to excessive muscle tension or arthritis in the neck at the base of the skull.

  1. Covid-19 related headaches. Frequent headaches following Covid-19 illness is becoming a more common phenomenon. Most of the time, this does not reflect an infection of the nervous system with the virus, but instead inflammation that simply needs time to dissipate.Examples of other secondary headaches that either require fixing the underlying cause or being more serious to overall health include:

  1. Meningitis or encephalitis. When a virus, bacteria, or fungus infects the covering of the brain or meninges, this can cause significant headache. Typically, this is associated with confusion, fever, and neck stiffness. This is a neurological emergency.

  1. Concussion or traumatic brain injury. Trauma to the head can result in recurrent headaches through this process.

  1. Intraparenchymal hemorrhage. Bleeding within the brain, often due to very high blood pressure or a broken blood vessel, can cause a serious headache and be life threatening. Typically, this will be associated with nausea and a focal neurological deficit, such as weakness, facial droop, or sensory loss.

  1. Subarachnoid hemorrhage. Bleeding around the brain in the subarachnoid space, often from a burst aneurysm, can be life threatening. This headache is often a “thunderclap” headache, reflecting the very sudden onset of the worst headache of the person’s life, as if someone suddenly clapped and it was profoundly severe.

  1. Cerebral Aneurysm or Arteriovenous Malformation (AVM). These blood vessel abnormalities – whether the outpouching of an aneurysm or the abnormal tangle of blood vessels of an AVM – can cause headaches. If diagnosed before they burst or break, treatment can be pursued to eliminate them before any serious damage is done.

  1. Giant Cell Arteritis (GCA). Sometimes called Temporal Arteritis, GCA is due to inflammation in a portion of the arteries in parts of the head. This autoimmune process can cause loss of vision or stroke. If diagnosed, steroids or immunotherapy can help both with the headache and preventing other complications

  1. Chiari malformation. This is an abnormality at the base of the skull that allows the brain to sag too low in the skull, causing headache. Occasionally, weakness, numbness, or incoordination can accompany the headache if the brain sags too low. Neurosurgery can fix this abnormality.

  1. Pseudotumor Cerebri, or Idiopathic Intracranial Hypertension. This headache is due to excessive pressure within the nervous system, without the presence of any true tumor or mass. This is occasionally seen with people with excessive body weight. If untreated, this can result in vision loss. Weight loss, medications, or cerebrospinal fluid shunts can help treat this pain and avoid complications.

  1. Brain Tumor. While often a worry of people with headache, fortunately a brain tumor is a less common cause of headache. The Neurologist can take a detailed history and exam to evaluate for certain features which may raise concern for this. If needed, an MRI of the brain with contrast can be performed to evaluate for this.

  1. Spinal Headache, or Intracranial hypotension. Due to low pressure within the nervous system, a spinal headache can occur after a spine procedure, spinal anesthesia, or trauma. This headache has a particular pattern and can be treated with increasing caffeine (which increases cerebrospinal fluid production), reducing activity, or a procedure called a blood patch.

  1. Trigeminal neuralgia. A severe sharp pain involving one side of the face that may be triggered by cold air, brushing of the skin or teeth, or other stimuli – trigeminal neuralgia can be very painful. This can occasionally be due to a blood vessel irritation to the trigeminal nerve or even multiple sclerosis attacking this nerve. Occasionally, no cause is found.

Questions Neurologists Ask About Headaches

A Neurologist will take a detailed history about the headache, including headache location, if the pain travels to anywhere, if any activities make the headache worse such as position change or straining, any associated symptoms, any triggers (such as food, stress, etc), headache frequency, and more. While it may seem like a lot of questions, these provide clues to the Neurologist as a detective to diagnose the headache or see if any further testing is needed.

This is of the utmost importance, so many times people can benefit from keeping a “headache diary” to reference later.

What are the “Red Flags” that Warrant Further Testing for a Secondary Cause?

An astute Neurologist can be aware that certain features of a headache can make it more or less likely to be a secondary headache or require further evaluation. One system for this is the “SNOOP” list. While these features do not always signify that there is a troubling underlying cause, they can warrant further investigations.

  1. Systemic Signs or Symptoms. Fever, weight loss, history of cancer, or other systemic findings.

  2. Neurologic Exam. While a normal neuro exam is reassuring, abnormalities such as weakness, sensory loss, abnormal speech, or difficulty walking can suggest the need for further evaluation.

  3. O If the headache is sudden like a “thunderclap” or only recently new onset, this may warrant further evaluation. Conversely, if the headache began to occur more than 6 months prior, that can be reassuring.

  4. Onset age. If the headache occurs for the first time before the age of 5 or after the age of 50, this may warrant an MRI of the brain.

  5. P If the overall pattern of the headache is getting worse or is changing over a period of weeks or years, this may warrant further testing.

In contrast with the SNOOP list, reassuring features would be a headache that has predictable or consistent triggers, if the person feels normal without problems between headaches, and if the headache pattern has been stable for over 6 months.

Tests to Evaluate Secondary Headaches

If the Neurologist does suggest further testing to evaluate for a secondary cause of headache, this may include an MRI of the brain, a lumbar puncture or spinal tap, or imaging of the blood vessels of the head or neck.

Primary headaches are more common than secondary headaches and not everyone requires this advanced testing, so make sure to talk to a Neurologist through NeuroX to both get relief from your headache and also make sure there is no other lurking cause.

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