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Headache is a very common presenting complaint that can be encountered in most healthcare settings. However, there are a wide range of different types of headaches and while some are chronic and benign, some are worrying and require emergency care. It is important therefore to be able to spot the red flags to be able to determine the severity of a headache presentation.
In this article, the red flags of headaches will be explained, as well as describing some of the most common types of chronic headaches, their characteristics and the features that help differentiate them from each other.
To figure out red flags in headaches, let’s first explore the potential causes for acute headaches. What is important to establish with headaches is whether they are primary (i.e. idiopathic) or secondary (i.e. there is an underlying condition causing it).
Examples of secondary headaches that will prompt rapid investigation and emergency assessment are those due to a vascular condition (e.g. subarachnoid haemorrhage, sinus venous thrombosis, giant cell arteritis), infection or inflammation of the brain (e.g. meningitis, encephalitis, brain abscess), ophthalmic emergencies (e.g. acute glaucoma), or systemic hypertension, caused by pre-eclampsia for instance.
Many of these pathologies can increase intracranial pressure, which can manifest with specific signs such as papilloedema.
A vascular cause such as a subarachnoid haemorrhage presents with a ‘thunderclap’ headache that is sudden in onset and very intense. These should narrow the diagnosis towards a vascular cause and should be treated as an emergency.
Accompanying systemic symptoms could indicate infection or systemic hypertension.
Neurologic symptoms can be indicative of glaucoma or presence of a space-occupying lesion.
Any new-onset headache in patients over 50 years old should be treated as a suspected malignancy until proven otherwise.
The following mnemonic can be used to memorise the main red flags: SPOON.
Table - The red flag symptoms of headaches, and which emergency condition each symptom might indicate
For more details on the investigation, diagnosis, and management of some of these secondary headaches, refer to the specific articles.
Brain tumours are a concern for many patients presenting with chronic headaches. It is important to ask specific questions to help rule this out before reassuring the patient, including signs of raised intracranial pressure, focal neurological signs (including more vague things such as personality change), and onset in patients over 50.
The most common type of brain tumour is a secondary brain tumours, as a result of metastasis from other types of tumours. Tumours that commonly metastasise to the brain include lung, breast, colon, kidney and skin cancers.
Primary brain tumours (that originate in the brain), on the other hand, are quite rare with only 11 000 people diagnosed with a primary brain tumour each year in the UK (source), only half of which will be cancerous.
Primary brain tumours are classified as either benign or malignant. Benign brain tumours are low grade (1 or 2), they usually have a slower growing rate and have a better prognosis whereas malignant brain tumours are high grade (3 or 4) and have a worse prognosis.
There are over 130 types of brain tumours (source) and these are named after the cell type they originate from. Astrocytomas are the most common types of primary brain tumour. They develop from astrocytes and form so-called ‘gliomas’. These can be low grade and slow growing, but can be aggressive and malignant, known as glioblastoma multiforme. Other types of brain tumours include neurofibromas (which originate from Schwann cells), ependymoma (these originate from the ependymal cells found adjacent to the CSF as they line the ventricular system), and neuronal tumours (from neurones but these are very rare).
Migraine usually presents as a unilateral, frontal headache, that often described as throbbing or pulsating. Episodes last from 4 to 72 hours. Migraine headaches are typically aggravated by light and noise, meaning patients may report phono- or photophobia, and prefer to be in a quiet, dark room. Most patients with chronic migraines find that going to sleep can help relieve symptoms, as well as taking medications such as triptans.
Some migraine episodes can be preceded by what is known as an ‘aura’, a characteristic feeling (can be visual, like flashing lights, sensory, like a strange smell or taste, etc.) and accompanied by nausea and vomiting in more severe cases. Some patients with chronic migraines find that their aura is so characteristic that they can predict when the headache is coming and can take medications to try to prevent the headache.
Pathophysiology of migraine is still unclear but there are factors that can trigger episodes such as certain foods (cheese, chocolate), stress, or lack of sleep. Family history also seems to play a role in susceptibility, and it affects women more than men. Most patients who suffer from migraines will have had their first episode before their 30s and the severity of the episodes seems to decrease with age.
Tension headache is the most common type of headache and typically presents as a bilateral frontal headache, sometimes radiating to the neck. It is often described as a squeezing, band-like type of pain and non-pulsatile with a mild to moderate intensity. It is usually worse at the end of the day as it is aggravated by stress, sleep deprivation, and poor posture.
It is considered chronic if it happens over 15 times per month or episodic if it happens less than that. It also affects women more than men and younger people. Onset after 50 years of age is unusual and should be seen as suspicious and malignancy should be excluded via investigations. In some cases, it can also present with mild nausea but usually responds to analgesics and rest. Pathophysiology is thought to be linked to tension building up in the occipitofrontalis muscle of the head and neck.
Medication overuse headache paradoxically arises from taking analgesia in the first place, most commonly as a treatment of headaches. It often presents with other co-morbidities such as depression and insomnia and can manifest with a variety of symptoms. It affects women more than men and typically within the 30-40 age range.
To be diagnosed as medication overuse headache, the headache must be present over 15 days per month, and the patient must be overusing analgesia. Overuse depends on the type of medication used: for paracetamol and ibuprofen, overuse is defined as using over 15 days per month, and for stronger medications like opioids or triptans, overuse is defined as using over 10 days per month. The mechanism behind this is thought to be due to an upregulation of the pain receptors in the brain.
Management consists in discontinuing the medication, which will worsen the symptoms before it improves them, usually within two months.
Cluster headaches are an intense type of headache that is localised to the orbital area (patients usually complain of pain around or behind the eye) and described as sharp and penetrating. This is a type of headache that is more common in men than women and onset occurs between 20 and 40 years old. Onset of this type of headache is usually sudden and ‘attacks’ last from a few minutes up to a couple of hours and can occur several times a day for clusters of 2 to 12 weeks, with remissions of months to years between the clusters. Like tension headaches, they can be chronic or episodic.
They most commonly present at night and to be a diagnosed cluster headache there must also be signs of impaired sympathetic activity such as red, watery eyes, ptosis and nasal congestion. Episodes are also associated with a variety of triggers such as alcohol, histamine, GTN spray, heat, exercise, sleep deprivation and inhalation of solvents. Other factors thought to increase susceptibility are head trauma, alcohol consumption and smoking. Pathophysiology is still not well understood but analgesics and high flow oxygen have shown to relieve symptoms in some cases.
Trigeminal neuralgia is a unilateral headache that occurs usually around the eye but can radiate to the lips, nose, and scalp, around the distribution of the trigeminal nerve (CN V). It is described as sharp and stabbing in nature almost like an ‘electric shock’ and it is severe in intensity.
Trigeminal neuralgia affects women more than men and has an increased incidence with age, usually peaking within the 50-60 age range.
Episodes occur with a rapid onset and last for a few seconds to minutes. Some triggers or factors that can make symptoms worse include eating, cold wind, vibration, or light touch to the face. It can also present with numbness and tingling in the area preceding the episode, almost like an aura. It is caused by compression of the trigeminal nerve, usually by a vascular malformation although there can be other pathological causes such as tumours or multiple sclerosis. Symptoms are usually difficult to relieve, but antiepileptics can be useful in some patients.
As described above, due to the many different types of headaches, it is important to gather a comprehensive history from patients to help narrow the diagnosis as management relies on the cause of the headache.
For chronic headaches, such as the ones mentioned previously, simple analgesia usually suffices or triptans in the case of migraines. However, any suspected red flag headaches should be treated as an emergency and referral for urgent care should be done if suspecting malignancy, raised intracranial pressure, or if there is presence of seizures, a change of personality, previous cancer, or any unexplained focal deficits.
It can be helpful to ask patients to keep a headache diary for the more chronic presentations although in acute cases, the investigation of choice is imaging – using either CT or MRI scans.
Edited by: Dr. Maddie Swannack
Reviewed by: Dr. Thomas Burnell
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