Dr Kevin McCarroll
Headache is one of the most common reasons for visiting your GP and accounts for about 25% of new referrals to neurologists. Nearly 50% of adults suffer from headaches in the last year and it is attributed as a reason for up to 20% of work absences. In Ireland, migraine attacks alone are estimated to affect up to 400,000 people annually and cost up to €250 million per year in lost work days.
In addition, research suggests that up to one in five Irish people experience a headache once a week or more leading to a huge consumption of the over-the-counter painkillers.
Whilst there are many secondary causes of headache, the commonest primary reasons are tension type and migraine. In most cases, diagnosis is based entirely on patient history.
Tension type headache affects about 40% of adults. It is characterised by a constant, tight gripping, but non-pulsating sensation that is often felt over both temples or behind the eyes and in many cases is also generalised.
It may last for as little as 30 minutes to up to several days and is often precipitated by stress. It is believed to be due to activation of pain receptors in the muscular tissue in our scalp and can be quite severe. It does however respond to simple anti-inflammatories like ibuprofen which can be taken with paracetamol.
Migraine affects about 10% of the population, is often underdiagnosed and undertreated but yet is the most common headache type in those seeking medical help. Pain is usually throbbing or pulsating and often only involves one side of the head. In up to 80% of sufferers it can be of disabling intensity and in about one third of cases requires bed rest during an attack.
Acute attacks typically last from between four hours to up to three days. An important distinguishing feature from tension type headaches is the presence of nausea, sensitivity to light and exacerbation with physical activity. In addition, in about 20% of cases an aura is present (visual, sensory or occasionally speech symptoms) that appear gradually and can last for up to 60 minutes. Of these, visual disturbances are the most common and include flickering lights, spots or lines though numbness and pins and needles can also occur.
Unclear
The cause of migraine is unclear but evidence suggests it is due to activation of pain receptors around blood vessels (which may go into spasm) as well as in other brain areas. There are several potential triggers including certain foods like chocolate and cheese, alcohol, hormonal changes around menstruation or puberty, the contraceptive pill, hunger, dehydration, caffeine excess or withdrawal, stress and sleep deprivation. Treatment of acute migraine is with anti-inflammatories and/or a specific class of tablets called triptans that appear to reduce spasm in the arteries. It can be difficult to ascertain what are the potential triggers and keeping a headache diary can help in identifying them. More than a quarter of migraine sufferers have recurrent attacks which requires them to go on any of a number of preventative treatments.
‘Medication overuse’ headache is a daily or almost daily headache that can occur in those who take painkillers chronically for migraine or tension headaches. It may in fact be the third most frequent cause of headache. Treatment involves gradually reducing culprit painkillers and substituting with preventative medications.
Cluster headaches are relatively rare but occur in groups, can be very severe and present with intense pain around one eye with bouts of frequent attacks sometimes lasting for months. The majority (70%) present before the age of 30 and medications can be used for both acute symptoms as well as prevention which is generally managed by a neurologist.
There are several ‘red flag’ features which suggest a more serious cause for headache. A sudden severe onset with maximum intensity within seconds to minutes is suggestive of an intracranial bleed. The presence of neck stiffness or a rash and difficulty looking at bright lights may indicate meningitis. Headaches that are worse after sneezing or coughing may be due to raised intracranial pressure. Furthermore, any headache which has changed dramatically in nature, failed to respond to treatment, occurs after head trauma or is associated with neurological features (other than migraine) such as altered consciousness or confusion needs urgent investigation.
There are several secondary causes of headaches. An acute form of glaucoma can lead to increased pressure in the eye causing blurred vision and headache. Referred pain from other areas may also give rise to headache such as from dental cavities, inflamed sinuses (sinusitis), ear infection and arthritis in the jaw or neck.
Fever and viral infections like the flu can cause a generalised headache. Neuralgia due to impingement of the trigeminal nerve can cause severe and episodic shooting or stabbing pain affecting the forehead, eyes and mouth. Treatment options include tablets, local injections and surgery.
Finally, it would be remiss of me not to mention the headache (hangover) caused by alcohol consumption. The exact cause is not known but several factors play a role including dehydration, reduced sleep quality and also its effect on blood vessel dilatation. In addition, congeners or chemicals which account for alcohol’s colour and flavour and are found in larger amounts in dark liquors, such as brandy, whiskey and red wine, can contribute to hangovers. Hydrating well with water, simple over the counter painkillers and extra bed rest, as needed, will help!
Dr Kevin McCarroll is a consultant physician in geriatric medicine in St James’ Hospital, Dublin.