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- Headache is common with many types and causes but most are benign
- Diagnose type of headache by taking a detailed history and performing a targeted examination
- Neuroimaging is not needed for people with normal neurological examination and no 'red flags'
- Discuss risks and costs of neuroimaging
Headache is common but most are benign
Global 1-year prevalence data show that about 1 in 2 people have had a headache: with 4 in 10 a tension-type headache and 1 in 10 a migraine. (Cluster headache was not reported because there are few population-based studies using International Headache Society criteria.)1
Discuss your diagnosis and provide information about how to manage headache
Explain that most headaches are benign (also known as primary headache). Diagnostic tests and investigations are not usually needed for primary headache.2 To help with the right diagnosis, suggest people use a headache diary for a few weeks (e.g. 4–6 weeks).2-4 A headache diary can be used to record details such as frequency, severity,
suspected triggers and medicines use; and is more likely to be an accurate account than recollection alone.3 This information can inform discussion of symptoms
and the impact of headache on quality of life, guide therapy and ensure appropriate follow up.4
Often people suffer from episodes of both tension-type and migraine headaches. Other types of headache are not discussed in this publication (e.g. medication-overuse headache: refer to NPS News 38 ).5
Most headaches are self-limiting and non-disabling: provide information, reassurance and suggestions for treating symptoms as needed. Most people can manage their headache symptomatically with over-the-counter analgesics and/or non-drug strategies (for more information, see NPS News 38 and NPS News 79).5,6 Identifying and eliminating trigger factors (e.g. lack of sleep) can reduce headaches.
Table 1: Diagnostic criteria for three types of primary headache in adults
(Adapted from the International Classification of Headache Disorders, 2nd edition8)
Headache lasting 30 minutes to 7 daysAt least two of:
Headache lasting 4–72 hours
At least two of:
At least one of:
Differentiating between migraine without aura and episodic tension-type headache may be difficult:
Headache lasting 15–180 minutes
Be alert for 'red flags' when diagnosing headache
Identifying a serious cause of secondary headache is an essential part of the initial diagnosis. 'Red flag' symptoms and signs are listed in Box 1. Consider secondary headache in anyone with new-onset acute headache or headache different from their usual headache.4 In the context of a comprehensive history and, careful physical and neurological examinations, the presence of red flag symptoms and signs may indicate the need for investigation, such as neuroimaging.7
Box 1: Some 'red flags' when diagnosing headache3,9
A 'new-onset' headache in a person
Headache associated with
Neuroimaging is not usually needed unless a red flag is present.2,10 Neuroimaging is unlikely to show the cause of primary headache and can result in incidental findings. Consider neuroimaging for people whose history and physical and neurological examinations suggest that their headache may be secondary to a serious cause (see above).
Neuroimaging is unlikely to show the cause of primary headache
Most people who present with headache have a primary headache disorder such as tension-type, migraine or cluster headache (Table 1).7 These people are likely to have normal examinations and are unlikely to have any red flag symptoms and signs. Neuroimaging is unlikely to show a cause because primary headaches do not result from structural brain abnormalities.7
Consider neuroimaging for people whose history and examination suggest that their headache may be secondary to a serious cause
People with an abnormal neurological examination are more likely to show a serious cause of headache with neuroimaging.4,11
For example, in a recent 5-year case series of 3655 people with acute headache, 530 had neuroimaging. Some of these people had a red flag indicating a possible serious cause of secondary headache while others did not (but, for example, some had hemiplegic migraine or cluster headache). All 11 serious causes of headache identified by neuroimaging had a red flag.12 Neuroimaging showed many insignificant findings that were unrelated to the headache: in about 1 in every 3 CT scans and about 1 in every 2 MRIs. The number of insignificant abnormalities seen is greater with MRI than with CT imaging (46% and 25%, respectively).12
Box 2: Some serious causes of secondary headache2,3
Neuroimaging can result in incidental findings
Bear in mind the medical, practical and ethical issues associated with incidental findings — neurological abnormalities incidental to the reason for neuroimaging. Incidental findings may cause patient anxiety and clinician uncertainty (which may result in further inappropriate investigations and/or treatment with associated risks).
A recent Canadian audit of CT scans detected incidental findings in about 20% of cases (compared with about 2% of findings potentially related to headache).13
A meta-analysis showed one incidental finding for every 37 people who did not have neurological symptoms and who had a brain MRI (for research purposes or, occupational, clinical or commercial screening).14
Neuroimaging has risks and costs. These include risks of the procedure (e.g. exposure to ionising radiation, adverse effects of contrast agents), risks in interpreting the results (e.g. incidental findings, false positives/negatives); and financial and logistic costs (e.g. out-of-pocket expenses to the individual, cost to the health system, waiting time, transport to and from the imaging facility).
Exposure to ionising radiation from a single head CT scan is estimated to increase the average lifetime attributable risk of death from cancer by 0.005% for a 45 year old person.15 Although the individual risk is small, increasing CT use contributes to increased mortality at a population level.15 Radiation dose varies depending on the source: there is no "safe" dose and all doses contribute to lifetime risk (Table 2).16 A 2005 report found that Australian GPs ordered a CT of the brain or head in about 1 in 10 headache problems.17 Avoid ionising radiation in pregnancy or when there is a possibility of pregnancy.9
Table 2: Some radiation sources and doses16
|Source of radiation exposure||Radiation dose millisieverts (mSv)||Range (mSv)|
(Average yearly dose Australians are unavoidably exposed to)
|Chest X-ray 2 views||0.08||0.05–2|
Alessandro S Zagami
Senior Staff Specialist in Neurology, Institute of Neurological Sciences, Prince of Wales Hospital Conjoint Associate Professor, Prince of Wales Clinical School, University of New South Wales
Consultant Neuroradiologist, Neurological Intervention and Imaging Service of Western Australia
Any correspondence regarding content should be directed to NPS. Declarations of conflicts of interest have been sought from all reviewers.
- Stovner LJ, Hagen K, Jensen R, et al. The global burden of headache: a documentation of headache prevalence and disability worldwide. Cephalalgia 2007;27:193–210.
- British Association for the Study of Headache. Guidelines for all health professionals in the diagnosis and management of migraine, tension-type headache, cluster headache and medication overuse headache. Hull: BASH, 2010. (accessed 13 December 2011).
- Therapeutic Guidelines: Neurology, Version 4 Updated November 2011 [eTG complete CD-ROM]. Melbourne: Therapeutic Guidelines Ltd, 2011.
- Scottish Intercollegiate Guidlines Network. Diagnosis and management of headache in adults. Edinburgh: NHS Quality Improvement Scotland, 2008. (accessed 19 December 2011).
- Headache and migraine. NPS News 38. Sydney: NPS, 2005. (accessed 13 December 2011).
- Headache: Diagnosis, management and prevention. NPS News 79. Sydney: National Prescribing Service, 2012. (accessed 1 June 2012).
- Schaefer PW, Miller JC, Singhal AB, et al. Headache: when is neurologic imaging indicated? J Am Coll Radiol 2007;4:566–9.
- IHS Classification ICHD-II. London: International Headache Society, 2004. (accessed 13 December 2011).
- Mendelson R. Diagnostic imaging pathways - headache. Perth: Government of Western Australia: Department of Health, 2011. (accessed 13 December 2011).
- Zagami AS, Goddard SL. Recurrent headaches with visual disturbance. Med J Aust 2012;196:178–83.
- Detsky ME, McDonald DR, Baerlocher MO, et al. Does this patient with headache have migraine or need neuroimaging? JAMA 2006;296:1274–83.
- Clarke CE, Edwards J, Nicholl DJ. Imaging results in a consecutive series of 530 new patients in the Birmingham Headache Survey. J Neurol 2010;257:1274–8.
- You JJ, Gladstone J, Symons S, et al. Patterns of care and outcomes after computed tomography for headache. Am J Med 2011;124:58–63.
- Morris Z, Whiteley WN, Longstreth WT, et al. Incidental findings on brain magnetic resonance imaging: systematic review and meta-analysis. BMJ 2009;339:b3016.
- Brenner DJ, Hall EJ. Computed tomography - an increasing source of radiation exposure. N Engl J Med 2007;357:2277–84.
- Wallace A, Cain T, Goergern S, et al. Radiation risk of medical imaging for adults and children. Inside Radiology. Sydney: The Royal Australian and New Zealand College of Radiologists, 2009. (accessed 23 February 2012).
- Charles J, Ng A, Britt H. Presentation of headache in Australian general practice. Aust Family Physician 2005;34:618–9.