Secondary headache

The vast majority of patients have primary headaches such as migraine, tension-type headache, and less commonly, cluster headache. However, secondary headaches account for around 10% of headaches presented in primary care. Secondary headache is common in patients with systemic infections and may also occur in association with head injury, vascular disorders or overuse of various drugs.

The most common causes of secondary headache are fasting (19%) and nasal/sinus disorders (15%), with only a small minority due to a more sinister condition such as non-vascular intracranial disease (including tumour).^[1] Warning signs of secondary headache include:

• Sudden onset (thunderclap headache)
• New headache onset after age 50 years
• Systemic signs (e.g. fever, myalgia, weight loss)
• Systemic disease (e.g. malignancy, AIDS)
• Change in headache pattern
• Progressive headache with loss of headache-free periods
• Change in frequency, severity or characteristics of headache
• Neurological symptoms or abnormal physical findings.

Almost all headaches that are encountered in primary care are subtypes of migraine, tension-type headache or chronic daily headache, and it is very rare that they are the result of a more serious condition.^[2] Nevertheless, physicians may have very real concerns about the presence of an underlying sinister disease in those patients who present with headache for the first time. The Headache Care for Practising Clinicians guidelines provide a proposed algorithm for the exclusion of sinister headache in primary care.^[2] If sinister headache is suspected, a full neurological examination is essential.

References:
1. Lipton RB, Bigal ME, Scher AI, Stewart WF. The global burden of migraine. J Headache Pain 2003;4: S3–S11.
2. Dowson AJ, Sender J, Lipscombe S, Cady RK, Tepper SJ, Smith R, et al. Establishing principles for migraine management in primary care. Int J Clin Pract 2003;57: 493-507.