6.4.1 Headache attributed to giant cell arteritis (GCA)

Previously used term:

Headache attributed to temporal arteritis.

Description:

Headache caused by and symptomatic of giant cell arteritis (GCA). Headache may be the sole symptom of GCA, a disease most conspicuously associated with headache. The features of the headache are variable.

Diagnostic criteria:
  1. Any new headache fulfilling criterion C
  2. Giant cell arteritis (GCA) has been diagnosed
  3. Evidence of causation demonstrated by at least two of the following:
    1. headache has developed in close temporal relation to other symptoms and/or clinical or biological signs of onset of GCA, or has led to the diagnosis of GCA
    2. either or both of the following:
      • a) headache has significantly worsened in parallel with worsening of GCA
      • b) headache has significantly improved or resolved within 3 days of high-dose steroid treatment
    3. headache is associated with scalp tenderness and/or jaw claudication
  4. Not better accounted for by another ICHD-3 diagnosis.
Comments:

Of all arteritides and collagen vascular diseases, giant cell arteritis (GCA) is the disease most conspicuously associated with headache, which is due to inflammation of cranial arteries, especially branches of the external carotid artery. The variability in the features of 6.4.1 Headache attributed to giant cell arteritis and in the other symptoms of GCA (polymyalgia rheumatica, jaw claudication) are such that any recent persisting headache in a patient over 60 years of age should suggest GCA and lead to appropriate investigations.

Recent repeated attacks of amaurosis fugax associated with headache are very suggestive of GCA and should prompt urgent investigations. The major risk is of blindness due to anterior ischaemic optic neuropathy, which can be prevented by immediate steroid treatment; the time interval between visual loss in one eye and in the other is usually less than 1 week. Patients with GCA are also at risk of cerebral ischaemic events and of dementia.

Histological diagnosis can be difficult, because the temporal artery may appear uninvolved in some areas (skip lesions), pointing to the necessity of serial sectioning.