This type of inflammatory disease of cranial arteries is an important cause of headache in older persons. All of our patients have been older than 55 years of age, most of them older than age 65. From a state of normal health, the patient develops an increasingly intense throbbing or nonthrobbing headache, often with superimposed sharp, stabbing pains. In a few patients the headache has had an almost explosive onset. The pain is usually unilateral, sometimes bilateral, and often localized to the site of the affected arteries in the scalp. The pain persists to some degree throughout the day and is particularly severe at night. It lasts for many months if untreated. The superficial temporal and other scalp arteries are frequently thickened and tender and without pulsation. Jaw claudication and ischemic nodules on the scalp, with ulceration of the overlying skin, have been described in severe cases.
Many of the patients feel generally unwell and have lost weight; some have a low-grade fever and anemia. Usually the sedimentation rate is greatly elevated (>50 mm/h and typically >75 mm/h) but elevation of the C-reactive protein (CRP) level is a more sensitive indicator of this inflammatory condition and is particularly helpful when the sedimentation rate is only mildly elevated. A few patients have a peripheral neutrophilic leukocytosis. Half of patients have generalized aching of proximal limb muscles, reflecting the presence of polymyalgia rheumatica (see Chap. 45, “Polymyalgia Rheumatica”). A relation of temporal arteritis to herpes zoster has been proposed.
The importance of early diagnosis relates to the threat of blindness from thrombosis of the ophthalmic or posterior ciliary arteries. This may be preceded by several episodes of amaurosis fugax (transient monocular blindness). Ophthalmoplegia may also occur but is less frequent, and its cause, whether neural or muscular, is not settled.
Masticatory claudication is a specific but not particularly sensitive symptom of cranial arteritis. The large intracranial vessels are occasionally affected, thereby causing stroke. Once vision is lost, it is seldom recoverable. For this reason, the earliest suspicion of cranial arteritis should lead to the administration of corticosteroids and then to biopsy of the appropriate scalp artery. Microscopic examination discloses an intense granulomatous or “giant cell” arteritis. If biopsy on one side fails to clarify the situation and there are sound clinical reasons for suspecting the diagnosis, the other side should be sampled. Arteriography of the external carotid artery branches is probably the most sensitive test but is seldom used, because of its relatively higher risk. Ultrasonographic examination of the temporal arteries may display a dark halo and irregularly thickened vessel walls. This technique has not been incorporated into routine evaluation because its sensitivity has not been established; our own experience suggests that it may miss cases, but it could be useful in choosing the site for biopsy of the temporal artery.
The administration of prednisone, 45 to 60 mg/d in single or divided doses over a period of several weeks, is indicated in all cases, with gradual reduction to 10 to 20 mg/d and maintenance at this dosage for several months or years, if necessary, to prevent relapse. The headache can be expected to improve within a day or two of beginning treatment; failure to do so brings the diagnosis into question. When the sedimentation rate or CRP is elevated, its return to normal, usually over months, is a reliable index of therapeutic response. Whether symptoms or the blood tests are a better guide to reducing the steroid dose is unclear, one should probably be cautious in lowering the medication if the erythrocyte sedimentation rate (ESR) and CRP remain high.
Headaches of Pseudotumor Cerebri (Benign or Idiopathic Intracranial Hypertension,
See Chap. 29)