Cranial arteritis M31.6

Hutchinson 1890; Horton 1934

Chronic, segmental, granulomatous, obliterating "large vessel" vasculitis, usually manifesting in the carotid artery and its branches. Preferential involvement of the temporal artery, ophthalmic artery, facial artery, occipital artery, lingual artery, maxillary artery with corresponding symptoms. There are no large vessels on the skin; however, the disease can affect vessels that supply skin areas, possibly leading to circumscribed necrosis.

Remark: 50% of the patients suffer additionally from polymyalgia rheumatica! 20% of patients with polymyalgia rheumatica also suffer from cranial arteritis.

Incidence: 9/1,00,000 population, in < 50-year-olds: <5/100,000; Dec 6: 40/100,000; Dec 7: 40/100,000 ; Dec 8 50/100,000 population.

The annual incidence in northern Europe is >17/100,000 in persons > 50 years of age. In southern Europe, the incidence is <12/100,000.

Unknown! A T-cell-dependent (auto)immune event with genetic predisposition is discussed.

Associations with viral infections (HBV, VZV, Parvovirus B19; SARS-CoV-2 - Mursi AM et al.2022) or Borrelia, Mycoplasma and Chlamydia (Chlamydia pneumoniae) are discussed. The occurrence of giant cell arteritis has been observed frequently after vaccination with covid vaccines (Mejren A et al. 2022).

Pathogenetically, it is a granulomatous giant cell arteritis in the area of media and adventitia of the affected arterial segments with consecutive sclerotic vessel wall aging.

Age group > 50 years; preferred in women (75%), mostly in Caucasians.

Sudden onset of disease!

General symptoms: initially: throbbing, temporal headache, fever, feeling sick, arthralgias, myalgias, morning stiffness and weight loss. 50% of patients have concomitant polymyalgia rheumatica. Furthermore: orthostatic dizziness (40%); seizures and hemiparesis (<10%); nonspecific skin involvement: erythema nodosum or urticaria (15%).

Arteriitis cranialis with variable often simultaneous pattern of involvement (Note: A. temporalis affected in most cases):

Temporal artery: often severe unilateral or bilateral throbbing headache, especially temporal and frontal (50%), not infrequently pain when chewing (jaw claudication; masseteric claudication), redness in the area of the cord-like thickened temporal artery: not infrequently small or large necroses of the skin (and galea) in the catchment area of the temporal artery may occur.

Ophthalmic artery (30% of cases): Visual disturbances, amaurosis fugax, risk of blindness; possibly double vision (diplopia).

Arteria lingualis: on the tongue painful redness, blisters, necrosis.

Apparative Diagnostics:

• Assessment of the temporal artery in lateral comparison (hardened, tortuous arteries, palpable, side-differentiated pulsations.
• Doppler sonographic examination of the head arteries (including exclusion of high-grade internal carotid artery stenosis).
• Color duplex of the temporal arteries (wall thickening, pulsations).

Histopathological algorithm of giant cell arteritis (lowest common denominator: italic, leading symptoms: bold) varies n. Ratzinger et al. 2105

Betriff arteries of the subcutis and deeper tissues.

Perivascular, intramural, and/or intraluminal leukocytoclasia.

Damage to endothelial cells

Fibrin in/in the area of vessel walls

Perivascular extravasation of erythrocytes

No edema in the papillary dermis

Characteristic giant cells, most commonly near the internal elastic membrane

Pathol. Changes limited to vessel, no extravascular, interstitial or soft tissue granulomas

No eosinophils

Plasma cells or fibrosclerosis to variable extent

Reorganization due to lymphocytic vasculitis

Clinical diagnosis according to American College of Rheumatology (ACR) criteria for diagnosis of temporal artery (Hunder et al. 1990):

age: > 50 years

new onset headache

Abnormal temporal arteries (pressure dolence, attenuated pulsation).

ESR > 50 mm in the first hour.

Histological changes on biopsy of temporal artery (Important: segmental vasculitis "skip lesions"; several biopsies may be necessary! Previous arterial Doppler to exclude flow murmurs!).

If 3 of 5 criteria are met, a sensitivity of 75-95%, a specificity of 90-93%, a positive predictive value of only 29% and a negative predictive value of 99% are achieved.

Furthermore, rheumatoid factor or antibodies against CCP (cyclic citrullinated peptide), CRP should be determined.

If necessary, biopsy of the temporal artery (possibly bilateral, approx. 3 cm long segment due to segmental involvement). Note: Before biopsy, doppler sonographic clarification of the arterial flow conditions.

Circumscribed necrosis, blindness, apoplexy, myocardial infarction.

In case of resistance to therapy, additional cyclophosphamide. Duration of therapy until freedom from symptoms and normalization of inflammation values.

Therapeutic goal is the reduction of vascular wall inflammation. Indicators are the humoral inflammatory symptoms. Of crucial importance is the ocular symptomatology. Flow in the central retinal artery should be measured and can be included as a therapeutic control symptom.

Glucocorticoids: Prednisone equivalents at an initial dosage of 1.0-1.5 mg/kg bw for 7-14 days, then reduction by 10 mg/day to a dosage of 25-40 mg/day for 4 weeks; further reduction by 5 mg/week to a maintenance dose of < 10 mg/day p.o. for 1 year. Subsequent therapy according to clinic (acute-phase response as indicator of inflammatory symptomatology).

Already in case of unilateral ocular symptomatology (visual disturbances up to blindness), higher prednisone equivalents (1.5-2.0 mg/kg bw/day) should be started. If this therapy regime is not sufficient (recurrences during treatment), an additive therapy with cyclophosphamide (2 mg/kg bw/day) according to the standard regimen of Fauci is necessary. This can still benefit about 4% (!) of glucocorticoid-resistant patients. As an alternative to cylophosphamide, methotrexate can be administered.

Non-steroidal anti-inflammatory drugs: Complementary to the therapy with glucocorticoids NSAIDs in medium dosage.

In 2017, the IL-6 receptor inhibitor tocilizumab (e.g., Actemra®) was approved as a biologic that demonstrated efficacy in RZA and showed superiority to glucocorticosteroids. The drug has already been approved for rheumatoid arthritis (RA) since 2009.