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Giant Cell Arteritis

*Arteritis gigantocellularis*

For medical students2 min readUpdated 2026-10-10

Giant Cell Arteritis (also known in clinical practice as temporal arteritis or Horton disease) is a specific granulomatous inflammation affecting predominantly the temporal arteries. The disease is characterized by primary destruction of the internal elastic membrane of the vessel, followed by the formation of a cellular infiltrate, which ultimately leads to critical narrowing of the arterial lumen.

Main TargetTemporal and, less commonly, other cranial arteries

Risk GroupElderly and senile patients (females are affected twice as often)

GeneticsDemonstrated association with HLA-DR antigens

Dangerous ComplicationRisk of vision loss due to involvement of retinal vessels

Epidemiology and Localization Variants

This pathology has a very specific epidemiological profile. The disease is a typical problem of the older age group and is diagnosed predominantly in elderly and senile patients. An important demographic feature is a pronounced gender disparity: statistically confirmed, women are susceptible to this disease twice as often as men.

From the topographic perspective of the pathological process, several clinical variants are distinguished:

Main form: characterized by isolated involvement of the temporal arteries. This feature gave the disease its alternative historical name.
Generalized form: granulomatous inflammation extends beyond the cranial basin and involves the mesenteric arteries, coronary arteries of the heart, and major limb vessels.
Giant cell aortitis: a prognostically significant variant in which specific lesions are localized directly within the wall of the aortic arch.

Clinical Presentation

The symptoms of the disease directly stem from morphological changes in the vascular bed and the localization of the affected arteries. The most typical and early symptom is pronounced pain. Patients experience acute or prolonged chronic head pain, which closely resembles a classical migraine in character.

Visual inspection frequently reveals local scalp inflammation that strictly follows the anatomical course of the affected blood vessel. The most severe and disabling clinical manifestation of this arteritis is the risk of blindness. Vision loss is due to the ability of the inflammatory process to spread to the retinal arteries of the eye, impairing its blood supply.

Etiological Factors and Pathogenesis

Despite long-term study of Horton disease, its exact etiology remains unknown. Researchers have failed to identify a specific trigger that initiates the disease. However, genetic predisposition is clearly traced in the pathogenesis: a reliable association between the development of arteritis and the presence of HLA-DR antigens in the patient has been established.

The pathogenetic mechanism is based on a cellular immune response. Histological examination within the thickness of the affected arterial wall reveals the presence of immunocompetent cells — CD4+ T lymphocytes and macrophages. These cells sustain the cascade of reactions leading to the destruction of the vessel's own tissues.

Morphological Changes

The pathological anatomy of giant cell arteritis is very specific and progresses through a series of sequential stages that can be observed under a microscope:

Initiation of the process: the primary morphological substrate is the destruction (degeneration) of the internal elastic membrane of the arterial wall.
Reactive phase: in response to the damage of elastic structures, a subsequent granulomatous cellular reaction develops.
Cellular composition: lymphocytes and macrophages predominate in the focus of inflammation. A key diagnostic marker is the appearance of foreign-body giant cells. These cells group around fragments of destroyed elastic fibers.
Outcome of inflammation: the chronic course predictably culminates in fibrous thickening of the inner layer of the vessel (intima). The proliferation of connective tissue leads to marked stenosis (narrowing) of the arterial lumen.
Complications: due to endothelial damage and blood flow stasis in the stenotic zone, thrombi may form within the lumen of the affected vessel, leading to complete occlusion.

Mnemonic

The rule of three "V's" (in Russian, V) for Horton disease: Vozrast (Age — elderly and senile patients), Visok (Temple — main localization of inflammation), Videnie (Vision — risk of vision loss due to retinal vessel involvement).

Frequently asked questions

What macroscopic changes of the temporal artery are detected in Horton disease?

In Horton disease, macroscopic examination reveals segmental involvement of the temporal arteries with marked narrowing of their lumen. The main changes in the vascular wall include:

Stenosis (stenosis) — a sharp narrowing of the vessel lumen due to fibrous thickening of the inner layer (intima).
Thrombosis (thrombosis) — thrombi may form within the lumen of the affected arteries.

Clinically, these changes may be accompanied by visible scalp inflammation along the course of the affected vessel.

With which systemic vasculitides is giant cell arteritis differentially diagnosed?

Sources do not provide a separate list of vasculitides for the differential diagnosis of giant cell arteritis. Its similarity to disseminated granulomatous vasculitis is noted, as well as its classification within the group of vasculitides affecting the aorta and its large branches alongside Takayasu arteritis. Polyarteritis nodosa is separately classified as a medium- and small-vessel vasculitis.

Which histological stains are used to visualize the damaged internal elastic membrane?

Elective histological stains are used to visualize elastic structures and detect their destruction. These include:

Orcein stain — elastic membranes stain selectively, acquiring the appearance of cherry-red lines.
Fucsin stain (e.g., Weigert's or similar elastic fibers stains) — elective staining for elastic fibers allowing the detection of their destruction or hyperplasia.

With standard hematoxylin and eosin (H&E) staining, elastic membranes do not stain and appear as pale bands.

Which cells predominate in the inflammatory infiltrate in Horton disease?

The cellular composition is dominated by lymphocytes, macrophages, and specific foreign-body giant cells that accumulate around fragments of destroyed elastic fibers.

What is the morphological outcome of giant cell arteritis?

The disease ends with fibrous thickening of the intima (inner layer), causing marked stenosis of the vessel lumen. Thrombus formation is also possible against the background of these changes.

Why can a patient with temporal arteritis go blind?

Vision loss occurs if granulomatous inflammation spreads to the blood vessels of the retina, leading to their narrowing and critical ischemia of the visual apparatus.

With which antigens is the development of this disease associated?

A clear pathogenetic link between the development of giant cell arteritis and the presence of HLA-DR antigens in the patient has been established.

Go deeper

Morphogenesis of the granulomatous cellular reaction in the vascular wall
Role of CD4+ T lymphocytes and macrophages in the pathogenesis of arteritis
Mechanisms of destruction of the internal elastic membrane
Pathological anatomy of giant cell aortitis (involvement of the aortic arch)
Hemodynamic consequences of intimal fibrous thickening and thrombosis