18th January 2024

Investigations

Confirming the diagnosis is vital, and the gold standard is currently temporal artery biopsy. Colour duplex ultrasonography has also been shown to be effective in diagnosing GCA and is gaining popularity due to being non-invasive and more easily available.

Other expected findings would be:

• Raised ESR/CRP
• Normocytic, normochromic anaemia
• Thrombocytosis
• Deranged liver function tests, in particular, a raised ALP

Histology

Histology of the temporal artery shows an occlusive vasculopathy with intimal proliferation and a reduction in diameter of the lumen. Inflammation is patchy (skip lesions); therefore, a normal biopsy cannot rule out GCA. The inflammatory infiltrate is predominantly composed of macrophages and CD4 lymphocytes. Only half of positive histological samples demonstrate giant cells.