Sir,

Giant cell arteritis is an inflammatory vasculitis affecting medium- and large-sized arteries and can result in arteritic anterior ischaemic optic neuropathy. C-reactive protein level and erythrocyte sedimentation rate are commonly used to aid diagnosis; however, inflammatory-marker negative disease does occur.

Case report

A 67-year-old Finish woman presented with a 2 day history of left visual loss. She had a history of polymyalgia rheumatica for which steroid treatment had been stopped 12 months prior.

On presentation best corrected visual acuity was 6/36 in the left eye. Clinical examination revealed a left relative afferent papillary defect and reduced colour vision. On dilated examination a pale, swollen left disc was observed. Erythrocyte sedimentation rate (ESR) was 62 mm/h and C-reactive protein (CRP) was normal (<8 mg/l).

The patient was admitted for intravenous Methylprednisolone and a temporal artery biopsy was consistent with a diagnosis of giant cell arteritis (GCA; Figure 1).

Figure 1
figure 1

A composite histology slide showing one cross-section through the temporal artery biopsy (TAB). The larger image shows a haematoxylin and eosin stain of the artery wall, and the inset is stained with leucocyte common antigen (CD45) highlighting the lymphocytic infiltrate of the media (A). Fragmented internal elastic lamina was also seen.

Full size image

Comment

The annual incidence of GCA in the Scandinavian populations is reported to be as high as 15–35/100 000 in those over the age of 50,1 higher than the incidence in the standard European population. Inflammatory markers are commonly used to aid diagnosis of GCA. CRP has been reported to be a more sensitive predictor of the disease than ESR (97.5–100% for CRP vs 76–92% for ESR).2, 3 Our case is unique in that it belongs to the rarer group of CRP-negative disease and highlights four pertinent facts about the pathophysiology of GCA:

  1. 1)

    ESR and CRP together have a superior sensitivity than either test alone.

  2. 2)

    Polymyalgia rheumatica and GCA are two closely related inflammatory syndromes.

  3. 3)

    The disease rarely burns out spontaneously and cessation of steroid therapy carries a high risk of reactivation or progression from polymyalgia rheumatica to full-blown GCA.

  4. 4)

    Scandinavian ancestry increases pretest probability.4

Including our case there are only three published cases of isolated CRP-negative GCA and only two cases of simultaneous ESR and CRP negativity (see Table 1).

Table 1 Summary of current literature
Full size table

Our review of the current literature demonstrates that simultaneous ESR- and CRP-negative disease is rare. Both parameters together offer a good safety net through which GCA will only rarely slip. It is important to consider medications affecting inflammatory markers. Hegg et al6 report that both nonsteroidal anti-inflammatory drugs and statins were associated with a lower ESR in biopsy-proven GCA. Fibrates have recently been shown to reduce CRP levels,7 however, our patient was not on fibrates and therefore her CRP negativity remains unexplained. Contrary to Hayreh et al’s observation2 ESR was more sensitive to detect GCA-related inflammatory activity in the presented case.