Steroid-responsive electromyographic abnormalities in polymyalgia rheumatica

Acute Brachial Radiculoplexopathy and Giant Cell Arteritis

INTRODUCTION

Giant cell arteritis (GCA), a vasculitis involving large-sized and medium-sized vessels (which most commonly involves temporal arteries), is easily recognized in older patients presenting with headache, scalp tenderness, and raised inflammatory markers. Neurological complications (either central or peripheral) are classically described in GCA.

CASE REPORT

We report the case of an 85-year-old woman with bilateral acute brachial radiculoplexopathy, a rare neurological complication of GCA. She also presented right oculomotor palsy (with ptosis) and raised inflammatory markers, but she did not complain of the other classic cranial symptoms of the disease. We compare this case with 16 similar cases reported in the medical literature.

CONCLUSIONS

In assessing a patient over 50 years of age with unexplained (unilateral or bilateral) brachial radiculoplexopathy (especially if C5-C6 nerve roots are affected) and elevated inflammatory markers, we would recommend specific enquiries with regard to the manifestations of GCA. The purpose is to reduce the risk of missing the wider spectrum of this condition and minimize the subsequent risk for disability of this treatable disease.

Laboratory investigations including liver in polymyalgia rheumatica/giant cell arteritis

The most useful investigation in supporting the clinical diagnosis of PMR/GCA is elevation of the ESR or viscosity. Acute phase proteins, particularly C-reactive protein, are also elevated but in most cases are not more helpful than the ESR in either diagnosis or follow-up. The definitive investigation is the demonstration of giant cell arteritis histologically, usually from temporal artery biopsy. The classical changes are internal elastic lamina fragmentation and destruction, with marked intimal thickening and an inflammatory infiltrate in the vessel wall with giant cells. Changes of healed arteritis can be distinguished from ageing changes and can therefore confirm the diagnosis. Positive biopsies are found in about 70% of patients with clinical GCA but are unlikely to be helpful in pure PMR. Elevation of alkaline phosphatase of liver origin is seen in one-third to half of patients with both PMR and GCA. Abnormal tracer uptake has been reported in radionuclide scans with a variety of non-specific abnormalities on liver biopsy. Promising developments include measurement of CD8+ lymphocytes and interleukins.