Neurovascular mechanisms as a possible cause of remission of rheumatoid arthritis in hemiparetic limbs

CASE REPORT A 64 year old woman with treated hypertension who smoked was referred with a 1 year history of left sided temporal headaches and pain in the proximal lower limbs. The headaches were intermittent but were increasing in frequency and intensity. She also described two episodes of blurred vision of short duration in the left eye. There were no other associated neurological symptoms. She gave a history of Raynaud’s phenomenon in both hands and worsening activities of daily living limited by fatigue. She was overweight with a body mass index of 27 kg/m; there were no mucocutaneous abnormalities. The temporal arteries were not palpable and a fundoscopic examination was normal. All peripheral pulses were present and there were no nailfold capillary changes. She had no tender or swollen joints; there was functional range of movement in axial and peripheral joints. Laboratory investigations showed haemoglobin of 127 g/l, a white cell count of 10.7610/l with a normal differential, and 625610/l platelets. The erythrocyte sedimentation rate (ESR) was 60 mm/1st h and C reactive protein (CRP) 290 mg/l. She had a serum urea and creatinine of 5.5 mmol/l and 96 mmol/l, respectively, with normal urine microscopy. The liver enzymes were not raised. Rheumatoid and antinuclear factor were absent. Based on her symptoms and raised inflammatory indices, a provisional diagnosis of temporal arteritis was made and treatment was started with prednisolone 50 mg daily. A left temporal artery biopsy showed atherosclerotic change without evidence of granulomatous inflammation. This negative result was attributed to sampling error. She continued to have multiple episodes of transient monocular visual loss which were highly suggestive of amaurosis fugax. She had also developed more troublesome acrocyanosis, livedo reticularis, and had a blood pressure of 190/83. The neurological examination was normal and there were no audible carotid bruits. Urine analysis remained negative, with normal renal function and inflammatory indices, but the total cholesterol was raised at 7.4 mmol/l. Her ECG did not suggest a rhythm abnormality. Formal fundoscopic examination showed a cholesterol crystal lodged in a vessel with background atherosclerotic change (fig 1). Carotid Doppler ultrasonography showed echolucent atherosclerotic plaques with a lumen diameter of 2 mm, while trans-oesophageal echocardiography did not show any mural thrombus or plaques in the aortic arch. A statin and aspirin were added to her drug treatment. Prednisolone was tapered over 2 weeks and stopped. When reviewed she denied further visual symptoms or other evidence of systemic emboli. DISCUSSION CES arises because of distal showering of cholesterol crystals into the circulation from atheromatous plaques. Panum first described this phenomenon in 1862. The presence of an aortic aneurysm, angioplasty, major vessel surgery, and use of thrombolytic and anticoagulating agents further increases the likelihood of CES. Our patient fulfilled three of the five classification criteria for giant cell arteritis formulated by the American College of Rheumatology. Furthermore, she had visual symptoms, myalgia, and a raised acute phase response, which further supported our diagnosis. But the partial response to corticosteroids, worsening visual symptoms, emergence of livedo reticularis, and acrocyanosis suggested an alternative explanation. Fundoscopic evidence of cholesterol emboli confirmed the occurrence of CES. Pseudovasculitis is sometimes used to describe the occurrence of fever, myalgia, leucocytosis, and raised ESR and CRP due to cholesterol emboli. The acute phase response is thought to arise from the inflammation provoked by the presence of cholesterol emboli in the vessel lumen and may explain the partial response to corticosteroids. No treatment has been proved to improve the outcome of CES, though statins have the theoretical benefit of plaque stabilisation. Interestingly, there is only one other case report of CES masquerading as giant cell arteritis (PubMed search). This is surprising given the similarity in the signs and symptoms of the two conditions and that both occur more frequently in those over the age of 50. Our case serves as reminder that not all older patients with headaches, myalgia, visual symptoms, and high ESR have giant cell arteritis. CES should be considered in those with a negative biopsy, a poor clinical response to corticosteroids, and risk factors for atherosclerosis.