Systemic lupus erythematosus: an occasional misdiagnosis.

1 February 1996 Case report A 54 year old West Indian woman with hypertension and diet controlled diabetes mellitus was admitted with a six week history of general malaise, fever, mouth ulceration, myalgia, arthralgia, and arthritis; previously she had been well. On examination she was noted to be feverish (38°C) with nail bed infarction, splinter haemorrhages, and mouth ulceration, but no rash or lymphadenopathy. There was generalised muscle and joint tenderness, with synovitis of the knees and ankles. Investigations revealed a normal haemoglobin concentration and platelet count, lymphopenia (1000/mm3; normal value (NV) >1 500/mm3), erythrocyte sedimentation rate (ESR) 59 mmllst h, and C reactive protein (CRP) 460 mg/l (NV <80 mgfl); creatine kinase, renal and liver function tests, electrocardiogram, and chest radiograph were normal. Echocardiogram revealed a moderate pericardial effusion, but no evidence of endocarditis, and screening for infection was negative. A provisional diagnosis of a connective tissue disease was made and, whilst serological tests were pending, the patient was discharged from hospital with non-steroidal anti-inflammatory medication. However she was readmitted with worsening joint pains, pleurisy, and a widespread urticarial rash. Further investigations revealed her to be antinuclear antibody (ANA) positive (homogeneous pattern, titre not stated) and anticardiolipin antibody positive, but anti-DNA antibody negative. Complement and immunoglobulin concentrations were increased; rheumatoid factor, hepatitis serology, and Coomb's test were negative. A biopsy specimen from involved, non-light-exposed skin showed non-specific inflammatory changes with no lupus band on immunofluorescence. A diagnosis of systemic lupus erythematosus (SLE) was made, and her treatment drug was changed to prednisolone 20 mg daily. The patient's condition rapidly improved and she was able to return to work; her ANA became negative and the steroid dosage was gradually reduced to a maintenance level of 5 mg daily. However, she continued to complain of general malaise and her ESR remained persistently >50 mi/lst h. Twenty months after first presentation there was a marked deterioration in the patient's liver function (serum alanine aminotransferase 72 IU/l (normal range (NR) 5-40 IU/1), alkaline phosphatase 917 IU/l (NR 30-100 IU/l), and y-glutamyltransferase 836 IU/l (NR 0-30 IU/ 1)), and mild hypercalcaemia (corrected calcium 2-65 mmol/l (NR 2-15-2-55 mmol/1)). Her ANA remained negative. A liver biopsy specimen revealed multiple non-caseating granulomata (figure) and her diagnosis was changed to sarcoidosis. Angiotensin converting enzyme concentration was subsequently found to be 284 IU/l (NV <105 IU/1); repeat chest radiography showed no evidence of lung or hilar disease. Her steroids were increased, azathioprine was added to her treatment, and currently she remains well.