Still's disease

SIR--Adult-onset Still's disease (AOSD) was first described by Bywaters who reported 14 adult patients with features similar to the systemic form of juvenile rheumatoid arthritis [1]. Many case series have since been published [2-5]. The disease has an equal sex incidence and in most patients onset is between the ages of 16 and 35 years. The oldest reported patient with AOSD was a 75-year-old Japanese woman [6]. We report a patient who first presented with fever, arthritis, liver dysfunction, hepatosplenomegaly and leucocytosis at the age of 80. The diagnosis of AOSD was made after careful exclusion of malignant, granulomatous and infective causes.

The patient presented with intermittent fever and asymmetrical polyarthritis involving the left knee, right elbow, both wrists and the metacarpophalangeal joints. There was no sore throat, morning stiffness, or limb girdle symptoms. Three months earlier, she had had a transient rash over both shins which was diagnosed as erythema nodosum by a general practitioner. No skin biopsy was performed.

On admission, physical examination revealed mild synovitis of the involved joints. There was no rash, subcutaneous nodules or lymphadenopathy. Abdominal, cardiovascular and chest examination were unremarkable. She had had an intermittent fever. Repeated cultures of blood, urine and sputum were negative and paired viral titres, Weil-Felix and Widal tests were not informative. The chest X-ray was normal and sputum and gastric aspirate for acid-fast bacilli were negative. A Mantoux test was negative. Her blood counts, serum biochemistry and immune marker test results arc shown in Table 1.

(a) Farr assay.

(b) Western blotting.

Anti-dsDNA, anti-double stranded DNA; Anti-ENA, anti-extractable nuclear antigen; ANCA, anti-neutrophil cytoplasmic antibody; ESR, erythrocyte sedimentation rate; Gamma-GT, gamma-glutaryl transferase; LDH, lactate dehydrogenase; SGOT, serum glutamic oxaloacetic transminase; SGPT serum glutamic pyruvic transminase.

An ultrasound of the hepatobiliary system showed gall stones but normal bile ducts. An endoscopic retrograde cholangiopancreatogram was normal. A liver biopsy (to exclude granulomatous disease]) was unremarkable. She was a non-drinker and her serology for hepatitis A, B and C was negative. Screening for underlying malignancies including a gynaecological and ear, nose and throat examination was negative. A computed tomography scan of the abdomen and pelvis showed radiological hepatomegaly and splenomegaly (12 cm) but no lymphadenopathy or mass lesions. A 24-h urine did not show any protein loss. A S-day stool for [Alpha]-1-antitrypsin clearance to exclude protein-losing enteropathy as a cause of the low serum albumin concentration was normal. Investigations for the cause of anaemia did not demonstrate any gastrointestinal blood loss or haemolysis. A bone marrow biopsy was performed because of the persistent fever and anaemia. The smear and culture of the marrow blood for acid-fast bacilli were negative and the marrow morphology favoured the diagnosis of anaemia of chronic disease. A gallium scan did not reveal any foci of increased uptake. X-rays of the involved joints did not show any erosions or bony ankylosis, although some degeneration with osteophyte formation was evident in both knees.

AOSD was diagnosed by exclusion and the patient was started on Naprosyn (250 mg three times daily). She responded dramatically with the subsidence of fever after the first dose and the arthritis gradually improved. She remained afebrile over the next few days and was discharged. There was no relapse of fever or arthritis on follow-up for 11 months and her C-reactive protein, erythrocyte sedimentation rate and ferritin concentrations returned to normal.

This patient presented with fever of unknown origin, arthritis, hepatosplenomegaly, leucocytosis and liver function abnormalities. Extensive investigations did not identify any haematological malignancies or infective causes. Follow-up for 11 months did not reveal any conversion to an autoimmune disorder or the development c)f malignancy. Although the presentation was atypical, we believe that the diagnosis of AOSD was correct because she fulfilled the diagnostic criteria proposed by Yamaguchi et al. [7] (with five features). Differential diagnoses include polymyalgia rheumatica and seronegative rheumatoid arthritis. The absence of girdle stiffness or coexisting temporal arteritis, and the marked response to Naprosyn, made the former unlikely. Moreover, the patient did not meet the American College of Rheumatology criteria for rheumatoid arthritis [8]. Serum ferritin concentration has been described as a useful diagnostic tool for AOSD [9]. Very high ferritin concentration can be detected in patients with AOSD during the active phase of the disease. Our patient was indeed hypefferritinaemic but the ferritin concentration was only 3-4 times normal. The ferritin concentration and other markers of the acute phase response returned to normal on subsequent visits.

This is the oldest person with AOSD reported in literature. AOSD in elderly patients may present atypically. A rash may not be present, the fever may not be typically high-spiking and sore throat and serositis may be absent. Moreover, the acute phase response may not be as marked as in younger patients. AOSD should be considered as a rare cause of prolonged fever in elderly patients and should be suspected if there is leucocytosis, arthritis, enlargement of the reticuloendothelial organs and tests for anti-nuclear antigen and rheumatoid factor are negative.

[1.] Bywaters EGL. Still's disease in the adult. Ann Rheum Dis 1971; 30:121-32.

[2.] Ohta A, Yamaguchi M, Kaneoka H et al. Adult Still's disease: review of 228 cases from the literature. J Rheumatol 1987; 14: 1139-46.

[3.] Larsen EB. Adult Still's disease. Evolution of a clinical syndrome and diagnosis, treatment anti follow-up of 17 patients. Medicine 1984; 63: 82-91.

[4.] Pouchot J, Sampalis JS, Beaudet F et al. Adult Still's disease: manifestations, disease course, and outcome in 62 patients. Medicine 1991; 70:118-36.

[5.] Reginato AJ, Schumacher HR, Baker Jr DG et al. Adult onset Still's disease: experience in 23 patients and literature review with emphasis on organ failure. Semin Arthritis Rheum 1987; 17: 39-57.

[6.] Tamura K, Kubota K, Kurabayashi H et al. Elderly onset of adult Still's disease: report of a case. Clin Rheumatol 1994; 13: 117-8.

[7.] Yamaguchi M, Ohta A, Tsunematsu T et al. Preliminary criteria for classification of adult Still's disease. J Rheumatol 1992; 19: 424-30.

[8.] Arnett FC, Edworthy SM, Bloch DA et al. The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum 1988: 31: 315-24.

[9.] Van Reeth C, Le Moel G, Lasne Y et al. Serum ferritin and isoferritins are tools for diagnosis of active adult Still's disease. J Rheumatol 1994; 21: 890-5.

CHI CHIU MOK, CHAK SING LAU, RAYMOND WOON SING WONG

Division of Rheumatology, Department of Medicine, Queen Mary Hospital, Pokfulam, Hong Kong. Fax: (+852) 2872 5828. Email: ccmok@netvigator.com

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