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Many diseases, such as infections, neoplasia, or immune diseases, can mimic adult onset Still’s disease (AOSD).1,2 Atypical forms are not so rare, and the search for a diagnosis marker is warranted. Recently, the usefulness of low serum glycosylated ferritin (GF) was suggested.3–5
CASE REPORT 1
An 80 year old woman presented with 4 weeks’ fever, myalgias, polyarthritis, and sore throat. Clinical examination disclosed a fixed generalised maculopapular rash, arthritis of wrists and ankles, and spleen enlargement. C reactive protein was 150 mg/l, haemoglobin level 80 g/l, white blood count 30×109/l with 90% polymorphonuclear neutrophils, 10% lymphocytes, and 600×109/l platelets. Transaminases were twice the normal value (2N). Ferritinaemia was 40 000 μg/l (normal 50–300). Extensive investigations for infections, antinuclear and antineutrophil cytoplasmic antibodies, and rheumatoid factor were negative. Echocardiography, thoracic and abdominal computed tomographic scan, bone marrow biopsy, lumbar puncture were normal, except for splenomegaly. Skin biopsy disclosed unspecific urticarial lesions. The outcome was marked by high spikes of fever, general malaise with low blood pressure, hypoxaemia, suggesting systemic inflammatory response syndrome, and necessitating admission to an intensive care unit.
Empirical antibiotic treatment was ineffective. The blood white cell count was 42×109/l, and ferritinaemia was 80 000 μg/l. The percentage of serum GF was <5%. Corticosteroid treatment improved the syndrome, with normalisation of the white blood count and ferritinaemia in 7 days. No systemic or neoplastic disease occurred with a follow up of 3 years.
CASE REPORT 2
A 51 year old woman presented to our department with 5 weeks’ fever, sore throat, and myalgias. Clinical examination showed permanent maculopapular rash, and liver enlargement. C reactive protein was 120 mg/l, haemoglobin 80 g/l, platelet count 30×109/l, and white blood cell count 3×109/l with 800 polymorphonuclear neutrophils, 1200 lymphocytes, and 800 monocytes. Fibrinogen was 2 g/l, factor V 30%, albuminaemia 22 g/l, transaminases 8N, and lactate dehydrogenase 3N. Ferritinaemia was 120 000 μg/l. Extensive infectious and immunological investigations were negative. Echocardiography, thoracic and abdominal computed tomographic scan, bone marrow biopsy, liver, skin, muscle, bone marrow biopsies were normal. Bone marrow aspiration disclosed haemophagocytosis features, according to the diagnosis of macrophage activation syndrome.
Empirical antimicrobial treatments were ineffective. GF was 3%. Intravenous pulses of methylprednisolone and cyclosporin dramatically improved the course of the disease. With a follow up of 3 years, no systemic or neoplastic disease occurred.
Our case reports present atypical presentations of AOSD, with a fixed skin eruption,6 associated with a life threatening disease outcome in a very old person, and a macrophage activation syndrome7 in the other. Extensive investigations did not contribute to a diagnosis, and antimicrobial treatments were unsuccessful. Ferritinaemia was very high in both patients. There is no specific clinical or biological marker of AOSD.2 Low GF led us to the diagnosis of AOSD, and long term follow up validates this conclusion. The normal value of GF is >50%, and the serum level is not significantly modified by inflammation. The usefulness of a low GF value for diagnosis of AOSD was shown by Fautrel et al.5 In their study the percentage of GF was <20% of the total ferritinaemia for 35 of 44 patients with AOSD, and for only 38 of 113 control patients with other inflammatory diseases. The combination of ferritinaemia fivefold above the upper normal value and a GF value <20% had a specificity of 92.9% and a sensitivity of 43.2% for AOSD. GF could be a powerful diagnostic tool for AOSD, particularly in atypical clinical presentations of the disease.
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