Amyloidosis secondary to rheumatic diseases - 16 cases

Secondary amyloidosis (SA) results of tissue deposition of an acute phase reactant protein produced by chronic inflammation. Its incidence appears to be declining, following the improvement of medical care to primary diseases. Our aim is to assess a group of Portuguese patients with amyloidosis secondary to inflammatory rheumatic diseases, and their evolution over the past 10 years.

The study comprised 16 patients with SA confirmed by tissue biopsy, hospitalized in the Rheumatology Department of Hospital São João in Oporto in the last 10 years. We made a protocol on epidemiological, clinical and analytical data focusing the rheumatic disease and SA, and possible elements of connection between them.

Of the 16 patients, mainly women (81,2%), with mean age at entry of 56 years, 68,8% had rheumatoid arthritis. Amyloidosis was diagnosed in average at 13,5 years of primary rheumatic disease, and its main manifestation was kidney involvement, which together with infection and orthopaedic surgery or its complications, were the leading causes of hospitalization. In this time interval, 6 patients died. They were older, with longer duration and lower rate of treatment of the primary rheumatic disease, and had SA diagnosed 1,5 years before death (different of the 5 years of those that still alive). They had higher rate of gastrointestinal, neurological and serious kidney involvement, and hospitalizations.

Improving medical care in rheumatic inflammatory diseases has reduced the incidence of SA. Also, biotherapy appears to be achieving positive results in established amyloidosis, whatever the mechanisms involved. Our data, on Portuguese patients, seems to follow this trend.