Secondary renal amyloidosis due to primary Sjogren's syndrome: a case report

Amyloidosis is a rare disorder characterized by the deposition of abnormal proteins in extracellular tissues, resulting in the dysfunction of vital organs and, eventually, death. The occurrence of amyloidosis due to primary Sjogren's syndrome (pSS) is a rare finding. This study describes a rare case of pSS complicated by amyloid-associated amyloidosis.

A 35-year-old male was diagnosed with nephrotic syndrome and secondary amyloidosis caused by pSS. He had microscopic hematuria, a creatinine level of 6.59 mg/dl, and an elevated erythrocyte sedimentation rate of 107 mm/hrs. Furthermore, investigations of antinuclear antibodies, antimitochondrial antibodies, SSA, SSA native, and Ro-52 recombinant as well as rheumatoid factor showed positive results. After establishing the diagnosis of pSS through clinical, physical, and laboratory assessments, a renal biopsy was performed, which revealed the occurrence of secondary amyloidosis.

The risk of developing secondary amyloidosis depends on the extent of elevated serum amyloid levels as well as persistent subclinical inflammation. The definitive diagnosis of amyloidosis requires histological confirmation of amyloid fibril deposition in tissue.

Secondary renal amyloidosis is an unusual condition in patients with pSS. Still, it should be regarded in the differential diagnosis of patients with proteinuria and/or renal failure, and a renal biopsy should be performed.