Amyloidosis presenting with edema and heavy proteinuria: A case report

Abstract

Amyloidosis is the disease caused by extra-cellular accumulation of amyloid substance within various organs leading to progressive dysfunction of the organs. The organs that are more commonly involved include the kidney and the heart. This report is aimed topresent a case of systemic amyloidosis in a 69-year-old Thai woman who presented with edema and heavy proteinuria. She was referred to our hospital because of anasarca, suspected of
amyloidosis. Her underlying diseases included diabetes mellitus, hypertension, hypothyroidism and chronic kidney disease stage 4 which were regularly and well controlled with medications.The physical examination confirmed the anasarca. Her vital signs were unremarkable. The blood tests revealed Hb10.2 g%, creatinine 1.98 mg%, FBS 96 mg%, HbA1c 5.6 %, albumin 2.4 g%, globulin 3.1 g%, cholesterol 149 mg%, positive ANA, FT4 1.18 mcg/dl, FT3 1.34 ng/ml, TSH 3.916 mIU/ml. The urinalysis showed no redblood cell, no white blood cell, no sugar, protein 4+ and the calculated urine protein to creatinine ratio (UPCR) was 8.8. The chest film revealed diffuse cardiomegaly and bilateral pleural effusion. The echocardiography showed granular sparkling at the interventricular septum which was highly specific for amyloidosis of the heart and moderate pericardial effusion. The abdominal fat pad biopsy was performed and found positive for Congo red with apparent apple green birefringence under polarized microscope. She was definitely diagnosed as nephrotic syndrome because of the systemic amyloidosis involving the heart and the kidney, not due to the diabetes, hypertension or systemic lupus erythematosus. Generally amyloidosis involving the kidney mostly accumulatesthe amyloid substance within the glomerulus and less commonly in the interstitium therefore the main manifestation is proteinuria which may vary from minimally asymptomatic to heavy proteinuria, 20 - 30 gram a day, accompanied by edema. If the patients are left untreated, the disease will progress to progressive kidney impairment and mortality.