Amyloidosis

A 58-year-old man from Mumbai presents with progressive dyspnea, orthopnea, and lower limb edema for 3 months. Echocardiography shows restrictive cardiomyopathy with biatrial enlargement and normal ejection fraction. Serum creatinine is 1.8 mg/dL with proteinuria (2.5 g/24 h). Cardiac MRI shows late gadolinium enhancement in a subendocardial pattern. Suspecting cardiac amyloidosis, what is the most appropriate next step in management?

A 52-year-old woman with a 10-year history of rheumatoid arthritis presents with nephrotic syndrome and renal biopsy shows AA amyloidosis. What is the drug of choice to prevent further amyloid deposition and slow renal disease progression?

A 52-year-old woman with a 10-year history of rheumatoid arthritis presents with nephrotic syndrome (proteinuria 4.5 g/day, serum albumin 2.1 g/dL). Renal ultrasound shows normal-sized kidneys without obstruction. Which investigation is most appropriate to confirm the diagnosis of secondary amyloidosis?

Which staining method is the gold standard for confirming amyloid deposition in tissue biopsies?

A 62-year-old woman from Delhi with a 15-year history of rheumatoid arthritis presents with progressive renal dysfunction. Serum creatinine is 2.8 mg/dL, 24-hour urine protein is 4.2 g/day, and urinalysis shows nephrotic-range proteinuria. Renal biopsy shows Congo red-positive deposits in the glomeruli and blood vessel walls with apple-green birefringence. Immunofluorescence microscopy is negative for immunoglobulin and complement deposition. What is the most likely diagnosis?