Gastrointestinal AA amyloidosis secondary to chronic pyelonephritis presenting with refractory diarrhea and severe hypoalbuminemia

Systemic AA amyloidosis with amyloid deposition in the peritoneum at the time of initiating peritoneal dialysis

Amyloidosis is characterized by the deposition of insoluble amyloid fibrils formed by disease-specific precursor proteins in the extracellular interstitium of various organs throughout the body, resulting in organ damage. Patients with amyloidosis often develop end-stage kidney disease (ESKD), which can be managed with dialysis or kidney transplantation. Peritoneal dialysis (PD) is advantageous over hemodialysis (HD) in managing the circulatory dynamics and removing the precursor proteins of amyloid fibrils. However, the clinical course of PD using an amyloid-deposited peritoneum has not been reported. In this paper, we describe a rare case of systemic AA amyloidosis with amyloid deposition in the peritoneum at the beginning of PD. The peritoneal equilibrium test (PET) at PD initiation revealed a high transport rate. The dialysis solution was temporarily changed to a high-glucose concentration peritoneal dialysate, and a weekly extracorporeal ultrafiltration method was added. The patient continued with PD treatment without any complications. The PET category changed from "high" to "high average" during the subsequent PD treatment course. The serum amyloid A levels improved post-nephrectomy and remained in the normal range. Amyloid A was not detected in the dialysate drainage. In conclusion, the amyloid-deposited peritoneum has no uniform effect on the clinical course of PD. Moreover, amyloidosis therapy can alter the peritoneal function with amyloid deposition. However, future studies should investigate the exact mechanism of the alteration of peritoneal function with amyloidosis therapy.

Systemic Amyloid A Amyloidosis Secondary to Xanthogranulomatous Pyelonephritis

The combination of systemic amyloid A (AA) amyloidosis and xanthogranulomatous pyelonephritis (XGP) resulting from a chronic urinary tract infection is extremely rare. We herein report a case of systemic AA amyloidosis secondary to XGP for which clinical remission developed after nephrectomy. To our knowledge, this is the first case report describing the clinical improvement of systemic AA amyloidosis secondary to XGP after nephrectomy in Japan. Clinicians should be aware of this uncommon combination and search for amyloid depositions in cases of XGP.