Amyloid related Nephropathy – Top USMLE Diseases

Amyloidosis is a disease caused by abnormal extracellular tissue deposition of fibrils composed of various misfolded low-molecular-weight protein subunits. These proteins are frequently byproducts of other pathological processes (e.g., multiple myeloma). These misfolded proteins can become deposited in different tissues, interfere with normal organ functions, and cause tissue-specific diseases (e.g., renal amyloidosis causes proteinuria). Diagnosis is established clinically and confirmed with tissue biopsy. Treatment should be directed toward the underlying cause and the reduction of amyloid deposition.

In the context of acute or chronic kidney failure, renal function may diminish to a point at which it is no longer able to adequately support life. When this happens, renal replacement therapy is indicated. Renal replacement therapy refers to dialysis and/or kidney transplantation. Dialysis is a procedure by which toxins and excess water are removed from the circulation. Hemodialysis and peritoneal dialysis (PD) are the two types of dialysis, and their primary difference is the location of the filtration process (external to the body in hemodialysis versus inside the body for PD).

Chronic kidney disease (CKD) is kidney impairment that lasts for ≥ 3 months, implying that it is irreversible. Hypertension and diabetes are the most common causes; however, there are a multitude of other etiologies. In the early to moderate stages, CKD is usually asymptomatic and is primarily diagnosed by laboratory abnormalities. Regardless of the etiology, progression of renal impairment is common and can ultimately lead to end-stage renal disease and the need for renal replacement therapy (e.g., transplantation or dialysis). The management of CKD includes treating the underlying etiology, aggressive risk factor modification, and addressing complications such as fluid overload and electrolyte imbalances.

The kidneys, solid organs located in the lower back, are extremely important in regulating homeostasis through their role in maintaining blood volume, electrolyte balance, acid–base equilibrium, blood-pressure regulation, and removal of metabolic waste from the blood. Evaluation of renal function and early detection of kidney dysfunction is of primary importance. Tests of renal function are useful in identifying the presence of renal disease, monitoring the response of kidneys to treatment, and determining the progression of renal disease.