00:00 / 00:00
Nephrotic syndrome is a disorder characterized by a constellation of signs and symptoms caused by conditions that affect the tiny glomeruli in the kidneys, resulting in excessive loss of protein through urine, called proteinuria.
First, let’s quickly review some kidney physiology! Remember that the nephron is the functional unit of the kidney, and its role is to filter waste products and water from the blood. Each nephron is made up of a renal corpuscle and a set of renal tubules, which are, in order: the proximal convoluted tubule, the loop of Henle, the distal convoluted tubule and finally, the collecting ducts which drain urine into the renal papillae and eventually empty into the renal pelvis. The renal corpuscle is made up of the glomerulus, which is a bundle of capillary loops, and Bowman’s capsule, which surrounds the glomerulus. Now, blood enters the glomerulus through the afferent arteriole, then inside the glomerulus, glomerular filtration occurs. Then, the remaining blood exits the glomerulus through the efferent arteriole. The glomerular capillary wall is a semi-permeable membrane with three layers: the endothelium, which is the inner layer; the basement membrane; and the epithelium, which is the outermost layer. For filtration to occur, the endothelial and epithelial cells that line the capillary wall are separated by small pores that filter water and small particles from the blood and into the Bowman capsule. Only small particles are filtered from the blood and never proteins, since they are larger molecules. Also, normally, there aren’t any red blood cells in the urine. For glomerular filtration to occur, the hydrostatic pressure created by the blood pressure needs to be greater than opposing forces, such as the tubular filtrate and oncotic pressure, which is the pressure of proteins. The final product of filtration is called filtrate or primary urine, which will flow through the Bowman capsule into the proximal convoluted tubule.
Ok, now, some of the most common causes of nephrotic syndrome includea cute glomerulonephritis, focal segmental glomerulosclerosis, and minimal change disease, as well as diabetes and systemic lupus erythematosus.
Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Cookies are used by this site.
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.