Nephrotic syndromes: Pathology review

On the Nephrology ward, two people came in with the same symptoms: peripheral and periorbital edema.

One of them is a 10 year old caucasian boy named Brian who had recently been stung by a bee, and the other one is a 55 year old Hispanic individual named Gregory.

Lab tests show that both of them have hypoalbuminemia, hyperlipidemia and urinalysis showed frothy urine with fatty casts.

A 24-hour protein collection was done which showed massive proteinuria with more than 3.5 grams of protein lost through urine per day.

Both Brian and Gregory have nephrotic syndrome, but Brian has minimal change disease, while Gregory has focal segmental glo-merulo-sclerosis.

Nephrotic syndrome happens when the glomeruli are damaged and they become more permeable, so they start letting plasma proteins pass from the blood to the nephron and then into the urine.

This leads to proteinuria, which is when more than 3.5 grams of protein is excreted through the urine per day.

One of the proteins lost through urine is albumin and this leads to hypoalbuminemia.

This causes peripheral and periorbital edema since there’s less oncotic pressure in the blood vessels and the fluid leaks out.

On your tests, a nephrotic patient could also present with a hypercoagulable state and you will need to understand the pathology.

The reason for this is that the person is also losing antithrombin III proteins which is the body’s anticoagulant.

This means that individuals with nephrotic syndrome are prone to thrombotic and thromboembolic complications.

Immunoglobulins are another type of proteins lost through urine, which means that there’s a higher risk for infection.

Now, apart from proteins, lipids are also lost through urine, which gives the urine a frothy or foamy appearance.

On microscopy, there could be fatty casts, which are hyaline from dead epithelial cells that contained a lot of fat globules.