What is nephrotic syndrome and what causes it?
Nephrotic syndrome is disease of the kidneys where the filtering system made of functional units called the nephrons, gets damaged. This is the name given to the collection of findings which develop as a result of such a damage. When the filtering system gets damaged, the kidney tends to filter substances which it usually doesn’t, and filter less of substances which it usually does. All of these issues give rise to some characteristic findings, which include:
- Large amounts of protein present in the urine which results from leakage of protein through the damaged nephrons which usually prevent protein leak. This is known as proteinuria in medical terms and is calculated according to your child’s age and body weight.
- Low levels of protein in the blood, which results from the protein leaking out into the urine, and is called Hypoalbuminemia.
- Edema or tissue swelling in all areas of the body, which is the result of reduced levels of protein in the blood. This swelling is especially evident around the eyes, in the face, and in the abdomen which is known as ascites. The swelling results because the protein in the blood actually acts like a sponge which helps to keep most of the fluid in the blood, and when there is a reduced amount of proteins in the blood, the water tends to leak out from the blood into the tissues, resulting in swelling.
- Increased levels of cholesterol in the blood, which results from reduced levels of protein in the blood which is a signal for the body to increase its production of certain types of fat.
The symptoms and signs of nephrotic syndrome:
The signs and symptoms that children often present with include:
- Malaise and fatigue
- Abdominal pain and swelling
- Frothy urine
- Increased body weight and facial edema
- Loss of appetite
- Paleness of the nail bed
- Dull hair
- Development of intolerance to certain food or allergies
- The cartilage of the ears may feel less firm
The different types of nephrotic syndrome:
There are different types of nephrotic syndromes in existence as a result of the different causes. Some of these causes include, diabetes, hepatitis B and C, medications such as corticosteroids, and conditions like systemic lupus erythematosis, and cancer of the kidneys. The most common type of nephrotic syndrome to affect children is one that is known as idiopathic nephrotic syndrome, where there is no identifiable underlying cause.
Nephrotic syndrome can also be categorized according to the way the kidney tissue appears when it is viewed under a microscope following a biopsy. According to this tow forms have been recognized, Minimal Change Disease (MCD) and Focal Glomerular Sclerosis (FSGS).
Minimal Change Disease (MSD):
This is most common form to affect children and you will see that the renal cells look almost normal when seen under the microscope. It responds well to steroids, and has a good outcome in most cases. This form doesn’t have any lasting damage on kidney function, and relapses less and less frequently as the child ages, and is usually absent in adulthood. It is very rare for a child affected by minimal change disease to require dialysis or kidney transplant.
Focal Glomerular Sclerosis (FSGS):
This form of disease is present only in about 10% of the children with nephrotic syndrome. It requires biopsies in order to be diagnosed and doesn’t usually respond to steroid therapy, and is an aggressive form, which more often than not requires the child to undergo dialysis or a kidney transplant.
What is congenital nephrotic syndrome?
As the word suggests this form of nephrotic syndrome is present at birth, but it is most likely that the condition will go unnoticed at the time of birth and be discovered only when the baby is few months old. It is a very rare condition and is caused by a genetic predisposition where both parents have to be carriers of the condition. It is a very aggressive and severe form of nephrotic syndrome where the affected baby will require a kidney transplant as soon as possible, ideally within the first few years of life. And till a transplant becomes possible, the baby will require transfusions of blood protein almost every day, because the protein leaks out from the kidneys at a rapid rate. They will also require frequent boosting of their immune system and hormones in order to keep them healthy till the transplant can be done, and till they reach the appropriate weight with which a transplant becomes possible, which is about 15 pounds when the child is roughly around one year.