Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention

Definition

Nephrotic syndrome is a group of symptoms that indicate problems with kidney function. These may include:

  • Excess protein in the urine
  • Swelling in limbs or abdomen from excess fluid
  • Sudden weight gain
  • High cholesterol levels in the blood

There are 2 types of nephrotic syndrome:

  • Primary—Linked to changes in the kidney itself. This is the most common type.
  • Secondary—Associated with medications or other diseases, such as an infection, autoimmune disease, or a blood disorder.

Anatomy of the Kidney

Glomerulonephritis
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Causes

The kidneys filter out wastes and excess fluid from the blood, while keeping important elements, like proteins, in the blood. The kidney can get injured by substances in the blood, from infections, autoimmune diseases, and other factors. The injury affects the microscopic filters of the kidney, making it harder for the kidneys to work properly. Proteins, which are supposed to stay in the blood, get filtered out and excreted in the urine. Over time, chronic injury causes waste products that should be filtered out to stay in the blood.

This is likely related to genetic or immune system factors. In children, the most common known cause is minimal change disease.

Risk Factors

Nephrotic syndrome is more common in males. Other factors that may increase the risk of kidney injury include:

Symptoms

Nephrotic syndrome may cause:

  • Swelling (edema) from excess fluid in the:
    • Face, especially under the eyes or around the lips
    • Abdomen
    • Legs, ankles, or feet
    • Lungs—may cause difficulty breathing
  • High blood pressure
  • Fatigue
  • Pale skin
  • Irritability
  • Weight gain from excess fluid in the body
  • General feeling of illness—malaise
  • Lack of appetite
  • Foamy urine

Diagnosis

The doctor will ask about your child’s symptoms and medical history. A physical exam will be done, which includes checking your child’s blood pressure.

To see how well the kidneys are working your doctor may take:

  • Urine tests to look for blood and abnormal levels of substances like protein
  • Blood tests to check protein levels and for substances normally filtered by the kidneys

A kidney biopsy may also be done. A sample of kidney tissue is removed and examined to look for change to kidney tissue.

On rare occasions kidney ultrasound may be done to look for structural problems or blockages

Treatment

Nephrotic syndrome can be managed. Treatment options may depend on the cause and type of nephrotic syndrome.

For primary nephrotic syndrome, corticosteroids may control the disease. Other treatment will be given to manage symptoms like fluid retention or high blood pressure. In many children, nephrotic syndrome resolves with age without long-term kidney damage.

With secondary nephrotic syndrome, the underlying condition will be treated. Other symptoms will also be treated.

Some children may have periods of remission when nephrotic syndrome does not cause problems. There may be other times when there is a relapse and symptoms are more active.

In some children, the first episode may require hospitalization to treat more severe symptoms like breathing problems. Medications may given through an IV until your child is stabilized.

Dietary Changes

Certain changes to the diet will help reduce symptoms, like swelling. The doctor may recommend limiting salt, saturated fats, cholesterol, and fluids.

Changes to dietary intake may change as your child grows and their condition improves.

Medications

Medications can be used to manage symptoms. These may include:

  • Corticosteroids or other medications to suppress the effects of the immune system and improve kidney function
  • Diuretics to increase urine output and reduce swelling
  • Angiotensin-converting enzyme inhibitors or angiotensin receptor blockers to reduce the amount of protein in the urine and control high blood pressure

If medications are causing nephrotic syndrome, your child’s doctor may stop or change them.

The doctor may advise certain vaccines for your child or family to reduce the risk of infection. These may include vaccines for the flu or pneumonia.

Prevention

There are no current guidelines to prevent nephrotic syndromes because in most cases, the causes are unknown.