What Causes Nephrotic Syndrome?   

As experts like Best Nephrologist in Lahore define, nephrotic syndrome is a group of symptoms indicating diminishing kidney function and release of too much protein in the urine. On its own, nephrotic syndrome is not a disease; rather, it is the result of blood vessel damage in the kidneys that subsequently results in suboptimal filtration and reabsorption with protein loss. Read on to know more about nephrotic syndrome and its treatment options:

What is nephrotic syndrome?

As mentioned before, nephrotic syndrome is not a disease in itself, but rather a group of symptoms indicating that the kidneys are diseased. The primary indicators of this are: loss of too much protein in the urine thereby causing protein loss from the blood and hypoalbuminemia, with consequent swelling or edema in the body and high levels of cholesterol and lipids in the blood.

The functioning unit of the kidneys are the filtering nephrons, with a bunch of blood vessels called the glomerulus. In nephrotic syndrome, these glomeruli are inflamed, allowing too much to leak from their filters. This inflammation can be secondary to a number of causes, as mentioned below.

What are the signs and symptoms of nephrotic syndrome?

Nephrotic syndrome presents with:

  • Severe edema in the body, especially in the dependent areas like the ankles, feet, and around the eyes.
  • Weight gain
  • High blood pressure
  • Signs of infection with elevated white cell count
  • Loss of appetite
  • Fatigue
  • Foamy urine
  • Excessive loss of protein from the urine
  • Low levels of serum protein—hypoalbuminemia
  • Hyperlipidemia with increased fat and cholesterol levels in the blood

What are the causes of nephrotic syndrome?

Nephrotic syndrome occurs secondary to the swelling in the glomeruli, which occurs due to the following disorders:

  • Focal segmental glomerulosclerosis (FSGS): this is the most common cause of nephrotic syndrome in adults. This disease follows viral illness like HIV/AIDS, genetic mutations, high blood pressure, vascular disease, obesity and medication.
  • Diabetes: the second most common cause of nephrotic syndrome in adults is diabetic nephropathy, particularly with uncontrolled hyperglycemia, which can damage the glomerular basement membrane with subsequent protein loss. In the early phase of diabetic nephropathy, there is microscopic loss of protein—called microalbuminuria, followed by massive loss of protein in the active stage of nephrotic syndrome—called macroalbuminuria.
  • Amyloidosis: in this disorder, there is buildup of amyloid proteins in the kidneys that impede the filtration process.
  • SLE—systemic lupus erythematosus: in this autoimmune disorder, there is deposition of autoantibodies—or antibodies against the body’s own cells—which damage the glomeruli and the nephrons.
  • Minimal change disease: this is the commonest cause of nephrotic syndrome in the children. This idiopathic disorder follows viral illness, medication, drugs like NSAIDs (non-steroidal anti-inflammatory drugs) and allergic reactions.
  • Membranous nephropathy: in this disorder, antibodies cause the glomeruli to thicken and render them unable to filter correctly. Membranous nephropathy occurs secondary to cancers, autoimmune disorder like lupus and vector illnesses like hepatitis B and malaria.
  • Renal vein thrombosis: when the blood vessel carrying blood back from the kidneys is blocked with a blood clot, it can interfere with the functioning of the kidney.
  • Others: the miscellaneous causes include infections and allergies, use of certain medication and genetic disorders.

How is nephrotic syndrome diagnosed?

The diagnosis of nephrotic syndrome is made with the following investigations after a thorough history and physical examination of the patient:

  • Urine complete exam: a sample of urine is collected to determine the amount of protein, red blood cells and white blood cells in it. In some cases, 24-hour urine is collected to check the protein levels.
  • Ultrasound of the kidneys: the image of the kidneys is created with an ultrasound to evaluate structural changes.
  • Blood tests: blood sample is evaluated for levels of protein, cholesterol and white blood cells.
  • Kidney biopsy: a sample of the kidney tissue is evaluated under the microscope to make the diagnosis. This test is performed under the surveillance of an experienced nephrologist available at MaxHealth Hospital.