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Nephrotic Syndrome

Overview

The term "nephrotic syndrome" refers to a constellation of symptoms caused by kidney dysfunction. In Nephrotic syndrome, your kidneys excrete an excessive amount of protein in your urine, resulting in low albumin(protein) levels in your blood and significant swelling. Weight gain, fatigue, and foamy urine are some other complaints.  

The most common cause of nephrotic syndrome is a disruption to the millions of tiny blood channels in your kidneys that remove toxins and extra fluid from the blood. Swelling occurs, especially in the lower limbs, in adults, while it appears most commonly on the face in children. The disease raises the risk of additional health issues as well.

There seem to be no red blood cells (RBCs) in the urine, which distinguishes it from the nephritic syndrome. The treatment focuses on the root of the problem. Controlling hypertension, hyperlipidemia, and risk of infection are other perspectives to be taken care of. 

Causes And Types

Your kidneys contain several tufts of small blood vessels called glomeruli. As your blood flows through the kidneys, the glomeruli sieve it, extracting what your body requires from what it does not. Functioning glomeruli prevent proteins (mostly albumin) from leaking into your bladder, which is necessary for maintaining the proper fluid balance in your body. Nephrotic syndrome is caused by glomeruli that are damaged and cannot hold back the protein, causing too much protein to escape the system.

Some of the causes that damage the glomeruli are described below;

Diabetic kidney disease is one of the several disorders that can destroy the glomeruli and cause nephrotic syndrome. Diabetic nephropathy, which damages the glomeruli, is a complication of diabetes.

Minimal Change Disease: It is the most prevalent cause of nephrotic syndrome in children. When kidney tissues are inspected under a microscope, they look healthy; however, minimal change disease causes aberrant renal function. In most cases, the source of the unusual function is unknown.

Focal segmental glomerulosclerosis is characterized by scarring of portions of the glomeruli. It can be caused by some other disease, a hereditary abnormality, or even certain drugs, or it might arise for no apparent reason.

Membranous nephropathy is a kind of kidney disease. The thickened membranes inside the glomeruli cause this kidney disease. The thickening is caused by the defense system's deposits. This can be linked to other illnesses, including lupus, hepatitis B, malaria, and malignancy, or it might happen for no apparent reason.

Epidemiology

The most common cause of nephrotic syndrome is diabetic nephropathy which accounts for 50 cases per million population in the US. In children, the ratio is 20 cases per million population. Since diabetes affects African Americans and Hispanics more, the same goes for nephrotic syndrome. Males are affected more than females. 

Risk Factors

Several illnesses and diseases can affect the kidneys and cause nephrotic syndrome;

  • High blood sugar, as in diabetes
  • Systemic lupus, 
  • Amyloidosis, 
  • Reflux nephropathy, 
  • Other kidney disorders, 
  • Nonsteroidal anti-inflammatory medicines 
  • Some antibiotics 
  • HIV infection, 
  • Hepatitis B or C,  
  • Plasmodium 

Symptoms And Signs

Initially, the nephrotic syndrome does not exhibit itself prominently. However, long-standing nephrotic syndrome can cause the body to adapt to counteract the effects resulting in further complications. When your blood’s protein levels drop, your liver produces more albumin. Your liver also produces extra cholesterol levels simultaneously. Impaired nephrons, as well as the accumulation of excess body fluid, may cause your blood pressure to rise. You are also at increased risk of acquiring infections due to Nephrotic syndrome. 

The signs and symptoms of nephrotic syndrome are as follows:

  • Swelling is present in the lower limbs and around the eyes.
  • Urine looks foamy
  • Obesity due to fluid retention
  • Feeling tired
  • Low appetite

Diagnosis

Diagnosis of nephrotic syndrome requires a holistic approach. Since many conditions may affect kidneys, a detailed history is required, finding out any cause related to kidney dysfunction. After history and physical examination, you may be advised of some tests to confirm the diagnosis. 

A Dipstick urine test; this basic test detects albumin in the urine. During an appointment at a doctor's office or a laboratory, you put the urine specimen in a jar. For the testing, a medical practitioner inserts a dipstick, which is a piece of chemically processed material, into the urine. If protein is present in the urine, the dipstick turns color.

24 hrs urine collection: for this type of test, you will need to obtain a urine specimen over 24 hours. After that, your medical practitioner will submit the specimens to a laboratory for examination.

Urine Albumin to Creatinine Ratio: This test estimates the quantity of albumin eliminated in 24 hours based on a single urine specimen. Albumin and creatinine are measured in this test.

Blood tests can reveal low quantities of albumin and a lower blood protein concentration altogether. Albumin loss is frequently linked with elevated blood cholesterol. The amounts of blood urea nitrogen in your blood may also be examined to determine how well your kidneys are working.

Biopsy; In a biopsy of the kidney, a tiny piece of kidney tissue may be removed for examination by your physician. A needle is pushed into your dermis and then to your kidney, and a small specimen of tissue is taken and submitted to a laboratory for analysis.

Differential Diagnosis

The disorders that may present as nephrotic syndrome include;

  • Heart failure
  • Cirrhosis
  • HIV-Related Renal Disorders
  • IgA Nephropathy
  • Light Chain-Associated Renal Disorders
  • Radiation Nephropathy
  • Sickle Cell Nephropathy

Treatment

Treatment of nephrotic syndrome requires eliminating the root cause, controlling the symptoms with medications, and halting the progression towards end-stage kidney disease. 

Treating high blood pressure: ACE inhibitors are among the best medications to bring the blood pressure down, as they also decrease the quantity of protein excreted in the urine. 

Lisinopril, captopril, and enalapril are examples of medicines in this group. ARBs, including losartan and valsartan, are another class of medications that function similarly. Additional drugs, like renin inhibitors, may be advised, although ACE inhibitors and ARBs are usually the first to be tried.

Water content controlling pills. These increase the fluid production from your kidneys, which helps to decrease edema. Furosemide is a common diuretic medicine (Lasix). Spironolactone and thiazides (hydrochlorothiazide, metolazone) are two others.

Statins are drugs that decrease the cholesterol concentration in your body. They include fluvastatin, simvastatin, and rosuvastatin.

Anticoagulants: your physician will prescribe these medications to lower the incidence of clot formation in your body. They include warfarin, heparin, apixaban, dabigatran

Medications to suppress the immune system sometimes your physician might advise these drugs to lower inflammation in your body due to nephrotic syndrome. They include corticosteroids, rituximab, and cyclophosphamide.

Prognosis

The outlook for nephrotic syndrome is usually favorable if timely care is given, but it varies depending on the actual reason and the patient's age. In kids, it is generally advantageous as minimal change disease reacts well to corticosteroids and does not lead to long-term illness. Proteins in urine, high blood pressure, and deranged GFR are all factors linked with a grim outcome.

Without therapy, nephrotic syndrome has an extremely poor prognosis, especially if the glomerulonephritis progresses quickly, leading to abrupt kidney problems in a matter of months. Malnutrition can come from the depletion of too much protein. Weight loss can occur as a result of this, which can be concealed by edema. Anemia and vitamin D deficiency are further complications of end-stage kidney disease.

Ultimately, the kidneys lose their function and accumulate harmful products that must be removed immediately using dialysis. Dialysis is an artificial method of eliminating excess liquids and toxins from your blood and is usually performed using a kidney dialysis machine.

If your kidney function deteriorates sufficiently, you may require a kidney transplant.

Lifestyle Modifications

Certain factors linked with nephrotic syndrome are unavoidable. However, you may take measures to protect your kidneys.

  • If you have hypertension or diabetes, start taking medications for it. 
  • Eat healthy meals and drink plenty of water to keep your kidneys healthy.
  • Get vaccinated for contagious diseases, mainly if you deal with people who have hepatitis or some other conditions.
  • Perform mild exercises regularly to keep you active. 
  • Whenever your physician recommends antibiotics, follow the directions carefully and finish the whole course, even though you begin to feel well.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 25, 2023.

References

Nephrotic Syndrome in Adults - NIDDK (nih.gov)

https://www.niddk.nih.gov/health-information/kidney-disease/nephrotic-syndrome-adults#:~:text=Nephrotic%20syndrome%20is%20a%20group,of%20your%20body%2C%20called%20edema

Nephrotic Syndrome - Primary Care: Clinics in Office Practice (theclinics.com)

https://www.primarycare.theclinics.com/article/S0095-4543(20)30056-7/fulltext