Nephrotic syndrome is a disorder of the kidneys that results in too much protein excreted into your urine. It is usually associated with damaged kidneys.
What is nephrotic syndrome?
Nephrotic syndrome is a disorder of the kidneys that results in too much protein excreted into your urine. It is usually associated with damaged kidneys specifically damage to the kidneys' filters, called glomeruli.
Kidney damage and nephrotic syndrome primarily include albuminuria, or large amounts of protein in the urine; hyperlipidemia, which is higher than normal fat and cholesterol content in the blood; edema, which is widespread swelling; and hypoalbuminemia, which is a low level of albumin in the blood.
Treatments include medications to relieve symptoms and assess underlying conditions as well as possible lifestyle adjustments.
In general, the evaluation of nephrotic syndrome should be done in the next 24-48 hours, but it is not a medical emergency and can generally be done by your primary care doctor. Diagnosis is done by blood tests, and treatment involves medications that reduce your fluid retention and stabilize your blood pressure.
Symptoms of nephrotic syndrome
There are few main symptoms of nephrotic syndrome that can be described as albuminuria, hypoalbuminemia, edema, and hyperlipidemia. They may present as the following:
- Weight gain: The weight gain is most commonly related to the edema and excess fluid retention associated with nephrotic syndrome but may also be related to weight gain associated with other related medical conditions.
- Foamy urine: This is related to the excess protein found in the urine (albuminuria).
- Loss of appetite: Too much protein escaping into the urine (albuminuria) leaves a lack of protein in your blood (hypoalbuminemia), which can result in malnutrition and change your perception about certain foods.
- Fatigue: Any chronic illness can cause you to feel extremely tired.
Complications of nephrotic syndrome include:
- Clots in the blood: Since the glomeruli cannot properly filter the blood, there is a loss of proteins that are important for preventing clots. This increases the risk of developing blood clots in your veins.
- Infections: In nephrotic syndrome, the damaged glomeruli cannot properly filter and retain important components of the immune system that help fight off infections.
- High blood pressure: Damage to the glomeruli results in buildup of wastes in the bloodstream that can increase blood pressure.
- Chronic kidney disease: Over time, the kidneys will gradually lose their function due to nephrotic syndrome and you may require dialysis (machine-based filtering of the blood) or a kidney transplant.
What causes nephrotic syndrome?
Nephrotic syndrome is a collection of symptoms that occur due to kidney damage. It is due to four main problems:
- Albuminuria: When the clusters of small blood vessels in your kidney responsible for filtering waste and excess water become damaged, the kidneys do not function properly, and excrete too much of a protein called albumin into the urine, called albuminuria.
- Hypoalbuminemia: This is a deficiency of protein in your blood when there is too much being lost in your urine.
- Edema (swelling): Albumin is a protein that acts like a sponge, drawing excess fluid from the body into the bloodstream. The albumin remains there until it is removed by the kidneys. When albumin leaks into the urine, the blood loses its ability to absorb extra fluid from the body, causing edema in the legs, feet, ankles, and sometimes the hands or face.
- Hyperlipidemia: Higher than normal fat and cholesterol levels in the blood, called hyperlipidemia, can be caused because the liver makes more albumin in an attempt to replace the loss in the blood.As a result, it releases more cholesterol and triglycerides.
Primary causes refer to conditions and diseases that directly affect the kidneys. Most often, these conditions damage or cause injury to the filtering blood vessels of the kidneys (the glomeruli). When the glomeruli are damaged, the kidney cannot properly filter albumin. For example, in a disease such as focal segmental glomerulosclerosis, scar tissue forms in the glomeruli. Whereas in a condition such as membranous nephropathy, the immune system forms harmful deposits on the glomeruli.
Secondary causes refer to systemic diseases that affect multiple organs in the body, including the kidney. The systemic conditions most likely to cause kidney problems include diabetes and lupus. Another secondary cause may pertain to the vasculature of the kidneys. For example, a blood clot in the veins of the kidney can result in nephrotic syndrome.
Who is most likely to be affected
Certain risk factors can also increase your risk of developing nephrotic syndrome. This includes:
- Having diabetes or lupus: These conditions can cause damage to the kidneys, also mentioned above.
- Chronic NSAID usage: Using nonsteroidal anti-inflammatory drugs (NSAIDs) and some drugs used to combat infections for long periods of time can predispose people to nephrotic syndrome.
- Having infections: HIV, hepatitis, and malaria can increase your risk of developing nephrotic syndrome.
Treatment options and prevention for nephrotic syndrome
Treatment for nephrotic syndrome includes properly addressing the associated symptoms as well as underlying medical conditions that may be causing the syndrome. Treatment options may include a combination of medications to address edema, blood pressure, cholesterol and inflammation, and lifestyle and at-home remedies.
Medication for edema and blood pressure
Your physician may prescribe specific medications to treat complications such as edema and high blood pressure. These medications reduce the pressure on the glomeruli and help reduce albuminuria as well as increase fluid output to help control swelling.
- Blood pressure medications: Drugs called angiotensin-converting enzyme (ACE) inhibitors reduce blood pressure and also reduce the amount of protein released in urine. Another group of drugs that works in a similar way is called angiotensin II receptor blockers (ARBs).
- Diuretics (water pills): These help control swelling by increasing your kidneys' fluid output, which will result in more frequent urination.
Cholesterol medication and immunosuppressants
Depending on other complications you have developed due to your nephrotic syndrome, your physician may prescribe medications to specifically target these problems. Some medications include:
- Cholesterol-reducing medications: Statins can help lower cholesterol levels.
- Immune system-suppressing medications: Corticosteroidsmay decrease the inflammation that accompanies underlying conditions and damages the kidneys, such as such as lupus.
Lifestyle and at-home treatments
Your physician may also suggest changes to your diet or refer you to a dietician in order to help with your nephrotic syndrome. Suggested changes may include:
- Eating lean sources of protein: Such as chicken or fish
- Eating a low-salt diet: To control and alleviate edema
- Limiting the amount of fatty foods you eat: To help control blood cholesterol
- Eating a balanced diet: To help control weight gain
When to seek further consultation for nephrotic syndrome
You should seek medical attention if you experience any symptoms of nephrotic syndrome, such as weight gain or edema, foamy urine, fatigue, or a loss of appetite, or if you have any conditions that can result in nephrotic syndrome.
Questions your doctor may ask to determine nephrotic syndrome
- Any fever today or during the last week?
- Do you have a cough?
- Have you lost your appetite recently?
- Are you sick enough to consider going to the emergency room right now?
- Have you had any changes in your weight?
Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.
Dr. Gambrah-Lyles is a resident pediatrician at the Children's Hospital of Philadelphia. She is a graduate of the University of Pennsylvania Perelman School of Medicine (2019). She graduated cum laude and received her undergraduate degree in Biochemistry and Spanish from Washington University in St. Louis (2013). Her research explores the intersections between neurology, public health, and infectious disease. She has investigated nutrition and cerebral palsy in Botswana, and completed a year-long project in Brazil, researching growth and developmental outcomes of Zika virus infection in pediatric patients as a Doris Duke International Scholar. Dr. Gambrah-Lyles speaks four languages, loves staying active, and enjoys sharing her love for medicine through teaching and writing.
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