What Is Nephrotic Syndrome?
What is nephrotic syndrome? I'm Dr. Frita, I'm a board-certified nephrologist, which means I'm a medical doctor who specializes in kidney disease and high blood pressure and I'll tell you exactly what it is. Nephrotic syndrome is a kidney disorder where you leak out excessive amounts of protein through your urine and it can lead to all kinds of complications. It can lead to swollen feet, ankles, legs, hands, a swollen belly, and swelling around the eyes. It can also lead to high blood pressure, high cholesterol, blood clots, and even cause kidney failure.
Nephrotic syndrome can be bad news for both adults and children. So it's very important that you understand exactly what it is. Today I'm going to break it down and explain this syndrome giving you the signs, symptoms, treatments, and causes.
Understanding This Rare Kidney Disorder and Its Impact
Nephrotic syndrome is a rare kidney disorder, but when it hits, it hits hard. It can lead to multiple complications including kidney failure, and it can affect both adults and children. So it's really important that you understand what it is.
If you think about your kidneys, you have these two bean-shaped organs, located in your lower back, in the flanks where the love handles are. Each kidney has 1 million glomeruli or 1 million nephrons. These are the filtering systems of the kidney. So each glomerulus, each of the filtering units is responsible for essentially, cleaning out the blood.
You also have these tiny capillaries, which allow blood to flow through them, and they filter out excess water and tiny particles in waste. In a normal kidney, these glomeruli (kidney functioning units) will hold onto bigger particles like red blood cells, white blood cells, and protein. In nephrotic syndrome, there is a problem with the way that these nephrons filter, and instead of holding onto protein in the blood, they filter out protein and allow the protein to get into the urine, and this is what leads to the problems.
Dangers and Complications of Excess Protein In Urine
When you have excess protein in the urine, it leads to multiple complications including edema, high blood pressure, high cholesterol, and even kidney failure. And I'll break it down and I'll explain exactly how.
Edema is a type of swelling that's commonly seen. This swelling isn't just limited to one area; it can appear in various parts of the body, including the feet, ankles, legs, and hands. And in some cases, it may even affect the entire body. You can also get periorbital edema or swelling around the eyes.
Now let us explore how this process unfolds. In nephrotic syndrome, there's an excessive leakage of albumin – a key protein – from the kidneys. Normally, albumin functions like a sponge within your blood vessels, playing a crucial role in keeping this fluid inside the vessels where it belongs.
When you urinate out excess protein like you do with nephrotic syndrome, you lose that sponge, and so you also lose the ability to keep fluid within the blood vessels. So what happens? That fluid leaks out into the tissues and that's when you get that swelling. It's because the protein is low. Beyond the swelling, and just being uncomfortable, it can also lead to issues like ascites or excess fluid in the belly. In addition, it can lead to excess fluid in the lungs and cause shortness of breath as well.
Edema is not the only complication from losing this excess protein in the urine, you can also get high cholesterol. Did you know that your liver plays a vital role in producing albumin? This essential protein is actually crafted right in your liver.
So when the liver senses that you've lost too much protein, you get low levels of protein in the blood. And what does the liver do in response? It decides it's going pump out more protein or more albumin. As the liver works hard to produce albumin, it also releases certain proteins connected to cholesterol, including LDL. This activity can sometimes lead to higher cholesterol levels. Essentially, in its quest to ramp up albumin production, the liver inadvertently produces more cholesterol.
And so nephrotic syndrome can lead to high cholesterol or dyslipidemia, which, of course, can lead to other complications like heart disease, strokes, and things of that nature. Be sure to watch my video on how to lower cholesterol naturally after you finish reading this article.
I mentioned that albumin, that protein is like a sponge that's supposed to keep fluid inside the vessels. When you have nephrotic syndrome, you've urinated out excess protein, and now you no longer have that sponge, and your blood vessels don't have as much fluid. Here's what goes on: when your kidneys filter the fluid moving through their vessels, capillaries, and glomeruli (those vital filtering units), there's a reduction in blood volume. Essentially, this means there's less fluid circulating in your blood vessels.
When your body senses a decrease in fluid levels, it triggers the renin-angiotensin system. This is your kidneys' way of responding to what they perceive as low pressure due to insufficient fluid. So, in an attempt to balance things out, they work to increase the pressure.
And so they activate certain mechanisms that cause you to hold onto salt, cause your blood vessels to tighten, and it can lead to high blood pressure. With nephrotic syndrome, one of the common responses your body has is elevated blood pressure, also known as hypertension.
In nephrotic syndrome, one of the proteins that you lose is known as antithrombin III. Typically, antithrombin III is a protein that will help to maintain proper clotting in your body. It helps to keep you from being hypercoagulable, meaning it'll keep your blood from clotting too much.
With this syndrome, you're losing all of these proteins through the urine, including antithrombin III, and so you lose your ability to keep the blood from clotting too much. So what happens? You can get blood clots or deep venous thrombosis (DVT). You can even get renal vein thrombosis. So basically, nephrotic syndrome can lead to a hypercoagulable state leading to blood clots. And we know that some of these blood clots can even go to the lungs causing pulmonary emboli, it's a problem.
With this disruption in the glomeruli, the filtering units of the kidney, it can ultimately lead to the kidneys not filtering anything properly, leading to end-stage renal disease, requiring dialysis or a kidney transplant. Nephrotic syndrome is pretty rare, but it can affect both adults and children.
According to the NIH (National Institutes of Health), The incidence of nephrotic syndrome in children is 1 to 2 cases per 100,000 children (16 years of age and younger). In adults, it's three cases per 100,000 adults.
How Much Protein Is Too Much Protein?
Now, I've explained that nephrotic syndrome is when you have excessive amounts of protein in the urine. And some of you reading this may be thinking, "Ah, you know, I've gone to my doctor, I've had my urine dipstick, and they told me that I had some protein. Maybe I have Nephrotic syndrome." Well, there's a very specific way that we quantify how much protein is too much protein, and how much protein we consider to be nephrotic syndrome.
Nephrotic syndrome is when you urinate out 3.5 grams of protein or more in your urine in 24 hours. That's 3,500 milligrams of protein, that you're excreting each day, that's a lot of protein! It's normal to have, essentially, no protein in your urine or certainly less than 300 milligrams.
Most Common Causes
Now let's talk about some of the most common causes. Very often, nephrotic syndrome is idiopathic, meaning we don't know where it came from and we don't know why it started. But there are some identifiable causes and we'll get into those.
- Minimal Change Disease - In children, the most common cause is minimal change disease. This is when kids, excrete a whole lot of protein in the urine and they get puffy faces, or they get swelling everywhere, and they may get some of the other complications we talked about. The good news is that in children, with most cases of minimal change disease, steroids are the treatment, and it does not progress to kidney failure.
- Diabetes - Now, for adults, the most common cause of nephrotic range proteinuria is diabetes. Having diabetic nephropathy or diabetic kidney disease can cause you to leak out more than 3.5 grams of protein in 24 hours, and it can lead to nephrotic syndrome.
- Lupus - Lupus or systemic lupus erythematosus, which is known to potentially cause significant protein loss in urine, falling within the nephrotic range.
- HIV - HIV associated nephropathy, a kidney condition, can develop as a complication in individuals living with HIV, affecting kidney function and health.
- FSG or Focal Segmental Glomerulosclerosis - FSG or focal segmental glomerulosclerosis, which is the most common cause of glomerular nephritis or inflammation of the glomeruli in people of African descent, can lead to nephrotic syndrome.
- Hepatitis - Hepatitis, a liver disease, can sometimes lead to this syndrome by affecting the kidneys and disrupting their normal filtering process.
- Membranous Nephropathy - Membranous nephropathy is an autoimmune disease that occurs when your body's immune system, which is meant to protect you, mistakenly attacks your own body, causing harm instead of providing defense. This can be a significant cause, affecting kidney function. There are all kinds of causes of membranous nephropathy including cancer or chronic inflammation. Lupus can lead to membranous nephropathy as well.
- Amyloidosis - Amyloidosis is an uncommon condition where a protein known as amyloid accumulates in various organs, impacting their normal function. This buildup can affect several key organs like the kidneys, heart, and liver, as well as the nervous system and digestive tract.
- Certain Medications - Some medications, such as Penicillamine, have been known to potentially lead to nephrotic syndrome by affecting kidney function.
Top Warning Signs and Symptoms
Here are the top warning signs and symptoms of nephrotic syndrome.
1. Protein in the urine: This can show up as foamy urine. And I don't mean just a couple of little bubbles when you urinate, I'm talking about foam. So like if you've seen those beer commercials where they're pouring beer out of the tap and there's all that white foam on top. A lot of foam in the urine can indicate that you have protein, and you definitely want to get that checked.
2. A surge in blood pressure: Remember, high blood pressure is defined as a systolic blood pressure of 130 or greater, or a diastolic blood pressure of 80 or greater. If you're getting surges in your blood pressure, that could be a warning sign.
3. Swelling: We talked about swelling. If you're noticing swelling around your eyes when you wake up, known as periorbital edema, or if your abdomen seems more bloated, your hands and feet feel puffy, and your shoes or socks are feeling tighter than usual, these could all be signs of edema, which is another indicator.
4. High Cholesterol Levels: If you go to the doctor and all of a sudden your LDL is sky high, along with high triglycerides, it's something to pay close attention to.
5. Blood Clots: Keep an eye out for symptoms like blood clots. For instance, if you experience pain, swelling, or redness in your leg, particularly behind the knee area (like behind the kneecap), it might indicate a DVT (Deep Venous Thrombosis). This is a condition that can be associated with nephrotic syndrome.
6. Severe Flank Pain: Severe flank or kidney pain that radiates towards the groin could also be a warning sign. While many conditions can cause this pain, the presence of blood in your urine is a red flag.
How To Identify The Early Signs
You don't want to wait and sit around until you have some catastrophic complication. The best thing to do is to see your doctor regularly because when you see your doctor, certain screening tests are done that could pick up some of the early signs. For example, when you have your routine histories and physicals, they always check your blood sugar levels or your glucose levels, and sometimes they check your hemoglobin A1C.
If you're having elevated glucose or an elevated hemoglobin A1C that could indicate pre-diabetes or diabetes. Remember, diabetes is the number one cause of nephrotic range proteinuria. This could be a clue to catch an early warning sign, indicating that you might be at risk.
Also, when your doctors check your urine, they often do a urinalysis, which will let them know if you have protein in your urine or they'll do one of those urine dipsticks to see if you have protein. If you have a lot of protein like 3+, then there are further evaluations that can be done to quantify the urine, such as a 24-hour urine analysis for protein.
Nephrotic vs Nephritic Syndrome
Now I want to briefly touch on the difference between nephrotic versus nephritic syndromes because it can be confusing. We've already established that nephrotic syndrome is when there's an abnormality in the way that the kidneys filter out protein and you get excessive protein in the urine.
Nephritic syndrome is characterized by an abnormality in how kidneys filter out red blood cells and other substances, leading to blood and red blood cells in the urine. This can result in urine that is dark-colored, resembling tea, or even visibly bloody. Additionally, nephritic syndrome can cause swelling around the eyes, known as periorbital edema, and other types of swelling. Although the swelling is usually more pronounced in nephrotic syndrome, it's definitely a symptom to watch for in nephritic syndrome as well.
The main difference is that in nephrotic syndrome, the issue is filtering out too much protein. Nephritic syndrome, the issue is filtering out too much blood, and some other toxins as well.
The approach to treating nephrotic syndrome varies depending on the underlying cause. For instance, minimal change disease, commonly seen in children, typically responds well to steroids. Similarly, steroids can also be effective in treating other forms of this syndrome, such as FSGS (Focal Segmental Glomerulosclerosis).
If diabetes is the root cause, then the focus shifts to managing the diabetes itself. This might involve lifestyle changes, like adopting a low-carb, high-protein diet and cutting out added sugars. Treatment could also include diabetes medications, such as insulin, Semaglutide, Tirzepatide, or Metformin, depending on the specific needs.
When lupus is behind this syndrome, steroids might be part of the treatment plan. Additionally, medications such as mycophenolate and hydroxychloroquine can also be effective in managing the condition.
If HIV is the culprit, the treatment plan typically includes antiretroviral medications. In cases where hepatitis is the cause, antiviral medications are the go-to solution. However, it's crucial to remember that diabetes is the leading cause of protein loss in the nephrotic range. Focusing on the prevention and management of diabetes is a significant step in reducing your risk of developing this condition.
Understanding "what is nephrotic syndrome?" is vital for both patients and caregivers. It's a complex condition and topic, and it's not exactly your everyday dinner conversation. But hopefully, now you have a better understanding.
If you're interested in a more personalized discussion about this or other health topics, or if you need a detailed medical consultation, I'm here to help with my concierge telehealth service. It's a chance for us to have a one-on-one chat, where I can learn about your specific health history and offer my medical advice. You'll have my complete attention, making sure that all of your medical questions are answered by me personally. Click here to book your VIP consultation today!
Always keep in mind that when it comes to your health, consulting with your physician is key. Regular doctor visits are essential, helping you possibly avoid conditions like nephrotic syndrome, or at least manage and slow their progression. Stay proactive with your health care.
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