What Is C1q Nephropathy?
C1q nephropathy is a kidney disorder in which large amounts of protein are lost in the urine. It is one of the many disorders that can lead to nephrotic syndrome. C1q is a normal immune system protein and can be found in the blood circulation of most healthy people. However, in C1q nephropathy, this protein can also be found deposited throughout the kidneys. Since these deposits can only be viewed under a microscope, a kidney biopsy is required for the diagnosis of C1q nephropathy.
The kidneys typically clean the blood of the natural waste products that get accumulated over time. To do this, the kidneys must filter all the blood in the body many times daily. That is, in fact, what urine is, filtered blood. Usually, this blood gets filtered by the kidney without losing any proteins that are supposed to remain in circulation. However, when the kidney filters get damaged, protein sometimes slips through and enters the urine. This condition is called proteinuria.
Being one of the more recently discovered kidney diseases, doctors are still trying to figure out exactly how to describe C1q nephropathy and treat it.
How Does C1q Nephropathy Look?
Here is a quick overview of the kidney- there are two kidneys, located one on each side of the lower back. All the blood in the body passes through the kidneys several times throughout the day, and every time the blood goes through, some of it gets filtered by the glomeruli of the kidney (singular is glomerulus). This filtering is the procedure in which the body cleans the blood, removes excess water, and some filtered blood becomes urine. The color of the urine is not red like blood. This is because the red blood cells (RBC), which give blood its color, are too large to pass through the filters. A glomerulus is made of a tiny bag of blood vessels through which blood filtration occurs, and all of the filtered-out blood (urine) moves into tubes (ureters) that eventually lead to the bladder.
In C1q nephropathy, the kidney filters can look normal under a standard microscope (although they may also have visibly scarred areas). The differences can only be seen when the special stains that are specific to the C1q protein are added to the sample. The areas where C1q deposits, these stains cause those areas of the biopsy to glow bright green under certain types of light. In addition, if the biopsy is evaluated in an electron microscope (which has the capacity to magnify an object over a million times), those C1q deposits themselves can be seen.
What Are the Causes of C1q Nephropathy?
It is still unknown why C1q nephropathy develops or why some people get C1q deposited in their kidneys while most do not. The deposited C1q seems to activate the immune system within the kidney itself. This resulting immune response and inflammation cause kidney damage. Similar to minimal change disease (kidney disorder with damage to glomeruli causing loss of protein in urine), C1q nephropathy is more common in childhood.
What Are the Symptoms of C1q Nephropathy?
The symptom of C1q nephropathy, which is the most noticeable, is often edema, or swelling, which can be profound. The swelling typically starts in the feet and legs but can also move into the hips and abdomen. Other symptoms include-
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High blood pressure.
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Increased cholesterol levels.
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A tendency to form blood clots.
A urine sample can measure protein levels, and a blood test can calculate kidney function, or it can be measured directly by adding a 24-hour urine collection. C1q nephropathy can cause only proteinuria or proteinuria and renal failure together, so a doctor must assess both. C1q nephropathy often leads to nephrotic syndrome.
When someone excretes an excess of protein in their urine, they can often develop a condition called nephrotic syndrome. The symptoms of this syndrome always include-
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More than three grams of protein in the urine per day (proteinuria).
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Peripheral edema (swelling).
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Hypoalbuminemia (less protein in the blood than usual).
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Hyperlipidemia (high cholesterol).
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Hypercoagulability (increased tendency to form blood clots).
How Is C1q Nephropathy Diagnosed?
C1q Nephropathy is a relatively recently discovered disease. It has been discovered with the help of a specialized electron microscope and immunofluorescence microscope that contains stains specific for the deposits of the C1q protein. Therefore, a kidney biopsy is required to diagnose C1q nephropathy.
What Is the Treatment for C1q Nephropathy?
The treatment for C1q nephropathy is generally the same as for nephrotic syndrome. It is essential to consult a kidney specialist regularly for the monitoring of kidney function, the severity of proteinuria, cholesterol, and blood pressure.
The most commonly used drug for the treatment of C1q nephropathy is steroids. However, several different types of immunosuppressants, or medications that suppress the immune system, can also be considered.
If these do not prove effective, it is essential to be on a drug that reduces the amount of protein in the urine. These medications are ACE inhibitors (angiotensin-converting enzyme inhibitors) and ARBs (angiotensin II receptor blockers).
A nephrologist may also recommend the following-
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Diuretics for the elimination of excess fluids in the body.
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Anticoagulants to prevent blood clots.
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Low sodium diet to help control edema (swelling).
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Statins to lower cholesterol levels.
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Blood pressure medications to lower high blood pressure.
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Maintaining a healthy diet is important. Appropriate quantity of protein and fluid intake according to the recommendations of the nephrologists. A healthy diet consists of low salt intake with an emphasis on fruits and vegetables and is low in saturated fat and cholesterol.
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Exercising.
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Quit smoking.
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Vitamins.
Conclusion:
Since it is both a relatively new and rare disease, it is pretty challenging to predict the course of C1q nephropathy. While some people have been observed to go into complete remission, a few others have developed an end-stage renal disease that may require dialysis or a kidney transplant. Fortunately, so far, complete renal failure seems to be the exception rather than the rule. The kidney biopsy can also help predict the course of the disease.
