Why are calcium levels low in renal failure?

There is a complex coordination between the calcium controlling glands (the parathyroid gland), vitamin D (made by the skin or a diet) and the kidneys that is affected once kidney disease progresses.
Renal failure usually causes calcium imbalance.
- During renal failure, the kidneys may no longer filter out extra phosphorus and remove it from the body or from urine. Over time, phosphorus may increase in the blood. Calcium and phosphorous usually keep each other in check. With the progression of kidney disease, high phosphorus levels may lead to low serum calcium by depositing it onto the bones and other tissues.
- Vitamin D usually aids in the absorption of calcium from food. Healthy kidneys usually change vitamin D from sunlight and foods into active vitamin D that may help in balancing calcium levels through absorption. When the kidneys fail, there is a short supply of active vitamin D. This causes calcium and phosphorus to get out of balance.
It should also be noted that renal failure may also lead to high calcium levels.
- Parathyroid hormone (PTH) may be produced in large quantities, stimulated by low levels of calcium in the blood. PTH tries to keep the calcium level in the blood normal by increasing calcium absorption from food, but it also takes calcium out of the bones. Eventually the parathyroid glands work so hard they go out of control and may cause persistently high calcium levels.
What is renal failure?
Renal or kidney failure is a condition in which the kidney does not perform its functions properly. This condition may be temporary or permanent. There are two different types of kidney failure
- Acute kidney injury: It may start suddenly and may be reversible. It may occur due to injury, infections, medication side effects or sometimes preexisting diseases.
- Chronic/severe kidney disease: It progresses slowly over at least three months and can lead to permanent kidney failure. It may be caused by various medical conditions including diabetes, high blood pressure, hereditary kidney disease, etc. It usually does not produce any symptoms until it progresses to advanced stages.
Stages
- Stage 1: 90% kidney function is usually preserved.
- Stage 2: 60% to 89% kidney function is preserved.
- Stage 3: Symptoms may include tiredness, puffiness, changes in appetite, dull back pain and urine changes. Kidney functioning may be reduced to 40% to 59%.
- Stage 4: Patients experience fatigue, swelling, changes in appetite, back pain, changes in urination, hypertension and slowed digestion. Kidney function may be reduced to 15% to 29%.
- Stage 5: This is end-stage kidney failure. The kidneys are only functioning at less than 15%.
How is renal failure treated?
Early stages of renal failure are usually treated with lifestyle modifications and by controlling underlying causes such as hypertension and diabetes.
When kidney function falls below 10% of normal, the options below may be used
- Dialysis: This is a way to pump blood through a machine that filters out waste and returns the blood to the body. There are two types of dialysis
- Hemodialysis: A tube is stuck into one of the veins (the neck, arm or leg) to remove toxins from the blood. This is usually done three times a week for three to four hours at a time.
- Peritoneal dialysis: This is done through a tube that is placed inside the belly.
- Kidney transplant: This is a procedure in which a surgeon puts a healthier kidney from another person into the person who has kidney disease. A kidney transplant is the best way to treat many patients with end-stage kidney failure. Kidneys for transplant come from people who have agreed to donate their kidneys when they die (deceased donors) or healthy people (living donors). Living donors are most often family members of the patient. There is a shorter wait time to surgery for a transplant from a living donor. This is because there is a waiting list for the kidneys from deceased donors and not enough donors. Additionally, patients with kidneys donated by living donors live longer (and the kidneys last longer) than those with kidneys from deceased donors or who just stay on dialysis.
What is the life expectancy with kidney failure?
Kidney disease or failure may affect the lifespan. Estimating a timeframe may be complex. In acute cases, death may occur within a few days to a week without treatment. In severe cases, life expectancy may be a few years at most without treatment. However, even people who have complete renal failure may live for years with proper care and regular dialysis treatments. A kidney transplant may also result in a longer survival period.

SLIDESHOW
Kidney Stones: Symptoms, Causes, and Treatment See SlideshowHealth Solutions From Our Sponsors
Endotext
Kidney Care UK
Top Why Are Calcium Levels Low in Renal Failure Related Articles
Diabetes and Kidney Disease
In the United States diabetes is the most common cause of kidney failure. High blood pressure and high levels of blood glucose increase the risk that a person with diabetes will eventually progress to kidney failure. Kidney disease in people with diabetes develops over the course of many years. albumin and eGFR are two key markers for kidney disease in people with diabetes. Controlling high blood pressure, blood pressure medications, a moderate protein diet, and compliant management of blood glucose can slow the progression of kidney disease. For those patients who's kidneys eventually fail, dialysis or kidney transplantation is the only option.Fotivda (tivozanib)
Fotivda (tivozanib) is a prescription medicine used to treat adults with advanced kidney cancer (advanced renal cell carcinoma or RCC) that has been treated with 2 or more prior medicines and has come back or did not respond to treatment. Serious side effects include high blood pressure, heart failure, heart attack and blood clots in the veins or arteries, bleeding problems, protein in urine, thyroid gland problems, wound healing problems, and others.Hypertensive Kidney Disease
High blood pressure can damage the kidneys and is one of the leading causes of kidney failure (end-stage renal kidney disease). Kidney damage, like hypertension, can be unnoticeable and detected only through medical tests. If you have kidney disease, you should control your blood pressure. Other treatment options include prescription medications.Kidney (Renal) Failure
Kidney failure can occur from an acute event or a chronic condition or disease. Prerenal kidney failure is caused by blood loss, dehydration, or medication. Some of the renal causes of kidney failure include sepsis, medications, rhabdomyolysis, multiple myeloma, and acute glomerulonephritis.
Post renal causes of kidney failure include bladder obstruction, prostate problems, tumors, or kidney stones.Treatment options included diet, medications, or dialysis.
Kidney Infection (Pyelonephritis)
Kidney infection (pyelonephritis) usually is caused by E. coli and other bacteria that have spread from the bladder from a UTI (urinary tract infection), poor hygiene, sexual intercourse, pregnancy, catheter, cystoscope exam, surgery, kidney stones, or prostate enlargement. Symptoms of kidney infection include back pain, frequent urination, pain during urination, fever, and or pus or blood in the urine. Kidney infection can be cured with antibiotic treatment. Cranberry juice may prevent UTIs, but that hasn’t been proven in all research studies.Kidney Pain: Symptoms, Treatment, and Causes
Kidney pain has a variety of causes and symptoms. Infection, injury, trauma, bleeding disorders, kidney stones, and less common conditions may lead to kidney pain. Symptoms associated with kidney pain may include fever, vomiting, nausea, flank pain, and painful urination. Treatment of kidney pain depends on the cause of the pain.Kidney Pain vs. Back Pain
The signs and symptoms of kidney pain and back pain depend upon the underlying cause. Doctors may use blood tests, X-rays, CT, and/or MRI to diagnose kidney pain and back pain. Treatment may include rest, ice, stretching, muscle strengthening, and pain-relieving medications.Polycystic Kidney Disease (PKD), ARPKD, and ADPKD
Polycystic kidney disease (PKD) is characterized by numerous cysts in the kidneys. Polycystic kidney disease is a genetic disorder. There are two major inherited forms of PKD, autosomal dominant PKD, and autosomal recessive PKD. Symptoms include headaches, urinary tract infections, blood in the urine, liver and pancreatic cysts, abnormal heart valves, high blood pressure, kidney stones, aneurysms, and diverticulosis. Diagnosis of PKD is generally with ultrasound, CT or MRI scan. There is no cure for PKD, so treatment of symptoms is usually the general protocol.What Are the Signs That Something Is Wrong With My Kidneys?
Most of the signs of kidney diseases are unnoticed, ignored, or appear very late in the disease. Over 37 million American adults have kidney diseases, and most are not aware of it.