What is chronic kidney disease (CKD)?
Chronic kidney disease (CKD) is the progressive and irreversible destruction of the kidneys. Your kidneys are essential parts of your body. They have several functions, including:
- helping maintain the balance of minerals and electrolytes in your body, such as calcium, sodium, and potassium
- playing an essential role in the production of red blood cells
- maintaining the delicate acid-base (pH) balance of your blood
- excreting water-soluble wastes from your body
Damaged kidneys lose their ability to perform these functions.
Each kidney contains about 1 million tiny filtering units, called nephrons. Any disease that injures or scars the nephrons can cause kidney disease. Diabetes and high blood pressure can both damage your nephrons.
High blood pressure can also damage the blood vessels of your kidneys, heart, and brain. The kidneys are highly vascularized, meaning they contain lots of blood vessels. So, blood vessel diseases are generally dangerous to your kidneys.
Autoimmune diseases such as lupus can damage blood vessels and can make antibodies against kidney tissue.
The risk of CKD increases for people older than 65 years. The condition also runs in families. It’s more likely to occur in African-Americans, Native Americans, and Asian-Americans. Other risk factors for CKD include:
- cigarette smoking
- high cholesterol
- diabetes (types 1 and 2)
- autoimmune disease
- obstructive kidney disease, including bladder obstruction caused by benign prostatic hyperplasia
- cirrhosis and liver failure
- narrowing of the artery that supplies your kidney
- kidney cancer
- bladder cancer
- kidney stones
- kidney infection
- systemic lupus erythematosus
- vesicoureteral reflux, which occurs when urine flows back into your kidney
CKD doesn’t cause any symptoms until most of your kidney is destroyed. Once the kidney is severely damaged, the symptoms of CKD can include:
- swelling around your eyes, called periorbital edema
- swelling of your legs, called pedal edema
- shortness of breath
- vomiting, especially in the morning and after eating
- a urine-like odor to your breath
- bone pain
- abnormally dark or light skin
- an ashen cast to your skin, called uremic frost
- mental cloudiness
- numbness in your hands and feet
- restless leg syndrome
- brittle hair and nails
- weight loss
- a loss of muscle mass
- muscle twitching and cramps
- easy bruising and bleeding
- blood in your stools
- excessive thirst
- decreased interest in sex
- sleep apnea
You may also have the symptoms of any diseases that are contributing to your kidney problems.
The diagnosis of CKD starts with a medical history. A family history of kidney failure, high blood pressure, or diabetes may alert your doctor. However, other tests are necessary to confirm that you have CKD, such as:
Complete blood count
A complete blood count can show anemia. Your kidneys make erythropoietin, which is a hormone. This hormone stimulates your bone marrow to make red blood cells. When your kidneys are severely damaged, your ability to make erythropoietin decreases. This causes a decline in red blood cells, or anemia.
Electrolyte level test
CKD can affect your electrolyte levels. Potassium may be high and bicarbonate levels may be low if you have CKD. There may also be an increase of acid in the blood.
Blood urea nitrogen test
Blood urea nitrogen can become elevated when your kidneys start to fail. Normally, your kidneys clear the products of protein breakdown from your blood. After kidney damage, these byproducts build up. Urea is one byproduct of protein breakdown and is what gives urine its odor. Your doctor may check for buildup.
As kidney function declines, your creatinine increases. This protein is also related to muscle mass.
Parathyroid hormone (PTH) test
The kidney and the parathyroid glands interact through the regulation of calcium and phosphorus. A change in kidney function affects the release of PTH. This affects calcium levels throughout your body.
When your kidney progresses to end-stage renal disease, it no longer excretes enough phosphorus and impairs vitamin D synthesis. Your bones may release calcium, too. This causes your bones to become weak over time.
Renal flow and scan
A renal scan is an imaging study of kidney function.
This noninvasive test provides images to help your doctor determine whether there’s an obstruction.
Additional tests for CKD include:
CKD is chronic and irreversible. Treatment, then, focuses on improving the underlying disease. Treatment can also prevent and manage complications of CKD, such as:
- fluid overload
- congestive heart failure
- brittle bones
- weight loss
- electrolyte imbalance
Controlling underlying problems, such as hypertension and diabetes, can slow the progression of kidney damage.
The treatment for CKD and ESRD includes:
You should decrease the fat, salt, protein, and potassium in your diet. Reducing salt and fluid intake can help control blood pressure and prevent fluid overload. Be sure to still get adequate calories to maintain your weight. If you have diabetes, restrict your carbohydrate intake.
Be sure you get adequate exercise. Quitting smoking if you smoke can also help.
Supplements and medication
Your treatment may involve:
- iron and vitamin supplements to manage anemia
- calcium and vitamin D supplements
- erythropoietin injections to stimulate the production of red blood cells
- phosphate binders
- stool softeners for constipation
- antihistamines for itching
If you have CKD associated with type 2 diabetes, then taking the prescription drug Kerendia (finerenone) may reduce the risk of:
- sustained GFR decline
- end-stage kidney disease
- cardiovascular death
- nonfatal myocardial infarction
- hospitalization for heart failure
You should only take Kerendia if you have been instructed to do so by your doctor.
You may need dialysis to purify your blood. In some cases, you may need a kidney transplant. You should also talk to your doctor about controlling your blood sugar and diabetes, if you have it.
You may be more susceptible to infection if you have CKD or ESRD. Doctors recommend that you get the following vaccinations:
- pneumococcal vaccine
- hepatitis B vaccine
- influenza vaccine
- H1N1 (swine flu) vaccine
You can’t always prevent CKD. However, controlling conditions like high blood pressure and diabetes can help. You should get regular screenings for CKD if you’re at high risk. Getting an early diagnosis of CKD can help slow its progression.