It is the product of the metabolism of creatine that is in muscle tissue and in the blood of vertebrates, which is excreted in the urine.
What do high levels of creatinine in urine mean?
Muscles make creatine phosphate from creatine to use the phosphate to help generate the energy they need, but when they remove phosphate, the creatine phosphate changes to creatinine.
Usually, creatinine is sent to the kidneys. Therefore, a high level of creatinine in the urine can signify abnormalities in the muscles or kidneys.
The pancreas, kidneys, and liver cells produce creatine from the amino acids methionine, arginine, and glycine.
Muscle cells will use creatine to make creatine phosphate.
When muscles are at rest, creatine is mainly in the form of creatine phosphate. However, when they need energy for muscle contraction, they take the phosphate, creatine phosphate, and transfer it to ADP, or adenosine diphosphate, to make ATP.
ATP stands for adenosine triphosphate, the molecule that cells use for energy. Therefore, muscle cells remove phosphate from creatine phosphate to generate power and create a creatinine substance.
Creatinine will be released by muscle cells and transported to the kidneys to be excreted from the body in the urine.
Creatinine levels in urine
The usual range of creatinine in a 24-hour urine sample is 500 to 2,000 mg per day. Since it is the breakdown of creatine sent to the kidneys, the laboratory monitors the level of creatinine in the urine.
A high urinary creatinine level can mean a problem in the muscles, as the muscle cells send creatinine to the kidneys. It can also mean a problem with the kidneys; that is, the kidneys cannot excrete creatinine.
High urinary creatinine levels and causes
Rhabdomyolysis is the medical term to describe the destruction or breakdown of skeletal muscle; it can cause a high level of creatinine in the urine.
It can occur over long distances, muscle trauma, electric shock, and as a result of some infections.
Kidney problems that can cause high urinary creatinine levels include kidney failure, glomerulonephritis, and obstructions of the urinary tract. In glomerulonephritis, the capillary network of the kidneys is inflamed.
Kidney disease raises creatinine. Kidney disease, also known as kidney failure, is a severe disease that affects the kidneys and removes metabolic waste from your body.
Kidney failure is the end stage of chronic kidney disease. Common signs and symptoms associated with kidney disease include:
- Elevated levels of creatinine and uric acid.
- Decreased urine output
- Decreased appetite.
- Soft spot.
- Trouble sleeping
- Decreased mental acuity.
- Muscle cramps.
- Swelling of the feet and ankles.
- Persistent itching
Kidney failure is a kidney-related condition that can cause elevated creatinine and uric acid levels.
Kidney failure is described as poor kidney function, possibly caused by reduced blood flow to the kidneys.
Renal artery disease or renal artery stenosis decreases blood flow to the kidneys.
Common signs and symptoms associated with kidney failure include:
- Elevated levels of creatinine and uric acid.
- Increased blood pressure.
- Fluid retention and heart problems.
Certain risk factors can increase your chance of developing kidney failure, including older age, gender, genetics, race or ethnicity, smoking, and obesity.
Congestive heart failure
Congestive heart failure can cause increased levels of creatinine and uric acid. Congestive heart failure is a persistent disease that develops gradually.
If you have congestive heart failure, your heart cannot pump adequate amounts of blood to your cells, tissues, and organs.
As your heart’s ability to pump blood decreases, blood can back up to your lungs, liver, or legs.
Common signs and symptoms associated with congestive heart failure include:
- Increased levels of creatinine and uric acid.
- Difficulty breathing.
- Soft spot.
- Irregular heartbeat
- Decreased ability to exercise.
- Persistent cough
- Abdominal swelling
- Sudden weight gain
- Lack of appetite.
Another cause is the loss of the architectural units where the filtration takes place: the glomerulus. Increased blood creatinine and reduced excretion are signs of loss of glomerular kidney function or glomerular filtration rate.
Diseases that affect the microscopic blood vessels in the glomerulus, such as diabetes, or inflammatory or autoimmune diseases of the kidney, such as lupus, can damage the delicate structures involved in kidney filtration.
Some inherited conditions (such as Goodpasture syndrome), response to infectious agents (such as Streptococcus), and damage caused by medications can also reduce kidney function.
Other conditions that can cause harm include:
- Muscular dystrophy.
- Strenuous exercise
- Shock causing blood loss.
Symptoms of high creatinine levels
Some people with elevated creatinine levels may experience the following symptoms:
- Weakness from confusion.
- Short of breath.
Fatigue and weakness are symptoms of high creatinine levels.
However, a high creatinine level is not a direct cause of the symptoms, and someone with higher than normal levels may notice no change.
The symptoms associated with high creatinine are caused by an underlying disease that affects kidney function. The most common cause is kidney disease itself.
Diabetes and high blood pressure are also associated with kidney failure. Other symptoms may indicate muscle breakdown, hypothyroidism, or diabetic ketoacidosis as the cause of elevated creatinine.
A high creatinine level does not necessarily mean that the person has chronic kidney disease, but it does indicate the need for other tests.
Factors That May Affect Your Creatinine Test Results
- Taking certain medications can affect creatinine test results.
- Medications: phenytoin, vitamin C, diuretics, some antibiotics, cimetidine, and quinine.
- Do strenuous exercise two days before the test.
- Eating large amounts of meat (eight ounces) within 24 hours of the test.
- Urinary tract obstruction and high creatinine levels.
Another way that kidney filtration can be affected is when something obstructs urine flow from the kidney.
A blockage in the urinary tract, especially the ureter (which transfers fluid from the kidney to the bladder), the bladder itself, or the urethra will obstruct flow.
In addition to production in the body’s skeletal muscle, creatine and creatinine are also present in the meat diet.
Vegetarians have a lower intake of these substances than people who eat a diet rich in animal meat, especially beef.
Creatine is a molecule that acts as a muscle energy reserve and breaks down into creatinine. People looking to improve muscle performance sometimes take creatine supplements, such as creatine salts or creatine esters.
A high intake of dietary or supplemental sources of creatine can increase creatinine production, raise plasma creatinine, and increase urine creatinine.
Your body converts creatine, a chemical your muscles use for energy, into creatinine, a waste product that is excreted through your kidneys.
High creatinine levels can signify that your kidneys are not working properly.
The diet for people with high creatinine aims to preserve kidney function and is low in protein, sodium, potassium, and phosphorus. Consult your doctor about your diet if your creatinine levels are high.
If your creatinine levels are high, your doctor may suggest that you limit the amount of protein in your diet. A registered dietitian can work with you to design a diet with the right amount of protein for you based on your kidney function.
Eating more protein than your body needs increases the amount of waste your kidneys must remove, making them work harder.
To limit the amount of waste produced, most of your protein should come from high biological value sources, such as lean meat, poultry, eggs, and milk.
Eat less sodium
Your kidneys are also responsible for removing sodium from your body. If your creatinine levels are high because your kidneys are not working correctly, sodium levels build up in your body.
Eating less sodium also helps you better control your blood pressure, preserving kidney function.
Your doctor can help you determine sodium limits, but you should at least limit your intake to less than 2,300 milligrams per day.
To reduce sodium intake, swap your processed foods, such as deli meats, French fries, and fast food, for more fresh foods such as fresh fruits and vegetables, meat, and seafood prepared without salt, pasta, rice, and milk.
Be careful with foods rich in potassium.
If your elevated creatinine level is due to kidney problems, you may also need to limit your intake of high potassium foods.
Your kidneys are responsible for balancing the amount of potassium in your body. High potassium levels can lead to an irregular heartbeat or even a heart attack.
Fruits and vegetables are the primary sources of potassium in the diet. Oranges, bananas, potatoes, and broccoli are considered high-potassium foods.
Eating low-potassium fruits and vegetables, such as apples, blueberries, corn, and cucumbers, can help you keep your blood potassium levels within a normal range.
Phosphorus and bone health
Phosphorous is another food nutrient you may need to watch out for when your creatinine levels are high due to kidney problems.
Like sodium, your kidneys are responsible for removing phosphorus from your blood. Having high levels of phosphorus in the blood causes the body to remove calcium from the bones, weakening them.