What Is CPK?
CPK stands for Creatinine Phosphokinase. It is also called Creatinine Kinase (CK).
- Creatinine phosphokinase is an intracellular enzyme present in the brain as well as muscular tissues.
- It is involved in maintaining blood pressure and enhances contractility of skeletal, cardiac and smooth muscles.
- CPK is also present in the following non-muscle cells:
➢ Bones and cartilages
➢ Retina photo-receptors
➢ Neurons (brain cells)
➢ Thyroid gland
➢ Brush border epithelial of the intestine
What Are Considered High CPK Levels?
|The normal range for CPK|
|In Males||38 – 174 U/L|
|In Females||26 – 140 U/L|
|CPK-MB||5 – 25 IU/L|
Any count of CPK beyond the upper limit of the normal range is considered to be high and abnormal which should be evaluated and treated accordingly.
CPK is the most commonly used marker to assess the presence of cardiac muscle damage due to myocardial infarction (heart attack) or as a means to differentiate cardiac and non-cardiac chest pain.
What Causes High CPK Levels?
It is evident from the discussion above that CPK can be found in several organs as well as smooth muscles, skeletal and cardiac muscles.
Therefore any clinical condition which results in the disruption of the cell membrane of CPK-rich tissues due to injury or lack of oxygen supply causes the release of creatinine phosphokinase (CPK) into systemic circulation.
Some common conditions however which show high CPK levels are listed below:
In acute myocardial infarction, CPK rises by 3-12 hours and return to normal levels by 48-72 hours.
ECG along with an assessment of cardiac enzymes is done for each patient presenting with chest pain.
Often shows CPK levels higher than 1000U/L
|It is a condition in which damaged skeletal muscles break down rapidly and cause the release of CPK into circulation. Rhabdomyolysis can occur due to the following conditions
|It is an inherited disorder characterized by the progressive breakdown of muscles over a long period of time. CPK is the most specific test for muscular dystrophy. CPK levels rise 50-300 times higher than the normal levels.|
|4.||Malignant Hyperthermia||It is a severe type of reaction against medicines used during general anesthesia.
The medications cause the release of stored calcium within the muscles causing them to contract and generate heat.
Certain Medical Conditions Which Present With High CPK Levels Are
- Prolonged seizures
What Are The Symptoms Of High CPK Levels?
Signs and symptoms of high CPK levels correspond to the underlying causative condition. In most cases, muscular damage is the prime cause for high circulating levels of CPK. The table below mentions possible causes for high CPK levels with their signs and symptoms.
|Sr. No.||Cause||Signs And Symptoms|
|1.||Acute Myocardial Infarction||
|2.||Congestive Cardiac Failure||
Complications include cardiac failure, cardiac arrest, the involvement of heart valves and sudden death.
Complications include low blood pressure and hypovolemic shock, electrolyte disturbances and abnormal heart rate and rhythm and disseminated intravascular coagulation (DIC).
The intensity of signs and symptoms depend upon the extent of muscular damage.
Rhabdomyolysis and metabolic acidosis are common complications.
How To Treat High CPK Levels?
Just like signs and symptoms, treatment for high CPK levels also depends upon the underlying condition.
The table below lists common causes for high CPK levels along with their treatment.
|Sr. No.||Cause For High CPK||Treatment|
|1.||Acute myocardial infarction||Old age is the most common cause for myocardial infarction. Other avoidable causes are
Treatment includes avoidance of causative factors and lifestyle modifications.
|2.||Congestive Cardiac Failure||The risk of having a cardiac failure is related inversely to the amount of physical activity. Preventive measures are lifestyle modifications such as:
|3.||Myocarditis||Treatment depends upon the cause for myocarditis:
|4.||Rhabdomyolysis||Rhabdomyolysis occurs due to a large variety of causes, therefore, the aim is to treat the cause for muscular damage.
|5.||Muscular Dystrophy||Currently, there are no specific medications for muscular dystrophy. However, treatment includes:
High CPK Levels Side Effects
It is quite obvious from the discussion above that high CPK levels are a clear indication of extensive muscular damage and break down due to any cause.
When a muscle breaks down, it releases creatinine phosphokinase (CPK), electrolytes and myoglobin into the blood. Myoglobin cannot be excreted through blood and remains deposited in capillaries of kidneys.
This myoglobin deposited in kidneys is recognized as a toxin by white blood cells present in the blood.
White blood cells aggregate and set up an inflammatory reaction within the kidneys capillaries in order to engulf and get rid of myoglobin from the kidneys; this eventually leading to infection and acute kidney injury (acute renal failure).
Renal failure in presence of high CPK levels is also associated with other factors such as electrolyte disturbances and metabolic acidosis which develops due to muscular breakdown and release of its components into the blood.
CPK is not routinely performed with blood tests for screening health check-up. Yet, you can request an additional test.
The asymptomatic rise in CPK can be dangerous as it is associated with some major medical conditions which require intensive care and prompt treatment. Levels of CPK directly indicate the extent of muscle damage.