Hyperkalemia is an excessive level of potassium in the blood. It causes symptoms including abnormal heartbeat, muscle weakness, and malaise, or a feeling of general discomfort. Because the symptoms are often vague, it is difficult to diagnose, but hyperkalemia can prove fatal if untreated. In fact, hyperkalemia is induced to cause death by lethal injection. There are many possible hyperkalemia causes.
Hyperkalemia causes fall into three basic categories: insufficient elimination of potassium, excessive release of potassium by the body's cells, and excessive intake of potassium. Ineffective elimination can be caused by kidney failure, certain medications, deficiency of the mineralocorticoid hormones, or the rare congenital disorder arthrogryposis, also called Gordon's syndrome. The body's cells may release excess potassium into the bloodstream as a result of tissue death or breakdown, or because of excessive blood transfusion. Excessive intake of potassium can be caused by potassium chloride infusion or by intoxication with a salt-substitute or dietary supplements containing potassium.
Potassium levels in the blood are regulated in a healthy individual by elimination through the urinary system. The kidneys remove potassium and other substances from the blood and excrete them in the urine. Therefore, problems with the kidneys or the urinary system are common hyperkalemia causes. Medications that interfere with urinary excretion include angiotensin-converting enzyme (ACE) inhibitors for high blood pressure, the antibiotic trimethoprim, the antiparasitic pentamidine, the immunosuppressants ciclosporin and tacrolimus, and nonsteroidal anti-inflammatory drugs (NSAIDs). Stopping or changing medication, when possible, can often cure drug-induced hyperkalemia.
Hyperkalemia causes involving mineralocorticoid deficiency include Addison's disease and congenital adrenal hyperplasia, in which the adrenal glands do not produce enough hormones. Type IV renal tubular acidosis, in which the kidneys are resistant to the mineralocorticoid hormone aldosterone, can also cause hyperkalemia. Hyperkalemia is also a common symptom of arthrogryposis, or Gordon's syndrome, which also causes deformities of the joints, high blood pressure, retarded growth, and respiratory problems.
Hyperkalemia is diagnosed through blood tests to identify abnormally high levels of potassium. Repeated tests are required to make a diagnosis. Acute hyperkalemia is treated with emergency lowering of blood potassium, which can be done through administering calcium, insulin, bicarbonate, or salbutamol. In very severe cases dialysis may be required.
Hyperkalemia can be managed or prevented through reducing potassium in the diet and through medication, which can take the form of diuretics, calcium polystyrene sulfonate, or sorbitol. However, some diuretics, such as amiloride and spironolactone, do not remove potassium from the body and can themselves be hyperkalemia causes. It is important to monitor the medications of a person with hyperkalemia, since many drugs can be the source of the disorder.