Hyperpotassemia

Hyperpotassemia – a state at which concentration of electrolytes of potassium (K+) in blood increases to the life-threatening person of level. The patient with a hyperpotassemia needs emergency medical service in connection with potential risk of a cardiac standstill at untimely treatment.

Normal level of content of potassium in blood makes from 3,5 to 5,0 мг-ݬó/l, about 98% of potassium contain in cells, and other 2% in extracellular liquid, including, and in blood.

Potassium is the most widespread intracellular cation which is important for many physiological processes, including, for maintenance of membrane potential of rest, a homeostasis of volume of cells and transfer of action potentials in nervous cells. Its main food sources are vegetables (tomatoes and potatoes), fruit (oranges and bananas) and meat. Removal of potassium happens through digestive tract, kidneys and sweat glands.

The hyperpotassemia develops at excess consumption or inefficient removal of potassium. Increase in extracellular level of potassium leads to depolarization of membrane potential of cells because of increase in equilibrium potential of potassium. Depolarization leads to tension of natrium channels, opens them, and also increases their inactivation that as a result leads to fibrillation of ventricles or an asystolia. Prevention of a recurrence of a hyperpotassemia usually includes reduction of the use of food potassium and kaliysberegayushchy diuretics.

Hyperpotassemia symptoms

Hyperpotassemia symptoms nonspecific and usually include:

• Indisposition;
• Emergence of high T-waves on an ECG;
• Ventricular tachycardia;
• Weakness of muscles;
• Increase in an interval of ORS at an ECG;
• Increase in an interval of PR at an ECG.

Also symptoms of a hyperpotassemia are cardiac arrhythmia, the T tooth point on an ECG and exceeding of level of potassium is more than 7,0 mmol/l.

Hyperpotassemia reasons

Inefficient elimination of a renal failure, Addison's disease and deficit of Aldosteronum can be the reasons of a hyperpotassemia. Also can lead reception to a hyperpotassemia:

• Inhibitors of an angiotensin-converting enzyme and blockers of receptors of angiotensin;
• Kaliysberegayushchy diuretics (amiloride, Spironolactonum);
• Non-steroidal anti-inflammatory drugs, such as ibuprofen, Naproxenum or целекоксиб;
• Inhibitors of a kaltsinevrin;
• Immunodepressants (cyclosporine and такролимус);
• Antibiotics (Trimethoprimum);
• Antiparasitic drug of pentamidine.

Also the inborn hyperplasia of bark of adrenal glands, Gordon's syndrome and acidosis of renal tubules of the IV type can be the cause of a hyperpotassemia.

Can lead the use of the nutritional supplements containing potassium, infusions of potassium chloride and the excessive use of kaliysoderzhashchy salt to a hyperpotassemia.

Diagnosis of a hyperpotassemia

To collect sufficient information for diagnosis of a hyperpotassemia it is necessary to measure constantly potassium level, its raised state can be connected with hemolysis in the first stage. Normal level of serumal potassium makes from 3,5 to 5 мг-ݬó/l. As a rule, diagnosing includes blood tests on function of kidneys (creatinine, a blood urea nitrogen), glucose, and sometimes and on a creatine kinase and cortisol. Calculation of a trans-tubular gradient of potassium sometimes helps with establishment of the reason of a hyperpotassemia, and the electrocardiography is carried out for determination of risk of cardiac arrhythmias.

Treatment of a hyperpotassemia

The choice of treatment depends on degree and the reason of a hyperpotassemia. When the content of potassium in blood exceeds 6,5 mmol/l it is necessary to lower urgently potassium level before normal contents. It can be reached by means of administration of calcium (calcium chloride or a gluconate of calcium) which increases threshold potential and recovers a normality of a gradient between the threshold potential and rest potential of a membrane which is increased at an abnormal hyperpotassemia. One ampoule of calcium chloride contains approximately three times more calcium, than a calcium gluconate. Calcium chloride begins to work less than in five minutes, and its effect lasts about 30-60 min. The dosage should be selected at continuous monitoring of changes of an ECG during introduction and the dose has to be repeated if changes on an ECG are not normalized within 3-5 minutes.

Also for treatment of a hyperpotassemia and decrease in risk of complications holding some medical procedures which for some time I help to suspend process of a hyperpotassemia is possible until potassium is removed from an organism. Treat them:

• Intravenous administration of 10-15 units of insulin together with 50 ml of 50% of solution of a dextrose for prevention of a hyperpotassemia leads to the shift of potassium ions in cells. Its action lasts several hours so sometimes it is necessary to undertake at the same time and other measures for suppression of level of potassium on more constant basis. Insulin is usually entered with the corresponding amount of glucose to prevent a hypoglycemia after administration of insulin;
• Bicarbonate therapy (infusion of 1 ampoule (50 мэкв) within 5 min.) is efficiently on potassium shift in cells. Ions of bicarbonate stimulate exchange of H+ for Na+ that leads to stimulation of sodium-potassium of Atfaza;
• Administration of salbutamol (Albuterolum, Ventolinum), β the 2-selection catecholamines on 10-20 mg. This drug also reduces the K+ level, accelerating its advance in cells.

Treatment of a hyperpotassemia in severe forms demands a hemodialysis or haemo filtering which are the most bystry methods of removal of potassium from an organism. They are usually used in cases when the main reason for a hyperpotassemia cannot be corrected quickly or not the answer to other taken measures.

Sodium polystyrene sulphonate with sorbite orally or is rektalno widely applied for the purpose of decrease in potassium within several hours, and furosemide is used for removal of potassium with urine.