Potassium in the blood: normal by age (table), reasons for increase and decrease

The role of potassium in the body

Potassium is a trace element necessary for the normal functioning of the body; it is responsible for alkalization of the blood and the level of magnesium in the serum. The amount is correlated with the intake of the mineral with food and the output with urine, sweat, and feces. Potassium, in addition to its basic functions, plays an important role in the conduction of impulses along neurofibers, eliminates depression, and stabilizes oxygen supply to the brain.

Separately, it is worth mentioning the role of potassium in the work of the heart: the microelement is necessary for normal contractility of the myocardium, and therefore normal blood circulation.

Potassium helps to minimize sensitization of the body, has a positive effect on all internal organs, is involved in the removal of excess fluid from the body (potassium-sodium pump), the synthesis of enzymes, neutralizes the effect of toxins on tissues, ensures normal contraction of skeletal muscles, maintains acid-base balance,

Mineral deficiency causes caries, destruction of bones, nails, and hair.

Detailed description of the study

Potassium is one of the main cations (positively charged ions) in the human body. The main part of it is located inside cells and only a small part is in the extracellular space, including blood plasma. Potassium supports the electrical activity of cells, participates in the processes of conducting nerve impulses, muscle contraction, regulating water balance and acid-base balance in the blood.

The concentration of potassium in plasma depends on its intake, redistribution, excretion from the body and is regulated by various substances. In this way, a balance is maintained between intra- and extracellular potassium protein in the cell membrane (sheath) - the potassium-sodium pump. Insulin increases the influx of ions into cells, while alpha adrenergic agonists increase their exit from it. Blood pH also affects the level of this cation. With an increase in acidity (acidosis), potassium is released into the plasma, and with a decrease in acidity (alkalosis), there is an influx into the cell.

The macronutrient enters the body with food: meat, fruits and vegetables. A lot of it is found in apricots, prunes, potatoes, and legumes. The daily norm for humans is 4-5 g. Potassium is absorbed mainly in the small intestine and enters the cells. It is filtered in the kidneys and reabsorbed in large quantities - it enters the blood again. The hormone aldosterone, which is produced by the adrenal glands, increases the excretion of macronutrients by the kidneys. Potassium is also excreted through the intestines and sweat glands.

The concentration of potassium in plasma is quite low and even small fluctuations can lead to disturbances in the body. A test for potassium in the blood plasma may show a decrease in its level (hypokalemia). It occurs due to insufficient intake of the macroelement from food, increased excretion in the urine (some kidney diseases), loss of the ion from intestinal contents (vomiting, diarrhea), and increased production of aldosterone. The main symptoms of hypokalemia are associated with impaired neuromuscular conduction. A person experiences fatigue, muscle weakness, decreased muscle tone, and heart rhythm disturbances.

Hyperkalemia occurs due to excess potassium intake into the body, for example, during intensive infusion of potassium-containing drugs. Also, an increase in the level of the cation in plasma can be observed with insufficient excretion by the kidneys and increased release from cells (destruction of red blood cells, disseminated internal coagulation syndrome and other reasons). Symptoms of hyperkalemia: weakness in the legs, muscle paresis, abdominal pain, numbness, heart rhythm disturbances with a decrease in contraction frequency, and in severe cases, cardiac arrest.

A biochemical blood test for potassium allows you to diagnose its excess or deficiency and take timely measures to correct disorders.

Normal blood potassium levels in adults and children

To be sure that the level of potassium in the bloodstream is normal, blood plasma is tested for the concentration of the trace element. This is necessary to understand whether a sufficient amount of metal circulates in the blood and whether there are prerequisites for the development of a particular pathological process.

Children

Women

During pregnancy, potassium concentration changes between trimesters. It is needed in increasing quantities for the normal functioning of mother and fetus. The optimal intake is 3.5 g/day. However, sometimes gestation causes an increase in the microelement by one and a half times compared to the desired norm and a significant drop in concentration after childbirth due to heavy blood loss, therefore such fluctuations are considered physiological.

Men

Potassium and its significance in a biochemical blood test (K)

Potassium (“K”) is an essential chemical element that creates the necessary conditions for various reactions to occur. It is found in the body in the form of cations - positively charged ions located inside the cell (in the intracellular fluid).

The content in the intercellular fluid is no more than 2% - this is exactly the potassium that is determined during biochemical analysis. A change in this indicator can be observed both in various physiological conditions and in pathology, and a decrease in the concentration in the blood - hypokalemia - is life-threatening and can have serious consequences.

The norm is 3.4 – 5.0 mmol/l. At the same time, it provides:

• Correct heart rate;
• Myocardial contraction;
• The work of skeletal muscles;
• Conduction of nerve impulses through neurons;
• Water-salt balance.

For normal maintenance of the above functions, a sufficient supply of “K” from food is necessary, since there are no own reserves of this chemical element. A lot is found in vegetables (especially greens, potatoes), fruits and grains.

The level of “K” is affected by the rate of its elimination. A decrease in concentration is caused by:

• Kidney diseases;
• Water-salt and acid-base imbalance;
• Hormonal changes (especially mineralocorticoids);
• Uncontrolled use of diuretics;
• Intoxication with repeated vomiting or diarrhea;
• Severe inflammatory processes;
• Deficiency of other minerals;
• Disorders of respiratory and circulatory function.

Hypokalemia – level in biochemistry less than 3.5 mmol/l. At the same time, it develops:

• Severe fatigue;
• Muscle pain;
• Arrhythmia up to cardiac arrest;
• Reduced activity of gastrointestinal motility with subsequent constipation up to dynamic intestinal obstruction;
• Slowing reflexes;
• Slowing down of mental processes;
• Pathology of urination.

Conditions in which the norm is exceeded - hyperkalemia - are somewhat less common. However, this happens when:

• Kidney failure;
• Reverse mineralocorticoid disorders;
• Release of the cation into the intercellular space due to extensive injuries, tumors, poisoning, taking antibiotics or chemotherapy drugs, acid-base imbalance;
• Overdose of drugs with “K”;
• Enhanced diet.

The clinical picture of hyperkalemia is similar to the symptoms that occur with ion deficiency. This is due to the general nature of the occurrence of such signs - a violation of the electrochemical potential of membranes, which is characterized by:

• Arrhythmia;
• Weakening of skeletal muscles up to paralysis;
• Apathetic mood;
• Blood pressure instability (jumps from low to high).

Thus, the exchange of “K” is extremely important for maintaining the normal functioning of both each individual cell and the entire organism as a whole. Therefore, if any symptoms appear that may correspond to hypo- or hyperkalemia, it is imperative to take biochemistry tests.

Indications for testing potassium levels

Potassium functions as an immunomodulator, resists hypoxia, and lowers blood pressure. A deficiency of a microelement provokes a malfunction of almost all internal organs; an excess leads to cardiac arrest.

A potassium test is necessary for all patients with diseases of the cardiovascular system, when taking antitumor or anti-inflammatory drugs. Indications for taking a test for potassium in the blood are: kidney pathologies of various origins, adrenal insufficiency, hypertension, arrhythmia. Monitoring the level of microelement is mandatory when undergoing hemodialysis, treatment with cardiac glycosides and diuretics.

2. Reasons

It would be logical to assume that hyperkalemia is caused by excessive consumption of potassium-rich foods, for example, dried fruits, legumes, potatoes, bananas, etc. However, in reality this is extremely rare: the body’s daily need for potassium is quite large (up to 5 g in adults), and with normal metabolism the balance is easily restored through the excretion of potassium in the urine.

Thus, one of the main factors in the development of hypercalcemia is disorders of the kidneys (chronic renal failure, diabetic nephropathy, etc.), when potassium excretion becomes difficult and it begins to be retained in the body. This can be caused, in particular, by hypocorticism (Addison's disease) - chronic functional insufficiency of the adrenal cortex, in which the kidneys simply do not receive the appropriate hormonal “commands”.

Another group of reasons is associated with long-term use of medications that contain potassium or prevent its excretion.

The massive release of potassium from cellular fluids into the bloodstream is accompanied by severe polytrauma with crushing of large volumes of muscle tissue, drug overdose, and extensive burns.

The progressive accumulation of potassium in the body can also be caused by pathologically rapid and intense hemolysis (decomposition of red blood cells) in anemia and some other diseases.

Rarely, hereditary hyperkalemia is recorded - familial hyperkalemic periodic paralysis.

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Causes of high potassium levels in the blood

Increased potassium in the blood - hyperkalemia

. The cause of this condition, first of all, is an excess of microelement intake into the body (unbalanced diet, improper administration of potassium-containing solutions, transfusion of a large volume of long-stored blood, taking drugs with potassium) or active release of the microelement outside the cell (tumor decay, hemolytic anemia, burns, rhabdomyolysis, soft tissue injuries, acidosis, insulin deficiency).

An increase in the level of potassium in the blood can be caused by: severe renal failure, cytolysis or hemodialysis, hypoaldosteronism, nephrotoxic effects of drugs.

1.General information

Potassium is one of the key macroelements in the human body. This substance, especially in interaction with sodium, is necessary for the regulation of contractile activity of muscles (including the myocardium), water-salt, acid-base and energy balance, higher nervous activity, normal fermentation and metabolism, secretory activity of the endocrine glands, functioning liver and kidneys. Up to half of all salts in the body are potassium compounds, and most of them are contained in intracellular liquid spaces.

For all micro- and macroelements, including potassium, a certain concentration range must be observed.

Otherwise, both deficiency and excess lead to the development of severe, sometimes life-threatening conditions. Hyperkalemia, i.e. Excessive potassium levels are a typical example.

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Causes of low potassium in the blood

Low serum potassium levels – hypokalemia

. The cause of the pathology can be: fasting, hypopotassium-containing diet, acidosis, Cushing's syndrome, Fanconi, aldosteronism, osmotic diuresis. All this provokes the excretion of potassium in urine. But the microelement is also removed with water through the intestines. This happens with: vomiting, diarrhea, intestinal villi adenoma, intestinal obstruction, fistulas. The level of microelement drops with excessive consumption of tea, soda, and coffee.

A decrease in potassium levels can be caused by insulinoma or long-term insulin therapy, taking folic acid, vitamin B12. A decrease in potassium occurs against the background of an excess of adrenaline and norepinephrine at the time of stress, thyrotoxicosis, rehabilitation after severe operations or illnesses. Taking hormones, diuretic herbs, intoxication with cesium, thallium and rubidium ions is also a reason for an increase in potassium in the blood.

3. Symptoms and diagnosis

The clinical picture of hyperkalemia is not specific enough, so preliminary, presumptive diagnosis requires a doctor to have a lot of experience, attention and vigilance in this regard. Most often, changes in the ECG in combination with patient complaints of tachycardia (accelerated heartbeat), general malaise and constant weakness cause alarm. In more severe cases, cardiac abnormalities caused by excess potassium may take the form of arrhythmia, asystole, ventricular fibrillation, and ultimately cardiac arrest.

The diagnosis is established by comparing the existing clinical manifestations, the electrocardiographic picture and the results of laboratory tests (determining the concentration of potassium in the blood plasma). Depending on the most likely causes, an additional specialized examination is prescribed - for example, nephrological or endocrinological.

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4.Treatment

With moderate and severe severity, hyperkalemia requires emergency intensive care due to the threat of cardiac arrest. One of the emergency measures is the intravenous administration of a special solution (calcium, insulin, glucose), but its effect is short-lived, and after relief of life-threatening symptoms, further therapy is required. Potassium-absorbing sorbents are prescribed (which ensures its excretion in feces); diuretics are used if renal function is preserved. Stop taking any medications that in one way or another affect the circulation of potassium in the body. Limit potassium intake from food. Since hyperkalemia is almost always secondary, a diagnostic examination (if the cause of the detected hyperkalemia is unknown) and treatment of the underlying disease are mandatory.