Hypokalemia: what is it, symptoms, causes and treatment, prognosis

What is hypokalemia?

Hypokalemia Is a metabolic imbalance characterized by extremely low levels of potassium in the blood. Hypokalemia is a symptom of another illness or condition, or a side effect of taking diuretics. The body needs potassium for muscle contraction (including the heart) and many complex proteins (enzymes) to function. Potassium is found mainly in skeletal muscles and bones, and together with sodium participates in the normal flow of body fluids between cells in the body. The normal concentration of potassium in the body is regulated by the kidneys by excretion in the urine.

When the kidneys are functioning normally, the amount of potassium in the diet is sufficient for the body to use, and the excess is usually excreted in urine and sweat. Body chemicals and hormones such as aldosterone also regulate potassium balance. Hormone secretion 

insulin, which is usually stimulated by food, prevents temporary hypokalemia caused by malnutrition by increasing the uptake of potassium by cells. In hypokalemia, an imbalance occurs due to dysfunction in this normal process, or a rapid loss of urine or sweat without replacing enough potassium.

Signs and symptoms

Most often, hypokalemia is asymptomatic, without obvious signs of a disorder. However, symptoms of hypokalemia can include bouts of severe muscle weakness, eventually leading to paralysis and possibly respiratory failure.

Muscle failure can lead to intestinal paralysis, low blood pressure, painful muscle twitching (tetany), and mineral deficiencies. Severe hypokalemia can also lead to the destruction of skeletal muscle cells, especially during exercise. A normal physical response to exercise requires the local release of potassium from the muscles. In potassium-depleted muscles, a lack of potassium prevents adequate dilation of blood vessels, resulting in decreased muscle blood flow, seizures, and skeletal muscle destruction.

Hypokalemia can also impair the kidneys' ability to concentrate urine, resulting in excessive urination (polyuria) and excessive thirst (polydipsia). Other symptoms may include loss of appetite, nausea and vomiting. There may also be disturbances in the work of the heart caused by changes in the electrocardiograph, confusion, bloating, decreased mental activity.

Causes and risk factors

Hypokalemia always results from excessive loss of potassium in urine, sweat, or stool. The condition is always a symptom of another disorder, not a disease that occurs on its own.

Excessive urinary potassium excretion (caliuresis) may result from the use of diuretics (which increases urination), magnesium deficiency in the blood, excess mineralocorticoids such as aldosterone in the blood that affect the electrolyte and balance of body fluids (usually caused by endocrine disorders), kidney problems, or use high doses of penicillin.

Loss of potassium through the gastrointestinal tract is usually caused by prolonged diarrhea or vomiting, chronic laxative abuse, insufficient potassium intake, intestinal obstruction or infections, such as fistulas in the intestines, that continuously drain intestinal fluid from the body. Besides, excessive sweating due to hot weather or exercise can cause hypokalemia.

Affected populations

Hypokalemia can affect both men and women. However, the condition occurs more frequently in women.

Related disorders

Symptoms of the following disorders include hypokalemia. Comparisons can be useful for differential diagnosis:

• Bartter's Syndrome - metabolic disorders affecting the kidneys. The main symptoms include stunted growth, weakness, excessive thirst, and excessive urination. Bartter's syndrome is characterized by excessive loss of potassium through the kidneys.
• Hypokalemic periodic paralysis (GLP) is a disorder characterized by episodes of paralysis with loss of deep tendon reflexes and inability of muscles to respond to electrical stimulation. The cause of HSP is unknown. Paralysis may be limited to certain muscle groups or may affect all four limbs. The attacks usually last 24 to 48 hours. Potassium levels are usually abnormally low (i.e., hypokalemia occurs).
• Metabolic alkalosis - a disorder characterized by an increase in the level of bicarbonate in the blood. Symptoms include irritability, neuromuscular hyperexcitability, low blood potassium (hypokalemia), muscle weakness, impaired gastrointestinal motility and excessive urination.

To find other disorders that include hypokalemia as a symptom, enter "Hypokalemia" as a search term in the disease database.

Diagnostics

In most cases, the cause of hypokalemia is obvious from the history and physical examination. First-line tests include urine potassium measurement, serum magnesium analysis, and an electrocardiogram (ECG). The measurement of potassium in urine is vital as it establishes the pathophysiological mechanism and is thus useful in differential diagnosis. This, in turn, will determine the choice of further tests.

Standard treatments

Initially, it is necessary to eliminate the root cause of hypokalemia. For severe hypokalemia, potassium chloride can be administered orally or intravenously. Treatment should be closely monitored by a physician. Any associated acid-base or hormonal imbalance should be assessed prior to planning treatment. Administration of potassium and potassium-sparing diuretics is usually not recommended for patients with kidney disease, diabetes mellitus or dysfunctions of the autonomic nervous system. An imbalance in external and internal potassium levels in these individuals may predispose them to life-threatening degrees hyperkalemia (i.e., an excessively high level of potassium in the body).

Hypokalemia in people with high blood pressure on diuretics can be improved by replacing lost potassium in the diet through certain fruits or potassium supplements. Hypokalemia can also be minimized by dietary salt restriction, as high sodium excretion rates promote urinary potassium loss. People who engage in vigorous sports or exercise in warm weather should definitely replace potassium, which is lost through excessive sweating. This can be accomplished through dietary supplementation.

Forecast

The prognosis for patients with hypokalemia depends entirely on the underlying cause of the disease. For example, a patient with an acute episode of hypokalemia resulting from diarrhea has an excellent prognosis. Hypokalemia due to a congenital disorder such as Bartter's syndrome has little or no potential for resolution.

Hypokalemia is usually associated with higher morbidity and mortality, especially from cardiac arrhythmias or sudden cardiac death. However, the independent contribution of hypokalemia to increased morbidity / mortality has not been conclusively established. Patients who develop hypokalemia often have many medical problems, making it difficult to separate and quantify the effects of hypokalemia per se.

How can hypokalemia be prevented?

About 20 percent of patients in hospitals experience hypokalemia, while only 1 percent of out-of-hospital adults have hypokalemia. A doctor or nurse usually monitors the patient during their hospital stay to prevent hypokalemia.

If you experience vomiting or diarrhea for more than 24-48 hours, you should see your doctor. Preventing prolonged bouts of illness and fluid loss is important to prevent hypokalemia from developing.

- Diet rich in potassium.

Eating a diet rich in potassium can prevent and treat low blood potassium levels. Discuss your diet with your doctor. Consuming too much potassium should be avoided, especially if potassium supplements are being taken. The following foods are good sources of potassium:

• avocado;
• bananas;
• figs;
• kiwi;
• oranges;
• spinach;
• tomatoes;
• milk;
• peas and beans;
• peanut butter;
• bran.