Hypokalemia

General text about the lack of minerals can be found here.

 

Hypokalemia means low level of potassium in the blood. Potassium ions are present in high concentration in the cells and there is only a relatively low concentration in the blood – approximately between 3.5 and 5.3 mmol/L. Potassium below 3.5 mmol/Lis referred to as hypokalemia. It is a potentially serious condition as well as the hyperkalemia.

Causes

There are many possible causes of hypokalemia, I shall mention at least the most important and most frequent.

Medications

There are some drugs decreasing the potassium concentration in blood. Such effects have especially certain drugs belonging among diuretics such as furosemide. Diuretics are often used in therapy of heart failure. These drugs promote urination and this causes increased ion losses into the urine.

Low blood sugar (hypoglycemia)

Potassium ion is closely linked to blood sugar. Without mentioning more complicated details, let's just say that decrease of blood sugar leads to hypokalemia and vice versa. This can be dangerous in diabetics who are hospitalized with hyperglycemia. Such people have also hyperkalemia. However, as we treat them and the blood glucose decreases, they may start to suffer from a sudden hypokalemia because the potassium ions leave blood and enter cells together with glucose molecules.

Inadequate potassium intake in the diet

People with malnutrition and dehydration may suffer from mineral deficiency including the potassium. A larger amount of potassium is for example in stone fruit.

Potassium gastrointestinal losses

Potassium ions are lost in prolonged diarrhea or excessive vomiting. Together with dehydration, this can cause a serious disturbance of the internal environment.

Conn's syndrome

This is a hormonal disorder caused by overproduction of aldosterone hormone by the adrenal glands. The usual cause is a benign adrenal tumor. The patient with Conn's syndrome suffers from a drug-resistant hypertension and hypokalemia.

Bartter syndrome

This is a rare genetic disease with impaired function of kidney tubules resulting in excessive ion and fluid losses into the urine.

Symptoms

Mild hypokalemia may be absolutely asymptomatic. Deeper hypokalemia causes fatigue, muscle weakness, constipation and certain changes of the ECG curve. The patient may suffer from palpitations and there is increased risk of arrhythmias, for example atrial fibrillation. The most serious cases end by a fatal arrhythmia or cardiac arrest.

Diagnosis

Blood potassium concentration can be easily detected from a sample of venous blood. ECG can theoretically help but its changes are often not present or unspecific.

Treatment

Compared to hyperkalemia, the treatment of hypokalemia is much easier (and less interesting). When someone has a lack of potassium, we have to supplement it either in tablets or intravenously. Intravenous potassium must be applied very slowly, ideally in an infusion. The supplementation must be very cautious as it is possible to cause hyperkalemia. When there is a pathological condition causing hypokalemia, it should be treated as well, if possible.