What is the cause of periodic hypokalemia

Many people are confused about periodic hypokalemia and have never even heard of it. In fact, periodic hypokalemia is periodic paralysis caused by hypokalemia. Many people don’t know what periodic hypokalemia is. This may be due to insufficient potassium intake in the patient’s daily diet.

1. Inadequate intake

Potassium is generally not lacking in food. When swallowing is impaired or fasting for a long time, the normal amount of intake cannot be achieved, which will cause potassium deficiency. Excessive loss of potassium in the body can be lost through the digestive tract and kidneys. Loss from the digestive tract: severe vomiting, diarrhea, high intestinal obstruction, and long-term gastrointestinal drainage can cause the loss of a large amount of digestive fluid, resulting in potassium deficiency (the potassium concentration in general digestive fluid is similar to that in plasma, while it is higher in gastric juice and large intestinal juice). The mechanism of potassium loss due to vomiting is relatively complex. In addition to the loss of potassium in the digestive juices, potassium is also excreted from the kidneys due to the secretion of aldosterone and alkali poisoning.

2. Renal loss

Increased aldosterone secretion (chronic heart failure, cirrhosis, ascites, etc.), increased secretion of adrenal cortex hormones (stress), long-term use of glucocorticoids, diuretics, osmotic diuretics (hypertonic glucose solution), alkali poisoning and certain kidney diseases (recovery period of acute tubular necrosis) are all factors that cause potassium loss. Abnormal distribution of potassium transfers from extracellular to intracellular. When this transfer causes changes in the potassium concentration inside and outside the cells, hypokalemia occurs.

3. Pathogenesis

The physiological function of K has been mentioned above. When intracellular potassium is deficient in extracellular potassium and there is acidosis at the same time, if the intracellular K decreases, the K exchanged with extracellular H will decrease. Therefore, potassium deficiency is often accompanied by metabolic acidosis. Chronic potassium deficiency can be seen in potassium-deficient nephropathy, which is mainly manifested by renal tubular insufficiency. Decreased blood potassium can also increase the resting potential of myocardial cells and prolong the action potential time, which is reflected in the electrocardiogram with a decreased ST segment, decreased T wave amplitude, flat or inverted, and the appearance of u waves that can merge with T waves. Due to the decrease in intracellular K of myocardial cells, the autonomy of myocardial pacemaker cells increases, and myocardial conduction is inhibited, so new ectopic excitation foci are easily generated, causing various arrhythmias. In severe cases, ventricular fibrillation occurs and leads to death. Atrioventricular conduction block may also occur.