My legs feel heavy and I always feel tired, what's going on?

Weakness in your leg muscles may be caused by illness. People who are malnourished for a long time may also have weak legs. You must pay attention to the nutritional balance of your diet, eat more high-protein foods, and eat appropriate amounts of fruits and vegetables. You should also exercise regularly to improve your body's immunity and strengthen your physical fitness. In this way, your legs will not always feel heavy and weak, and they will gradually become stronger.

Potassium ions are an important basis for maintaining cellular electrophysiological activities. When hypokalemia occurs in the human body, potassium ion metabolism becomes disordered and it is unable to perform its inherent functions, resulting in serious consequences.

1. Neuromuscular system

① Skeletal muscle weakness and paralysis

Muscle weakness generally starts from the lower limbs, especially the quadriceps, and manifests as difficulty walking and unstable standing. As hypokalemia worsens, muscle weakness worsens and affects the trunk and upper limb muscles until it affects the respiratory muscles and respiratory failure occurs. Generally, muscle weakness may occur when the serum potassium concentration is lower than 3 mmol/L, and paralysis may occur when it is lower than 2.5 mmol/L, and respiratory failure is also likely to occur. In patients with impaired lung function, hypokalemia leading to respiratory failure or worsening of respiratory failure is more common, but it is easy to be overlooked clinically.

② Smooth muscle weakness and paralysis

Symptoms include abdominal distension and constipation. In severe cases, paralytic intestinal obstruction and urinary retention may occur.

2. Central nervous system symptoms

The patient is irritable, has mood swings, and is weak. In severe cases, he or she may become listless, drowsy, confused, and even fall into a coma.

3. Circulatory system symptoms

① Arrhythmia: Various arrhythmias may occur, including sinus bradycardia, atrial or ventricular premature beats, supraventricular tachycardia and atrial fibrillation, atrioventricular conduction block, and even ventricular tachycardia and ventricular fibrillation. In addition, digitalis poisoning is also prone to occur. The electrocardiogram findings are of certain value in the diagnosis of hypokalemia.

② Heart failure: Changes in myocardial function and structure caused by severe hypokalemia can directly induce or aggravate heart failure, especially in patients with poor underlying heart function.

③ Hypotension: may be related to vasodilation caused by autonomic nervous system dysfunction.

4. Rhabdomyolysis can sometimes induce acute renal failure.

5. Acid, alkali and other electrolyte disorders, resulting in metabolic alkali poisoning. In case of metabolic alkali poisoning, the ability to retain chloride decreases accordingly, resulting in decreased blood chloride.

6. Renal impairment

Director Xu Binhua kindly reminds everyone: In clinical practice, you need to be alert to the occurrence of hypokalemia when sudden limb weakness occurs. Hypokalemia is just a superficial symptom. There are many causes of hypokalemia, and they are quite complicated. Actively finding the cause is the key. In addition to organic lesions, nausea, vomiting, sweating, drinking large amounts of water and urination will cause excessive potassium loss and induce transient hypokalemia. Regardless of the cause, timely detection and early correction of hypokalemia is key, otherwise it will be life-threatening. While correcting hypokalemia, it is also necessary to closely monitor vital signs, urine volume, renal function, etc. to avoid excessive and rapid potassium supplementation leading to hyperkalemia.