Abnormal acidic urine

Abnormal aciduria is closely related to alkali poisoning. According to medical personnel, after alkali poisoning, our urine will generally become alkaline. But there are special cases. For example, when we suffer from hypokalemic alkali poisoning, our urine becomes acidic after the kidneys adjust a series of our body functions. This is what we call abnormally acidic urine. Then, abnormal acidic urine

How can this be explained medically?

Generally, urine is alkaline in case of alkali poisoning, but in case of hypokalemic alkali poisoning, there is a competitive exchange relationship between potassium ions and hydrogen ions in the renal tubular epithelial cells and sodium ions in the renal tubular urine, that is, whichever has a higher concentration between potassium ions and hydrogen ions can be exchanged with sodium ions. Since there is less potassium than hydrogen in hypokalemia, hydrogen is dominant and exchanges with sodium ions, increasing the hydrogen ions in the urine and making the urine acidic. It is therefore called paradoxical aciduria.

The kidneys play an important role in the compensatory regulation of metabolic alkali poisoning. The decrease in plasma H+ inhibits the activity of carbonic anhydrase and glutaminase in the renal tubular epithelial cells, so the renal tubular secretion of H+ and NH4+ is reduced, the reabsorption of HCO3- is reduced, and the plasma HCO3- is reduced. Therefore, in metabolic alkali poisoning, the kidneys secrete less H+ and increase HCO3- excretion, making the urine alkaline. However, in case of potassium-deficient alkali poisoning, the renal tubules secrete less K+ and more H+, but the urine becomes acidic, which is called paradoxical aciduria.

The kidneys play an important role in the compensatory regulation of metabolic alkali poisoning. The decrease in plasma H+ inhibits the activity of carbonic anhydrase and glutaminase in the renal tubular epithelial cells, so the renal tubular secretion of H+ and NH4+ is reduced, the reabsorption of HCO3- is reduced, and the plasma HCO3- is reduced.

Glutaminase is a type of amidase, an enzyme that catalyzes the hydrolysis of L-β-glutamine into L-glutamate and ammonia. This enzyme is also found in some bacteria and plant roots, but it is more active in higher animals. The optimum pH for enzymes in animal kidneys and livers is 8.0, while the optimum pH for enzymes in the cerebral cortex and retina is 8-9, which are different in properties. Enzyme from Escherichia coli, pH 4.7-5.1. This enzyme is inhibited by glutamate and has two types: one activated by phosphate and the other inactivated. In the body, the ammonia generated by glutamine transferred from peripheral tissues has the function of regulating the body's alkali storage (kidneys) and urea synthesis (liver).

Therefore, in metabolic alkali poisoning, the kidneys secrete less H+ and increase HCO3- excretion, making the urine alkaline. However, in case of potassium-deficient alkali poisoning, the renal tubules secrete less K+ and more H+, but the urine becomes acidic, which is called paradoxical aciduria.