Renal tubular acidosis
Kidneys - the main bodies to ensure removal of the excess of non-volatile acids from the body.This is of vital homeostatic function, aimed at maintaining the constancy of the pH of the blood and other fluids.In the kidney, resulting in dissociation of water generated H + and OH-ions.The hydrogen ion is secreted into the lumen of the renal tubule.OH ion involved in the formation of carbonic acid anion (NSOZ-), which undergoes an inverse absorption in the renal tubules.These mechanisms and the pH is maintained constancy of the internal environment due to the fact that H + anion provides a pH shift to the acid side, and the anion OH - in bulk.Kidneys have a major role in the regulation of a constant ratio between the anions in the human body, and this is supported by the constancy of the pH of the blood and other fluids in the body, thus providing optimal conditions for the functioning of all human organs and systems.For example, blood pH equals 7,34.Shifting the pH of the biological fluid to 0.4 to one or
Distinguish renal tubular acidosis, proximal and distal type.Renal proximal tubular acidosis type is associated with impaired reabsorption anion of carbonic acid in the proximal tubule.Distal renal tubular acidosis is caused by a defect secretion (excretion from the body) H + ions in the distal nephron.The first signs of renal tubular acidosis occur in the first year of life and are to reduce appetite until the complete refusal of food intake (anorexia), the allocation of a much larger than normal amount of urine (polyuria), excessive thirst (polydipsia), weakness.Children begin to lag behind in physical development.At the end of the 1st year of life appear rahitopodobnyh skeletal deformities (frontal and parietal hillocks, "beads", "brasletki" lower limb deformation), marked reduction in muscle tone, sometimes reaching a degree of paralysis.Later nephrocalcinosis (kidney stones) can be detected.
Radiographic changes in bone does not have the specific features and resemble his picture violations detected while the disease De Toni-Fanconi Debre- (systemic osteoporosis, deformation of long bones, a violation of the structure of growth zones).
for renal tubular acidosis following biochemical disorders characterized by: metabolic acidosis (shift of pH of the internal environment to the acid side), hypophosphatemia (reduction in serum phosphate), hypocalcemia (reducing the amount of calcium in blood serum), elevated alkaline phosphatase, lowacid excretion levels in urine, a urine high pH (basic shift direction), a significant decrease in the concentration of kidney function (reduction of relative density of urine).In some cases, the protein can be observed and the appearance of leukocytes in the urine (proteinuria and leykotsituriya respectively).During the special methods of investigation (excretory urography) in almost all patients with this pathology revealed multiple kidney stones (nephrolithiasis and nephrocalcinosis).
Renal tubular acidosis is inherited in an autosomal recessive manner.There are descriptions of autosomal dominant inheritance, sporadic cases are possible due to primary mutations.
Patients with proximal renal tubular acidosis type often identified other defects proximal tubule function: the appearance of amino acids in urine and glucose (aminoaciduria and glycosuria, respectively).Some authors propose to allocate a third type - combined failure of the proximal and distal tubules.The disease is characterized by early-onset, severe rahitopodobnyh syndrome, the formation of kidney stones, sometimes marked increase in protein content in the blood.