Pyrrolidine and guaridineuria

Introduction Pyrrolidine and acridine are characteristic of pediatric renal amino aciduria. Hyperaminoaciduria is a type of metabolic disease characterized by excessive amino acid excretion in the urine, which can be divided into pre-renal, renal and mixed. The treatment effects of various types of high amino aciduria vary widely. Some can achieve good results by strictly controlling the intake of the corresponding amino acids in the diet or supplementing certain vitamins. Some even take various measures to make the plasma amino acid level close to normal. It also does not improve clinical symptoms. Renal amino aciduria is a proximal tubular reabsorption of amino acid disorders that causes large amounts of amino acids to be excreted from the urine. The amino acids excreted from the urine are mainly glycine, taurine, methyl histidine and the like. In addition, serine, threonine, leucine, phenylalanine and the like may also be discharged in a small amount.

Cause

(1) Causes of the disease

It is a family hereditary disease and is an autosomal recessive hereditary disease. Influencing factors include age, gender, diet, physiological changes, and heredity. Causes and classification:

1. Physiological amino acid urine: caused by physiological changes.

2. Pathological amino acid urine: Amino acid urine caused by disease:

(1) "prerenal" amino acid urine:

1 "spill" amino acid urine: such as phenylketonuria, maple sapuria, is caused by a certain amino acid metabolism defect.

2 "competitive" amino acid urine: such as hyperprolineemia, etc., caused by competition in the renal tubules with the amino acid of the same transport system.

(2) "Kidney" amino acid urine: caused by a defect in the transport of proximal convoluted tubules.

1 a single group of amino acid transport system defects: that is, the proximal tubules are defective in the transport system of a group of amino acids, and the group of amino acids are excreted from the urine, including lysine, arginine, ornithine, cystine, and guanidine. Amino acid, hydroxyproline, glycine, aspartic acid, glutamic acid, and the like.

2 groups of amino acid transport system defects: due to multiple functional defects in the proximal curved tube, a variety of amino acid urine, accompanied by diabetes, high phosphate urine, uric acid dysfunction, such as Fanconi syndrome, Lowe syndrome Wait.

(two) pathogenesis

Increased total excretion of amino acids in the urine or a significant increase in individual amino acid excretion is called amino aciduria. Amino acids are an important nutrient in the human body, and most of the amino acids in the body can be used to synthesize proteins. Amino acids in the plasma can be freely filtered out of the urinary tract into the original urine, most of which can be reabsorbed back into the blood through the proximal tubules. When renal tubular function declines, the amino acid excretion in the urine increases. There are many causes of amino aciduria, most of which are genetic diseases, and kidney damage caused by drugs or poisons.

Pathological amino acid urine can be divided into spilled amino acid urine and renal amino acid urine. The former refers to an increase in blood amino acids, which exceeds the reabsorption capacity of the renal tubules; the latter is due to congenital tubular lesions such as Fanconi syndrome and hepatolenticular lesions. Renal amino aciduria is a hereditary disease, including basic amino aciduria (cystineuria), neutral amino aciduria (Hartnup disease), other amino acid urine, etc., which is caused by a defect in the proximal convoluted tubule transport. Alkaline amino acid urine (cystineuria) is the most common amino acid urine, which is easy to form cystine stones and provides bare nuclei for oxalate stone formation. Neutral amino aciduria (Hartnup disease) is more common in children. Other iminoglycine urine, simple cystineuria, simple glycine urine, and dicarboxy amino acid urine are less common.

an examination

Related inspection

Urine routine renal dynamic imaging

1. Urine test: The urine contains a lot of cystine, lysine, arginine and ornithine. The method for testing urinary cystine is as follows:

(1) urinary cystine crystal examination: those with larger urinary cystine excretion can see cystine crystals in concentrated urine sediment, which is of great value for the diagnosis of this disease. Morning urine was taken for centrifugation, and a hexagonal flat crystal similar to a benzene ring was observed under light microscopy. Crystallization often shows a concentration of urinary cystine exceeding 200-250 mg/L.

(2) Cyanide nitroprusside test: The stone is positively reacted with sodium cyanide cyanide and can be used as a screening diagnostic test. The stone is ground into a powder, put a little in the test tube, add 1 drop of concentrated ammonia water, then add 1 drop of 5% sodium cyanide, and add 5 drops of 5% sodium nitroprusside after 5 minutes.

(3) Quantitative measurement by urine chromatography: it is helpful for confirmation and typing.

(4) pyrrolidine and acridine urine: due to the absorption of these amino acids by the jejunum, a large amount of lysine and ornithine are degraded in the intestine to produce cadaverine and putrescine, which are reduced to pyrrolidine and acridine from the urine after absorption. cause.

(5) urine routine examination: urinary tract stones often cause repeated hematuria, secondary white blood cells increase infection.

2. Blood test: a small number can be combined with hyperuricemia, hypocalcemia and so on.

3. Fecal examination: Amino acids are largely lost from the feces due to poor absorption of amino acids by the jejunum. Abdominal plain film examination showed that the stones were lightly shadowed, and stones could be found by angiography and B-ultrasound examination. Electroencephalography and brain CT examinations can detect abnormalities, and authors of severe encephalopathy may have diffuse brain atrophy.

Differential diagnosis

True bacterial urine means:

1 bladder puncture urine culture, bacterial growth, or colony number > 102 / ml.

2 urinary bacteria quantitative culture 105 / ml.

3 The middle-stage urine quantitative culture was 105/ml, and the accuracy was 80%. The same strain was obtained by two consecutive cultures, the number of colonies was 105/ml, and the accuracy was 95%.

Specific amino acid urinary: mainly threonine serine histidine alanine hydroxyproline excretion is normal, so it can be distinguished from all amino acid urinary glycine valine and hydroxyproline excretion can be distinguished from iminoglycine urine The excretion of two base amino acids in the urine is also normal to be distinguished from cystine urine.

Renal glucosuria: refers to a disease of diabetes caused by a decrease in glucose function in the proximal tubules when the blood glucose concentration is normal or lower than the normal renal sugar threshold. Clinically divided into primary renal glucosuria and secondary renal glucosuria. Renal glucosuria can be associated with many tubular defects, including amino aciduria and renal tubular acidosis. If the system appears alone, and other kidney functions are normal, it is mostly autosomal dominant hereditary features, and even invisible, the isolated renal glucosuria and diabetes secondary to diabetes occur at a ratio of about 2:1000. The maximum glucose reabsorption rate is reduced, and glucose is excreted in the urine. In addition to the rare glucose-galactose malabsorption, intestinal transport of glucose is normal.

Asymptomatic bacteriuria: also known as occult bacteriuria, is a occult urinary tract infection, which means that the patient has true bacterial urine (quantitative culture of urinary bacteria in the middle of cleaning is more than 105/ml for 2 consecutive times, and the same 2 strains are the same And the false positives of the results were excluded without any symptoms of urinary tract infection, but in some cases, mild symptoms were found after careful inquiry. Its bacteria come from the kidneys or from the bladder. Asymptomatic bacterial urine has a higher incidence than symptomatic patients. The incidence rate is 4% in women aged 16 to 65 and 0.5% in men. Although 1/4 of bacteriuria disappears in female patients, New bacterial urine is also constantly occurring, so the incidence of 4% is quite constant.

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