Special rat odor in urine

Introduction The patient's liver cannot synthesize stupid alanine hydroxylase, so that the phenylalanine in the food cannot be oxidized to tyrosine, and can only be converted to phenylpyruvate in the kidney by the transaminase. Phenylalanine and other metabolites have toxic effects on the development of nerve cells, while glutamate formation disorders affect the formation of myelination during the development of nerve fibers. Its clinical features are severe mental retardation, with the most severe speech disorder, and 85% of patients are at the level of idiotism. With motor dysfunction, muscle tension is high or low, can't sit down, can't walk, or sway when walking. The hair is light or yellow, the skin is fair, and the iris of the eye is yellowish or light blue and is typical of the blue. Skin eczema is also more common, urine has a special mouse urine smell. There may be pyramidal tract signs and other pathological reflexes. Most patients have abnormal EEG. Excessive phenylpyruvate is excreted in the urine. By controlling the intake of phenylalanine in the diet after birth in most cases, brain damage can be successfully prevented. Neonatal patients can be asymptomatic, but if the treatment is delayed for one year, irreversible brain damage can occur, so early diagnosis and treatment are extremely important. The incidence rate varies widely around the world, rare among black people, and the incidence rate in China is 1:16000.

Cause

Phenylalanine is one of the essential amino acids in the human body. In addition to protein synthesis, phenylalanine in the human body produces tyrosine by the action of phenylalanine hydroxylase and its cofactors in the liver. A small amount of phenylalanine enters the secondary metabolic pathway and becomes phenylpyruvate via transamination. Tyrosine is also an essential amino acid for the synthesis of important hormones such as dopamine, adrenaline, norepinephrine and neurotransmitters and melanin. It can also be metabolized to form urinary acid into the tricarboxylic acid cycle to provide energy for the body. Some people suffer from genetic defects, and if the phenylalanine hydroxylase (or cofactor) is deficient or its activity is reduced, its main metabolic pathway is blocked. The concentration of free phenylalanine in the blood is abnormally elevated, and the secondary metabolic pathway is active. The phenylpyruvate, which is a small amount in the normal metabolism, is obviously increased in the body fluid, and the phenylpyruvate in the urine is increased, thus producing high phenylalanine. Blood and phenylketonuria. The elevated phenylalanine in the blood and other amino acids compete for the transport system when entering the nerve cells, causing amino acid imbalance in the nerve cells, thereby inhibiting protein synthesis and synapse formation, affecting the microtubules (the basic components of the spindle) The formation of the brain causes irreversible damage to the brain. It is said that the harmful substance causing stagnant or stunted growth of the central nervous system in newborns may be phenylalanine itself.

Phenylalanine can be produced by metabolic bypass to produce phenyl lactic acid phenylacetic acid phenyl acetyl glutamine. These metabolites are excreted by sweat and urine, causing sweat, urine, urine or horse manure smell. Therefore, the patient's body may have a mildew odor similar to rat urine.

an examination

Related inspection

Phenylalanine deaminase test serum phenylalanine

It is not difficult to diagnose after the appearance of typical symptoms, but it is often too late. In order to make a timely diagnosis, at present, all neonates in China have a neonatal screening for hyperphenylalaninemia, and should be carried out after the baby can take protein (breastfeeding). The identification of PKU with other types of hyperphenylalaninemia is based on the phenylalanine food tolerance test. The diagnosis of cofactor-deficient cases requires a more specific approach. Advances in genetic diagnostics have made it possible to diagnose the disease in the fetal phase, screens.

The only reliable method for timely diagnosis is to screen for hyperphenylalaninemia in neonates. The key to successful screening is:

1 Determination of all newborns.

2 After the baby can take protein (breastfeeding). Because the PKU baby is born, the phenylalanine in the blood can be at a normal level. The test method is the Guthrie test (when phenylalanine is contained in the blood, the growth of Bacillus subtilis cannot be inhibited by -2-thiophene alanine).

This disease is one of the few treatable metabolic diseases, and it is necessary to seek early diagnosis and treatment to avoid irreversible damage of the nervous system. Because the child does not develop symptoms at an early stage, it must be tested by laboratory.

Differential diagnosis

Urine ammonia smell: urine in the urine can have ammonia smell. The diagnosis of urinary sensation can not rely solely on clinical symptoms and signs, but rely on laboratory tests. Some people have reported the analysis of 297 patients with urinary sensation, and only 66.5% of those with symptoms. Anyone with true bacterial urine should be diagnosed with urinary sensation. True bacterial urine refers to: bacterial growth in qualitative culture of bladder puncture; quantitative culture of urinary bacteria 100,000/ml; quantitative culture of clean middle urinary 100,000/ml, and the same strain can be determined as true bacterial urine. It must be pointed out that women with obvious urinary frequency and dysuria may have more white blood cells in the urine. For example, the number of bacteria in the middle part of the urine is >100/ml, and it can be diagnosed as urinary sensation. Even when waiting for the culture report, it may be diagnosed first. For the urine.

Urine rotten apple flavor: The urine of patients with diabetic ketoacidosis is rotten apple flavor. Symptoms of thirst, polydipsia, polyuria and weight loss are aggravated, and there is general fatigue, weakness, and even coma.

Urine odor: If there is a urinary tract infection, the urine will become cloudy and stench. Diagnostic criteria are often divided into upper and lower urinary tract infections according to the location of urinary tract infection. Upper urinary tract infection refers to pyelonephritis, which can be divided into acute and chronic pyelonephritis according to clinical features. Pyelonephritis may be associated with a lower urinary tract infection, while lower urinary tract infections are often present separately.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.