Pediatric black aciduria syndrome
Introduction
Introduction to pediatric black aciduria syndrome Children with black aciduria syndrome (alkaptonuria) is Garrod syndrome, also known as brownish yellow syndrome. The condition is characterized by darkening of urine, sclera and auricular cartilage with melanin deposition, polyarthritis and pubic symphysis. It is a congenital metabolic deficiency disease and hereditary disease. basic knowledge The proportion of sickness: 0.004% - 0.005% Susceptible people: children Mode of infection: non-infectious Complications: uremia
Cause
The cause of pediatric black aciduria syndrome
Genetic (40%):
There is a lack of metabolic genetic disease caused by urinary acid oxidase in tyrosine metabolism. It is believed that this disease is autosomal recessive. A person must have two copies of an abnormal allele to develop an autosomal recessive disorder. Normal parents may give birth to sick babies.
Lack of urinary acid oxidase (30%):
La Dn et al. proved that black aciduria syndrome is caused by the lack of urinary acid oxidase in the liver and kidney, which causes the urinary acid produced by tyrosine catabolism to be further decomposed into acetoacetic acid, making the uric acid no further It oxidizes and accumulates in the body, increases and sinks, and is excreted from the urine. Exposure to oxygen under alkaline conditions oxidizes and polymerizes into a substance similar to melanin, thereby making the urine black. This enzyme is found in the liver and kidneys. It has been confirmed that the liver of patients with black aciduria has this enzyme deficiency. If it is discharged from the sweat, the sweat also turns black. It was later understood that uric acid was an intermediate in the metabolism of phenylalanine.
Prevention
Pediatric black acid syndrome prevention
1, the causes of congenital diseases are very complex, including infection during pregnancy, advanced birth, close relatives, radiation, chemical substances, autoimmune, genetic material abnormalities.
2, preventive measures include avoiding the marriage of close relatives, carrier genetic testing, prenatal diagnosis and selective abortion to prevent the birth of children.
3. Because most cases are caused by genetic mutations that are completely unpredictable by unaffected parents. Therefore, a systematic examination is required during the antenatal care during pregnancy.
4, pre-marital physical examination plays a positive role in the prevention of birth defects, the size of the effect depends on the inspection items and content, mainly including serological examination (such as hepatitis B virus, treponema pallidum, HIV), reproductive system examination (such as screening for cervical inflammation) ), general physical examination (such as blood pressure, electrocardiogram) and asking about the family history of the disease, personal medical history, etc., do a good job in genetic disease counseling. For family history, genetic counseling can help adults with selective fertility. Systemic birth defect screening is required during antenatal care during pregnancy, including regular ultrasound, serological screening, and, if necessary, chromosomal examination.
Complication
Pediatric black acid syndrome complications Complications uremia
Pigmentation can occur in various tissues:
Melanin, which is deposited on the joints, can cause osteoarthritis and progressive changes in the joints.
Sinking in the heart valve can cause rapid arteriosclerosis, heart valve disease, can still cause blood circulation dysfunction and lead to death. Most of the causes of death are cardiovascular diseases.
It is deposited in connective tissue such as the sclera, conjunctiva, and cornea. Brown.
Calming in the urinary system can cause chronic prostatitis. Porous black kidney stones can occur in a small number of patients. Most of the causes of death are uremia.
Symptom
Pediatric black and sour syndrome symptoms Common symptoms Urine black acid sweat nails, ear cartilage out...
Pediatric clinical features are characterized by darkening of urine and often more severe in men.
Black urine: It usually occurs within a few days after birth. Once the baby is ingested, the urine will be excreted in the urine, and the amount of urinary acid will be proportional to the amount of tyrosine and phenylalanine. The main symptoms of fresh urine color are normal, under alkaline conditions such as: urine after standing or alkalized into black. When the diaper is washed, the urine traces become black and the like.
Black sweat: Melanin is excreted with sweat, which can make sweat black.
As you get older, the following symptoms can slowly occur:
Melanosis: clinical examination revealed melanin deposition in the sclera and auricular cartilage. With the increase of urinary acid, it has been deposited in connective tissue for a long time. In the adolescent stage, the sclera and auricular cartilage may have blue-black pigmentation and the auricle becomes hard. The same pigmentation can occur in other tissues.
Joint lesions: joint lesions, pain, stiffness, and severe pain in the pubic symphysis.
Examine
Examination of pediatric black aciduria syndrome
Urine test
Take a portion of the patient's urine and observe that when the urine is exposed to air, it will turn black after standing or alkalizing.
2. Screening method
(1) Test for reducing substance in urine (plaque test): Positive reaction. Because of the alkaline effect, the positive reaction is not orange-red and brown. It can be confirmed by a glucose oxidase test that this reducing substance reaction is not caused by glucose.
(2) Ferric chloride test: The urine of the sick child was positively reacted with ferric chloride, which was purple-black.
(3) Silver nitrate test: 0.5 ml of urine, added with a saturated aqueous solution of silver nitrate (redissolved with ammonia), and immediately turned black.
3. Diagnosis
After screening by the above method, and then by chromatography, spectrophotometry, or urine oxidase activity measurement, urine chromatography can be confirmed.
4. X-ray inspection
It can be seen that the large joints are degenerative, the intervertebral space is narrowed, the intervertebral disc is calcified, the intervertebral space is narrowed, and the vertebrae of the vertebrae are formed.
5. Some cases have joint exudate, and the rheumatoid factor test is positive.
6. Histopathological examination: there is light brown pigment in the dermis, silver nitrate staining is not colored, and color black is stained with cresyl violet and methylene blue. Vascular endothelial cells, sweat gland basement membranes, macrophages, and the like have fine brown particles. Brown pigments are also seen in collagen fiber bundles and elastic fibers.
7. If necessary, do an electrocardiogram, echocardiography, X-ray chest and other examinations.
Diagnosis
Diagnosis and diagnosis of pediatric black aciduria syndrome
diagnosis
According to the clinical manifestations and urine uric acid can be diagnosed.
Differential diagnosis
It should be differentiated from the urine brown-black color presented in the urine plaque qualitative test of diabetes, and other substances that can make the urine dark, such as bilirubin, porphyrin, myoglobin, hemoglobin.
Acquired browning disease: Acquired browning disease caused by a drug or chemical that inhibits the sulfhydryl group contained in the urinary acid oxidase, no uric acid or no joint disease in the urine.
Long-term use of mepacrine (Api) can cause brown pigmentation-like pigmentation. Repeated application of phenol (carbolic acid) for the treatment of skin ulcers can also cause yellow pigmentation, which should be identified.
Clinically, it should be differentiated from hematoporphyria, myosinuria, bilirubinuria and hematuria.
