pediatric polycystic kidney disease
Introduction
Introduction of Pediatric Polycystic Kidney Polycysticidosis (PK) has numerous cysts containing urine-like fluids in the renal cortex and medulla, which are diffusely distributed. There are two kinds of genetic forms, one is autosomal dominant polycystic kidney disease, which usually occurs in adulthood, but it can also appear in newborns. In the past, this type has been called adult PK; the other type is often stained. Sexual heredity, formerly known as infant-type PK, is a symptom of birth and even death in the neonatal period, but it has been found in adults in recent years. The former type is more common, about 12 to 24 times that of the latter type. basic knowledge The proportion of illness: 0.005% Susceptible people: children Mode of infection: non-infectious Complications: hypertension, anemia, uremia
Cause
Pediatric polycystic kidney disease
(1) Causes of the disease
The cause of polycystic kidney disease is gene deletion. The adult polycystic kidney disease is often due to the deletion of the chromosome 16 gene. Occasionally, due to the gene deletion of chromosome 4, it is a dominant inheritance with 100% penetrance, so single parent Chromosomal deletion will give children a 50% chance of inheriting the disease. Infant polycystic kidney disease is autosomal recessive, and both parents have genetic changes in the disease to make their children sick, with a probability of 25%.
(two) pathogenesis
1. Pathogenesis The renal cyst is derived from the epithelial structure of the kidney, originating in the renal tubules and the bursal sac. All renal cysts have some common structural components, including the upper cortex, and the expanded cyst contains the glomerular filtrate. .
(1) Autosomal dominant type PK: More than 95% of typical patients are caused by abnormal genes on the short arm of the 16th pair of chromosomes. In addition, infection and poisoning act on the tubules, which stimulates the cyst gene to alter the metabolism of the tubule cells. Causes necrosis of epithelial cells, causing obstruction and promoting cell proliferation leading to cyst formation.
(2) Autosomal recessive PK: caused by DNA mutation, but the chromosomal location of the defective allele is still unclear, and the parents of the child are not sick, but the genes carrying the disease can make The disease is rare in children.
2. Pathological changes
(1) Infantile polycystic kidney: is an autosomal recessive inheritance with liver lesions. Although it is mainly seen in young children, it can also occur in older children and adults, and the kidneys are significantly enlarged. The shape remains normal and the surface is smooth, but the lobular state of the fetal kidney is more obvious than that of the normal kidney. Because the cortex of the kidney is invaded by small cysts, the cut surface is spongy or honeycomb-like, histological examination, and the renal parenchyma is mostly Instead of a long cyst arranged at right angles to the surface of the kidney, a few normal glomeruli and curved vessels can be seen under the capsule. Renal function tests show that the cyst is a functional part of the nephron, and the microscopic anatomy shows that the cyst is a collection of expansion. Tube, ureter and bladder development are normal, severe cases, due to fetal oliguria leading to bladder dysplasia, according to the age of the symptoms, infantile polycystic kidney disease can be divided into 4 clinical subtypes: 1 perinatal period (perinatal period): Because the baby's abdomen is bulging, the labor process is often long and not smooth. It can be seen that the children have poor circulation and difficulty in breathing, showing a typical Potter face, sometimes due to complicated pulmonary hypoplasia. There is a cyanosis and a significant difficulty in breathing. It can die at birth or shortly after birth. Some babies can reach huge kidneys at birth, have uremia, pyuria, hematuria and high blood pressure after birth, and may survive during perinatal period. 90% or more of the kidneys have cystic or dysplasia, venous urography is not developed, renal ultrasonography can confirm large and polycystic kidney, urinary bladder urethra shows normal bladder, no reflux , no urethral obstruction, such as uremia at birth, the prognosis is poor, the percentage of stillbirth is high, most uremia infants die within the perinatal period or within 3 months after birth, 2 neonatal type: in the newborn Survival, often with progressive uremia, high blood pressure, and can reach bilateral renal enlargement, renal ultrasonography, a wide range of cyst lesions, about 60% of nephron dysplasia, more than 6 months after birth Uremia, some children with appropriate restrictions on protein in the diet, treatment of renal acidosis, hyperphosphatemia and hypertension can reduce uremia, improve kidney function, sick children can survive to childhood, but liver disease Change gradually with age, 3 infant type: 25% to 50% of nephrons have cystic renal dysplasia, clinical manifestations of growth retardation, progressive uremia and childhood liver failure, difficult to regenerate at birth The difference between the child type, but the infant type has no progressive uremia in infancy, 4 childhood type: due to bilateral renal cystic lesions less than 10%, and liver lesions are widespread, so liver disease is manifested at 10 to 20 years old, only autopsy It was only when I found out that there was polycystic kidney disease.
(2) Adult polycystic kidney: The disease is autosomal dominant, about 3% of cases begin to have symptoms in childhood, but rare in children with renal failure, bilateral renal enlargement Irregular cysts scattered in the cortex and medulla, mixed with normal renal parenchyma, cysts can be in any part of the nephron or collecting duct, glomerular cyst is a characteristic of adult polycystic kidney in the early stage, adult concurrency Symptoms (bleeding, stones and infections) are not common in children, and are often not serious. Focal hepatic cysts account for only 1/3 of adult patients, and do not produce dysfunction. Spleen and pancreatic cysts are not common.
Prevention
Pediatric polycystic kidney prevention
Genetic counseling helps prevent the occurrence of polycystic kidney disease. In recent years, due to in-depth study of genetic diseases, it has been found that there are hemoglobin -chain genes and phosphoglycollate phosphatase genes on the short arm of chromosome 16 The chorionic villus specimens are subjected to DNA analysis by a special DNA probe, and prenatal diagnosis can be correctly performed on adult polycystic kidney disease, so that early termination of pregnancy can be considered. The early diagnosis in the past mainly relies on ultrasonic examination, but Before the appearance of fetal renal cysts, ultrasound examination is also ineffective. Now, DNA probes can be used to detect adult polycystic kidney disease before birth, and adult polycystic kidney disease and other renal cystic diseases can be found after birth or for adults. Identification.
Complication
Pediatric polycystic kidney disease Complications, hypertension, anemia, uremia
Often complicated by acute infection, stones, severe chronic renal insufficiency, can be complicated by hypertension, anemia, and eventually uremia.
Symptom
Pediatric polycystic kidney symptoms common symptoms chronic renal insufficiency back pain edema portal hypertension renal failure hematuria
Symptoms before the age of 50, long survival time, often family history, symptoms are divided into two aspects, on the one hand related to cysts, on the other hand related to impaired renal function, symptoms associated with cysts are discomfort, low back pain, waist Masses, hematuria, acute infections, and colic can occur when hematuria or complicated stones pass through the ureter. When the lesion progresses, the kidney tissue is compressed, and renal function is impaired, there is chronic renal insufficiency, eventually uremia, renal failure Before the emergence, there is often a decrease in urine concentration, more than 70% of patients have high blood pressure, physical examination can touch the double kidney, the surface is nodular.
1. Autosomal dominant PK can be asymptomatic for decades, until symptoms appear when the cyst grows to a large extent. Early symptoms and signs include waist, back pain, abdominal mass, gross hematuria, urinary tract infection and hypertension. Kidney stones are more common than the general population. Rarely, intracranial hemorrhage secondary to ruptured aneurysms, swollen liver is common, and about half of patients have renal insufficiency.
2. Autosomal recessive PK The enlarged kidney is associated with lung dysplasia, Potter's special face and renal insufficiency, mainly found in newborns, in older children, hypertension, edema, urinary tract infections and portal hypertension Can be a critical signal.
Examine
Pediatric polycystic kidney examination
In addition to mild proteinuria and low urine specific gravity, urine routine examinations often have no abnormal findings. When there is hematuria and infection, there are red urine, white blood cells, peripheral white blood cells, and renal function is impaired, creatinine is increased. In uremia, electrolyte imbalance, metabolic acidosis, etc. Ultrasound, intravenous urography and CT examination are the main methods of diagnosis. The shape of the kidney is enlarged, the contour is irregular, and the renal pelvis and renal pelvis are deformed by the cyst. can be extended, curved like spider legs or crescent, X-ray is similar to renal tumor, but the lesion is extensive and bilateral, the above X-ray findings are rare before the age of 10, but B-mode ultrasound can be compared Early detection of cysts, retrograde pyelography has the risk of infection, and renal biopsy has the possibility of bleeding, about 1/3 of cases with hepatic cysts, but does not cause liver dysfunction, other organs such as bladder, epididymis, lung The ovaries, testes, pancreas, spleen, thyroid and uterus may also have cysts, and 6% of patients have cerebrovascular accidents.
Diagnosis
Diagnosis and diagnosis of polycystic kidney disease in children
Clinical manifestations and family history can often suggest this disease, ultrasound or CT examination can confirm the diagnosis, for patients with a family history of subarachnoid hemorrhage, feasible cerebrovascular MRI, ultrasound can be used for the screening of this disease, has not been established A gene deletion screening method for clinical and perinatal diagnosis.
The diagnosis of this disease is not difficult in the late stage. It must be differentiated from renal tumor, hydronephrosis, von Hippel-Lindau disease and pyelonephritis. CT scan is beneficial to exclude kidney tumors. MRI can help identify other cystic diseases and identify congenital Hydronephrosis, the location, distribution, number, size of cysts, whether it is connected with renal pelvis and renal pelvis, and whether there are complications such as hypertension or repeated urinary tract infections, can help identify renal cystic diseases. In patients with mild symptoms, this disease Often misdiagnosed with simple cysts such as simple renal cysts and solitary multiple cysts. Family history and concurrent hepatic cysts can help differential diagnosis. Hematuria must be associated with other diseases such as neoplasms, kidney stones and other hematuria. Identification, attention to polycystic kidney stones or cysts, etc., should be screening for clotting (PT, APTT and platelets), to rule out bleeding disorders.
