Polycystic kidney disease

Introduction of polycystic kidney Polycystic kidney disease has numerous cysts of different sizes in the renal parenchyma. The larger ones can be large, the small ones can only be visible to the naked eye, the whole kidney volume is enlarged, the surface is uneven and cystic, and the capsule is light. Yellow serum, sometimes dark brown or reddish brown due to bleeding. There are two types of polycystic kidney, autosomal recessive (infant) polycystic kidney and autosomal dominant (adult) polycystic kidney. basic knowledge The proportion of illness: 0.03-0.05% Susceptible people: no specific population Mode of infection: non-infectious Complications: Kidney stones Urinary tract infections

Polycystic kidney disease

(1) Causes of the disease

The cause of polycystic kidney disease is gene deletion. The adult polycystic kidney disease is often the gene deletion of chromosome 16. It is accidentally deleted by the gene of chromosome 4, which is a dominant inheritance with 100% penetrance. Therefore, 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%.

The evidence related to heredity is that Buck et al. reported that eight brothers and sisters, six of whom were kidney cysts, whose father and uncle died of uremia, and five of them had kidney disease in the next generation; Brasck et al. Reported that 1 family of 4 generations of polycystic kidney disease; Reason et al reported that the twins have this disease; Crawford reported that 17 of a family of 40 people found polycystic kidney disease.

70% to 90% of the disease is bilateral, of the 62 cases reported by Lejars, only 3 cases are unilateral; Oickinson reported a ratio of unilateral to bilateral 1:26; see the polycystic kidney volume in the general specimen examination Compared with normal kidney, it is more than 2 to 3 times larger. It has been reported that 1 case of bilateral polycystic kidney weight is 14436g, Schacht reports that 1 cystic kidney is 7248g, and the appearance of polycystic kidney is irregular cystic nodules. See countless cysts of varying sizes in a honeycomb shape.

Infant type (Potter I type) polycystic kidney cyst is the size of the needle, between the cysts, the kidney tissue is very small, when the cyst is enlarged, the renal parenchyma is atrophied due to compression, so the medulla and cortex are incomplete, the cyst It contains yellow-brown mucus, purulent or bloody liquid, etc. The cyst and the renal pelvis are not connected to each other; the normal kidney tissue is extremely rich in adult cysts, and can be connected with the renal pelvis (adult type is Potter III type), Kasper et al. Potter type II polycystic kidney disease, mostly left kidney, generally no clinical symptoms, but also ureteropelvic obstruction or atresia, while other two types of renal pelvis and ureter are often narrowed due to compression, but not blocked; interlobular Arterial branches also have signs of significant oppression. The cystic wall is composed of cuboidal epithelial cells with a secretory function. There are many small arteries underneath, which can cause hematuria due to increased pressure and rupture.

(two) pathogenesis

The pathogenesis of this disease is unclear. Hilde-brand et al believe that polycystic kidney disease may be caused by the expansion of Bowman's capsule, or it may be caused by the expansion of the renal tubule, which is a glomerulus developed from the posterior kidney germ. The communication with the collection tube developed by the Wolffian tube is obstructed; Bialestack suggests that some cysts are abnormally enlarged nephrons, called giant kidney units, and some cysts are considered to have excretory function; Bricker et al. The chemical analysis of the liquid in the cyst proved that the components contained in it were close to the urine; Norris et al. believed that many temporary nephrons could not be atrophied normally, and some nephrons were locally narrowed and segmented, thus forming different sizes. Cyst; Hepler et al. believe that the blood circulation of the kidney is not normal, resulting in renal parenchymal degeneration; Hidd-brant believes that the secretion (derived from renal tissue and some glomeruli) and excretory (from the kidney) The collecting tube of ureteral buds, renal pelvis, etc.) lose contact with each other during development, the secretory part becomes a blind end, and its secretions are not discharged, so most cysts are formed; others think it is a machine Factors such as local inflammation caused by fetal period fiber excretory duct obstruction, or because of tube obstruction and insoluble calcium salts, so that poor results of urine caused by renal tubular expansion, there are the following two statements could explain some clinical phenomena:

1. Lambert through the continuous section of the kidney, detailed study of infants and adults with cystic kidneys, pointed out that polycystic kidney cysts have three forms and sources: 1 glomerular cyst; 2 tubular cyst; 3 drain cyst, cyst wall Lined with cuboidal or squamous cells, the interstitial fibers are rich in connective tissue, medulla and cortex are incomplete, and most of the normal nephrons disappear; he found all cysts in the cystic kidney of the baby that are connected to the renal tubules and function. The small tubules are not connected, and the nephrons with cysts have no function; the adult kidneys, in addition to the above types of cysts, some cysts have their own function of the renal tubules and renal pelvis, and the normal renal tissue between the cysts is extremely Rich, and functional activities, so early without clinical symptoms, even when the adjacent kidney tissue is compressed and atrophy can maintain function until the cyst continues to increase, when the renal atrophy occurs, the kidney function declines and dies. However, there is still no proper explanation for the cause.

2. Dammin believes that the glandular system has excessive formation of ductal epithelial cells during normal embryonic development. In the period of development, glandular epithelial cells generally degenerate, digest and disappear, and the initial stage of degeneration is to complete the epithelial tube. Section, if the segment is isolated and does not retreat, the cyst is formed, that is, the segmental expansion of the proximal end of the renal tubule in the renal cyst, which is still connected with the glomerular filtrate, which is considered to be the post-renal embryo and the ureteral bud. The theory that can not be connected is the opposite, and can explain the phenomenon that polycystic kidney disease can have multiple cystic diseases of liver, spleen, pancreas and even ovary, uterus and bladder.

The disease is generally affected by both kidneys and is rarely unilaterally affected. The weight of a single kidney in a normal adult is about 150g. In asymptomatic adult polycystic kidney disease, the average weight of a single polycystic kidney is 256g; in symptomatic adult polycystic In kidney patients, the average weight of a single polycystic kidney is 465g. In adult polycystic kidney disease, diffuse cysts are common in the kidney. Both the renal cortex and the medulla are covered with cysts of different sizes, resembling a bunch of grapes, and the wall epithelial cells. There is localized hyperplasia, polypoid formation, abnormal proliferation of extracellular matrix, cyst formed by proximal tubule bulging, cystic fluid composition like plasma; cyst formed by distal tubule, sodium in cystic fluid, low chloride content, and urea and The concentration of creatinine is higher. In patients with symptomatic polycystic kidney disease, with the increase of age, the number of cysts increases, the cystic cavity increases, the diameter is 2~3cm, and the long diameter of the kidney can reach 20~30cm. The whole kidney is almost cyst. Occupied, common cysts > 3 cm in diameter contain more bloody fluid or blood clots.

The polycystic kidney section showed that the cyst was consistently distributed in the cortex and medulla, and the renal pelvis and renal pelvis were often significantly deformed. In severe cases, almost no obvious residual renal tissue was observed, but in patients with mild symptoms, the disease was often complicated with multiple Cysts (such as simple renal cysts, isolated multifamily cysts) are confused.

Microscopic observation showed that the normal kidney tissue was compressed by the adjacent cyst. On the basis of vascular sclerosis or pyelonephritis, glomerular sclerosis, tubule atrophy and interstitial fibrosis were performed. It is difficult to identify the tissue source of the cyst unless the cyst remains. The normal position of the original tissue and the morphological features of the epithelium, cysts from the renal sac sometimes contain deformed small squamous glomerular vascular plexus; cysts derived from the deep concentrating system are often thin-walled; occur in the subcapsular collecting system The cyst wall is thicker and often wraps around dense fibrous connective tissue. The specific plant lectin binding assay can be used to identify the tissue source of the cyst as a proximal tubule, a collecting duct or the like.

Polycystic kidney disease prevention

Since there is no effective treatment, prevention and treatment of kidney complications and maintenance of renal function are the main preventive purposes.

For patients with this disease, close contact activities should be avoided, especially collision and squeezing to prevent cyst rupture.

Patients with this disease are prone to high blood pressure, urinary tract infections, especially in women, such as induced pyelonephritis or cyst infection, kidney pain increased with obvious fever, hematuria and pyuria, severe cases can lead to urinary tract sepsis, therefore, must be positively symptomatic Support treatment, control high blood pressure, prevent urinary tract infections, prevent and treat complications such as kidney stones, and prolong the normal survival of patients.

Polycystic kidney disease Complications, kidney stones, urinary tract infection

1. Kidney stones This disease is usually dull pain, colic and accompanied by gross hematuria suggestive of kidney stones.

2. ADPKD patients found in middle-aged multiple cysts in other organs, about half of them have polycystic liver disease, about 70% after 60 years old, generally considered to be slower to develop, and more cystic kidneys are about 10 years later, and their cysts are lost. The bile duct is expanded. In addition, the pancreas and ovaries can also be complicated by cysts, and the colonic diverticulum rate is also high.

3. The cerebral artery aneurysm complicated with this hemangioma is 10% to 40%, often due to rupture of the hemangioma, further examination of cerebral hemorrhage is found, in addition, thoracic aortic aneurysm and heart valve disease (such as valvular insufficiency and off Dang) is also more common, in infantile polycystic kidney disease, may be associated with portal hypertension and alveolar dysplasia.

4. Hypertension or repeated urinary tract infections and other complications.

Polycystic kidney disease common symptoms cyst nausea and fatigue bladder irritation blood and urine prerenal renal insufficiency

When the disease is young, the kidney size is normal or slightly larger. The number and size of cysts increase and increase with age. In most cases, the kidney volume increases to a considerable extent until 40 to 50 years old. Kidney enlargement, pain in the kidney area, hematuria and high blood pressure.

1. Kidney lesions on both sides of the kidney are asymmetrical, and the size is different. In the late stage, the two kidneys can occupy the entire abdomen, and there are many cysts on the surface of the kidney, which makes the kidney shape irregular, uneven, and hard.

2. Kidney area pain is an important symptom, often for back pressure or dull pain, but also severe pain, sometimes abdominal pain, pain can be caused by physical activity, walking time is too long, sedentary, etc., can be relieved after bed rest, kidney Internal bleeding, stone movement or infection is also the cause of sudden severe pain.

3. About half of the patients with hematuria are microscopic hematuria, which may have paroxysmal gross hematuria. This is caused by rupture of the cyst wall. When hemorrhage occurs, blood clots can cause colic through the ureter. Hematuria is often accompanied by leukocyteuria and proteinuria. The amount of protein is small, generally not more than 1.0g / d, pyuria in the kidney infection, hematuria increased, low back pain with fever.

4. Hypertension is a common manifestation of ADPKD. Before serum creatinine is not elevated, about half of them develop hypertension, which is related to the cystic compression of surrounding tissues and activation of the renin-angiotensin-aldosterone system. For nearly 10 years, Graham PC, Torre V and Chapman AB have confirmed the normal tissue in the kidney of the disease. The cysts are adjacent to the interstitial and cystic epithelial cells, and the renin pigment is increased, and the renin secretion is increased. These are closely related to the growth of cysts and the occurrence of hypertension, in other words, high. Blood pressure cysts grow faster and can directly affect the prognosis.

5. Renal insufficiency This disease will occur sooner or later with renal insufficiency. In some cases, renal failure occurs in adolescence. Generally, there is little renal dysfunction before the age of 40. About 70% still maintain renal function at the age of 70, but the development of hypertension The process of kidney failure is greatly shortened, and some patients can still maintain kidney function at the age of 80.

6. ADPKD patients found in middle-aged polycystic liver disease, about half of them have polycystic liver disease, about 70% after 60 years old, generally considered to be slower to develop, and more cystic kidneys are about 10 years later, and their cysts are dilated by labile bile duct In addition, pancreas and ovary can also occur cysts, colonic diverticulum rate is higher.

Clinical manifestations of polycystic kidney disease:

Adult polycystic kidney disease usually develops in early adulthood, often with hematuria, hypertension or renal insufficiency. Abdominal palpation can reveal large polycystic kidney disease, renal function is mostly progressive, hypertension, obstruction or Pyelonephritis is an important cause of accelerated renal dysfunction. Autosomal recessive (infant) polycystic kidney disease occurs in infancy, clinically rare, mostly in infancy, and very few people with mild disease can live to adulthood.

The degree of anemia in this disease is often lighter than that of uremia caused by other causes. The reason is that the cyst of the kidney can generally produce erythropoietin.

Polycystic kidney disease examination

Laboratory inspection

1. Urine examination often has pyuria (94%), hematuria (43%), proteinuria (93%), tubular urine (11%), 40% of urine specific gravity below 1.010, and urine culture of pyuria. It has been found that Escherichia coli and the like often have renal insufficiency in the advanced stage.

2. Blood tests with infection may have white blood cells increased, neutral classification increased, urea nitrogen and creatinine increased in late renal insufficiency.

Film degree exam

1. Imaging examination including X-ray abdominal plain film examination, CT and MRI examination, angiographic examination [intravenous pyelography (IVP), ureteral pyelography, radionuclide angiography] are routine examination methods, the disease is treated by pyelography (If the kidney lacks excretory function, it must be retrograde angiography) examination, it can be found that the early renal pelvis is compressed by the cyst, see the semilunar deformity of the renal pelvis; the late renal pelvis and renal pelvis are extended, the renal pelvis is widened, the boundary is obvious, and other Examination of the abdominal X-ray film shows that the size of the kidneys on both sides changes significantly, and there are cyst-like or calcified shadows.

CT and MRI are generally not used as the initial examination method. Because of the large amount of radiation received, the price is more expensive, but the advantage is that it can display different densities of tissues, provide detailed anatomical structure, and CT can better define the location and nature of lesions. It is a helpful method of examination. It is replacing traumatic retrograde and anterior pyelography. MRI is also like CT, and it can clearly show the density of each tissue and determine the cause of obstruction and the nature of the lesion.

2. Ultrasound examination Ultrasound examination is very effective in diagnosing renal pelvis and renal pelvis enlargement. It is a method for diagnosing renal cystic changes and hydronephrosis. Because it is a non-invasive examination, it is highly sensitive to the diagnosis of renal cystic changes. Also suitable for polycystic kidney examination, ultrasound examination can be found that the kidney volume is increased, cysts, renal pelvis and renal pelvis are often significantly deformed, and the cyst wall is thicker or different degrees of calcification and obstruction, ultrasound can also be used for screening of this disease .

Polycystic kidney diagnosis

Clinical manifestations of large kidneys on both sides, abnormal urine, high blood pressure, etc. should be suspected of the disease, such as a family history can be more suggestive of the disease, B-mode ultrasound, CT and magnetic resonance imaging can find characteristic double kidney cysts, Diagnosis can be established, the number of early renal cysts in this disease is not much, can be unilateral, re-examination within a few years such as the increase in the number of renal cysts or extra-renal cysts, the diagnosis of ADPKD is also certain, in recent years, the application of 3'HVR, PGP and 24-1 DNA probes are extremely reliable for the diagnosis of cyst genes by gene linkage analysis. The heterozygous family members and asymptomatic patients can be detected. The diagnosis of this disease depends on the following tests to exclude other related diseases.

CT scan is beneficial to exclude kidney tumors. MRI can help identify other cystic diseases, as well as identify congenital hydronephrosis, the location, distribution, number, size of cysts, whether it is connected with renal pelvis and renal pelvis, and whether there is hypertension or Complications such as repeated urinary tract infections can help identify renal cystic diseases.

In patients with mild symptoms, the disease is often misdiagnosed as simple renal cysts, solitary multiple cysts and other simple cysts, family history and concurrent hepatic cysts can help differential diagnosis.

Hematuria should be identified with new diseases such as neoplasms, kidney stones and other hematuria. Pay attention to polycystic kidney stones or cysts, etc. Coagulation screening (PT, APTT and platelets) should be performed to rule out bleeding disorders. Patients with a family history of subarachnoid hemorrhage have a cerebrovascular MRI.

The disease must be associated with simple renal cysts, solitary multiple cysts and other simple cysts, kidney tuberculosis, liver or kidney hydatidosis, kidney tumors, hydronephrosis, chronic nephritis, pyelonephritis and other organ cysts in the abdomen. Identification, the occurrence of hematuria must be identified with new diseases, kidney stones and other diseases causing hematuria.

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