Polycystic Kidney Disease

　　Polycystic kidney disease is a hereditary kidney disease in which multiple cysts appear in the cortex and medulla of the kidneys. Polycystic kidney disease has two types: one is an autosomal dominant type, which generally appears symptoms in adulthood; the other is an autosomal recessive type, which generally shows obvious symptoms in infants. The exact cause of polycystic kidney disease is not yet clear, so what factors are related to it?

　　90% of ADPKD patients have abnormal genes located on the short arm of chromosome 16, known as the ADPKD1 gene, and the product of the gene is not yet clear. Many coding genes in this region have been elucidated and cloned, and it is expected that ADPKD1 can be confirmed in the near future. Another less than 10% of patients have abnormal genes located on the short arm of chromosome 4, known as the ADPKD2 gene, and the encoded product is also not clear. The two groups differ in the age of onset, the appearance of hypertension, and the age of entering renal failure.

　　The exact etiology of this disease is not yet clear. Although most symptoms appear after adulthood, the formation of the disease begins in the fetal stage. Cysts originate from the renal tubules, and their liquid nature varies depending on the origin, with those originating from the proximal tubules having a similar composition to plasma in terms of Na+, K+, CI-, H+, creatinine, urea, etc. Those originating from the distal tubules have lower concentrations of Na+ and K+ in the cyst fluid, while CI-, H+, creatinine, and urea have higher concentrations.

　　The abnormal proliferation of renal glomerular epithelial cells in patients with polycystic kidney disease is one of the significant characteristics of ADPKD, which is in an immature or redeveloping state, strongly suggesting that there is a disorder in the development and maturation regulation of bacteria, causing the cells to be in an immature state, thus showing strong proliferative characteristics. The abnormal transport of these cells is another significant feature of ADPKD, manifested as changes in the composition, distribution, and activity expression of the subunits of Na+-K+-ATP ase closely related to cell transport. Abnormal cell signal transduction and changes in ion transport channels. Abnormal hyperplasia of the extracellular matrix is the third significant feature of ADPKD.

　　Many studies have proven that these abnormalities are all involved in the participation of active factors related to cell growth. However, the key abnormal links and pathways are not yet clear. In summary, the changes in cell growth and the abnormal formation of stroma caused by gene defects are one of the important pathogenic mechanisms of the disease.

　　The kidneys of patients with polycystic kidney disease are of normal size or slightly larger in childhood, and with the increase of age, the number and size of cysts gradually increase and enlarge. Most cases do not show symptoms until the kidney volume increases to a certain extent at the age of 40 to 50. If this disease is not treated in a timely manner, it may lead to the following complications:

　　1. Renal calculi

　　The lumbar pain in this disease is usually dull, and when there is colic pain accompanied by gross hematuria, it indicates the occurrence of renal calculi.

　　2. Multiple cysts in other organs

　　About half of the patients with ADPKD discovered in middle age have polycystic liver, and about 70% after the age of 60. It is generally believed that its development is slower and about 10 years later than that of polycystic kidney disease. The cysts are formed by the dilatation of the atretic bile ducts. In addition, the pancreas and ovaries may also have cysts, and the incidence of colonic diverticula is also high.

　　3. Cerebral cavernous angioma at the base of the brain artery

　　About 10% to 40% of patients with this vascular malformation are found to have cerebral cavernous angioma, often discovered due to cerebral hemorrhage caused by vascular malformation rupture. In addition, thoracic aortic aneurysm and valvular heart disease (such as valve insufficiency and prolapse) are also common. In infantile polycystic kidney disease, portal hypertension and pulmonary alveolar hypoplasia may be accompanied.

　　The kidneys of patients with polycystic kidney disease are of normal size or slightly larger in childhood, and with the increase of age, the number and size of cysts gradually increase and enlarge. Most cases do not show symptoms until the kidney volume increases to a certain extent at the age of 40 to 50. The main symptoms are bilateral renal enlargement, renal pain, hematuria, and hypertension. The following is a specific introduction to the common symptoms of this disease:

　　1. Renal enlargement

　　The renal lesions on both sides progress asymmetrically, with differences in size. By the late stage, the two kidneys can occupy the entire abdominal cavity. The renal surface is covered with many cysts, making the kidney shape irregular and uneven, with a relatively hard texture.

　　2. Renal pain in the renal area

　　It is an important symptom, often presenting as a sense of pressure or dull pain in the lumbar and thoracic region, and sometimes severe pain. There may also be abdominal pain. The pain can be exacerbated by physical activity, prolonged walking, prolonged sitting, etc., and can be relieved after lying down. Renal hemorrhage, stone movement, or infection can also be the cause of sudden severe pain.

　　3. Hematuria

　　About half of the patients present with microscopic hematuria, which can be accompanied by gross hematuria. This is caused by the rupture of blood vessels in the cyst wall. When bleeding is severe, blood clots passing through the ureter can cause colic pain. Hematuria is often accompanied by leukocyteuria and proteinuria, with a small amount of protein, generally not exceeding 1.0g/d. In cases of renal infection, pyuria is marked, hematuria worsens, and back pain is accompanied by fever.

　　4. Hypertension

　　ADPKD is a common manifestation, with about half of the patients developing hypertension before the serum creatinine level increases. This is related to the compression of surrounding tissues by cysts, which activates the renin-angiotensin-aldosterone system. In the past decade, Graham PC, Torre V, and Chapman AB have all confirmed that the normal renal tissue, adjacent interstitium, and renal epithelial cells of ADPKD have an increase in renin granules, and there is an increase in renin secretion, which is closely related to the growth of cysts and the occurrence of hypertension. In other words, patients with hypertension have faster cyst growth, which can directly affect the prognosis.

　　5. Renal insufficiency

　　Renal insufficiency will eventually occur in this disease, and some cases may appear renal failure in adolescence. Generally, there is little renal function decline before the age of 40, and about half of the patients still maintain renal function at the age of 70. However, the process of developing renal failure in patients with hypertension is greatly shortened, and there are also individual patients who can maintain renal function at the age of 80.

　　6. Polycystic liver

　　About half of the ADPKD patients discovered in middle age have polycystic liver, and about 70% after the age of 60. It is generally believed that its development is slow and about 10 years later than polycystic kidney disease. The cysts are formed by the dilation of the bile ducts. In addition, cysts can also occur in the pancreas and ovaries, and the incidence of colonic diverticula is relatively high.

　　The exact cause of polycystic kidney disease is not yet clear. Although most symptoms appear in adulthood, the disease begins to form in the fetal stage. So how should we prevent this disease? Let's introduce it to everyone below.

　　1. Prevent colds

　　Patients with polycystic kidney disease suffer greatly internally, as polycystic kidney disease is a lifelong hereditary disease that needs to be accompanied throughout life. Even with extra attention and care from family members, it cannot prevent the continuous enlargement of cysts. At this time, if patients have a cold, especially recurrent colds, it will worsen the renal damage in patients with polycystic kidney disease, exacerbating the deterioration and accelerating the progression of renal function damage.

　　2. Control diet well

　　A reasonable diet for patients with polycystic kidney disease is very important for controlling the deterioration of renal function. It is recommended to consume 2-3 grams of salt per day, eat less potassium and phosphorus-rich foods, and follow a low-protein, low-fat diet. It is also advisable to eat more vitamin and plant roughage-rich foods to maintain smooth bowel movements.

　　3. Prevent trauma

　　As the cysts of polycystic kidney disease continue to enlarge, the intracystic pressure increases continuously, forcing the patient's kidneys to enlarge continuously and increasing the intra-abdominal pressure. At this time, any slight trauma, such as sprains, bumps, or falls, can increase the intra-abdominal pressure or directly impact the enlarged cysts, causing high-pressure cysts to rupture and hemorrhage, which is very prone to infection.

　　4. Control blood pressure well

　　Most patients with polycystic kidney disease will develop hypertension before renal function is impaired, and we call this the onset of polycystic kidney disease: the appearance of hypertension will accelerate the damage to renal function, and hypertension will also cause damage to the heart and blood vessels, leading to serious complications such as cerebral hemorrhage and stroke in patients with polycystic kidney disease accompanied by cerebral aneurysms, so controlling blood pressure is crucial for delaying the progression of renal function deterioration and preventing complications.

　　Polycystic kidney disease is a relatively uncommon disease that occurs in the kidneys. Generally, the following examinations are required for this disease:

　　1. Laboratory examination

　　1. Urinalysis

　　There are often symptoms such as purulent urine (94%), hematuria (43%), proteinuria (93%), and cylinder urine (11%), with urine specific gravity below 1.010 accounting for 40%. Urine culture in patients with purulent urine can detect Escherichia coli and other bacteria, and in the late stage, renal insufficiency is common.

　　2. Blood examination

　　When accompanied by infection, blood routine may show an increase in white blood cells and neutrophils. In the late stage of renal insufficiency, blood urea nitrogen and creatinine levels may increase.

　　Second, imaging examination

　　1. Imaging examination

　　Including X-ray abdominal flat film examination, CT and MRI examination, contrast examination [intravenous pyelography (IVP), ureteropyelography, radionuclide renal imaging] are routine examination methods. This disease can be diagnosed by renal pelvis examination (if the kidney lacks excretory function, then retrograde imaging is required). It can be found that in the early stage, due to the compression of cysts, renal calyces show a crescent-shaped deformation; in the late stage, renal pelvis and calyces extend, renal calyces widen, and boundaries are distinct. Other examinations such as abdominal X-ray flat film show significant changes in the size of both kidneys, and there are cystic or calcified shadows.

　　CT and MRI are generally not used as initial examination methods because they involve a large amount of radiation and are expensive. However, their advantages are that they can display different tissue densities and provide detailed anatomical structure information. CT can better clarify the location and nature of the lesions and is a helpful examination method. It is replacing the traumatic retrograde and antegrade pyelography. MRI is like CT and can more clearly display tissue density, clarify the cause of obstruction and the nature of the lesions.

　　2. Ultrasound examination

　　Ultrasound examination is very effective in diagnosing dilatation of renal pelvis and calyces. It is the preferred examination method for diagnosing renal cystic change and hydronephrosis. Since this is a non-invasive examination, it has high sensitivity in diagnosing renal cystic change and is also suitable for the examination of polycystic kidney disease. Ultrasound examination can detect enlargement of kidney volume, cysts, and significant deformation of renal pelvis and calyces, and there are also thicker cyst walls or varying degrees of calcification and obstruction. Ultrasound can also be used for the screening of this disease.

　　Polycystic kidney disease is a type of hereditary kidney disease. This disease is not uncommon in clinical practice. In order to help patients recover better, it is recommended that patients pay attention to the following dietary suggestions:

　　Note one for diet

　　Increase the intake of low-fat foods: crucian carp, sturgeon, flounder, clam meat, crab meat, shrimp, oysters, asparagus, eggplant, fresh green beans, lettuce, green peas; potatoes, spinach, pumpkin, tomatoes, cabbage, broccoli, cucumbers, green peppers, carrots, white radishes, rice, bread, pasta, salted soda crackers, corn flour, etc.

　　Note two for diet

　　Patients with kidney disease should eat less food high in phosphorus: peanuts, walnuts, prawns, flatfish, yellow croaker, sardine, meat soup, lean pork, lean beef, pork liver, kidneys, brain, eggs, cream, cheese, milk, etc.

　　Note three for diet

　　Increase the intake of foods high in potassium: bananas, grapes, watermelons, apricots, oranges, honeydew melon, cantaloupe, dried red dates, spinach, coriander, amaranth, rapeseed, kale, cucumbers, chives, scallions, green garlic, lettuce, potatoes, yams, fresh green peas, soybeans, taros, potatoes, mushrooms, toon trees, lilies, pickled vegetables, cauliflower, dried lily bulbs, dried peanuts, tea leaves, vinegar, malted milk powder, etc.

　　There is currently no method to stop the progression of the disease. Early detection, prevention of the occurrence and development of complications, and timely and correct treatment of existing complications are crucial.

　　1. General Treatment

　　In general, after a patient is diagnosed with polycystic kidney disease, the first thing to do is to maintain an optimistic attitude. If it has not affected the patient's normal life, pay attention to not eating or eating less salty, spicy, and other stimulating foods in daily life, keep a regular schedule, and maintain a stable and optimistic mood. If it affects the patient's normal life, pay attention to the above-mentioned points in daily life, and treatment should also be carried out as soon as possible. Otherwise, if it is allowed to develop into renal failure and uremia, it is too late.

　　2. Cyst Decapitation and Decompression

　　This operation relieves the pressure of the cyst on the renal parenchyma, protects most of the remaining renal units from compression and further damage, improves the renal ischemia condition, restores some renal function units, and delays the progression of the disease. The key to surgical success is to perform the operation as early as possible, the decompression of the cyst must be thorough, and the decompression of small cysts and deep cysts should not be abandoned. Both sides should be operated on, and the interval between bilateral operations is generally more than half a year. For late-stage cases where there is renal function damage and uremia, regardless of whether hypertension is present or not, decompression treatment is no longer meaningful, and the impact of surgery can worsen the condition.

　　3. Dialysis and Transplantation

　　When entering the terminal stage of renal failure, dialysis treatment should be initiated immediately, with hemodialysis being the first choice. The survival rate of kidney transplantation in polycystic kidney disease is similar to that of others, but due to accompanying diseases, it increases the difficulty of postoperative management and affects the effect of transplantation.

　　4. Treatment of Hematuria

　　When hematuria occurs, in addition to giving treatment as soon as possible to clarify the cause, activities should be reduced or bed rest should be adopted. For patients who have dialysis or are about to have dialysis and have recurrent severe and uncontrollable hematuria, consider using percutaneous renal artery embolization.

　　5. Treatment of Infection

　　Renal parenchymal infection and intracystic infection are the main complications of the disease, and generally antibiotics are used in combination.

　　6. Treatment of Upper Urinary Tract Stones

　　Treat according to the principles of urinary tract stone treatment based on the location and size of the stone.

　　7. Hypertension Treatment

　　Hypertension is mainly caused by the activation of renal ischemia and the renin-angiotensin-aldosterone system, and antihypertensive drugs should be selected accordingly.