Cystic medullary disease

　　1. Etiology

　　It is related to autosomal recessive or autosomal dominant inheritance, and there are also other unknown factors.

　　2. Pathogenesis

　　The pathogenesis of the disease is unknown. It may be caused by the cystic dilatation of collecting tubes to form spongy cystic cavities.

　　This type is a common cause of end-stage renal disease in children and adolescents, and may be a group of combined diseases. In addition to renal lesions, patients or family members may have pigmentary retinopathy, cataracts, macular degeneration, myopia, or nystagmus, etc.; medullary cystic disease in adults is an autosomal dominant inheritance. The pathological changes of the four types of kidneys are similar, characterized by tubular atrophy, interstitial fibrosis, glomerulosclerosis, and small cysts in the renal interstitium.

　　1. Medullary sponge kidney:The main complications of its clinical manifestations are renal calculi and renal infection.

　　2. Juvenile nephrotic medullary cystic disease:In addition to renal lesions, patients or family members may have pigmentary retinopathy, cataracts, macular degeneration, myopia, or nystagmus, etc.

　　3. Autosomal dominant polycystic kidney disease:Early renal cysts are very small, without clinical manifestations, and diagnosis is difficult. Definite diagnosis has the following clinical manifestations: imaging examination shows that the kidneys are filled with numerous cysts of various sizes in the cortex and medulla; there is a clear family history of inheritance; there are extrarenal manifestations such as liver cysts, intracranial hemangiomas, pancreatic cysts, etc. For patients with unclear extrarenal manifestations, unclear family history, and only unilateral renal cysts or a small number of cysts, imaging follow-up examination should be performed, including ultrasound, CT, and MRI. Diagnosis can be made when cysts increase in size, the number increases, and the contralateral kidney is involved. Genetic linkage analysis can provide diagnostic reference for patients who have not yet developed cysts, but it is expensive and technically demanding.

　　4. Autosomal recessive polycystic kidney disease:The diagnosis is established based on the age of onset, the above clinical manifestations, and the typical family history.

　　Clinical symptoms

　　1. Medullary sponge kidney:The disease exists at birth, but there are no symptoms. Urinalysis and renal function are normal. The clinical manifestations are mainly caused by complications, such as renal calculi and renal infection. Therefore, it is often discovered due to acute colic, hematuria, urinary tract irritation symptoms, pyuria, and further examination. In patients with extensive cystic lesions, there may be a decrease in urine concentration and acidification function, an increase in urinary calcium excretion, a good prognosis, and rare renal failure.

　　In the past, most patients were diagnosed by IVP, as half of the patients have renal calculi. An array of stones arranged radially in the papillary area can be found on abdominal X-ray films. The contrast medium enters the cystic cavity of the papilla, forming a rose-like pattern. The renal pelvis is often enlarged and wide, and the renal outline is normal or slightly enlarged.

　　2. Juvenile nephrotic medullary cystic disease:Most cases start in childhood or adolescence, with clinical manifestations of reduced urine concentration function before renal failure, characterized by polydipsia, polyuria, nocturia, and nocturnal enuresis. Urine may have no abnormalities except for hyponatremia. Growth and development are delayed, accompanied by anemia, poor renal sodium conservation function, frequent hyponatremia and hypovolemia, increased urinary calcium excretion, leading to hypocalcemia and tetany. It can lead to hyperparathyroidism and renal osteodystrophy, and gradually develop to renal failure within 5 to 10 years after onset.

　　This type is a common cause of end-stage renal disease in children and adolescents, and may be a group of associated diseases. In addition to renal lesions, patients or family members may have pigmentary retinopathy, cataracts, macular degeneration, myopia, or nystagmus, etc.; adult onset medullary cystic disease is an autosomal dominant inheritance, with similar renal pathological changes in all four types, characterized by tubular atrophy, interstitial fibrosis, glomerulosclerosis, and small cysts in the renal interstitium.

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

　　Patients with this disease are prone to urinary tract infections, especially in women. If pyelonephritis or cyst infection is induced, the pain in the renal area will worsen with significant fever, hematuria, and pyuria. In severe cases, it can lead to urinary tract sepsis. Therefore, it is necessary to actively treat the symptoms and provide supportive treatment to control urinary tract infections and prevent complications such as kidney stones.

　　First, urine examination:There are often a large number of red blood cells and white blood cells, and proteinuria and casturia can be seen in the late stage. Urine specific gravity decreases below 1.010, and pyuria and hematuria can be seen in concurrent infection.

　　Second, blood biochemistry examination:In the late stage, there is often renal insufficiency, with elevated serum urea nitrogen and creatinine.

　　Third, X-ray examination

　　1. Urinary tract X-ray film:Small stones of varying sizes and an indeterminate number are visible in the lateral renal papilla and renal medulla, mostly in the form of millet-like, showing a multifocal or radiating arrangement. Other examinations, such as abdominal X-ray films, show significant changes in the size of the kidneys on both sides, and there are cystic or calcified shadows.

　　2. Intravenous urography:There are fusiform small cysts filled with contrast agent around the renal pyramids and small calyces, most of which are arranged in a fan-shaped grape-like or bundle-like pattern; the renal small calyces are widened, and the cup opening is expanded.

　　3. Retrograde pyelography:It shows the expansion of the renal calyces.

　　Fourth, CT and MRI examination:CT and MRI are generally not used as initial examination methods due to their high radiation dose and expensive cost, but their advantages are that they can show the different densities of tissues and provide detailed anatomical structure information. CT can better clarify the location and nature of the lesion, which is a helpful examination method and is replacing the traumatic retrograde and antegrade pyelography. MRI is similar to CT and can more clearly show the density of various tissues, and can clearly identify the cause of obstruction and the nature of the lesion.

　　Fifth, Ultrasonic examination:As this is a non-invasive examination with high sensitivity to diagnosing renal cystic changes, it is also suitable for the examination of polycystic kidney disease. Ultrasonic examination can detect changes in kidney volume, deformation of renal pelvis and calyces, and there are also thickened cyst walls or varying degrees of calcification and obstruction.

　　Regarding the occurrence and development of renal medullary cystic disease, the impact of dietary conditions can be summarized as follows:

　　1. Unregulated diet:If one is too hungry, they will lack nutrition; if one is too full, it is easy to injure the digestion and absorption functions of the spleen and stomach, and cause obstruction of Qi and blood circulation; and if one eats too much rich and delicious food, it is easy to generate internal heat.

　　2. Unsanitary diet:Mild cases can easily lead to gastrointestinal diseases, severe cases can cause poisoning or even threaten life.

　　3. Dietary preferences:If too much cold and cool food is eaten, it is easy to injure the spleen and stomach's Yang; if too much spicy and warm food is eaten, it can cause heat accumulation in the gastrointestinal tract; and if the five flavors are preferred, it is easy to injure the internal organs over time.

　　The impact of the above-mentioned dietary habits on the body is obvious. They also directly or indirectly affect the changes and development of cystic diseases.

　　For cystic diseases, we emphasize the following aspects in clinical practice: spicy and stimulating foods such as chili, alcohol, smoking (including passive smoking), chocolate, coffee, seafood, shrimp, crabs, etc. 'inducing' foods; salty foods, especially pickled foods; contaminated foods such as unhygienic foods, rotten and deteriorated foods, leftover meals and dishes; grilled foods; in addition, animal high-protein, high-fat and greasy foods, i.e., the aforementioned 'rich and delicious' foods should also be restricted, and bean products should be restricted, especially for patients with renal insufficiency.

　　1. Treatment

　　There is no specific treatment for this disease. Correcting electrolyte balance, especially supplementing sodium to correct hyponatremia and hypovolemia, can improve renal function and delay the progression of renal failure.

　　Mnemonic Sponge Kidney does not require treatment if there are no symptoms and complications. If there is urinary tract infection, it should be treated with standard antibacterial therapy for pyelonephritis. Patients with concurrent stones should drink more water, keeping daily urine output above 2000ml, and try to use stone expelling and stone-dissolving drugs. Patients with hypercalciuria should take thiazide diuretics. If the lesion is localized to a part of one kidney, nephrectomy of the affected kidney or the lesion site can be considered.

　　2. Prognosis

　　Patients with the disease, if treated actively, can have a significant improvement in prognosis.