One third of people older than 50 years develop renal cysts. Although most are simple cysts, renal cystic disease has multiple etiologies. Broad categories of cystic disease include the following:
●Developmental -Multicystic dysplastic kidney (MCDK)
●Developmental -Multicystic dysplastic kidney (MCDK)
●Genetic -Autosomal recessive polycystic kidney disease (ARPKD),autosomal dominant polycystic kidney disease (ADPKD), juvenile nephronophthisis (JNPHP), medullary cystic kidney disease (MCKD), glomerulocystic kidney disease (GCKD)
●Cysts associated with systemic disease -Von Hippel-Lindau syndrome(VHLS), tuberous sclerosis (TS)
●Acquired - Simple cysts, acquired cystic renal disease, medullary sponge kidney (MSK)
●Malignancy -Cystic renal cell carcinoma (RCC)
The most common larger cysts include acquired cysts, simple cysts, and cysts associated with ADPKD. Smaller cysts characterize ARPKD, JNPHP, MCKD, and MSK. In adults, renal angiomyolipomas and RCC may also have cystic components.
Cysts develop from renal tubule segments and most detach from the parent tubule after they grow to a few millimeters in size. Cyst development is generally attributed to increased proliferation of tubular epithelium, abnormalities in tubular cilia, and excessive fluid secretion.
Developmental cystic renal disease
MCDK represents abnormal development or formation of the kidney and may involve part, or all of, one or both kidneys. This condition is thought to be secondary to dysfunctional genetics, abnormal differentiation of the metanephros or in utero ureteral obstruction. Patients are observed unless complications arise directly from the kidney or its associated conditions.
Inherited cystic renal disease
ADPKD is due to mutations in the genes PKD1 and PKD2, which encode polycystin proteins. The genetic mechanism of cyst development requires a "second hit," a somatic mutation of the normal PKD allele, which accounts for the onset of ADPKD, usually in those aged 30-50 years. Symptoms primarily include pain, hypertension and renal failure. The goal of treatment is to control blood pressure and to slow the onset of renal failure. ADPKD is associated with involvement of other organs, particularly intracranial aneurysms.
ARPKD is due to mutations in PKHD1, a large gene that encodes fibrocystin/polyductin, which plays critical roles in collecting-tubule and biliary development. This disease carries a high neonatal mortality rate, and many individuals who survive eventually require renal transplantation. Symptoms include hypertension and liver disease. Diagnosis is often made in utero. Treatment is supportive in severe cases but otherwise is similar to that for ADPKD.
GCKD is often confused with ADPKD, as it is common in individuals with a family history of ADPKD. This disease is distinguished histologically and symptoms and treatment are similar to those in ADPKD.
JNPHP and medullary cystic disease are two diseases that some consider a disease complex.[1] They share similar pathologic features but are due to different genetic mutations and have different inheritance patterns. JNPHP is inherited in an autosomal recessive manner and presents in childhood, while MCKD is inherited autosomal dominantly and affects adults. Both diseases present with symptoms of salt wasting and polyuria.
ADPKD is due to mutations in the genes PKD1 and PKD2, which encode polycystin proteins. The genetic mechanism of cyst development requires a "second hit," a somatic mutation of the normal PKD allele, which accounts for the onset of ADPKD, usually in those aged 30-50 years. Symptoms primarily include pain, hypertension and renal failure. The goal of treatment is to control blood pressure and to slow the onset of renal failure. ADPKD is associated with involvement of other organs, particularly intracranial aneurysms.
ARPKD is due to mutations in PKHD1, a large gene that encodes fibrocystin/polyductin, which plays critical roles in collecting-tubule and biliary development. This disease carries a high neonatal mortality rate, and many individuals who survive eventually require renal transplantation. Symptoms include hypertension and liver disease. Diagnosis is often made in utero. Treatment is supportive in severe cases but otherwise is similar to that for ADPKD.
GCKD is often confused with ADPKD, as it is common in individuals with a family history of ADPKD. This disease is distinguished histologically and symptoms and treatment are similar to those in ADPKD.
JNPHP and medullary cystic disease are two diseases that some consider a disease complex.[1] They share similar pathologic features but are due to different genetic mutations and have different inheritance patterns. JNPHP is inherited in an autosomal recessive manner and presents in childhood, while MCKD is inherited autosomal dominantly and affects adults. Both diseases present with symptoms of salt wasting and polyuria.
Systemic disease with associated renal cysts
TS is caused by mutations in the suppressor genes TSC1 and TSC2, which encode hamartin and tuberin, respectively. Renal cysts and angiomyolipomas are part of a syndrome that includes seizures and dermatologic findings.
VHLS is due to mutations in the VHL gene, which increases the risk for malignancy, including RCC. Affected individuals develop cysts in multiple organs, including the kidney, pancreas, liver, and epididymis.
TS is caused by mutations in the suppressor genes TSC1 and TSC2, which encode hamartin and tuberin, respectively. Renal cysts and angiomyolipomas are part of a syndrome that includes seizures and dermatologic findings.
VHLS is due to mutations in the VHL gene, which increases the risk for malignancy, including RCC. Affected individuals develop cysts in multiple organs, including the kidney, pancreas, liver, and epididymis.
Acquired cystic renal disease
The exact cause of this disease is not known. It occurs exclusively in patients on dialysis. The severity of disease is directly related to the duration of therapy. Typically, acquired cystic renal disease is asymptomatic but it is known to subsequently increase the risk of RCC.
The exact cause of this disease is not known. It occurs exclusively in patients on dialysis. The severity of disease is directly related to the duration of therapy. Typically, acquired cystic renal disease is asymptomatic but it is known to subsequently increase the risk of RCC.
Frequency
United States
MCDK has an incidence of 1 per 1000-4000 live births.
ADPKD has an incidence of 1 per 400-1000 persons among whites and accounts for 8-10% of all cases of end-stage renal disease (ESRD).
ARPKD has an incidence of 1 per 6000-55,000 live births, with a heterozygous carrier frequency of 1 per 70.
JNPHP affects 1 per 5000 persons.
JNPHP and MCKD account for 10-20% of children with chronic renal failure and for 1-5% of all patients undergoing dialysis or transplantation.
TS has an incidence of 1 per 10,000-50,000 persons, and 20-25% of these patients have renal cysts.
VHLS has an incidence of approximately 1 per 39,000 persons, and two thirds of these individuals develop renal cysts.
In acquired cystic renal disease, cysts are present in 8-13% of patients with chronic renal failure prior to dialysis. Following initiation of therapy, 10-20% of patients have acquired cystic renal disease after 3 years of dialysis, 40-60% after 5 years, and more than 90% after 10 years.
MSK has an estimated incidence of 1 per 5000 persons and is found in approximately 20% of patients with nephrolithiasis.
Simple cysts are the most common cystic renal lesions. They are present in 5% of the general population, increasing in frequency to 25-33% of patients older than 50 years, and account for 65-70% of renal masses.
Cystic RCC accounts for less than 1% of RCC cases.
United States
MCDK has an incidence of 1 per 1000-4000 live births.
ADPKD has an incidence of 1 per 400-1000 persons among whites and accounts for 8-10% of all cases of end-stage renal disease (ESRD).
ARPKD has an incidence of 1 per 6000-55,000 live births, with a heterozygous carrier frequency of 1 per 70.
JNPHP affects 1 per 5000 persons.
JNPHP and MCKD account for 10-20% of children with chronic renal failure and for 1-5% of all patients undergoing dialysis or transplantation.
TS has an incidence of 1 per 10,000-50,000 persons, and 20-25% of these patients have renal cysts.
VHLS has an incidence of approximately 1 per 39,000 persons, and two thirds of these individuals develop renal cysts.
In acquired cystic renal disease, cysts are present in 8-13% of patients with chronic renal failure prior to dialysis. Following initiation of therapy, 10-20% of patients have acquired cystic renal disease after 3 years of dialysis, 40-60% after 5 years, and more than 90% after 10 years.
MSK has an estimated incidence of 1 per 5000 persons and is found in approximately 20% of patients with nephrolithiasis.
Simple cysts are the most common cystic renal lesions. They are present in 5% of the general population, increasing in frequency to 25-33% of patients older than 50 years, and account for 65-70% of renal masses.
Cystic RCC accounts for less than 1% of RCC cases.
Cystic renal disease accounts for approximately 10% of all ESRD cases.
ADPKD is 1 of the top 4 causes of ESRD and is the etiology of renal failure in 5-10% of patients undergoing dialysis. ARPKD accounts for 5% of ESRD in children.
Neonatal mortality secondary to ARPKD approaches 25-35% and is usually related to respiratory compromise.
More than 50% of patients with ARPKD require kidney transplant before age 20 years.
JNPHP is the most common cause of genetic ESRD in children.
TSC is associated with a high frequency of angiomyolipoma.
Patients with acquired cystic disease are more likely to develop RCC (5-25%). Additionally, tumors are commonly bilateral, and 15% are metastatic.
Race
ADPKD is found throughout the world in all racial and ethnic groups.
Acquired cystic renal disease is most common in white men and African Americans.
Sex
Multicystic dysplastic kidney is more common in males than in females.
Symptomatic progression of ADPKD appears to be more rapid in men.
VHLS affects men and women with equal frequency.
Acquired cystic renal disease is more common in men.
MSK has a male-to-female ratio of 2:1.
Age
ADPKD has a bimodal distribution of onset, with some cases presenting in infancy or childhood.[3]
ARPKD presents in infancy, childhood, or adolescence.
VHLS typically presents in the third or fourth decade of life with visual or central nervous system symptoms.
MSK typically presents between the third and fifth decades of life.
Simple cysts are very rare in children but increase in frequency with age.
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