Cystic Diseases of the Kidney Clinical Presentation
- Author: Thomas Patrick Frye, DO; Chief Editor: Bradley Fields Schwartz, DO, FACS more...
Presentation in patients with renal cysts varies with the underlying disease.
Developmental cystic renal disease
Multicystic dysplastic kidney (MCDK) is almost uniformly identified during prenatal sonographic examination. The involved kidney partially or completely improves with age in 40-90% of patients. Bilateral renal involvement is not compatible with life.
MCDK can exist independently or as part of syndromes such as the vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, and radial and renal anomalies (VATER) association; Zellweger syndrome; or BOR syndrome.
Inherited cystic renal disease
Inherited cystic renal disease includes the following disorders:
Autosomal dominant polycystic kidney disease (ADPKD)
Autosomal recessive polycystic kidney disease (ARPKD)
Glomerulocystic kidney disease (GCKD)
Juvenile nephronophthisis (JNPHP)
Medullary cystic kidney disease
Autosomal dominant polycystic kidney disease
Manifestations of ADPKD vary by patient age, as follows:
Patients present in the fourth decade of life with flank pain or intermittent hematuria
Patients may also experience cyst hemorrhage, renal infection, or nephrolithiasis
Hypertension and chronic renal failure are noted in the fifth decade of life
Patients progress to end-stage renal disease (ESRD) in the sixth decade of life
Hypertension is seen in 50% of patients with ADPKD aged 20-34 years
The disease course varies considerably among affected individuals. While all gene carriers are believed to exhibit symptoms by the end of their eighth decade of life, only 50% of carriers actually progress to renal failure. Kidney size (a direct reflection of cyst volume) increases exponentially over time and appears symmetric in a given individual, with an equal growth rate in both kidneys.
All aspects of the disease appear to develop more significantly in patients with the PKD1 genotype. Despite similar rates of cystic growth, these patients develop more cysts at a younger age than patients with PKD2 mutations, and subsequently develop hypertension and ESRD at a younger age; the onset of ESRD in persons with the PKD1 genotype occurs at a mean age of 53 years, while the onset of ESRD in persons with the PKD2 genotype occurs at a mean age of 69 years.
In addition, studies have suggested that the type of PDK1 mutation also affects prognosis. In one series, patients with non-truncating mutations (about 20%) developed ESRD 12 years later than those with truncating mutations, at 67.9 versus 55.6 years of age, respectively.
Hepatic cysts are the most common extrarenal manifestation of ADPKD. These increase in number with age (20% in the third decade of life, 75% after the sixth decade of life) and may cause chronic pain. However, even with extensive cystic involvement, liver function is not compromised.
In a study of 558 patients with ADPKD, hepatomegaly was common even in early-stage disease and was not accounted for by cysts alone. Compared with the liver volumes of patients without ADPKD, parenchymal volumes were larger, even in patients who did not have cysts. Polycystic liver disease severity was associated with altered biochemical and hematologic laboratory tests and a lower quality of life.
Other clinical associations in ADPKD include the following:
Cardiac valve disease (particularly mitral valve prolapse [25%])
Cerebral aneurysms (5-10%)
Seminal vesicle cysts 
Autosomal recessive polycystic kidney disease
ARPKD affects renal and hepatic development (dysgenesis of the portal triad). However, the degree of organ involvement varies in relation to the age of onset.
In the neonatal period, pulmonary disease, resulting from nephromegaly and oligohydramnios, dominates the presentation. Typically, the neonate has profound respiratory compromise, often exacerbated by pneumothorax or pulmonary hypoplasia. This presentation may result in neonatal death.
Symptoms in infancy include hypertension (80%), diminished urine-concentrating ability, renal insufficiency, and subsequent electrolyte abnormalities. Most affected children develop hypertension within the first few years of life. Growth retardation has been reported in one fourth of children. Up to 26.5% develop significant hyponatremia. Fifty percent of affected individuals develop ESRD in the first decade of life, requiring dialysis or transplantation.
In older children (4-8 y), the kidneys often are less severely affected, while hepatic disease may predominate. Hepatic involvement usually presents with symptoms secondary to portal hypertension, particularly varices and splenomegaly. Twenty-three percent of children with ARPKD experience variceal bleeding by a mean age of 12.5 years. Hepatic disease may also result in acute bacterial cholangitis or thrombocytopenia secondary to hypersplenism.
Glomerulocystic kidney disease
GCKD occurs in early (neonatal) and late (adult) forms. Neonates present with hypertension, abdominal masses, and variable degrees of renal failure. Adults typically present with flank pain, hematuria, and hypertension. Hepatic cysts may also develop.
JNPHP has several different phenotypic expressions, depending on the gene involved. Infantile (NPHP2), juvenile (NPHP1, NPHP4) and adolescent (NPHP3) forms of the disease exist, but most symptoms appear during the first decade of life. These include growth retardation, urine concentrating defects (polyuria and polydipsia), skeletal dysplasia, anemia, and progressive renal failure. Additionally, some degree of hepatic fibrosis and biliary duct enlargement is usually present. Cysts usually occur secondary to ESRD and in the corticomedullary junction.
Medullary cystic kidney disease
This disorder is clinically milder than JNPHP, occurs later in life (third to fourth decades), and has limited extrarenal manifestations. Individuals with this disease due to mutations in the MCKD2 gene present with uremia sooner than those with disease due to MCKD1 mutations and are more likely to develop hyperuricemia and gout.
Systemic disease with associated renal cysts
Clinical features of tuberous sclerosis (TS) include facial nevi, cardiac rhabdomyomas, epilepsy, angiofibromas, and mental retardation. Approximately one half of patients have multiple renal angiomyolipomas. Twenty to 25% of patients have renal cysts, although diffuse renal cystic disease, which may result in chronic renal failure, is rare.
Clinical features of von Hippel-Lindau syndrome (VHLS) include retinal and cerebellar hemangioblastomas, pheochromocytomas, and cystic disease of the kidneys, pancreas, and epididymis. Renal cysts are very common, occurring in two thirds of patients. Renal cell carcinoma (RCC) develops in as many as 40% of patients.
Acquired cystic renal disease
Acquired renal cystic disease (ARCD) may be found in patients with all etiologies of ESRD, particularly in those who are dialysis dependent. The incidence, number, and size of cysts all increase in proportion to the duration of dialysis. Most patients are asymptomatic, but symptoms may include gross hematuria, flank pain, renal colic, or a palpable renal mass. Hemorrhagic cysts occur in 50% of patients.
Medullary sponge kidney (MSK) is usually detected on radiographic evaluation of adults with nephrolithiasis. Fifteen to 20% of patients with calcium oxalate and calcium phosphate renal calculi have MSK. Patients may also have a history of hematuria or urinary tract infection (UTI). Most patients with MSK, however, are asymptomatic. Approximately 10% of patients develop recurrent nephrolithiasis, bacteriuria, and pyelonephritis. Involvement is usually bilateral.
Simple cysts usually are clinically silent. Occasionally, however, they hemorrhage and cause acute pain.
In developmental cystic renal disease, MCDK may be palpable as a flank mass in an otherwise healthy infant. MCDK is the most common cause of a renal mass and the second most common cause of a palpable abdominal mass in neonates.[23, 3]
Inherited cystic renal disease produces the following findings:
ARPKD: Bilateral flank masses are palpable in 30% of neonates and infants with this disease; older children may demonstrate signs of portal hypertension
ADPKD: The enlarged kidneys and liver may be palpable
In acquired cystic renal disease, simple cysts rarely become large enough to be palpable.
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