INTRODUCTION — Autosomal dominant polycystic kidney disease (ADPKD) often leads to progressive kidney failure due in part to continued enlargement of the cysts. Kidney size typically increases to more than five times normal for years prior to the loss of kidney function, and measured total kidney volume is the strongest predictor for the development of kidney function impairment . Other kidney manifestations that can occur include hypertension, urinary tract infection, concentrating defect, hematuria, nephrolithiasis, and acute or chronic flank and abdominal pain; protein excretion is generally not a prominent feature but when present is associated with increased risk [2,3]. All complications relate directly to the extent of kidney cyst involvement, which can be assessed by total kidney volume measurements.
HEMATURIA — Hematuria, which is often grossly visible, occurs at some time in the course in approximately 35 to 50 percent of patients with ADPKD, usually occurs prior to loss of kidney function, and may be the presenting symptom of the disease [2,4]. A precipitating event, such as a urinary tract infection or strenuous activity, can often be identified, and recurrent episodes are not uncommon . Early onset gross hematuria is associated with more rapid progression of kidney disease in ADPKD .
Rupture of a cyst into the collecting system is thought to be responsible for the development of hematuria. Although hemorrhage into a cyst is also common, the typical presentation is pain, rather than hematuria, since many cysts do not communicate with the collecting system . The hematuria due to cyst rupture generally resolves within two to seven days with conservative therapy. Conservative therapy consists of bedrest, hydration, and analgesics that exclude nonsteroidals. In some cases, antihypertensive medications may be held . Occasionally, bleeding can persist for several weeks. With unusual and severe bleeding, percutaneous arterial embolization or even nephrectomy may become necessary .
Gross hematuria is more likely among individuals with larger kidneys (particularly when >15 cm in length), hypertension, and higher plasma creatinine concentrations [4,6]. Frequent episodes of gross hematuria before 30 years of age may be associated with worse kidney outcomes; this may possibly reflect accelerated cyst expansion .
Nephrolithiasis is another cause of hematuria in ADPKD patients. The hematuria associated with nephrolithiasis is usually microscopic. The hematuria should resolve with passage or removal of the stone. Prolonged or recurrent hematuria, particularly in a man over 50 years of age, raises the possibility of an underlying renal cell carcinoma (RCC)  or of an unrelated problem, such as bladder cancer, prostate cancer, or immunoglobulin A (IgA) nephropathy . (See 'Renal cancer' below.)
CONCENTRATING DEFECT — Almost every patient with ADPKD has a mild concentrating defect. Patients with ADPKD most often complain of increased thirst, polyuria, nocturia, and urinary frequency. A decrease in urinary concentrating ability is one of the earliest manifestations of ADPKD. It is initially mild and worsens with increasing age and declining kidney function. The renal concentrating defect is closely related to the severity of anatomical deformities induced by the cysts independent of age and glomerular filtration rate (GFR). In a series of 53 children with a mean age of 12 years, nearly 60 percent had an abnormal response to desmopressin . In one series of 177 adult patients with normal kidney function, all patients had a modest impairment in concentrating ability in response to overnight water deprivation, which worsened with age in parallel to the decline in concentrating ability of unaffected family members .
The concentrating defect may not be clinically evident, unless a history of polydipsia or polyuria is elicited . The underlying cause is not known, but disruption of tubular architecture, defect in principal cell function, and early tubulointerstitial disease are postulated factors. A central cause has been excluded since vasopressin levels are elevated in this disorder . The increase in arginine vasopressin (AVP) concentrations may be a compensatory response that occurs early in the course of the disease in order to preserve water balance. This was suggested by a carefully performed water deprivation study of 30 individuals with and without ADPKD . All subjects had an estimated GFR (eGFR) ≥60 mL/min/1.73 m2. Baseline urine osmolality was similar in ADPKD patients and age- and sex-matched healthy controls (710 versus 742 mosmol/kg), but, after at least 14 hours of water deprivation, the maximal urine osmolality was lower among ADPKD patients versus controls (758 versus 915 mosmol/kg). While the urinary concentrating capacity was at a plateau (implying maximal concentrating capacity), ADPKD patients had a higher mean plasma osmolality and higher mean plasma levels of AVP and an AVP precursor, copeptin.
Urine diluting capacity appears to be intact in ADPKD . Increased vasopressin concentration may play a role in disease progression, and strategies to inhibit vasopressin action with vasopressin v2 receptor antagonists or to reduce vasopressin levels with increased free water intake are potential therapeutic modalities in ADPKD. (See "Autosomal dominant polycystic kidney disease (ADPKD): Treatment", section on 'Increased fluid intake'.)
PROTEINURIA — Proteinuria is not considered a major feature of ADPKD. In one study of 270 patients, for example, mean urinary protein excretion was 260 mg/day . Only 48 (18 percent) excreted more than 300 mg of protein per day. Patients with more advanced kidney dysfunction have more proteinuria (mean of approximately 900 mg/day) [14,15]. Overall, secondary focal segmental glomerulosclerosis plays a relatively minor role in most patients in the progression of this disorder to kidney failure . (See "Autosomal dominant polycystic kidney disease (ADPKD): Treatment" and "Autosomal dominant polycystic kidney disease (ADPKD): Evaluation and management of hypertension".)
The nephrotic syndrome has rarely been reported and usually reflects a superimposed glomerular disease. One review found that focal segmental glomerulosclerosis was most common, but minimal change disease, membranous nephropathy, immunoglobulin A (IgA) nephropathy, and membranoproliferative glomerulonephritis also occurred . This report did not present sufficient information to distinguish primary from secondary glomerulosclerosis; as noted above, however, the latter seems to be extremely unusual in ADPKD.
NEPHROLITHIASIS — Kidney stones occur in up to 25 percent of patients with ADPKD [18,19]. In contrast to the predominance of calcium oxalate in idiopathic stone formers, more than one-half of stones in ADPKD are composed of uric acid, with most of the remainder being composed of calcium oxalate .
Increased kidney volume may be a risk factor for nephrolithiasis in patients with ADPKD. In one study, kidney volume determined by unenhanced computed tomography (CT) was greater in 35 patients with ADPKD and nephrolithiasis compared with those who had ADPKD but no nephrolithiasis (508 versus 220 mL) . However, in the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease (CRISP) study of 241 individuals, no association between nephrolithiasis and kidney volume could be established . Other abnormalities that predispose to stone disease include low urinary volume, low urinary citrate, and, less often, hyperuricosuria and hypercalciuria [16,21]. The factors responsible for the hypocitraturia are not well understood. (See "Kidney stones in adults: Epidemiology and risk factors".)
The possible presence of a kidney stone should be suspected in any ADPKD patient with acute flank pain (see 'Flank and abdominal pain' below). However, establishing the diagnosis by ultrasonography is more difficult than in idiopathic stone formers because of the large cysts obscuring the view of the collecting system and of calcifications that may be present in the cyst walls. Most stones can be detected by intravenous pyelography, but CT scanning is more sensitive for the detection of small or radiolucent stones . In the study cited above, among 125 patients with ADPKD, unenhanced CT detected calculi in 32 of 35 patients who had nephrolithiasis, including 20 patients in whom ultrasound failed to detect calculi .
The treatment of obstructing stones is more difficult than in patients with idiopathic stone disease . Dilation of the collecting system is often absent due to the presence of peripelvic cysts. Cystoscopy may be complicated by an infected cyst, while the large cysts may make percutaneous nephrostomy or extracorporeal shock wave lithotripsy (ESWL) harder to perform. Thus, ESWL is not typically the first approach for stone removal in ADPKD. (See "Kidney stones in adults: Diagnosis and acute management of suspected nephrolithiasis" and "Kidney stones in adults: Surgical management of kidney and ureteral stones".)
Despite these concerns, ESWL has been used successfully in patients with small stones (<2 cm in diameter) in the renal pelvis or calyces . The frequency of residual fragments is higher in ADPKD than in other stone formers, a probable reflection of attempts to minimize the number of shock waves in these patients . Percutaneous nephrolithotomy has also been used in a limited number of patients [22,23].
FLANK AND ABDOMINAL PAIN — Flank and abdominal pain is a common problem in polycystic kidney disease and can be due to renal or extrarenal etiologies. Acute pain related to the kidney may be caused by infections (cystic or parenchymal), nephrolithiasis, or cyst hemorrhage. Pain may also be caused by cysts in the liver. Chronic kidney pain is more common in advanced disease in patients who have enlarged kidneys. It is often dull and persistent and is thought to reflect either stretching of the capsule or traction on the renal pedicle . (See "Autosomal dominant polycystic kidney disease (ADPKD): Pain syndromes".)
RENOMEGALY — Kidney cysts and therefore total kidney volume increase progressively over time even though cyst formation occurs in less than 5 to 10 percent of nephrons . Patients over 50 years of age may have enormous kidneys that can reach 40 cm in length (three to four times normal length) and 8 kg in weight, usually associated with significant kidney dysfunction and symptoms . The mass effect of enlarged polycystic kidneys can cause discomfort, limitation of daily physical activities, and early satiety or anorexia, sometimes leading to malnutrition.
RENAL CANCER — Renal cell carcinoma (RCC) is an infrequent complication of ADPKD [25-27]. Although it does not appear to occur with increased frequency when compared with the general population, studies are conflicting. A report from the Danish national registry of 823 ADPKD patients with end-stage kidney disease (ESKD; on dialysis or kidney transplantation) showed a surprisingly low number of RCC (only six cases or <1 percent) after 15 years of follow-up and did not show any increased risk of nonskin malignancies (including RCC) in ADPKD patients compared with other patients with ESKD . Another registry study of posttransplant ADPKD patients did not show an increase in RCC . However, a nationwide cohort study from Taiwan that compared 8692 individuals with and without ADPKD showed an increase risk of kidney cancer (adjusted subhazard ratio 2.45, 95% CI 1.29-4.65) . Further prospective studies are needed to establish the risk of RCC in ADPKD, particularly in the setting of transplantation.
There are a number of differentiating characteristics of RCC in ADPKD :
●Patients frequently present with fever (32 versus 7 percent in patients without ADPKD who develop RCC).
●The tumors are more often bilateral at presentation (12 versus 1 to 5 percent), multicentric (28 versus 6 percent), and sarcomatoid in type (33 versus 1 to 5 percent). These observations suggest the presence of multiple foci of cellular proliferation, although the absence of increased prevalence suggests a possible alteration in the biologic behavior of this tumor when it develops in ADPKD .
The diagnosis of RCC is difficult to establish in ADPKD . Findings such as hematuria; a flank mass; or, due in part to bleeding into cysts, a complex cyst (or cysts) on ultrasonography, computed tomography (CT) scanning, or magnetic resonance imaging (MRI) are common in ADPKD in the absence of malignancy. Some clinical clues may be helpful. As an example, the possible presence of an underlying malignancy should be suspected if the patient complains of systemic signs and symptoms (fever, anorexia, fatigue, weight loss) that are out of proportion to the severity of the kidney disease and unassociated with demonstrable kidney infection or if there is rapid growth of a complex cyst. Percutaneous aspiration and cytologic examination can be performed on suspicious cysts. In addition, CT scanning, using thin slices in areas of interest, and MRI, without and with gadolinium enhancement, are often able to distinguish malignancy from a complex cyst . If present, evidence of metastatic disease to the local lymph nodes or inferior vena cava is also important diagnostically.
The approach to screening transplant candidates for RCC in ADPKD patients has not been systematically developed. Some recommend ultrasound screening (followed by CT or MRI if suspicious masses or complex cysts are present), followed by annual or biannual posttransplant ultrasounds in all kidney transplant patients to monitor for the presence or occurrence of kidney cancers . Since MRI became widely available in the 1990s, many transplant centers performed screening MRIs with and without gadolinium injection. This approach was justified as it allowed visualization of the recipients’ abdominal vasculature (with respect to arterial calcifications) and because of the superiority of MRI to detect kidney cancers.
Contrast-enhanced MRI was previously restricted to patients with eGFR >30 mL/min/1.73 m2 due to concern about gadolinium-induced nephrogenic systemic fibrosis. However, with the use of next-generation gadolinium-based contrast agents (table 1), which prevent the release of gadolinium from chelating agents, nephrogenic systemic fibrosis is extremely uncommon . (See "Patient evaluation before gadolinium contrast administration for magnetic resonance imaging", section on 'Approach to preventing nephrogenic systemic fibrosis' and "Nephrogenic systemic fibrosis/nephrogenic fibrosing dermopathy in advanced kidney disease", section on 'Prevention'.)
ANEMIA — Interstitial cells adjacent to the walls of proximal-type cysts (those that have a sodium concentration similar to that in the plasma (see "Autosomal dominant polycystic kidney disease (ADPKD): Treatment")) also can produce erythropoietin . This response, which may again be mediated by focal areas of ischemia, probably accounts, in part, for several observations that have been made in polycystic kidney disease:
●In patients with advanced kidney function impairment, plasma erythropoietin levels in polycystic kidney disease are roughly twice as high as those seen in other kidney diseases . Although previously reported to be associated with a modestly higher average hemoglobin concentration and hematocrit , ADPKD participants in the Modification of Diet in Renal Disease (MDRD) study did not have higher hemoglobin levels. Many of these patients were treated with angiotensin-converting enzyme (ACE) inhibitors, which can reduce erythrocytosis.
●Increased erythropoietin production also may occur early in the course as approximately 5 percent of nonazotemic men with ADPKD have a clearly elevated hemoglobin concentration (above 18 g/dL) .
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Chronic kidney disease in adults".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topic (see "Patient education: Polycystic kidney disease (The Basics)")
●Beyond the Basics topic (see "Patient education: Polycystic kidney disease (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
●Kidney manifestations of ADPKD – Autosomal dominant polycystic kidney disease (ADPKD) often leads to progressive kidney failure due in part to continued enlargement of the cysts. Other kidney manifestations include hypertension, urinary tract infection, concentrating defects, hematuria, nephrolithiasis, and acute or chronic flank and abdominal pain; protein excretion is generally not a prominent feature. All complications relate directly to the extent of kidney cyst involvement, which can be assessed by total kidney volume measurements. (See 'Introduction' above.)
●Hematuria – Hematuria occurs in 35 to 50 percent of patients and may be the presenting symptom of the disease. Hematuria due to cyst rupture generally resolves with bedrest and hydration, although, with unusual and severe bleeding, percutaneous arterial embolization or even nephrectomy may become necessary. Gross hematuria is more likely among individuals with larger kidneys, hypertension, and higher plasma creatinine concentrations and is associated with more rapid progression of kidney disease. (See 'Hematuria' above.)
●Urinary concentrating defect – Many patients have a mild concentrating defect, which may not be clinically evident unless a history of polydipsia or polyuria is elicited. The underlying cause is not known. A central cause has been excluded since vasopressin levels are elevated in this disorder. (See 'Concentrating defect' above.)
●Kidney stones – Kidney stones occur in up to 20 percent of patients. More than one-half of stones in ADPKD are composed of uric acid, with most of the remainder being composed of calcium oxalate. Increased kidney volume may be a risk factor for nephrolithiasis. Other abnormalities that predispose to stone disease include low urinary volume, low urinary citrate, and, less often, hyperuricosuria and hypercalciuria. (See 'Nephrolithiasis' above.)
●Pain – Flank and abdominal pain is common and may be caused by cystic or parenchymal infections, nephrolithiasis, or cyst hemorrhage. Chronic kidney pain is more common in advanced disease in patients who have enlarged kidneys and may reflect either stretching of the capsule or traction on the renal pedicle. Massive polycystic liver enlargement, although uncommon, may also cause pain. (See 'Flank and abdominal pain' above.)
●Renomegaly – The mass effect of enlarged polycystic kidneys can cause discomfort, limitation of daily physical activities, and early satiety or anorexia, sometimes leading to malnutrition. (See 'Renomegaly' above.)
●Renal cell carcinoma – Renal cell carcinoma (RCC) is an infrequent complication of ADPKD. The diagnosis of RCC is more difficult to establish in ADPKD than in the general population since findings such as hematuria, a flank mass, or complex cysts on ultrasonography, computed tomography (CT) scanning, or magnetic resonance imaging (MRI) are common in ADPKD in the absence of malignancy. Malignancy should be suspected if the patient complains of systemic signs and symptoms that are out of proportion to the severity of the kidney disease or if there is rapid growth of a complex cyst. (See 'Renal cancer' above.)
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