Signs and symptoms include high blood pressure, headaches, abdominal pain, blood in the urine, and excessive urination. Other symptoms include pain in the back, and cyst formation (renal and other organs).

Polycystic kidney disease (PKD or PCKD, also known as polycystic kidney syndrome) is a genetic disorder in which the renal tubules become structurally abnormal, resulting in the development and growth of multiple cysts within the kidney. These cysts may begin to develop before birth or in infancy, in childhood, or in adulthood. Cysts are non-functioning tubules filled with fluid pumped into them, which range in size from microscopic to enormous, crushing adjacent normal tubules and eventually rendering them non-functional also.

PKD is caused by abnormal genes which produce a specific abnormal protein which has an adverse affect on tubule development. PKD is a general term for two types, each having their own pathology and genetic cause: autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD). The abnormal gene exists in all cells in the body: as a result, cysts may occur in the liver, seminal vesicles, and pancreas. This genetic defect can also cause aortic root aneurysms, and aneurysms in the circle of Willis cerebral arteries, which if they rupture, can cause a subarachnoid hemorrhage.

Diagnosis may be suspected from one, some, or all of the following: new onset flank pain or red urine; a positive family history; palpation of enlarged kidneys on physical exam; an incidental finding on abdominal sonogram; or an incidental finding of abnormal kidney function on routine lab work (BUN, serum creatinine, or eGFR). Definitive diagnosis is made by abdominal CT exam.

Complications include hypertension due to the activation of the renin–angiotensin–aldosterone system (RAAS), frequent cyst infections, urinary bleeding, and declining renal function. Hypertension is treated with angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs). Infections are treated with antibiotics. Declining renal function is treated with renal replacement therapy (RRT): dialysis and/or transplantation. Management from the time of the suspected or definitive diagnosis is by a board-certified nephrologist.

In terms of the signs/symptoms of medullary cystic kidney disease, the disease is not easy to diagnose and is uncommon. In this condition, loss of kidney function occurs slowly over time, however the following signs/symptoms could be observed in an affected individual:

Some individuals with this disease develop gout, which is a condition in which patients develop severe pain and swelling in the big toe or another joint such as the knee. If untreated, it becomes chronic and affects the joints most of the time, instead of intermittently.

Symptoms and signs include abdominal discomfort, polyuria, polydipsia, incidental discovery of hypertension, abdominal mass. The classic presentation for ARPKD is systemic hypertension with progression to end-stage renal disease (ESRD) by the age of 15. In a typical presentation, a small number of ARPKD sufferers live to adulthood with some kidney function; but with significant deterioration in liver function. This outcome is postulated to result from expression of the polycystic kidney and hepatic disease gene PKHD1, which is located on chromosome 6p. In severe cases, a fetus will present with oligohydramnios and as a result, may present with Potter sequence.

Cystic kidney disease refers to a wide range of hereditary, developmental, and acquired conditions. With the inclusion of neoplasms with cystic changes, over 40 classifications and subtypes have been identified. Depending on the disease classification, the presentation of disease may be from birth, or much later into adult life. Cystic disease may involve one or both kidneys and may or may not occur in the presence of other anomalies. A higher incidence of cystic kidney disease is found in the male population and prevalence increases with age. Renal cysts have been reported in more than 50% of patients over the age of 50. Typically, cysts grow up to 2.88 mm annually and cause related pain and/or hemorrhage.

Of the cystic kidney diseases, the most common is Polycystic kidney disease; having two prevalent sub-types: autosomal recessive and autosomal dominant polycystic kidney disease. Autosomal Recessive Polycystic Kidney Disease (ARPKD) is primarily diagnosed in infants and young children. Autosomal dominant polycystic kidney disease (ADPKD) is most often diagnosed in adulthood.

Another example of cystic kidney disease is Medullary sponge kidney.

Most cases are asymptomatic or are discovered during an investigation of blood in the urine. Symptomatic patients typically present as middle-aged adults with renal colic, kidney stones, nephrocalcinosis and/or recurrent urinary tract infections; however, MSK also may affect children very rarely. In addition to the typical clinical phenotype of recurrent stone disease, other clinical profiles have now been recognized, that is, an indolent, almost asymptomatic MSK, and a rare form characterized by intractable pain.

Medullary sponge kidney (also known as Cacchi–Ricci disease) is a congenital disorder of the kidneys characterized by cystic dilatation of the collecting tubules in one or both kidneys. Individuals with medullary sponge kidney are at increased risk for kidney stones and urinary tract infection (UTI). Patients with MSK typically pass twice as many stones per year as do other stone formers without MSK. While described as a "benign" disorder with a low morbidity rate, as many as 10% of patients with MSK have an increased risk of morbidity associated with frequent stones and UTIs. While some patients report increased chronic kidney pain, the source of the pain, when a UTI or blockage is not present, is unclear at this time. Renal colic (flank and back pain) is present in 55% of patients. Women with MSK experience more stones, UTIs, and complications than men. MSK was previously believed not to be hereditary but there is more evidence coming forth that may indicate otherwise.

Medullary cystic kidney disease (MCKD) is an autosomal dominant kidney disorder characterized by tubulointerstitial sclerosis leading to end-stage renal disease. Because the presence of cysts is neither an early nor a typical diagnostic feature of the disease, and because at least 4 different gene mutations may give rise to the condition, the name autosomal dominant tubulointerstitial kidney disease (ADTKD) has been proposed, to be appended with the underlying genetic variant for a particular individual. Importantly, if cysts are found in the medullary collecting ducts they can result in a shrunken kidney, unlike that of polycystic kidney disease. There are two known forms of medullary cystic kidney disease, mucin-1 kidney disease 1 (MKD1) and mucin-2 kidney disease/uromodulin kidney disease (MKD2). A third form of the disease occurs due to mutations in the gene encoding renin (ADTKD-REN), and has formerly been known as familial juvenile hyperuricemic nephropathy type 2.

Glomerulocystic kidney disease (GCKD) is a cystic disorder of the kidneys. GCKD involves cystic dilation of Bowman's capsule. It can occur with or without congenital abnormality.

Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent, potentially lethal, monogenic human disorder. It is associated with large interfamilial and intrafamilial variability, which can be explained to a large extent by its genetic heterogeneity and modifier genes. It is also the most common of the inherited cystic kidney diseases — a group of disorders with related but distinct pathogenesis, characterized by the development of renal cysts and various extrarenal manifestations, which in case of ADPKD include cysts in other organs, such as the liver, seminal vesicles, pancreas, and arachnoid membrane, as well as other abnormalities, such as intracranial aneurysms and dolichoectasias, aortic root dilatation and aneurysms, mitral valve prolapse, and abdominal wall hernias. Over 50% of patients with ADPKD eventually develop end stage kidney disease and require dialysis or kidney transplantation. ADPKD is estimated to affect at least 1 in every 1000 individuals worldwide, making this disease the most common inherited kidney disorder with a diagnosed prevalence of 1:2000 and incidence of 1:3000-1:8000 in a global scale.

Many forms of cystic kidney disease can be detected in children prior to birth. Abnormalities which only affect one kidney are unlikely to cause a problem with the healthy arrival of a baby. Abnormalities which affect both kidneys can have an effect on the baby's amniotic fluid volume which can in turn lead to problems with lung development. Some forms of obstruction can be very hard to differentiate from cystic renal disease on early scans.

The hallmark of a stone that obstructs the ureter or renal pelvis is excruciating, intermittent pain that radiates from the flank to the groin or to the inner thigh. This pain, known as renal colic, is often described as one of the strongest pain sensations known. Renal colic caused by kidney stones is commonly accompanied by urinary urgency, restlessness, hematuria, sweating, nausea, and vomiting. It typically comes in waves lasting 20 to 60 minutes caused by peristaltic contractions of the ureter as it attempts to expel the stone.

The embryological link between the urinary tract, the genital system, and the gastrointestinal tract is the basis of the radiation of pain to the gonads, as well as the nausea and vomiting that are also common in urolithiasis. Postrenal azotemia and hydronephrosis can be observed following the obstruction of urine flow through one or both ureters.

Pain in the lower left quadrant can sometimes be confused with diverticulitis because the sigmoid colon overlaps the ureter and the exact location of the pain may be difficult to isolate due to the close proximity of these two structures.

Typically, the signs and symptoms of juvenile nephronophthisis are limited to the kidneys. They include polyuria, polydipsia, weakness, and fatigue.

Anemia, growth retardation, no hypertension.

Proteinuria and hematuria are usually absent. Polyuria is resistant to vasopressin.

When other organ systems are affected, symptoms can include situs inversus, heart abnormalities, and liver fibrosis. Juvenile nephronophthisis can also be associated with other rare disorders, including Senior–Løken syndrome and Joubert syndrome.

Though this condition is usually asymptomatic, if symptoms are present they are usually related to the causative process, (e.g. hypercalcemia). Some of the sympotoms that can happen are blood in the urine, fever and chills, nausea and vomiting, severe pain in the belly area, flanks of the back, groin, or testicles.

These include renal colic, polyuria and polydipsia:

- Renal colic is usually caused by pre-existing nephrolithiasis, as may occur in patients with chronic hypercalciuria. Less commonly, it can result from calcified bodies moving into the calyceal system.

- Nocturia, polyuria, and polydipsia from reduced urinary concentrating capacity (i.e. nephrogenic diabetes insipidus) as can be seen in hypercalcemia, medullary nephrocalcinosis of any cause, or in children with Bartter syndrome in whom essential tubular salt reabsorption is compromised.

There are several causes of nephrocalcinosis that are typically acute and present only with renal failure. These include tumor lysis syndrome, acute phosphate nephropathy, and occasional cases of enteric hyperoxaluria.

Urolithiasis refers to stones originating anywhere in the urinary system, including the kidneys and bladder. Nephrolithiasis refers to the presence of such stones in the kidneys. Calyceal calculi are aggregations in either the minor or major calyx, parts of the kidney that pass urine into the ureter (the tube connecting the kidneys to the urinary bladder). The condition is called ureterolithiasis when a calculus is located in the ureter. Stones may also form or pass into the bladder, a condition referred to as bladder stones.

Dent's disease often produces the following signs and symptoms:

- Extreme thirst combined with dehydration, which leads to frequent urination

- Nephrolithiasis (kidney stones)

- Hypercalciuria (high urine calcium - >300 mg/d or >4 mg/kg per d) with normal levels blood/serum calcium)

- Aminoaciduria (amino acids in urine)

- Phosphaturia (phosphate in urine)

- Glycosuria (glucose in urine)

- Kaliuresis (potassium in urine)

- Hyperuricosuria (excessive amounts of uric acid in the urine)

- Impaired urinary acidification

- Rickets

In a study of 25 patients with Dent's disease, 9 of 15 men, and one of 10 women suffered end-stage kidney disease by the age of 47.

Renal cysts and diabetes syndrome (RCAD), also known as MODY 5, is a form of maturity onset diabetes of the young.

HNF1β-related MODY is one of the less common forms of MODY, with some distinctive clinical features, including atrophy of the pancreas and several forms of renal disease. HNF1β, also known as transcription factor 2 (TCF2), is involved in early stages of embryonic development of several organs, including the pancreas, where it contributes to differentiation of pancreatic endocrine Ngn3 cell progenitors from non-endocrine embryonic duct cells. The gene is on chromosome 17q.

The degree of insulin deficiency is variable. Diabetes can develop from infancy through middle adult life, and some family members who carry the gene remain free of diabetes into later adult life. Most of those who develop diabetes show atrophy of the entire pancreas, with mild or subclincal deficiency of exocrine as well as endocrine function.

The non-pancreatic manifestations are even more variable. Kidney and genitourinary malformation and diseases may occur, but inconsistently even within a family, and the specific conditions include a range of apparently unrelated anomalies and processes. The most common genitourinary condition is cystic kidney disease, but there are many varieties even of this. Renal effects begin with structural alterations (small kidneys, renal cysts, anomalies of the renal pelvis and calices), but a significant number develop slowly progressive renal failure associated with chronic cystic disease of the kidneys. In some cases, renal cysts may be detected in utero. Kidney disease may develop before or after hyperglycemia, and a significant number of people with MODY5 are discovered in renal clinics.

With or without kidney disease, some people with forms of HNF1β have had various minor or major anomalies of the reproductive system. Male defects have included epididymal cysts, agenesis of the vas deferens, or infertility due to abnormal spermatozoa. Affected women have been found to have vaginal agenesis, hypoplastic, or bicornuate uterus.

Liver enzyme elevations are common, but clinically significant liver disease is not. Hyperuricaemia and early onset gout have occurred.

Usually, the diagnosis of ADPKD is initially performed by renal imaging using ultrasound, CT scan, or MRI. However, molecular diagnostics can be necessary in the following situations: 1- when a definite diagnosis is required in young individuals, such as a potential living related donor in an affected family with equivocal imaging data; 2- in patients with a negative family history of ADPKD, because of potential phenotypic overlap with several other kidney cystic diseases; 3- in families affected by early-onset polycystic kidney disease, since in this cases hypomorphic alleles and/or oligogenic inheritance can be involved; and 4- in patients requesting genetic counseling, especially in couples wishing a pre-implantation genetic diagnosis.

The findings of large echogenic kidneys without distinct macroscopic cysts in an infant/child at 50% risk for ADPKD are diagnostic. In the absence of a family history of ADPKD, the presence of bilateral renal enlargement and cysts, with or without the presence of hepatic cysts, and the absence of other manifestations suggestive of a different renal cystic disease provide presumptive, but not definite, evidence for the diagnosis. In some cases, intracranial aneurysms can be an associated sign of ADPKD, and screening can be recommended for patients with a family history of intracranial aneurysm.

Molecular genetic testing by linkage analysis or direct mutation screening is clinically available; however, genetic heterogeneity is a significant complication to molecular genetic testing. Sometimes a relatively large number of affected family members need to be tested in order to establish which one of the two possible genes is responsible within each family. The large size and complexity of PKD1 and PKD2 genes, as well as marked allelic heterogeneity, present obstacles to molecular testing by direct DNA analysis. The sensitivity of testing is nearly 100% for all patients with ADPKD who are age 30 years or older and for younger patients with PKD1 mutations; these criteria are only 67% sensitive for patients with PKD2 mutations who are younger than age 30 years.

Autosomal recessive polycystic kidney disease (ARPKD) is the recessive form of polycystic kidney disease. It is associated with a group of congenital fibrocystic syndromes. Mutations in the "PKHD1" (chromosomal locus 6p12.2) cause ARPKD.

Nephrocalcinosis Is connected with conditions that cause hypercalcemia, hyperphosphatemia, and the increased excretion of calcium, phosphate, and/or oxalate in the urine. A high urine pH can lead to Nephrocalcinosis. In conjustion with Nephrocalcinosis, hypercalcemia and hypercalciuria the following can occur:

- Primary hyperparathyroidism: Nephrocalcinosis is one of the most common symptoms of primary hyperparathyroidism.

- Sarcoidosis: Nephrocalcinosis is one of the most common symptoms.

- Vitamin D therapy: This can cause nephrocalcinosis because of Vitamin D therapy becauseit increase the absorption of ingested calcium and bone resorption, resulting in hypercalcemia and hypercalciuria.

Infantile, juvenile, and adolescent forms of nephronophthisis have been identified. Although the range of characterizations is broad, people affected by nephronophthisis typically present with polyuria (production of a large volume of urine), polydipsia (excessive liquid intake), and after several months to years, end-stage kidney disease, a condition necessitating either dialysis or a kidney transplant in order to survive. Some individuals that suffer from nephronophthisis also have so-called "extra-renal symptoms" which can include tapetoretinal degeneration, liver problems, ocularmotor apraxia, and cone-shaped epiphysis (Saldino-Mainzer syndrome).

Juvenile nephronophthisis causes fibrosis and scarring of the kidneys, which accounts for the symptoms observed. The kidneys also often have corticomedullary cysts.

- Inability to conserve sodium because of defect of tubules leading to polyuria and polydipsia.

- Anemia is attributed to a deficiency of erythropoietin production by failing kidneys.

- Growth retardation, malaise and pallor are secondary to anemia.

- No hypertension as nephronophthisis is a salt-losing enteropathy.

When a diagnosis of multicystic kidney is made in utero by ultrasound, the disease is found to be bilateral in many cases. Those with bilateral disease often have other severe deformities or polysystemic malformation syndromes. In bilateral cases, the newborn has the classic characteristic of Potter's syndrome.

The bilateral condition is incompatible with survival, as the contralateral system frequently is abnormal as well. Contralateral ureteropelvic junction obstruction is found in 3% to 12% of infants with multicystic kidney and contralateral vesicoureteral reflux is seen even more often, in 18% to 43% of infants. Because the high incidence of reflux, voiding cystourethrography usually has been considered advisable in all newborns with a multicystic kidney.

Acute tubular necrosis is classified as a "renal" (i.e. not pre-renal or post-renal) cause of acute kidney injury. Diagnosis is made by a FENa (fractional excretion of sodium) > 3% and presence of muddy casts (a type of granular cast) in urinalysis. On histopathology, there is usually "tubulorrhexis", that is, localized necrosis of the epithelial lining in renal tubules, with focal rupture or loss of basement membrane. Proximal tubule cells can shed with variable viability and not be purely "necrotic".

Renal medullary fibroma, also renomedullary interstitial cell tumour and medullary fibroma, is a benign kidney tumour. It is commonly an incidental finding.