It has been estimated that VUR is present in more than 10% of the population. Younger children are more prone to VUR because of the relative shortness of the submucosal ureters. This susceptibility decreases with age as the length of the ureters increases as the children grow. In children under the age of 1 year with a urinary tract infection, 70% will have VUR. This number decreases to 15% by the age of 12. Although VUR is more common in males antenatally, in later life there is a definite female preponderance with 85% of cases being female.

Urethral strictures most commonly result from injury, urethral instrumentation, infection, non-infectious inflammatory conditions of the urethra, and after prior hypospadias surgery. Less common causes include congenital urethral strictures and those resulting from malignancy.

Urethral strictures after blunt trauma can generally be divided into two sub-types;

- Pelvic fracture-associated urethral disruption occurs in as many as 15% of severe pelvic fractures. These injuries are typically managed with suprapubic tube placement and delayed urethroplasty 3 months later. Early endoscopic realignment may be used in select cases instead of a suprapubic tube, but these patients should be monitored closely as vast majority of them will require urethroplasty.

- Blunt trauma to the perineum compresses the bulbar urethra against the pubic symphysis, causing a "crush" injury. These patients are typically treated with suprapubic tube and delayed urethroplasty.

Other specific causes of urethral stricture include:

- Instrumentation (e.g., after transurethral resection of prostate, transurethral resection of bladder tumor, or endoscopic kidney surgery)

- Infection (typically with Gonorrhea)

- Lichen sclerosus

- Surgery to address hypospadias can result in a delayed urethral stricture, even decades after the original surgery.

There are two types of prostatic stent: temporary and permanent.

Although a permanent prostatic stent is not a medical treatment, it falls under the classification of a surgical procedure. Placement of a permanent prostatic stent is carried out as an outpatient treatment under local, topical or spinal anesthesia and usually takes about 15–30 minutes.

A temporary prostatic stent can be inserted in a similar manner to a Foley catheter, requiring only topical anesthesia.

Posterior urethral valves; urethral or meatal stenosis. These causes are treated surgically when possible.

Urethral dilation and other endoscopic approaches such as direct vision internal urethrotomy (DVIU), laser urethrotomy, and self intermittent dilation are the most commonly used treatments for urethral stricture. However, these approaches are associated with low success rates and may worsen the stricture, making future attempts to surgically repair the urethra more difficult.

A Cochrane review found that performing intermittent self-dilatation may confer a reduced risk of recurrent urethral stricture after endoscopic treatment, but the evidence is weak.

A prostatic stent is a stent used to keep open the male urethra and allow the passing of urine in cases of prostatic obstruction and lower urinary tract symptoms (LUTS). Prostatic obstruction is a common condition with a variety of causes. Benign prostatic hyperplasia (BPH) is the most common cause, but obstruction may also occur acutely after treatment for BPH such as transurethral needle ablation of the prostate (TUNA), transurethral resection of the prostate (TURP), transurethral microwave thermotherapy (TUMT), prostate cancer or after radiation therapy.

Duplicated ureter is the most common renal abnormality, occurring in approximately 1% of the population.

Race: Duplicated ureter is more common in Caucasians than in African-Americans.

Sex: Duplicated ureter is more common in females. However, this may be due to the higher frequency of urinary tract infections in females, leading to a higher rate of diagnosis of duplicated ureter.

In one report, about 20% of individuals with mealtime syndrome had strictures upon sialography. For unknown reasons, strictures seem to be more common in females.

Gastroesophageal reflux disease (GERD) affects approximately 40% of adults. Strictures occur in 7 to 23% of patients with GERD who are untreated.

The female homolog to the male verumontanum from which the valves originate is the hymen.

Frisch & Simonsen (2016) carried out a very large scale study in Denmark, which compared the incidence of meatal stenosis in Muslim males (mostly circumcised) with the incidence of meatal stenosis in ethnic Danish males (mostly non-circumcised). The risk of meatal stenosis in circumcised males was found to be as much 3.7 times higher than in the intact, non-circumcised males.

Ectopic ureter (or ureteral ectopia) is a medical condition where the ureter, rather than terminating at the urinary bladder, terminates at a different site. In males this site is usually the urethra, in females this is usually the urethra or vagina. It can be associated with renal dysplasia, frequent urinary tract infections, and urinary incontinence (usually continuous drip incontinence). Ectopic ureters are found in 1 of every 2000–4000 patients, and can be difficult to diagnose, but are most often seen on CT scans.

Ectopic ureter is commonly a result of a duplicated renal collecting system, a duplex kidney with 2 ureters. In this case, usually one ureter drains correctly to the bladder, with the duplicated ureter presenting as ectopic.

Anal stricture or anal stenosis is a narrowing of the anal canal. It can be caused by a number of surgical procedures including: hemorrhoid removal and following anorectal wart treatment.

Strictures tend to be diagnosed based on difficulty with insertion and manipulation during sialendoscopy, or by sialography or ultrasound.

Duplicated ureter or Duplex Collecting System is a congenital condition in which the ureteric bud, the embryological origin of the ureter, splits (or arises twice), resulting in two ureters draining a single kidney. It is the most common renal abnormality, occurring in approximately 1% of the population. The additional ureter may result in a ureterocele, or an ectopic ureter.

Neonates with TEF or esophageal atresia are unable to feed properly. Once diagnosed, prompt surgery is required to allow the food intake. Some children do experience problems following TEF surgery; they can develop dysphagia and thoracic problems. Children with TEF can also be born with other abnormalities, most commonly those described in VACTERL association - a group of anomalies which often occur together, including heart, kidney and limb deformities. 6% of babies with TEF also have a laryngeal cleft.

The protection provided by the foreskin for the glans penis and meatus has been recognized since 1915. In the absence of the foreskin the meatus is exposed to mechanical and chemical irritation from ammoniacal diaper (nappie) that produces blister formation and ulceration of the urethral opening, which eventually gives rise to meatal stenosis (a narrowing of the opening). Meatal stenosis may also be caused by ischemia resulting from damage to the frenular artery during circumcision.

Extravasation of urine due to blunt renal trauma or ureteral obstruction can lead to the formation of an urinoma.

It can be caused by a lesion at any point in the urinary tract.

Causes include urolithiasis, posterior urethral valves and ureteral herniation.

In the Western world, about 15% of all people have gallstones in their gallbladder but the majority are unaware of this and have no symptoms. Over ten years, 15–26% will suffer one or more episodes of biliary colic (abdominal pain due to the passage of gallstones through the bile duct into the digestive tract), and 2–3% will develop complications of obstruction: acute pancreatitis, cholecystitis or acute cholangitis. Prevalence of gallstone disease increases with age and body mass index (a marker of obesity). However, the risk is also increased in those who lose weight rapidly (e.g. after weight loss surgery) due to alterations in the composition of the bile that makes it prone to form stones. Gallstones are slightly more common in women than in men, and pregnancy increases the risk further.

Although SRUS is not a medically serious disease, it can be the cause of significantly reduced quality of life for patients. It is difficult to treat, and treatment is aimed at minimizing symptoms.

Stopping straining during bowel movements, by use of correct posture, dietary fiber intake (possibly included bulk forming laxatives such as psyllium), stool softeners (e.g. polyethylene glycol, and biofeedback retraining to coordinate pelvic floor during defecation.

Surgery may be considered, but only if non surgical treatment has failed and the symptoms are severe enough to warrant the intervention. Improvement with surgery is about 55-60%.

Ulceration may persist even when symptoms resolve.

A group of conditions known as Mucosal prolapse syndrome (MPS) has now been recognized. It includes SRUS, rectal prolapse, proctitis cystica profunda, and inflammatory polyps. It is classified as a chronic benign inflammatory disorder. The unifying feature is varying degrees of rectal prolapse, whether internal intussusception (occult prolapse) or external prolapse.

If suspected antenatally, a consultation with a paediatric surgeon/ paediatric urologist maybe indicated to evaluate the risk and consider treatment options.

Treatment is by endoscopic valve ablation. Fetal surgery is a high risk procedure reserved for cases with severe oligohydramnios, to try to limit the associated lung underdevelopment, or pulmonary hypoplasia, that is seen at birth in these patients. The risks of fetal surgery are significant and include limb entrapment, abdominal injury, and fetal or maternal death. Specific procedures for "in utero" intervention include infusions of amniotic fluid, serial bladder aspiration, and creating a connection between the amniotic sac and the fetal bladder, or vesicoamniotic shunt.

There are three specific endoscopic treatments of posterior urethral valves:

- Vesicostomy followed by valve ablation - a stoma, or hole, is made in the urinary bladder, also known as "low diversion", after which the valve is ablated and the stoma is closed.

- Pyelostomy followed by valve ablation - stoma is made in the pelvis of the kidney as a slightly "high diversion", after which the valve is ablated and the stoma is closed

- Primary (transurethral) valve ablation - the valve is removed through the urethra without creation of a stoma

The standard treatment is primary (transurethral) ablation of the valves. Urinary diversion is used in selected cases, and its benefit is disputed.

Following surgery, the follow-up in patients with posterior urethral valve syndrome is long term, and often requires a multidisciplinary effort between paediatric surgeons/ paediatric urologists, pulmonologists, neonatologists, radiologists and the family of the patient. Care must be taken to promote proper bladder compliance and renal function, as well as to monitor and treat the significant lung underdevelopment that can accompany the disorder. Definitive treatment may also be indicated for the vesico-ureteral reflux.

Obstructive uropathy is a structural or functional hindrance of normal urine flow, sometimes leading to renal dysfunction (obstructive nephropathy).

It is a very broad term, and does not imply a location or cause.

Acute cholangitis carries a significant risk of death, the leading cause being irreversible shock with multiple organ failure (a possible complication of severe infections). Improvements in diagnosis and treatment have led to a reduction in mortality: before 1980, the mortality rate was greater than 50%, but after 1980 it was 10–30%. Patients with signs of multiple organ failure are likely to die unless they undergo early biliary drainage and treatment with systemic antibiotics. Other causes of death following severe cholangitis include heart failure and pneumonia.

Risk factors indicating an increased risk of death include older age, female gender, a history of liver cirrhosis, biliary narrowing due to cancer, acute renal failure and the presence of liver abscesses. Complications following severe cholangitis include renal failure, respiratory failure (inability of the respiratory system to oxygenate blood and/or eliminate carbon dioxide), cardiac arrhythmia, wound infection, pneumonia, gastrointestinal bleeding and myocardial ischemia (lack of blood flow to the heart, leading to heart attacks).