Hydroureteronephrosis  is a condition marked by dilation and distention of the kidneys’ urinary collecting system, i.e., the calices, renal pelvis, and infundibula. It is typically caused due to blockages to the free outflow of urine from the kidneys. It is a term used for the dilation and distention of the ureters. The literal meaning of the term ‘hydronephrosis’ is ‘water within the kidneys.’

Normally, urine is carried to the bladder from the kidneys by the ureters. Urine then gets stored in the bladder and eventually eliminated from the body. However, if there is any obstruction that affects the normal flow of urine, such as a constricted or blocked ureters, then the kidneys may become swollen. The backward pressure exerted by the blocked urine is what causes dilation or distention of the kidneys. CT scan of the urinary system can be used to determine the reason for the blockage.

Types

Hydroureteronephrosis may be classified into non-obstructive and obstructive types.

• Non-obstructive hydroureteronephrosis: In this, dilation of ureters and renal pelvis may be due to chronic distention instead of any kind of obstruction. For e.g., a distended system can occur due to reflux.
• Obstructive hydroureteronephrosis: Ureters blockage may occur in the below listed ways
  • Constriction of the wall:A ureteroscopy or other past surgeries, or impairment during open dissections can result in the formation of a structure. Tumor can cause stenosis. Fibrous construction may develop after schistosomiasis or renal tuberculosis. Classical obstruction can occur if the pelviureteric junction muscle fails to relax normally.
  • Mass inside the lumen: Trapping of a blood clot, ureteral stone, and worn necrotic papilla inside the ureter can result in obstruction.
  • Mass at ureter’s outer end: The bladder wall may develop prostate carcinoma or bladder carcinoma, thereby narrowing the opening of the ureter. Cervical carcinoma can cause similar problems in women. Chronic distention of the bladder can exert backward pressure, thereby causing hydroureteronephrosis.
  • Outside pressure exerted on the ureter: Retroperitoneal fibrosis or metastatic lymph nodes can exert pressure on the ureter from outside causing it to slowly narrow or compress.

Symptoms of hydroureteronephrosis

The occurrence of the signs and symptoms of hydroureteronephrosis is dependent on whether the obstruction occurs slowly or quickly.

• Acute hydroureteronephrosis occurs because of some sudden blockage and the associated symptoms are experienced by the patients in a few hours after the obstruction. A few symptoms include fever, vomiting, nausea, UTI/urinary tract infection, abdominal swelling, flank pain, painful urination, and frequently passing urine.
• Chronic hydroureteronephrosis is usually asymptomatic and it occurs over many weeks or even months. Some patients may elicit discomfort or dull achy pain on the affected kidney’s side.Others may suffer from low urine outflow and/or mild pain.

Hydroureteronephrosis symptoms during pregnancy: Enlargement of the uterus during pregnancy is what increases the risk of developing hydroureteronephrosis. The expanding uterus keeps taking up more space in the abdominal area and thus poses problems to the free flow of urine from the kidneys. This then results in sporadic and sharp pain next to the hips and ribs.

Hydroureteronephrosis symptoms in children and infants: Affected infants are usually born with hydroureteronephrosis. It is also possible for the condition to develop during childhood. It may form due to some blockage or defect of the one-way valve which regulates urine flow.

• Affected children and infants may experience symptoms such as urinary infections, pain, abdominal swelling, bleeding, and reduced urination. Reduced or nil removal of toxins from the body may trigger the onset of a skin rash. Affected babies may suffer from lower back or abdominal pain causing them to cry incessantly.

Causes of hydroureteronephrosis

Hydroureteronephrosis can occur due to causes such as obstructive uropathy, kidney stones, and/or backward urine flow to the kidneys from the bladder.

Unilateral hydroureteronephrosis occurs when there is blockage of one of the ureters. Such blockage may be caused due to:

• Formation of a kidney stone or ureter stone
• Tumor development next to the ureter or kidney
• Constriction of the ureters caused by certain infections or injuries; as a birth defect; or due to surgery.
• Damage of the muscles or nerves of the ureters due to varied causes
• Incorrect formation of kidneys marked by a higher point of attachment of the ureter to the kidneys.
• Incorrect positioning of a vein or artery which causes the ureter to get squeezed.

Bilateral hydroureteronephrosis occurs when both the kidneys are affected. It is generally caused due to failure of urine passage from both the kidneys to the bladder via the ureters. This urine flow failure is often caused due to some obstruction in the bladder or next to it. The blockage may be caused due to:

• Development of bladder stone
• Damage of the bladder’s one way valve due to some other underlying disorder. Impaired valve function can cause urine to flow backwards from the bladder to kidneys, thereby causing hydroureteronephrosis.
• Formation of tumor or a blood clot inside the bladder.
• Bladder problems due to increased pressure exerted on it by conditions such as an enlarged prostate gland or prostate cancer.

Treatment of hydroureteronephrosis

The treatment includes dialysis and other surgical and non-surgical treatment options to remove the obstructions to the free flow of urine.  Untreated cases of hydroureteronephrosis may ultimately result in progressive atrophy of the kidneys.