Hydronephrosis is a progressive expansion of the calyx-pelvic complex with subsequent atrophy of the renal parenchyma, developing due to a violation of the outflow of urine from the kidney. It is manifested by pain in the lower back (aching or by the type of renal colic), hematuria, painful frequent urination, arterial hypertension. Diagnosis may require ultrasound of the bladder and kidneys, catheterization of the bladder, intravenous urography, cystourethrography, CT or MRI of the kidneys, pyelography, renal scintigraphy, nephroscopy. Treatment of hydronephrosis involves the elimination of the cause of the violation of the passage of urine; the method of emergency care is nephrostomy.
ICD 10
Q62.0 N13
Meaning
Hydronephrosis or hydronephrotic transformation of the kidney is a consequence of a violation of the physiological passage of urine, which leads to pathological expansion of the kidney cavities, changes in interstitial renal tissue and parenchymal atrophy. At the age of 20 to 60 years, the incidence of hydronephrosis is higher in women, due to reasons related to pregnancy and gynecological oncological diseases. After 60 years, hydronephrosis develops more often in men, mainly against the background of prostate adenoma or prostate cancer.
Causes
The causes of the disease are variable, but can be divided into two groups: caused by obstruction or obstruction in any part of the urinary system (ureters, bladder, urethra) or reverse flow of urine caused by the failure of the bladder valves. By localization and nature, the causes of hydronephrosis can be internal, external and functional.
- At the level of the urethra. Among the internal lesions of the urethra, diverticula, urethral strictures, urethral atresia contribute to the development of hydronephrosis. External obstacles, as a rule, are hyperplasia and prostate cancer.
- At the level of the bladder. From the side of the bladder, internal factors of the development of hydronephrosis can be urolithiasis, cystocele, carcinoma, diverticulum of the bladder, contracture of the neck of the bladder. An external obstacle to the outflow of urine from the bladder can occur with pelvic lipomatosis.
- At the level of the ureters. Internal causes of hydronephrosis are more often tumors, fibroepithelial polyps, blood clots, concretions, fungal lesions of the urethra (aspergilemma, mycetoma), ureterocele, tuberculosis, endometriosis, etc. An external obstacle to the passage of urine in the ureteral segment can be created by retroperitoneal lymphoma or sarcoma, pregnancy, cervical cancer, uterine prolapse, ovarian cysts, tubal-ovarian abscess, prostate tumors, abdominal aortic aneurysm, lymphocele, abnormally located renal artery squeezing the ureter.
With hydronephrosis, the defeat of the urinary tract at various levels can also be caused by congenital dyskinesia and obstruction of the urinary tract, their injuries, inflammation (urethritis, cystitis), spinal cord injuries. When the obstruction to the outflow of urine is localized below the pelvic-ureteral segment, not only the pelvis but also the ureter expands, which leads to hydroureteronephrosis. Functional disorders include the presence of neurogenic bladder and vesicoureteral reflux.
Pathogenesis
Violation of the urine flow leads to an increase in pressure inside the ureter and pelvis, which is accompanied by noticeable violations of glomerular filtration, renal tubule function, pyelolymphatic current, pyeloarterial and pyelovenous blood flow. The outcome of hydronephrosis is atrophy of the renal tubules and the death of the structural units of the kidney – nephrons.
Classification
According to the time of development, hydronephrosis can be primary (congenital) or acquired (dynamic). According to the severity of the course, mild, moderate and severe hydronephrosis is distinguished; according to localization, unilateral and bilateral. In practical urology, hydronephrosis of the right and left kidneys occurs with the same frequency; bilateral hydronephrotic transformation is observed in 5-9% of cases.
The course of hydronephrosis can be acute and chronic. In the first case, with timely correction, complete restoration of renal functions is possible; in the second, kidney functions are irreversibly lost. Depending on the presence of infection, hydronephrosis can develop in an aseptic or infected type.
Symptoms of hydronephrosis
The manifestations of pathology depend on the localization, rate of development and duration of obstruction of the urinary tract segment. The severity of symptoms is determined by the degree of expansion of the cup-pelvic complexes of the kidney. Acute hydronephrosis develops rapidly, with pronounced paroxysmal pain in the lower back of the type of renal colic spreading along the ureter, into the thigh, groin, perineum, genital area. There may be frequent urge to urinate, its soreness, nausea and vomiting. With hydronephrosis, blood appears in the urine, visible to the eye (macrohematuria) or determined in the laboratory (microhematuria).
Unilateral aseptic chronic hydronephrosis is latent for a long time. In most cases, there is discomfort in the lumbar-rib angle, periodic dull pain in the lower back, which increases after physical exertion or taking a large amount of fluid. Over time, chronic fatigue and decreased ability to work progresses, transient arterial hypertension occurs, hematuria appears.
With an increase in body temperature, as a rule, one should think about infected hydronephrosis and acute purulent obstructive pyelonephritis. In this case, pus (pyuria) appears in the urine. A pathognomonic sign for hydronephrosis is the patient’s preference to sleep on his stomach, since this position leads to a change in intra-abdominal pressure and an improvement in the outflow of urine from the affected kidney.
Complications
Chronic hydronephrosis often contributes to the occurrence of urolithiasis and pyelonephritis, hypertension, which further burden the clinic of hydronephrotic transformation of the kidney. Sepsis sometimes develops against the background of infected hydronephrosis. The course of hydronephrosis may be complicated by the development of renal failure. In this case, especially with bilateral hydronephrosis, the death of the patient occurs from intoxication with nitrogen metabolism products and violation of the water-electrolyte balance. A life-threatening complication of hydronephrosis can be a spontaneous rupture of the hydronephrotic sac, as a result of which urine is poured into the retroperitoneal space.
Diagnostics
In hydronephrosis, the diagnostic algorithm consists of the collection of anamnestic data, physical examination, laboratory and instrumental studies. In the process of studying the anamnesis, a nephrologist finds out the presence of causes that may contribute to the development of hydronephrosis. Physical data are uninformative and non-specific.
With deep palpation of the abdomen, a stretched bladder can be determined, in children and thin adult patients, an enlarged kidney. Percussion of the abdomen in the area of the altered kidney, even with a small hydronephrosis, reveals tympanitis. With renal colic, tension and bloating, bladder catheterization is often resorted to. The release of a large volume of urine through a catheter may indicate obstruction at the level of the urethra or the outlet of the bladder. The determining methods of diagnosis of hydronephrosis are X-ray and ultrasound examinations.
- Echography. Ultrasound of the kidneys is performed polypositionally, examining longitudinal, transverse, oblique projections in the patient’s position on the abdomen and on the side. With echography, the size of the kidneys, the state of the cup-pelvic complexes, the presence of additional shadows, and the state of the ureters are evaluated. If necessary, an ultrasound of the bladder is additionally performed to determine the amount of urine, the ultrasound of the renal vessels. Endoluminal echography allows to identify changes in the area of the pelvic-ureteral segment and the parochial fiber.
- Radiodiagnostics. Priority for the detection of hydronephrosis are radiopaque studies, primarily excretory urography and retrograde ureteropyelography, which allow us to judge the excretory function of the kidney. In some cases, chromocystoscopy, renal angiography, percutaneous antegrade pyelography, MRI and CT of the kidneys are resorted to to determine the causes of kidney obstruction in hydronephrosis. Radioisotope dynamic nephroscintigraphy and renoangiography are used to assess organ blood flow.
Endoscopic methods – urethroscopy, cystoscopy, ureteroscopy, nephroscopy – can be used to visualize obstacles to the outflow of urine in hydronephrosis. Signs of impaired renal function in hydronephrosis can be detected by blood and urine tests. Biochemical blood parameters are characterized by an increase in creatinine, urea, and changes in the electrolyte balance (sodium, potassium). In the general analysis of urine, leukocyturia, pyuria, hematuria are determined. If necessary, a sample of Rehberg, Zimnitsky, Nechiporenko, Addis-Kakovsky, urine bacposev is examined.
Hydronephrosis should be distinguished from similar symptomatic conditions that are not complicated by hydronephrotic transformation of the kidney, such as kidney stones, nephroptosis, polycystic kidney cancer.
Treatment of hydronephrosis
Conservative therapy is ineffective. It can be aimed at relieving pain, preventing and suppressing infection, lowering blood pressure, correcting renal failure in the preoperative period. The method of emergency care for acute hydronephrosis is percutaneous (percutaneous) nephrostomy, which allows you to remove accumulated urine and reduce pressure in the kidney.
The types of surgical treatment of hydronephrosis can be different and are determined by the cause of this condition. All methods of surgical treatment of hydronephrosis are divided into reconstructive, organ-preserving and organ-removing. Indications for reconstructive plastic surgery are the preservation of parenchymal function and the possibility of radical elimination of the cause of hydronephrosis. With urethral strictures or ureteral strictures, balloon dilation, bougie, endotomy, and ureteral stenting are performed.
In case of obstruction caused by hyperplasia or prostate cancer, prostate resection, urethral dilation, prostatectomy or hormone therapy may be performed. In the case of urolithiasis, lithotripsy or surgical removal of concretions from the obstruction zone is indicated. Open operations are performed for retroperitoneal tumors, aortic aneurysm, inability to perform endoscopic stenting or shock wave lithotripsy. Nephrectomy – the removal of an altered kidney – is resorted to when its function is lost and complications are at risk.
Prognosis and prevention
The rapid elimination of the causes of hydronephrosis allows the kidney to restore its functions due to large reserve capabilities. In case of prolonged obstruction, damage to another kidney or infection, the prognosis of hydronephrosis is serious. To prevent the development of hydronephrosis, it is possible to undergo periodic examination by a urologist with ultrasound of the kidneys, prevention of diseases of the urinary tract.