Hydronephrosis is a term of great concern to urologists. The so-called hydronephrosis is a manifestation of a kidney that is propped up and enlarged in form due to retention of urine, which cannot drain smoothly from the kidney to the bladder due to obstruction or blockage. Most hydronephrosis occurs unilaterally, but it can also occur bilaterally at the same time. It is seen in people of any age, and due to technological advances, it is even found in some children in the fetal stage.
Left: normal kidney, right: hydronephrosis kidney
The urinary system includes the kidneys, ureters, bladder and urethra, and its main function is to remove excess fluid and metabolic waste from the body. The kidneys are like a blood filter that filters out waste and body fluids to form urine, which gradually collects and expands through tiny ureters into the calyces and renal pelvis, and then leaves the pathway ureters to the bladder. Here it gradually accumulates to a certain level and is excreted from the urethra through the voiding reflex.
Obstruction of any part of the urinary stream or reflux of the urine stream can enlarge the structures within the kidney (renal pelvis, calyces, etc.) and create hydronephrosis. Nevertheless, hydronephrosis does not always cause clinical symptoms. Hydrocele commonly presents as pain in the affected low back, abdomen or groin, but of course other urinary symptoms (frequency, urgency, effort to urinate), nausea and fever can also be present. The symptoms are often related to the cause and severity of the obstruction.
What causes hydronephrosis?
Hydronephrosis is a manifestation in itself and is not a disease name. The presence of hydrocele is often the surface of another underlying disease, such as kidney stones, congenital developmental malformation, stricture (from previous surgery, infection or trauma), tumor or cancer (ureteral ureteral cancer, bladder cancer, prostate cancer, etc. inside the urinary tract; or cervical cancer, rectal cancer, etc. outside the urinary tract), blood clots, prostate enlargement, pregnancy, urinary tract infection, inflammatory response of the urinary tract caused by other pathologies, etc.
Left picture: tumor compression (arrow), right picture: severe hydronephrosis (arrow)
How to diagnose hydronephrosis?
Severe hydronephrosis is sometimes detected through physical examination by a doctor, but due to the deep location of the kidney, other methods are needed to confirm the diagnosis in most cases.
A single ultrasound examination may be sufficient to make a diagnosis. Ultrasound is an ultrasound scan of the kidney that is harmless and simple to obtain. In most cases, it is better to confirm the extent of the fluid, but it is less able to identify the cause of the fluid and sometimes it is not easy to distinguish between mild dilatation of the renal pelvis and fluid, and parapelvic cysts.
The different hydronephrosis manifestations are dark in the middle for hydronephrosis and around the hydronephrosis is the parenchyma of the kidney. Therefore, the doctor will prescribe other tests such as X-ray, imaging, CT or MRI to further determine and confirm.
Angiography, CT, MRI (left, middle, right)
When an effusion and a preliminary cause are obtained, endoscopic means such as cystoscopy + retrograde intubation angiography or ureteroscopy may also be used if surgical intervention is considered or if the cause needs to be further discerned.
Cystoscopy, ureteroscopy (left and right)
Isotope renal scan (also known as nephrogram) depicts the different excretion of the two kidneys separately by injecting drugs, which facilitates the understanding of the function of each kidney and the severity of the effects of fluid accumulation (fractional renal function) separately, and has a very important role in clinical practice.
Renogram
Of course, routine examination of hematuria and urine must not be missing to find out whether there is blood in the urine, renal function, electrolytes, etc. for comprehensive analysis. A considerable number of patients with hydronephrosis will progress, due to poor urine excretion, the pressure in the kidney will be higher and higher, then the pressure will be required to the renal parenchyma to space. Prolonged compression and co-infection etc. can squeeze the function of urine-secreting kidney down, or even occupy it completely. Clinically, the degree of hydronephrosis is usually classified as mild, moderate or severe, with a grade of 1-4 or 1-5, with higher numbers indicating a more severe degree of hydronephrosis. This is why urologists pay so much attention to hydronephrosis.
How to treat hydronephrosis?
As mentioned above, hydronephrosis is a symptom, treating the cause of hydronephrosis is the right way to go, i.e. the goal of treatment is to restore urine flow. If stones are caused, we will try to remove them, which may be self-expulsion, drug lithotripsy, extracorporeal lithotripsy, endoscopic lithotripsy, or even laparoscopic or open surgery. Most developmental malformations require surgical shaping, and prostate enlargement triggered by prostate hypertrophy is targeted at surgery of the prostate enlarged tissue. In conclusion, those occurring within the lumen can be treated by open or lumpectomy, while external pressure lesions are treated from the outside or supported internally, and malignant lesions are removed by surgery, radiotherapy, and targeted therapy.
Ureteropelvic junction stenoplasty (common congenital malformation)
In some more urgent or called palliative cases, a soft, thin tube may be able to relieve fluid retention and drain urine. For example, in bilateral hydronephrosis caused by an enlarged prostate, a tube with a urinary catheter can be a lifesaver; in cases such as ureteral stenosis or compression, the tube placed is called a ureteral stent; if the stent cannot be inserted, the tube can be placed directly into the kidney by percutaneous puncture, called a nephrostomy. The key is to drain the urine out of the kidney, the faster the better!
Lower ureter in men
Ureteral stent, nephrostomy (left and right)
It is not always correct to order treatment simply by the degree of fluid accumulation. The heavier the fluid, the longer the obstruction, but it is not necessarily completely blocked, so it can be treated at a later stage after the cause is determined by perfect examination. Acute complete obstruction will be accompanied by colic, nausea and vomiting, which can be controlled by appropriate drugs; however, combined with intrarenal infection and fever, we should pay high attention to it, and doctors will also take emergency treatment.
If bilateral hydronephrosis is prolonged and the obstruction is heavy, or bilateral acute complete obstruction, there is a possibility of renal failure. The former requires dialysis or kidney transplantation, while the latter requires emergency drainage. Similar to other diseases, doctors usually try to fully grasp the condition before taking action, and most patients with hydronephrosis do not fall into this extreme category. As long as hydronephrosis is detected, it can be recovered with proper and timely treatment.