Stretching of the renal pelvis as a result of obstruction to urinary outflow. SYN: nephrydrosis. SEE: illus. .
ETIOLOGY: Anything that obstructs the ureter or bladder may cause hydronephrosis. Lodged kidney stones are a common cause of unilateral hydronephrosis; bilateral hydronephrosis often results from bladder outlet obstruction (e.g., in men who have hyperplasia of the prostate). Neurogenic bladder dysfunction, pregnancy, urogenital cancer, urinary tract inflammation, congenital malformations, ureteral strictures, and even parasites (schistosomiasis) may cause hydronephrosis. If urinary flow is not restored, the kidney tissue dilates and atrophies, and chronic renal failure may occur.
SYMPTOMS: Hydronephrosis often causes no localizing symptoms, except when it is associated with kidney stones (when the primary symptom is severe flank pain).
DIAGNOSIS: Ultrasonography of the urinary tract is used to confirm the diagnosis.
TREATMENT: Unilateral hydronephrosis caused by a kidney stone resolves spontaneously if the stone passes. If the stone does not pass, procedures such as shock wave lithotripsy, surgical removal of the stone, nephrotomy, or nephrostomy tube drainage of the kidney may be needed. Bilateral hydronephrosis caused by prostatic hyperplasia may be relieved if a catheter can be inserted through the obstructed urethra into the bladder. Hydronephrosis caused by other diseases (e.g., tumors) is often treated surgically.
NURSING-IMP: Renal function studies (e.g., blood urea nitrogen, serum creatinine, and serum potassium levels) are monitored daily. As appropriate, urine specific gravity is tested at the bedside. The condition, planned diagnostic procedures, and expected sensations are explained to the patient and family; if the patient is scheduled for a surgical procedure, the surgeon's explanations of the planned procedure are reinforced. Questions are answered, and misconceptions are corrected. The patient is prepared physically for the procedure according to institutional protocol or the surgeon's wishes. Emotional support is provided, postoperative care and activities are explained, a signed informed consent form is obtained, and prescribed preoperative sedation is administered.
Postoperatively, intake and output, vital signs, and fluid and electrolyte balance are monitored (a rising pulse rate and cool, clammy skin may signal impending hypovolemia or hemorrhage and shock). Prescribed analgesics and noninvasive measures are used to relieve pain as necessary. Postobstructive diuresis may cause the patient to lose great volumes of dilute urine over hours or days along with excessive electrolyte loss. If this occurs, IV fluids are administered at a prescribed constant rate plus an amount equal to a given percentage of the patient's hourly urine output to safely replace intravascular volume. A dietitian can provide assistance to plan a diet consistent with the treatment plan while including foods that the patient enjoys and will eat. If a nephrostomy tube has been inserted, the tube is irrigated as specifically prescribed, checked for patency, and never clamped or kinked. Meticulous skin care is provided to the tube entry site; if urine leaks around the tube, a protective skin barrier is provided to prevent excoriation, and the wound area is bagged to preserve the patient's dignity and to help prevent infection.
If the patient will be discharged with the nephrostomy tube in place, proper care of the tube and skin at the insertion site is reviewed. Prescribed drug therapies, such as antibiotics, are administered, and the patient is taught about expected outcomes, adverse effects to report, and the necessity to complete the prescribed course of therapy even if feeling better. To prevent the progression of hydronephrosis to irreversible renal disease, older male patients (esp. ones with a family history of benign prostatic hyperplasia or prostatitis) should have routine medical checkups.
"Taber's Cyclopedic Medical Dictionary," Copyright © 2005 by F. A. Davis Co., Phil., PA
Note added at 6 mins (2005-04-10 17:30:57 GMT)