urinary tract obstruction (2).docx

[Urinary tract Obstruction] BY: Dr.Akram jauda Al-Zaidy Objectives: - Define urinary tract obstruction. - Incidence. - Etiology/pathophysiology. - Clinical presentation. - Diagnosis. - Treatment and management. Urine production - Pressure gradient from g...

[Urinary tract Obstruction] BY: Dr.Akram jauda Al-Zaidy Objectives: - Define urinary tract obstruction. - Incidence. - Etiology/pathophysiology. - Clinical presentation. - Diagnosis. - Treatment and management. Urine production - Pressure gradient from glomerulus to bowman capsule. - Peristalsis of renal pelvis and ureters. - Effects of gravity. - - - Urinary tract obstruction - Restricted flow of urine from the kidneys through the urinary tract to the external urethral orifice. - Common cause of acute and chronic renal failure is urinary tract obstruction.  Potentially it is curable form of kidney disease. - Obstruction to the flow of urine impairs renal and urinary conduit functions and is a common cause of acute/chronic kidney injury (obstruction nephropathy) [especially if] [stasis and elevation of urinary tract pressure.] - Early diagnosis prompt therapy is essential to minimize the devastating effects of obstruction on kidney structures and function. Definition of terms: - No data available in unselected populations. - 20-35% prevalence in large survey among elderly men. - 3.8% (adults); 2.0% (children) postmortem examinations. - No gender difference until 20 years - Women 20-60; men \>60 [Age:] - Special consideration in pediatric patients Etiology ======== - Mechanical blockade - Foundation defects Normal points of narrowing include: 1. Ureteropelvicjunction. 2. Ureterovesical junction. 3. Bladder neck. 4. Urethral meatus. a. congenital malformations, such as narrowing of the ureteropelvic junction and anomalous (retrocaval) location of the ureter. b. Vesicoureteral reflux is a common cause of potential hydronephrosis and if severe can lead to recurrent urinary infection and renal scarring in childhood. c. Posterior urethral valves are the most common cause if bilateral hydronephrosis in boys. d. Bladder dysfunction may be secondary to congenital urethral stricture, urethral meatus stenosis, or bladder neck obstruction. a. Mainly due to acquired defects pelvis tumor, calculi, and urethral stricture predominate. b. Ligation of, or injury, to the ureter during pelvic or colonic surgery can lead to hydronephrosis which[, if unilateral, may remain relatively silent and undetected.] c. Schistosoma haematobium and genitourinary tuberculosis are infectious causes of ureteral obstruction. d. Obstructive uropathy may also result from extrinsic neoplastic (carcinoma of cervix or colon) or inflammatory disorders. e. Retroperitoneal fibrosis, an inflammatory condition in middle -aged men , must be distinguished from other retroperitoneal causes of ureteral obstruction, particularly lymphomas and pelvic and colonic neoplasms. Pathophysiology --------------- - Unilateral (UUO). - Bilateral (BUO). - Obstruction relieved or not. - Time. clinical features: - Pain: - - - - excretory function is impaired. - bladder outlet obstruction, - bilateral renal pelvic or ureteric obstruction  solitary functioning kidney. Hypertension is frequent in acute and subacute unilateral obstruction and is usually a consequence of increased release of renin by the involved kidney (Chronic Hydronephrosis) ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Diagnosis - Pain, renal colic - Inability to void effectively (S Prostatism) - Alteration in pattern of micturition (anuria, polyuria, nocturia) - Recurrent UTI - New-onset or poorly controlled hypertension - Polycythemia - Recent gynecologic or abdominal surgery. Physical Examination ==================== - Signs of dehydration and intravascular volume depletion.  Peripheral edema. - , hypertension. - signs of congestive heart failure. - Palpable kidney or bladder. - Enlargement of pelvic organs (eg. Prostate, uterus). - Examination of external urethra for phimosis, meatal stenosis.  Diagnostic Imaging ---------------------------------------- - Renal US 1. Safe in pregnant and pediatric patients 2. No need for IV contrast 3. ,May have false negative in acute obstruction (35%) 4. Doppler- measures renal resistive index (RI), an assessment of obstruction - Excretory Urography - Limited use in patients with renal insufficiency Increased risk of contrastinduced nephropathy. - Cannot use in patients with contrast allergy. ###  Whitaker Test Invasiveness and discordant results limit clinical usefulness. (Normal \< 15 cm H20) (Indeterminate = 15-22 cm H20 ) (Obstruction \>22 cm H2O). ###  Nuclear Renography (Normal = T ½ \< 10 min) (Indeterminate = T ½ 10-20 min) ( Obstructed T ½ \> 20 min)  СТ ---- - Most accurate study to diagnose ureteral calculi. - More sensitive to identify cause of obstruction - Helpul in surgical planning ###  MRI - Can identify hydro but unable to identify calculi and ureteral anatomy of unobstructed systems - Diuretic MRU can demonstrate obstruction ,Especially accurate with strictures or congential abnormalities - IV gadopentetate-DTPA allows functional assessment of collecting system while providing anatomic detail. - GFR assessment - Renal clearance - Still several limitations in its use. ###  Voiding cystourethrography -- ###  Endoscopic visualization Treatment and management ======================== - Prehospital Care - Pulmonary edema - Salt and water retention - Hypovolemia Emergency department care ------------------------- Investigate and begin treatment of potentially life-threatening complications - Pulmonary edema - Hypovolemia - Urosepsis - Hyperkalemia - Surgical drainage necessary if with: - - - - Position of stone determines preferred method of removal Prognosis =========