Essentials of Diagnosis
Urinary tract obstruction should be included in the differential diagnosis of acute or chronic kidney disease.
The diagnosis of obstructive uropathy usually requires the presence of hydronephrosis, hydroureter, and/or bladder distention.
Ultrasound is the imaging study of choice to determine if obstructive uropathy is present.
Urinary tract obstruction is not uncommon and can present at any age, although it is more commonly encountered in the elderly. Obstructive uropathy is defined as the blockage of urine drainage from the kidney, ureter, or bladder. While lower urinary tract symptoms may be present when bladder or urethral causes of obstruction exist, upper urinary tract obstruction may be asymptomatic. Urinary tract obstruction can lead to acute and chronic kidney disease. Urinary tract imaging should be included in the evaluation of individuals who present with impaired renal function.
Individuals at high risk of urine retention should be screened for symptoms and examined for bladder distention. These include patients with diabetes, Guillain–Barré syndrome, peripheral neuropathy and older males. Medications associated with urine retention include sympathomimetics, anticholinergics, antihistamines, and muscle relaxants and these medications should be avoided in those with risk factors for urine retention. If urinary tract infection has been excluded, urodynamic testing can be performed to determine the best treatment option for those with lower urinary tract symptoms.
Patients with a history of kidney stones should undergo metabolic evaluation to determine the cause and appropriate treatment if an abnormality is found. Unless contraindicated, all patients with a history of kidney stone should increase water intake to greater than 2.5 L daily. Temporary placement of ureter stents should be considered in individuals undergoing renal transplant or complex pelvic surgeries to reduce the risk of ureter-related complications.
Individuals with obstructive uropathy may present with lower urinary tract symptoms, including frequency, nocturia, incontinence, dysuria, hesitancy, weak stream, or straining to void. Incomplete obstruction can result in fluctuating urine output. Acute obstruction can result in pain due to distention of the bladder and/or collecting system or renal capsule. Renal colic due to calculi is often sudden and severe, with pain beginning in the flank and radiating into the groin. This can be accompanied by nausea, vomiting, and/or hematuria. Patients with renal colic prefer to be in motion, compared to patients with peritonitis, whose pain is worsened with movement. Occasionally, patients may develop a superimposed urinary tract infection due to the blockage and stasis of urine flow. In this case, patients may have fever or even present with sepsis.
A distended bladder or the presence of a flank or abdominal mass on physical examination is suggestive of obstruction. Hypertension can occur in obstructive uropathy due to volume expansion and activation of the renin–angiotensin–aldosterone system. Patients with obstruction of a ...