++
General Considerations
++
It is helpful to categorize the mechanism as prerenal (eg, resulting from decreased or abnormal renal perfusion), renal (eg, resulting from intrinsic renal disease), or postrenal (eg, disease of the urinary collecting system distal to the renal parenchyma). Prerenal and postrenal causes are often suggested by the history and physical examination. Additionally, it is be helpful to determine the presence and extent of acute kidney injury (AKI) that frequently accompanies oliguria and anuria.
++
Prerenal causes include hypovolemia, sepsis, and heart failure.
++
Renal causes include tubular, glomerular, vascular, or interstitial disease.
++
Supravesical Obstruction
++
Supravesical obstruction rarely causes oliguria or anuria, because bilateral disease is required to reduce decreased urine flow. There are two types of supravesical obstruction: (1) ureteral obstruction (usually tumor) and (2) ureteropelvic or ureterovesical obstruction.
++
Intravesical or Infravesical Obstruction
++
Intravesical or infravesical obstruction is more common than supravesical obstruction and may be from many causes (Table 39–1).
++
++
Differentiate between reduced urine output (with normal or nearly normal voiding patterns) and oliguria associated with difficult in voiding, feeling of incomplete voiding, and diminished urinary stream. The latter findings suggest obstruction.
++
Associated Medical Conditions
++
Ask about coexisting cardiac, pulmonary, renal, or other underlying disease that might contribute to renal or prerenal oliguria.
++
The patient's medications might cause problems with urination or be nephrotoxic. Anticholinergics and sympathomimetics are most often the culprits of urinary retention.
...