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IMMEDIATE MANAGEMENT OF SERIOUS AND LIFE-THREATENING CONDITIONS
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General Considerations
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It is helpful to categorize the mechanism of oliguria or anuria 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 elicited by the history and physical examination. It is helpful to determine the presence and severity of acute kidney injury (AKI) that frequently accompanies oliguria and anuria.
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Prerenal causes include hypovolemia, sepsis, and heart failure.
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Renal causes include tubular, glomerular, vascular, or interstitial renal disease.
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1. Supravesical obstruction
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Supravesical obstruction, which is above the bladder, 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.
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2. Intravesical or infravesical obstruction
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Intravesical or infravesical obstruction is more common than supravesical obstruction in the etiology of oliguria or anuria. See Table 39–1 for causes.
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One must differentiate between reduced urine output with normal or near-normal voiding patterns, and oliguria associated with difficulty in voiding, which can include the feeling of urgency, suprapubic fullness and diminished urinary stream. The latter findings suggest obstruction.
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2 Associated medical conditions
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