Differential Diagnosis of Spontaneous Renal Rupture in Pregnant Women

"Spontaneous Renal Rupture During Pregnancy," a case report by Van Winter and colleagues that was published in the February issue of the Proceedings (pages 179 to 182), pro­ vided an excellent description of an unusual condition. The authors discussed the differential diagnosis of a pregnant woman with right flank pain and fever. Two results of the laboratory studies suggest that an early diagnosis of renal rupture could be suspected. Unremarkable findings on uri­ nalysis are unusual in urinary tract infection or in urolithiasis and should imply another diagnosis. Nonetheless, it is proba­ bly more common to encounter patients with normal findings on urinalysis in association with a common condition, such as urinary tract infection or urolithiasis, than the rare case of renal rupture. Another laboratory result may be an increasing serum creatinine concentration. When urine extravasates from the collecting system, the filtered creatinine is not excreted from the body. The creatinine reenters the extracellular fluid and causes the serum creatinine level to increase. Did serial serum creatinine measurements before placement of a stent demon­ strate increasing values? A pregnant patient with fever and flank pain usually has pyelonephritis, sometimes attributable to urolithiasis. When a pregnant patient has fever, flank pain, and normal findings on urinalysis with an increasing serum creatinine value, spontaneous renal rupture should be considered early in the assessment of the patient.