COLLECTIVE REVIEW cystitis; pyelonephritis Cystitis and Pyelonephritis [Abraham E, Brenner BE, Simon RR: Cystitis and pyelonephritis. Ann Emerg Med 12:228-234, April 1983.] INTRODUCTION Acute urinary tract infections may be separated into two broad categories: loWer tract {cystitis, acute urethral syndrome) and upper tract (pyelonephri- tis}. Lower tract infections are localized, involving superficial mucosal sur- faces without any systemic symptomatology. Upper tract infections, on the other hand, involve the renal parenchyma, and may have such systemic manifestations as chills, fever, and leukocytosis. Upper tract infections are of special concern because of the fear of sepsis and renal damage leading to renal failure. Traditionally upper and lower urinary tract infections have been differentiated on the basis of history and physical findings. Lower tract infec- tions are characterized by frequency, dysuria, and suprapubic pain without the findings of flank pain, fever, rigors, nausea, and vomiting that are be- lieved to accompany upper tract infections. Differentiation of upper from lower tract infections is frequently inaccu- rate if based only on clinical signs and symptoms.~-s In addition, the urinary tract infections previously attributed to bacteria also can be caused by non- bacterial organisms, primarily chlamydia. 6'7 Because therapy is different for lower and upper urinary tract infections 4'8'9 and for bacterial and chlamydial infections, 7,~° separation of these pathologic entities is important. We review the diagnosis and microbiology of urinary tract infections. Methods used in distinguishing cystitis from pyelonephritis are considered. Finally the therapy of urinary tract infections is discussed. Edward Abraham, MD Barry E. Brenner, MD, PhD Robert R. Simon, MD Los Angeles, California From the Emergency Medicine Center, UCLA Center for the Health Sciences, Los Angeles, California. Address for reprints: Barry E. Brenner, MD, PhD, Emergency Medicine Center, UCLA Center for the Health Sciences, Los Angeles, California 90024. DIAGNOSIS Diagnosis of urinary tract infection is usually based on a symptom com- plex coupled with examination and culture of the urine. Findings on mi- croscopic urine examinations of pyuria, bacteriuria, and occasionally of mi- croscopic hematuria are consistent with urinary infection. Culture of a midstream urine specimen showing greater than 100,000 colonies per milli- liter of urine connotes bacterial infection and is almost never found in a contaminated urine specimen. ~1-14 Microscopic examination of uncentri- fuged urine showing one organism or more per oil immersion field is con- sistent with a culture of more than 100,000 organisms per milliliter of urine) s This does not provide specific bacteriologic identification and does not exclude significant bacteriuria if organisms are not seen, because 20% of cultures with greater than l0 s organisms per milliliter will not show organ- isms consistently on microscopy. ~sq7 The Enterobacteriaceae are the most commonly found organisms in un- complicated bacterial urinary infections {those unassociated with obstructive lesions or major defects in voiding), accounting for 80% to 95% of these infections. 2,4A8 Escherichia coli are responsible for approximately 80% of the urinary tract infections produced by the Enterobacteriaceae, with Klebsiella, Proteus, and Enterobacter found less frequently. ¢8'19 Pseudomonas, staphylo- cocci, and Group D streptococci are responsible for the remainder of uncom- plicated infections.2,4,sA 8A9 12:4 April 1983 Annals of Emergency Medicine 228/61