• Treat asymptomatic bacteriuria in pregnant patients.

• Be aware of local bacterial resista nce patterns when

treating UTI.

in the elderly and the most common hospital-acquired

infection.

The bacterial organisms that usually cause UTI are the

enteric flora that colonize the perineum. Gram-negative

aerobic organisms and Escherichia coli are the most common, causing more than 80% of infections. Staphylococcus

saprophyticus has the ability to adhere to urinary tract tissue, even with normal urinary flow, and causes 10-15% of

UTis. Other less common causative bacteria include the

gram-negative species Klebsiella, Proteus, Serratia, and

Pseudomonas.

CLINICAL PRESENTATION

� History

The patient history should be used to determine the presence of UTI, differentiation of upper versus lower tract

infection, and the presence of any complicating factors.

Uncomplicated cystitis symptoms include urinary fre ­

quency, urgency, dysuria, and mild suprapubic pain. Upper

tract infection often begins with similar symptoms fol ­

lowed by pain extending to the back or abdomen and may

have additional symptoms of fever and vomiting. Other

important historical information includes pregnancy,

1 70

URINARY TRACT I NFECTIONS

recent hospitalization, immunosuppression, prostatic

hypertrophy, urinary stones, and the presence of recent

urinary tract instrumentation or bladder catheterization.

...... Physical Examination

Patients with lower urinary tract infection should be afebrile and have normal vital signs. Mild suprapubic tenderness may be present. An external genital examination

should be performed to assess for extraurethral causes of

dysuria. Pyelonephritis is indicated by flank tenderness

over one or both kidneys. Fever and tachycardia may be

present. The remainder of the examination should be

directed at ruling out other diagnoses. A pelvic examination should be performed to assess for cervicitis, pelvic

inflammatory disease, or pregnancy. In a male, the GU

exam may reveal urethritis, epididymitis, or prostatitis.

The abdominal examination should assess for possible

cholecystitis, appendicitis, diverticulitis, or an abdominal

mass that may be causing obstruction to urinary flow.

Lung examination may reveal that fever and flank pain are

due to a lower lobe pneumonia.

DIAGNOSTIC STUDIES

...... Laboratory

A urinalysis should be performed on all patients with symptoms consistent with UTI. The urine collection method should

vary based on patient presentation. A dean-catch midstream

specimen is usually adequate. Bladder catheterization should

be performed for pediatric patients, the obese, women who are

menstruating or have vaginal discharge, and the debilitated.

Expected findings on urinalysis are listed in Table 40-1. A urine

pregnancy test should be performed on all women of childbearing age. Asymptomatic bacteriuria in pregnancy should

be treated, as this condition has been linked to prematurity,

fetal morbidity, and stillbirth. Urine cultures should be sent if

complicated UTI is suspected. Complicating factors include

pregnancy, recurrent UTI, pyelonephritis, urosepsis, immunosuppression, indwelling bladder catheter, and fever without a

source.

Table 40-1. Urina lysis interpretation.

Urinalysis

Results Bacteria WBCs RBCs

A complete blood count and renal function tests (blood

urea nitrogen/ creatinine) are warranted in patients with systemic symptoms such as pyelonephritis to assess for renal

insufficiency, dehydration, electrolyte derangement, or sepsis,

but are not indicated for simple cystitis. Other lab tests (liver

function tests, lipase) may help with the differential diagnosis

but are not routinely indicated. Blood cultures are obtained

if the site of infection is unclear or if the patient has sepsis.

..... Imaging

Imaging is indicated when the clinical presentation indicates possible urinary obstruction, extensive disease with

abscess, or to diagnose other conditions in the differential.

Imaging may also be performed for relapses or recurrent

UTis to assess for an unsuspected nidus for infection such

as renal stone. Noncontrast computed tomography ( CT) of

the abdomen and pelvis is the most common study

obtained and readily diagnoses kidney stones and hydronephrosis. Renal ultrasound may be performed to assess for

hydronephrosis in patients in whom CT is contraindicated

(pregnancy), but is less sensitive for the presence of stones.

MEDICAL DECISION MAKING

The differential diagnosis for patients with lower tract UTI

includes urethritis, vaginitis, and cervicitis. For patients

with systemic symptoms and possible upper tract UTI, the

differential includes nephrolithiasis, pneumonia, diverticulitis, appendicitis, cholecystitis, and pelvic inflammatory

disease (Figure 40-1).

TREATMENT

Treatment of UTI is based on the type of infection, simple

versus complicated, severity of illness, and local resistance patterns. Ideally, treatment for all complicated UTis should be

based on urine culture results; however, these results are not

usually available at the time of empiric antibiotic administration in the ED. Also local and hospital bacterial resistance patterns should be considered when prescribing empiric treatment.

Table 40-2 is a general guide to empiric treatment in the ED.

Nitrite

Leukocyte

Esterase

Epithelial

Cells

Normal None <5 per HPF None Negative Negative <5 per HPF

UTI <5 per HPF

Contaminated

Sample

Any >5-10 per HPF variable Positive (specific but

insensitive)

HPF, high-power field; R BCs, red blood cells; WBCs, white blood cells.

Positive (sensitive but

nonspecific)

>5 per HPF

Uncompl icated

l ower tract

Discharge with

3 days antibiotics

CHAPTER 40

( UTI Suspected J

+

H&P:

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