Urinary Tract Infections

Objectives


Bacterial infection of the lower urinary tract (UTI), one of the most common infectious processes, occurs in all age groups, from the newborn to the elderly. However, presentation and treatment of UTI varies according to the age of the patient.

Adults

Etiology

UTI is caused by the ascent of bacteria up the urethra. Organisms that cause UTI are common normal rectal and perineal bacterial flora and include E. coli, Klebsiella, and Staph epidermidis.

Symptoms

Symptoms include dysuria, frequency, urgency, and suprapubic pain. Fever may be present, but is frequently absent.

Physical Exam

The exam usually will be normal. Limited findings may include flank pain and low-grade temperature.

Lab

Urinalysis will often reveal pyuria >5-10 wbc per HPF and bacteriuria, with occasional hematuria. Urine containing significant squamous epithelial cells suggests contamination, and urinalysis should be repeated.

Females - Age 12 or Older

Because of their anatomic predisposition (i.e., short urethra), females have a greater infection rate.

Differential Diagnosis: Other diseases could cause similar symptoms in females:

Treatment

Of the many effective drugs, inexpensive choices include bactrim, macrodantin, ampicillin, and amoxicillin (25% of UTIs will be resistant to ampicillin/amoxicillin). Other, more expensive drugs are the fluoroquenolines (Floxin, Norfloxacin), oral cephalosporins, and cipro. Certain antibiotic choices are to be avoided in pregnant patients, such as the quinalone and tetracycline class antibiotics.

Duration of AB therapy ranges from 3-5 to 7-10 days. Young, healthy adults usually require 3-5 days' treatment. Pregnant women and patients with DM, chronic disease, or sickle cell disease usually require the complete 7-10 day course.

If patients are not asymptomatic in 3 days, consider drug failure, obstruction due to stones, or renal abscess. Urine cultures should be done on all pregnant women; patients with DM, sickle cell, or chronic disease; and treatment failures. If patients have recurrent UTI (>3/year), consider placement on suppression therapy - Bactrim DS 1/2 tab qd.

Prevention

Women should be instructed to wipe themselves from the front to the rear after urinating and to void after sex.

Adult Males

The most common cause of dysuria in otherwise healthy adult males is urethritis due to a sexually transmitted disease. A true UTI in the male requires a GU workup to rule out structural abnormalities. Antibiotic choices are the same as for females.

Neonates

Because of congenital anomalies, UTI is more common in the male infant. Patients usually present with nonspecific symptoms ranging from FTT, lethargy, and fever, to sepsis. Neonates with lethargy and fever must be admitted for IV antibiotics. All neonates with UTI require a GU workup to rule out congenital anomalies.

Children

Etiology

Infections of the urinary tract in children range from asymptomatic bacteriuria to severe symptomatic pyelonephritis. Females have a higher incidence of UTI because of a short urethra, poor perineal hygiene, and infrequent voiding.

Symptoms

Signs and symptoms are less specific in younger children. Preschool children may experience abdominal pain, vomiting, strong-smelling urine, fever, enuresis, increased frequency, dysuria, or urgency. School-age children usually present with the more classic adult symptoms.

Differential Diagnosis

Children with a diagnosis of cystitis may be experiencing urethral irritation caused by bubble baths, pinworms, vaginitis, or feminine hygiene spray. This also may be in the differential with adult urethritis.

Treatment

Antibiotic choice is the same as for adults. All children need a repeat urine culture after therapy to confirm successful treatment, and periodic urinalysis should be done until the patient has remained infection-free for one year. Males with UTI require a GU workup to rule out urinary tract abnormalities. Females with a second UTI require a GU workup.

Geriatrics

In the elderly, UTIs occur predominantly in the male secondary to prostate disease (i.e., prostatis or BPH). Some patients may complain of dysuria, frequency, or urgency, but most will present with nonspecific symptoms. Patients may be lethargic, disoriented, or confused, and may or may not have fever and sepsis. Patients with urosepsis must be admitted and treated with IV antibiotics.


D. Heard, MD
updated 8/30/05


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