Definition
A.Urinary tract infection (UTI) is an infection of the urinary bladder. UTI is defined as the presence of at least 100,000 organisms per mL of urine in an asymptomatic patient or more than 100 organisms per mL of urine with accompanying pyuria (>7 white blood cells [WBC]/mL) in a symptomatic patient. Asymptomatic bacteriuria (ASB) when left untreated is a risk factor for acute cystitis (40%) and pyelonephritis in 25% to 30% of pregnant women.
B.UTIs can be divided anatomically into upper and lower tract (cystitis) infections. For a discussion of upper tract infection, see the section Pyelonephritis
in this chapter.
C.UTIs may be considered uncomplicated or complicated.
1.An uncomplicated UTI is noted in a healthy person with a normal urinary tract system and may be treated with oral antibiotics.
2.A UTI noted in a person with a structural or functional urinary tract system or in a person who is immuno-compromised is considered complicated. It may require parental therapy until afebrile.
Incidence
A.Incidence depends on age and gender. The prevalence of UTI in males varies according to age.
1.Young men aged 15 to 50 years rarely develop a UTI.
2.The incidence of a UTI in geriatric males may be as high as in geriatric females (up to 15%).
B.Over 50% of women will have one UTI in their lifetime.
1.Prevalence for females increases by 1% per decade and 2% to 4% throughout childbearing years.
2.The incidence of UTIs in pregnancy ranges from 4% to 7%. In pregnancy, the increased incidence is related to both hormonal influence and anatomic changes that increase the risk of urinary stasis and vesicoureteral reflux.
3.By age 30, approximately 25% of women have experienced symptoms of a UTI.
Pathogenesis
A.Bacteria ascend from the perineum through the urethra. The greater susceptibility of younger women and girls is related to a shorter urethra. In older women, it is related to estrogen-mediated dilation of the urethra.
B.The normal male urinary tract has many natural defenses to infection. The greater susceptibility of elderly males is related to problems with the prostate and other urologic diseases and can be linked to the instrumentation required for therapy.
C.Gram-negative bacilli are the most common pathogens; 80% to 90% of cases are related to coliform bacteria (Escherichia coli). It originates from fecal floras that colonize the periurethral area.
D.Other gram-negative bacteria include Klebsiella pneumonia or Proteus mirabilis. Staphylococcus saprophyticus (grampositive coccus) accounts for about 10% to 15% of UTIs.
E.Other pathogens include Enterobacter, Pseudomonas, Enterococci, and Staphylococci.
F.The incubation period depends on the pathogen.
Predisposing Factors
A.Female (until elderly, then equal frequency in males and females).
B.Pregnancy.
C.Poor hygiene.
D.Trauma.
E.Instrumentation.
F.Sexual intercourse.
G.Oral contraceptive or diaphragm use.
H.Females diagnosed with diabetes (there is no increased risk for diabetic males).
I.Anomalies of the genitourinary (GU) tract.
J.Neurologic factors.
K.Vesicoureteral reflux.
L.Obstruction: Stones.
M.Foreign bodies.
N.Bubble baths and hot tubs.
O.Douching.
P.Anal intercourse.
Q.HIV.
R.Uncircumcised penis.
S.Catheterization.
T.Nosocomial infection.
U.Phimosis.
Common Complaints
A.Burning on urination.
B.Frequency.
C.Cloudy or bloody urine.
D.Urgency.
E.Geriatrics:
1.May not present with classic symptoms.
2.Fever.
3.Incontinence.
4.Mental confusion.
Other Signs and Symptoms
A.Asymptomatic.
B.Frequency, dysuria, bladder spasms, suprapubic discomfort, urgency, and nocturia.
C.Suprapubic pain.
D.Fever.
E.Costovertebral angle (CVA) tenderness.
F.Hematuria.
Subjective Data
A.Review the onset, course, and duration of symptoms.
B.Does the patient have a fever and chills or back or flank pain (unilateral or bilateral)?
C.Are there any other genital problems such as herpes lesions or vaginal discharge?
D.Review the associated factors: Sexual intercourse (specifically review for anal intercourse), douching, or bubble bath.
E.Ask female patients if they use appropriate hygiene practices after urination and bowel movements (BMs):
1.Wiping from front to back.
2.Frequent changes of hygienic products.
3.Handwashing.
F.Is the patient pregnant? If not, what type of birth control does she use?
G.Is there any history of previous UTIs? How often, and how were they treated? Were any tests performed in a workup by a urologist?
H.How much liquid or water does the patient drink every day? Note the amount of caffeine.
I.In older men, review the strength of the urinary flow, dribbling, hesitancy, and so forth.
J.In the postmenopausal woman, review whether she has a known prolapse and/or vulvo vaginal atrophy. Does she use any systemic or local estrogen medications?
K.Is there any history of other medical diseases, including diabetes or sickle cell disease?
L.Review for the presence of neurologic disorders, including spinal cord injury or multiple sclerosis
(MS).
M.Does the patient require self-catheterization?
Physical Examination
A.Check temperature, blood pressure (BP), pulse, and respirations. The absence of a fever does not exclude the presence of an infective process.
B.Inspect:
1.General observation of general appearance for discomfort before and during examination.
C.Auscultate:
1.Heart and all lung fields.
D.Palpate:
1.Palpate the abdomen: Kidneys, masses; assess for suprapubic tenderness.
2.Palpate the back; note costovertebral (CVA) tenderness.
3.Check for inguinal lymph node enlargement.
4.Palpate the suprapubic area.
E.Percuss: Percuss over the bladder and the CVA area for tenderness.
F.Females:
1.Pelvic examination:
a.Inspect external genitalia for lesions, Bartholin’s gland cysts, irritation, and discharge.
b.Milk urethra for discharge.
2.Assess rectal area.
3.Speculum exam: Evaluate vaginal vault for discharge, cervicitis, and inflammation; evaluate for atrophic vaginal changes and torn tissue.
4.Bimanual exam: Check for cervical motion, tenderness, and masses.
G.Males:
1.Inspect the penis/urinary meatus for phimosis, lesions, signs of inflammation, and discharge. Retract the foreskin (if present) and assess for hygiene and smegma.
2.Palpate the testes and epididymides for inflammation, tenderness, and masses.
3.Rectal examination is mandatory in males. Check for swollen and tender prostate. In patients with suspected acute bacterial prostatitis, palpation should be very gentle because of the potential for bacteremia.
Diagnostic Tests
The diagnosis of a UTI can often be made based on a focused history and the presenting symptoms.
A.Urinalysis: Clean-catch urinalysis may be performed. However, catheterization or suprapubic aspiration may need to be obtained for elderly, obese, microscopic hematuria, or for functionally impaired patients. Catheterization should be reserved for patients with an obstruction or for those who cannot cooperate or collect a clean-catch urine specimen. Urinalysis dipstick findings:
1.Appearance: Should be clear. Cloudy urine may indicate the presence of pyuria, pus, blood, cells, phosphate, or lymph fluid.
2.Odor: Usually faint aromatic odor; ammonia odor indicates Proteus, which is related to food changes; offensive odor indicates bacterial infection.
3.pH: Normal is around 6 (acid); may normally vary from 4.6 to 7.5. Greater than 7.5 may indicate infection.
4.Specific gravity: Reflects the kidney’s ability to concentrate urine and the body’s hydration or dehydration status. Normal is 1.005 to 1.025.
5.Color: Shows concentration; usually yellow or amber.
a.Straw color = dilute urine.
b.Dark color = concentrated (dehydrated).
c.Red or red-brown to blood = transfusion reaction, drugs, and bleeding lesions.
d.Yellow brown = bile duct disease, jaundice.
e.Dark brown or black = melanoma or leukemia.
6.Positive for leukocyte esterase and positive for nitrites.
A negative urine dipstick does not rule out an infection.
B.Microscopic exam of urine findings: WBCs greater than 2 to 5; WBC/high-power microscope field (HPF); bacteria; positive Gram stain for cocci or rods, yeast, and blood indicates infection.
C.Urine culture and sensitivity:
1.Positive culture standard 10⁵ colony-forming units; symptomatic female 10²; symptomatic males 10³.
2.Screening for asymptomatic bacteria is recommended for patients in pregnancy, for elderly males with documented prostatic or urologic abnormalities, for patients with a recent catheterization, and for patients with known stones or documented structural abnormalities.
D.Culture for sexually transmitted infections (STIs) if suspected.
E.Wet prep for female, if indicated.
F.Imaging:
1.Ultrasound.
2.Conventional voiding cystourethrography.
3.Urodynamic evaluation.
Differential Diagnoses
A.UTI: Watch for systemic symptoms of pyelonephritis.
B.Vaginal or pelvic infection.
C.Prostatitis or epididymitis: Tender, enlarged prostate; tender testicle or scrotum.
D.Bladder tumor.
E.Interstitial cystitis (IC).
F.Urinary calculi.
G.Benign prostatic hypertrophy (BPH): Changes in urinary stream and nocturia.
H.Overactive bladder (OAB)/urge incontinence.
I.Pelvic organ prolapse.
J.Irritant urethritis.
K.Consider the possibility that chronic, asymptomatic infections are a potential source of disseminated infection, such as endocarditis. This is particularly likely in the male patient with prostate disease and infection requiring instrumentation.
Plan
A.General interventions:
1.Treatment of acute cystitis is aimed at identifying the underlying cause and initiating treatment as soon as possible.
2.If antibiotic therapy is initiated, stress the importance of taking all medication as directed, even if symptoms improve before the end of treatment.
B. 
See Section III: Patient Teaching Guide Urinary Tract Infection (UTI).
C.Dietary management:
1.Instruct the patient to increase fluids and drink at least one large glass of liquid every hour.
2.Instruct the patient to avoid foods that irritate the bladder: Caffeine, alcohol, tomatoes, citrus, and spicy foods.
3.Encourage the patient to drink cranberry juice to help fight bladder infections. If the patient dislikes the taste of plain cranberry juice, it can be mixed 1:1 with another juice, such as grape juice.
D.Pharmacologic therapy:
1.Antibiotics: 3-day course may be efficacious and is less expensive than the traditional 7- to 10-day course of therapy for uncomplicated infections.
2.The antibiotic of choice depends on the specific bacteria found upon culture. Empiric antimicrobial therapy should cover all likely pathogens.
3.First-line therapy: