Chapter 89: Drug Therapy of Urinary Tract Infections (Lehne) Pages 1066 -1070

For treatment of complicated UTIs to succeed,

the identity and drug sensitivity of the causative organism must be determined. To do so, urine for microbiologic testing should be obtained before giving any antibiotics.

Acute uncomplicated pyelonephritis is an infection of

the kidneys. The disorder is common in young children, older adults, and women of child-bearing age. Clinical manifestations include fever, chills, severe flank pain, dysuria, urinary frequency, urinary urgency, pyuria and, usually, bacteriuria.

UTIs may be classified according to

their location, in either the lower urinary tract or upper urinary tract. In this classification scheme, cystitis and urethritis are considered lower tract infections, whereas pyelonephritis is considered an upper tract infection.

Nitrofurantoin is a first-choice drug for

uncomplicated cystitis.

Mild to moderate pyelonephritis can be treated

at home with oral antibiotics.

For community-acquired infections, three types of oral therapy can be used:

(1) single-dose therapy, (2) short-course therapy (3 days), and (3) conventional therapy (7 days).

The majority of uncomplicated, community-acquired UTIs are caused by

Escherichia coli.

Hospital-acquired UTIs frequently are caused by

Klebsiella, Proteus, Enterobacter, and Pseudomonas species; staphylococci; and enterococci. E. coli is responsible for fewer than 50% of these infections. Although most UTIs involve only one organism, infection with multiple organisms may occur, especially in patients with an indwelling catheter, renal stones, or chronic renal abscesses.

____________ are the most common infections encountered today.

Urinary tract infections (UTIs)

Symptoms that reappear shortly after completion of a course of therapy suggest

a structural abnormality of the urinary tract, involvement of the kidneys, or chronic bacterial prostatitis, the most common cause of recurrent UTI in male patients.

Complicated UTIs occur in male and female patients who have

a structural or functional abnormality of the urinary tract that predisposes them to developing infection. Symptoms of complicated UTIs can range from mild to severe. Some patients even develop systemic illness, manifesting as fever, bacteremia, and septic shock.

Bacterial prostatitis responds well to

antimicrobial therapy.

It is important to note that many women (30% or more) with symptoms of acute cystitis also have

asymptomatic upper UTI (subclinical pyelonephritis).

Infections may be limited to

bacterial colonization of the urine, or bacteria may invade tissues of the urinary tract.

The bacteria that cause UTIs differ between

community-acquired infections and hospital-acquired infections.

UTIs are referred to as

complicated or uncomplicated. Complicated UTIs occur in both males and females and, by definition, are associated with some predisposing factor, such as calculi, prostatic hypertrophy, an indwelling catheter, or an impediment to the flow of urine. Uncomplicated UTIs occur primarily in women of child-bearing age and are not associated with any particular predisposing factor.

Severe pyelonephritis requires

hospitalization and IV antibiotics.

Acute bacterial prostatitis is defined as

inflammation of the prostate caused by local bacterial infection. Clinical manifestations include high fever, chills, malaise, myalgia, localized pain, and various urinary tract symptoms (dysuria, nocturia, urinary urgency, urinary frequency, urinary retention). In most cases (80%), E. coli is the causative organism.

When reinfections are frequent (three or more per year), __________ may be indicated

long-term prophylaxis may be indicated. Prophylaxis can be achieved with low daily doses of several agents. Prophylaxis should continue for at least 6 months.

Acute cystitis is a

lower UTI that occurs most often in women of child-bearing age. Clinical manifestations are dysuria, urinary urgency, urinary frequency, suprapubic discomfort, pyuria, and bacteriuria.

Two urinary tract antiseptics are available:

nitrofurantoin and methenamine. Both are used only for UTIs. These drugs become concentrated in the urine and are active against the common urinary tract pathogens. Neither drug achieves effective antibacterial concentrations in blood or tissues.

More than 80% of recurrent UTIs in female patients are due to

reinfection. These usually involve the lower urinary tract and may be related to sexual intercourse or use of a contraceptive diaphragm.

Recurrent UTIs result from

relapse or from reinfection. Relapse is caused by recolonization with the same organism responsible for the initial infection. In contrast, reinfection is caused by colonization with a new organism.