Lower urinary tract infection
Cystitis and urethritis, the two forms of lower urinary tract infection (UTI), are nearly 10 times more common in females than in males and affect approximately 10% to 20% of all females at least once. Lower UTI is also a prevalent bacterial disease in children, with females again most commonly affected. In males and children, lower UTIs are frequently related to anatomic or physiologic abnormalities and therefore require extremely close evaluation. UTIs often respond readily to treatment but recurrence and resistant bacterial flare-up during therapy are possible.
PEDIATRIC TIP All children with proven UTI should receive a work-up to exclude an abnormality of the urinary tract that would predispose them to renal damage.
Causes and incidence
Most lower UTIs result from ascending infection by a single, gram-negative, enteric bacterium, such as Escherichia coli, Klebsiella, Proteus, Enterobacter, Pseudomonas, or Serratia. However, in a patient with neurogenic bladder, an indwelling catheter, or a fistula between the intestine and bladder, lower UTI may result from simultaneous infection with multiple pathogens. Recent studies suggest that infection results from a breakdown in local defense mechanisms in the bladder that allow bacteria to invade the bladder mucosa and multiply. These bacteria can’t be readily eliminated by normal micturition.
Bacterial flare-up during treatment is generally caused by the pathogenic organism’s resistance to the prescribed antimicrobial therapy. The presence of even a small number (less than 10,000/µl) of bacteria in a midstream urine sample obtained during treatment casts doubt on the effectiveness of treatment.
In 99% of patients, recurrent lower UTI results from reinfection by the same organism or from some new pathogen; in the remaining 1%, recurrence reflects persistent infection, usually from renal calculi, chronic bacterial prostatitis, or a structural anomaly that may become a source of infection.
The high incidence of lower UTI among females may result from the shortness of the female urethra (1¼" to 2" [3 to 5 cm]), which predisposes females to infection caused by bacteria from the vagina, perineum, rectum, or a sexual partner. Males are less vulnerable because their urethras are longer (7¼" [18.4 cm]) and because prostatic fluid serves as an antibacterial shield. However, in men older than age 60, incidence rates match those of women. In both males and females, infection usually ascends from the urethra to the bladder.
ELDER TIP As a person ages, his bladder muscles weaken, which may result in incomplete bladder emptying and chronic urine retention — factors that predispose the older person to bladder infections.
Signs and symptoms
Lower UTI usually produces urgency, frequency, dysuria, cramps or spasms of the bladder, itching, a feeling of warmth during urination, nocturia, and possibly urethral discharge in males. Inflammation of the bladder wall also causes hematuria and fever. Other common features include low back pain, malaise, nausea, vomiting, abdominal pain or tenderness over the bladder area, chills, and flank pain.
ELDER TIP The most common initial symptoms of lower UTI in elderly patients are lethargy and a change in mental status.
Diagnosis
Characteristic clinical features and a microscopic urinalysis showing red blood cells and white blood cells greater than 10/high-power field suggest lower UTI.
CONFIRMING DIAGNOSIS A clean-catch midstream urine specimen revealing a bacterial count above 100,000/µl confirms the diagnosis.
Lower counts don’t necessarily rule out infection, especially if the patient is voiding frequently because bacteria require 30 to 45 minutes to reproduce in urine. Careful midstream, clean-catch collection is preferred to catheterization, which can reinfect the bladder with urethral bacteria.
Sensitivity testing determines the appropriate therapeutic antimicrobial agent. If patient history and physical examination warrant, a blood test or a stained smear of the discharge rules out venereal disease. Voiding cystoureterography or excretory urography may detect congenital anomalies that predispose the patient to recurrent UTIs.
Treatment
Appropriate antimicrobials are the treatment of choice for most initial lower UTIs. A course of antibiotic therapy lasting from 7 to 10 days is standard, but recent studies suggest that a single dose of an antibiotic or an antibiotic regimen of 3 to 5 days length may be sufficient to render the urine sterile. After 3 days of antibiotic therapy, urine culture should show no organisms. If the urine isn’t sterile, bacterial resistance has probably occurred, making the use of a different antimicrobial necessary. Single-dose antibiotic therapy with amoxicillin or co-trimoxazole may be effective in females with acute noncomplicated UTI. A urine culture taken 1 to 2 weeks later indicates whether or not the infection has been eradicated.
Recurrent infections due to infected renal calculi, chronic prostatitis, or structural abnormality may necessitate surgery; prostatitis also requires long-term antibiotic therapy. In patients without these predisposing conditions, long-term, low-dosage antibiotic therapy is the treatment of choice.
PEDIATRIC TIP Fluoroquinolones aren’t used for children because of possible adverse effects on developing cartilage.
Special considerations
The care plan should include careful patient teaching, supportive measures, and proper specimen collection.
❑ Explain the nature and purpose of antimicrobial therapy. Emphasize the importance of completing the prescribed course of therapy or, with long-term prophylaxis, of adhering strictly to the ordered dosage. Urge the patient to drink plenty of water (at least eight glasses a day). Stress the need to maintain a consistent fluid intake of about 2 qt (2 L)/day. More or less than this amount may alter the effect of the prescribed antimicrobial. Fruit juices, especially cranberry juice, and oral doses of vitamin C may help acidify the urine and enhance the action of the medication.
❑ Watch for GI disturbances from antimicrobial therapy. Nitrofurantoin macrocrystals, taken with milk or a meal, prevent such distress. If therapy includes phenazopyridine, warn the patient that this drug may turn urine red-orange.
❑ Suggest warm sitz baths for relief of perineal discomfort. If baths aren’t effective, apply heat sparingly to the perineum but be careful not to burn the patient. Apply topical antiseptics, such as povidone-iodine ointment, on the urethral meatus as necessary.
❑ Collect all urine samples for culture and sensitivity testing carefully and promptly. Teach the female patient how to clean the perineum properly and keep the labia separated during voiding. A noncontaminated midstream specimen is essential for accurate diagnosis.
❑ To prevent recurrent lower UTIs, teach the female patient to carefully wipe the perineum from front to back and to clean it thoroughly with soap and water after defecation. Advise an infection-prone woman to void immediately after sexual intercourse. Stress the need to drink plenty of fluids routinely and to avoid postponing urination. Recommend frequent comfort stops during long car trips. Also stress the need to completely empty the bladder. To prevent recurrent infections in males, urge prompt treatment of predisposing conditions such as chronic prostatitis. Have the patient use a commode rather than a bedpan to promote sitting up, which assists in emptying the bladder.
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
Other Book Chapters Related to Bladder symptoms
Read excerpts from these other book chapters related to Bladder symptoms:
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- Urethral Discharge
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
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- Bladder distention
- "Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series" (2007)
- [ read ]
Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2008 Williams & Wilkins.
More About Causes of Bladder symptoms
» Next page: Neurogenic bladder (Professional Guide to Diseases (Eighth Edition))
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