Module 11.0 - Urinary Tract Infections Flashcards
What is bacteriuria?
- Bacteriuria is defined as isolation of a quantitative count of bacteria in a urine specimen from an individual with or without associated signs and symptoms.
- > 100,000 cfu/mL of bacteria in an asymptomatic patient.
- Between 100 and 10,000 cfu/mL in a symptomatic patient.
- The presence of pyuria (< 10 leukocytes/mm3) is NOT sufficient for a diagnosis of bacteriuria.
What organs does a lower urinary tract infection involve?
bladder and urethra
What organs does an upper urinary tract infection involve?
kidney and ureters
What is a complicated UTI?
occurs in conjunction with abnormal urinary anatomy/function or in individuals with significant co-morbidities (ex. Critically ill patients)
What is an uncomplicated UTI?
A UTI occurring in a setting with normal anatomy and function
Describe the etiology of UTI’s
A. UTIs occur more frequently in women than men
B. Prevalence of UTIs in women increases with age (>20% in women > 80 years of age) and sexual activity (4.7% in premenopausal women).
C. Prevalence of UTIs in men > 75 years old is 6-15%; rare in healthy young men.
D. In the older adult, the first sign of a UTI may be the onset of confusion/mental status changes.
What are common urinary pathogens?
- Escherichia coli most common causative organism (65% of cases); more common in elderly females
- Staphylococcus aureus (6%)
- Proteus mirabilis (4.7%); more common in elderly men
- Providencia spp. (1.7%); more common in institutionalized patients
How do UTI’s occur with Foley catheter use?
A. Patho- caused by a layer of uropathogens living along catheter (termed biofilm)
B. Avoid catheterizing whenever possible and remove urinary catheters as soon as possible.
C. Candida spp. – common cause of fungal UTI infections
What are the risk factors for UTI development?
- Females: short urethra, sexual intercourse, use of spermicide, pregnancy, history of UTI, new sexual partner
- Males: prostatic enlargement (results in urinary retention); prostatitis, uncircumcised male; homosexuality, HIV infection
- Both genders: History of DM, recent urinary instrumentation, urinary obstruction (nephrolithiasis, ureteral strictures, tumors); history of neurogenic bladder, vesicoureteral reflux
What are the signs/symptoms of a lower urinary tract infection?
Dysuria, frequency, urgency, suprapubic pain, hematuria w/ bacteriuria, malodorous urine, incontinence, no flank or costovertebral pain
What are the signs/symptoms of an upper urinary tract infection?
- Flank pain and/or costovertebral angle tenderness, fever (> 38.0F)/chills, hematuria, N/V, mental status changes (especially in elderly patients), lethargy, rigors
- If symptoms > 3 days, consider abscess formation (in the absence of treatment)
What are the labs/diagnostic tests used to diagnose a UTI?
A. Urinalysis – includes clean-catch and dipstick (point of care testing)
- Pyuria: > 10 leukocytes/mL
- Bacteriuria: > 100,000 cfu/mL
- If UA obtained by straight cath/suprapubic catheterization- 100-10,000 cfu/mL
- RBCs, WBC casts, mild proteinuria may be present in pyelonephritis
- Elevated ESR (erythrocyte sedimentation rate) in pyelonephritis
- Urinary pH > 7.5 generally suggests a UTI
B. Urine culture and sensitivity: gold standard of diagnosis
C. Leukocyte esterase dipstick test: positive (turns purple within 60 seconds); positive results detect WBCs in urine (pyuria)
D. Nitrate dipstick test: positive (turns pink within 30 seconds); positive results indicate protein, blood nitrates in urine; can have false negatives.
E. CBC: leukocytosis with a left shift in acute pyelonephritis
F. Blood culture: if suspected pyelonephritis or concerns for sepsis
G. To rule out obstructive nephropathy, obtain: (for males with UTIs or recurrent UTIs in females)
- Voiding cysto urethrogram (xray)
- CT scan abd/pelvis with and without contrast
- Ultrasound: pelvis/urethra
- MRI of pelvis- +/- contrast
How do you treat acute cystitis?
- First line therapy is single dose (of Fosfomycin) or 3 day dosage (preferred) of sulfonamide (Bactrim DS bid po x 3 days)
- Second line therapy is quinolones (Ciprofloxacin or Levofloxacin for 3 days)
How do you treat an uncomplicated upper UTI?
- Outpatient: Quinolones x 7 days
- Inpatient: Cefotaxime or ceftriaxone IV; Fluororquinolone IV if PCN allergic
How do you treat catheter-associated UTI?
- If bacterial, treat for 7-14 days
- If candiduria (fungal), treat with fluconazole 200-400mg/day for 14 days
How do you treat acute bacterial pyelonephritis?
Needs hospitalization; CT imaging to rule out obstructive uropathy;first-line therapy with aminoglycosides (gentamycin)- dose dependent upon renal function and individualized; avoid in pre-renal disease; normal dosing 15mg/kg with peak levels of 5-10mg/L and trough levels < 2 mg/L; second line therapy: PCN; Consider susceptibility and patient allergies
