Hunter: UTIs Flashcards
Two infections of the lower urinary tract
urethritis
cystitis (bladder)
The most common upper urinary tract infection is called (blank) (kidney and ureter)
pyelonephritis
Less common but more serious complication of pyelonephritis
perinephric abscess
These populations have higher rates of UTI
women (30:1)
older age
increased sexual activity
postmenopausal women because of bladder and uterine prolapse and hormonally induced changes
men in the 5th decade of life due to benign prostatic hypertrophy
(blank) is the most common cause of uncomplicated UTI in all age groups (80-90%)
E. coli
(blank) is the second most common cause of these infections, particularly in sexually active females between the ages of 13 and 40
Staphylococcus saprophyticus
Most common causes of complicated UTI, such as those resulting from anatomic obstructions from catheterization
E. coli Proteus mirabilis Klebsiella Enterococcus spp. Pseudomonas aeruginosa
This fungus can cause UTIs
candida spp
UTIs are frequently caused by (blank) organisms
multi-drug resistant
Risk factors for UTI
women (closer proximity of urethra to anus)
sexual intercourse (contamination of urethral opening with fecal organisms)
Benign prostatic hypertrophy (or anything obstructing elimination of urine)
Urethral catheters
Stones in the urinary tract
Physiologic changes leading to incomplete emptying of the bladder (pregnancy)
Reflux of urine from bladder to kidney
What is vesicoureteral reflux?
Reflux of urine from the bladder to the kidney
How does a UTI occur?
bacterial organisms in the feces contaminate the periurethral region
these bugs can ascend up the urethra to the bladder, and sometimes they can even reach the kidney
**ascension of organisms is facilitated by bacterial fimbrae that bind to uroepithelium
What are some host factors that protect against UTI?
normal daily urine flow
constant uroepithelial cell sloughing
large numbers of lactobacilli in the vaginal mucosa (pH)
Blood borne infections of the urinary tract are infrequent, but can be due to (blank)
Staph aureus
What are some virulence factors of E.coli?
Type 1 fimbriae
P fimbrae
hemolysin
Bind to mannose-containing host epithelial receptors; Cystitis»_space; pyelonephritis patients
Type I fimbriae (fimH)
Bind to glycosphingolipid host epithelial receptors (abundant in kidney epithelium); P-fimbriated strains cause pyelonephritis (90%) and can cause bacteremia
P fimbrae (papGAP)
Most uropathogenic strains of E.Coli have a (blank) that can damage uroepithelium
hemolysin
Genes for these virulence factors are carried on (blank)
pathogenicity islands
Signs and symptoms of cystitis?
urgency and frequency of urination
voiding small volumes of urine
painful urination
suprapubic tenderness just before or immediately after voiding
How to treat patients with a cystitis in an outpatient setting
trimethoprim-sulfamethoxazole (bactrim)
or cipro for 3 days
Why do you do a urinalysis if you suspect a UTI?
to determine urine pH (most bacterial causes like E.coli do not elevate the pH, but urease-producing organisms like Proteus mirabilis do elevate the pH)
you also want to look for white blood cells in urine (pyuria) and bacteria in urine
The pH of the urine is usually determined using a (blank)
The pH is not elevated with most bacterial causes of urinary tract infection.
If the pH is greater than 7.9 and the urine contains bacteria and white blood cells, the patient usually has a UTI due to (blank)
dipstick test; Proteus mirabilis (urease producing organism)
Pyuria can be determined using traditional microscopic wet mount examination of spun urine, a cell-counting chamber technique, or a dipstick test for (blank)
leukocyte esterase
Bacteriuria can be determined using a dipstick test to check for the presence of (blank) in the urine
nitrites
*many uropathogens convert nitrates to nitrites when growing in urine (e.g., E. coli and P. mirabilis)
For cultures, how should you obtain a urine specimen? How should you analyze the culture?
use a clean-catch urine specimen;
if more than 100,000 colony-forming units per mL, the patient has clinically significant bacteriuria
**often times the bacteriuria is asymptomatic
Three groups of patients with asymptomatic bacteriuria have been shown to benefit from treatment:
pregnant women
renal transplant pts
pts who are going to undergo GU surgery
What are these symptoms suggestive of?
fever (38+ C)
nausea and vomiting
flank pain and tenderness
costovertebral angle tenderness
pyelonephritis
What should be used to treat pyelonephritis?
trimethoprim-sulfamethoxazole (Bactrim) for 14 days
the kidney is somewhat enlarged, and discrete, yellowish, raised abscesses are apparent on the surface
acute pyelonephritis
What is the pathognomonic histologic feature of acute pyelonephritis?
suppurative necrosis or abscess formation w/i the renal substance
One or both kidneys contain gross scars and there are inflammatory changes in the pelvic wall with papillary atrophy and blunting
The parenchyma shows interstitial fibrosis with an inflammatory infiltrate of lymphocytes, plasma cells, and occasionally neutrophils
chronic pyelonephritis
How to treat a perinephric abscess?
IV antibiotics (ceftriaxone & gentamicin) drain the abscess
A motile gram-negative rod that can cause UTI; it has swarming growth on agar
It can cause stones to form when it produces urease which catalyzes the breakdown of urea to ammonia and carbon dioxide
Proteus mirabilis
Proteus mirabilis releases urease, which converts urea to ammonia and CO2. What kind of stones can you get from ammonia buildup in urine?
magnesium ammonium phosphate stones
**struvite calculi
Risk factors for Proteus mirabilis infection?
catheterization
recurrent UTI
anatomical defects
How to treat Proteus mirabilis infection?
ceftriaxone
How to treat acute vs severe pyelonephritis?
acute: bactrim for 14 days as outpatient
severe: treat inpatient with IV antibiotics until 24 hrs after fever breaks, then oral antibiotic for 14 days
How to prevent UTIs?
high fluid intake (to ensure good urine output) cranberry juice (tannins prevent binding of the bacteria to uroepithelial cells) empty the bladder as soon as you feel the need to urinate
What can sexually active women do to prevent UTI recurrence?
take a spermicide-containing contraceptive
or take an antimicrobial agent before having intercourse
How can postmenopausal women prevent recurrent UTI?
take oral or vaginal estrogen which will shift the vaginal flora to lactobacilli –> this lowers the vaginal pH and reduces colonization of the vagina
Most common cause of acute bacterial prostatitis
E. Coli
Other bacteria that can cause prostatitis
Klebsiella Pseudomonas Enterobacter Serratia Proteus
Who gets prostatitis?
sexually active males
males with previous episodes of prostatitis
**most common malady of prostate in pts younger than 35
How does prostatitis occur?
The E. coli strains that cause prostatitis appear to use the same virulence factors that cause other UTI
Infected urine refluxes into the glandular prostatic tissue via the ejaculatory and prostatic ducts
Infiltrating neutrophils around the acini are associated with intraductal desquamation and cellular debris
Tissue invasion by lymphocytes, plasma cells, and macrophages
How can you diagnose prostatitis?
urine specimen via midstream catch procedure –> should have 100,000+ CPU/mL
rectal exam –> prostate will be warm, swollen, tender to touch
PSA testing –> if asymptomatic, may have elevated PSA in bloodstream
Symptoms of prostatitis
fever
chills, aches esp in lower back
painful and frequent urination
How to treat prostatitis?
Trimethoprim-sulfamethoxazole (Bactrim) or cipro for 10-14 days
T/F: Some infections of the prostate can be prevented using a condom during sex
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