UTIs Flashcards
Dr. Trotter
Epidemiology -Patient population UTIs
-younger adults: often in female and childbearing age
-also over age of 65:
->BPH/Obstruction (kidney stones)
->SNF, hospitalization
->neuromuscular disease (stroke)
->Catherization
How does the bacteria usually reach the bladder?
-mostly originates from the colon and ascends up the urethra -> to the bladder
-Hematogenous spread is less common
Host defense mechanism
-low pH (prevents replication, pH alteration may increase the risk for an infection)
-increased micturition when the bladder is introduced to bacteria (flush out)
-Lactobacillus (in vaginal flora) helps to maintain low pH
-Estrogen (helps with the production of Lactobacillus) -> lack of estrogen in older women causes increased risk for an infection
Classification of UTIs
-Asymptomatic Bacteriuria (bacteria in the urine but no symptoms - usually not treated)
-Symptomatic Abacteriuria (symptoms, but not due to bacteria - usually not treated)
-Cystitis (UTI) - Complicated vs Uncomplicated
-Pyelonephritis (infection travels through the Ureter to the kidney - treated more aggressive)
How is complicated Cystitis different from uncomplicated cystitis?
Complicated: higher likelihood of severe infection, more difficult to treat, a wider variety of bugs causing them
Uncomplicated: the simplest form of UTI, young and healthy without morbidities
Risk factors for UTIs - Female
-Previous UTI
-sexual intercouse
-Diaphagram/spermicides (affects the pH)
-Urologic instrumentation (stents, catheter)
-Pregnancy (anatomical changes)
-diabetes
-estrogen deficiency(reduced lactobacilli in the vaginal flora)
-meds: SGLT2 (glucose in the urine), Anticholinergic, Tricyclic antidepressants -> reduced urination (residual volume, not flushing as much)
Risk factors for UTIs - Male
-Previous UTI
-Obstruction (calculi, strictures)
-BPH
-vaginal E.coli colonization in partner
in all patients:
incomplete bladder emptying
neurologic malfunction (stroke)
-fecal incontinence
-vesicoureteral reflux (reflux of urine into the kidneys)
Risk for Pyelonephritis
-extremes of age
-anatomic abnormalities
-foreign bodies (catheters)
-immunosuppression
-obstruction
-pregnancy
-inappropriate abx use
Asymptomatic Bacteriuria
-more than 10^5 bacteria /ml (10^8/L) without symptoms
-2 specimens when female, one if male
-common in the elderly (ov 65)
-not often treated
-special populations are treated (pregnant or before urological procedure)
Why are asymptomatic Bacteriuria not treated?
-no benefit
-doesn’t really clear the bacteria or prevent the progression
-but increases the risk of resistance
Symptomatic Abacteriuria
-Symptoms like pyuria (cloudy urine due to WBC) or dysuria (painful urinating) with less than 10^5/ml (10^8/L) of urine
-not so common: (50% of female patients with symptoms)
Uncomplicated cystitis
-otherwise healthy
-premenopausal, non-pregannt
-no structural or functional urinary tract abnormalities
-some physicians include postmenopausal women and those who are unlikely to have adverse effects
Complicated cystitis
-any other patient
-male (often with structural or neurological abnormalities)
-children
-pregnancy
-HCA
-comorbidities (T2D, CKD, immunocompromised)
-urinary tract abnormalities, catheter
Which type of Cystitis is treated with broad-spectrum antibiotics?
Complicated Cystitis
-E.coli (50%)
-Enterococcus faecalis
-Enterobacter
-Proteus spp
-Klebsiella pneumoniae
-Pseudomonas
in uncomplicated cystitis
-Ecoli (90%)
-Staphylus, Klebsiella, Proteus spp
What is the gold standard for UTI diagnosis?
-Urine culture
-Urinalysis (if there are indications for an infection -> a urine culture is ordered)
-other ways: Signs/symptoms, physical assessment
Symptoms of Cystitis (UTI)
-Dysuria (pain urinating)
-Urgency, frequency
-Nocturia
-Hematuria
-Suprapubic pain
-in the elderly: confusion, delirium
Why is confusion not an indication of Urinalysis?
Because delirium in elderly could be due to many other reasons and we don’t want to increase resistance unnecessarily
-rule out other causes before treating with antibiotics
Symptoms of Pyelonephritis
-Cystitis symptoms
systemic symptoms
-flank pain
-fever (>100.9 F)
-Nausea/vomiting
-malaise
-costovertebral tenderness (CVAT) on exam
When to collect Urin
if symptoms are present -> urine collection
-midstream clean catch (preferred)
-Catherization (need aseptic technique)
-suprapubic aspiration
Urinary test results indicating UTIs
-Pyuria: WBC more than 10^6/ml
-nitrite-positive urine (nitrate converted into nitrite by the bacteria
->gram (+) do not produce nitrites - False negative
->Phenazopyridine - False positive
-Leucoctye esterase-positive: indicates presence of WBC
When are Urine cultures ordered?
-symptoms and urinalysis in complicated UTI
-candidates for treatment of asymptomatic bacteriuria (screening: pregnant, urological procedure)
-Findings: more than 10^5 CFU/L, pathogen, abx sensitivity
Non-pharm and Self-care
-Fluids
-Cranberry (evidence mixed): acidify (lower) the pH, blocks E.coli adhesion to the bladder wall
-Lactobacillus maintains vaginal flora
-Phenazopyridine (in AZO products): targeting the symptoms -> may mask the real infection, antibiotics usually work within a day (so no point), and it shouldn’t be used w/o antibiotics!
Contraindication of Phenazopyridine
-renal disease
-severe hepatic disease
-Counsel: orange urine
Empiric Treatment for Uncomplicated Cystitis
-Nitrofurantoin 100 mg BID x 5 days
-TMP/SMX 160/800 BID x 3 days -> unless the local resistance is greater than 20% or Bactrim was used in the last 3 months
-Fosfomycin 3g, single dose
ß-lactam: Augmentin 500 mg q8h
Cefdinir, Cefaclor, Cefpodoxime-proxetil
-> all 3-7 days
When to consider second-line treatment in uncomplicated Cystitis?
-poor renal function: avoid Nitrofurantoin (Macrobid) or Bactrim
-cost: Fosfomycin
-pregnancy: avoid bactrim go with ß-lactam
-instead: ß-lactam 3-7 days: Augmentin, cefdinir, cefaclor, cefpodoxime-proxetil
-FQ: AVOID if possible
Empiric treatment for Complicated Cystitis
-Fosfomycin 3g 48-72h x 2-3 doses (not often used)
-Bactrim 1 tab BID 7-10 days (longer duration than in uncomplicated treatment)
-Levofloxacin 750 mg once daily, x 5 days
-Ciprofloxacin 250-500 mg BID x 7-10 days
-ß-lactams (Augmentin, keflex, cefpodoxime) x 5-7 days
Which organism is resistant to Fosfomycin?
Klebsiella
Considerations for Bactrim
-Renally eliminated, (CAUTION: renal impairment, if the kidney is not working the drug will not be filtered into the kidney)
-rising E. coli resistance
-Pro: high urinary concentration
ADE: rash, photosensitivity, renal failure (nephrotoxic)
Considerations for Nitrofurantoin (Microbid)
-Avoid in CrCl <30 ml/min (CAUTION in renal impairment)
-Macrobid (BID) vs Macrodantin (QID)
-GI intolerance, pulmonary fibrosis, hepatotoxicity with long-term use (Beer’s list)
-lack of resistance
Considerations for FQ (Levo, Cipro)
-Cipro over Levofloxacin
-Collateral damage (resistance, Cdiff, ADRs)
-ADRs: tendon rupture, QTprolongation
-used in pyelonephritis (but also in complicated cystitis)
Considerations for ß-lactams
-Augmentin is preferred due to resistance
-watch out for allergies
-safer than FQ (coverage is smaller)
Pyelonephritis Treatment
-always culture-> tailor the therapy to the results, symptoms are systemic and cause more problems
-start with IV, usually ceftriaxone -> may be changed to PO
-7-14 days
-Nitrofurantoin is not appropriate -> low Vd in the kidney
-Fosfomycin is not appropriate for pyelonephritis bacteremia
Outpatient Pyelonephritis Treatment
-if mild-moderate and the patient can take PO, is hydrated and otherwise well
-FQ preferred if local resistance is <10%
if >10% initiate IV dose of gentamicin (CAUTION: nephrotoxic) or ceftriaxone
Cipro over Levo
-Bactrim can be used if susceptibility is known (due to resistance)
-beta-lactams are second line due to resistance
Inpatient Pyelonephritis Treatment
-broad spectrum treatment
-Carbapenem
-FQ
-Aminoglycoside (CAUTION nephrotoxic) +/- Ampicillin (cover enterococcus)
-Pip/tazo (Zosyn): if Pseudomonas, enterococcus, staph is suspected
-change to PO ASAP
Which cephalosporins get well into the urine?
Cephalexin (keflex), cefuroxime, cefotaxime
Catheter-associated UTI
-biggest risk factor: duration of catheterization
-difference between CA-asymptomatic bacteriuria and CA-UTI
-Symptoms: flanked/suprapubic pain, costovertebral angle tenderness, catheter obstruction, fever, malaise, hematuria, lethargy, SIRS
When to treat Catheter-associated UTI
-only when symptomatic, bc they will be colonized anyway
-remove the catheter and take a midstream sample, or through a new catheter or catheter-port
Treatment of CA-UTIs
-based on past cultures
-narrow the spectrum when culture arrives
-similar to complicated UTIs: Fosfomycin, Bactrim, FQ, ß-lactams
-7-14 days
Why are pregnant prone to UTIs?
-reduced bladder tone/decreased ureteral peristalsis
-urinary reflux into the kidneys -> risk of pyelonephritis
-risk for asymptomatic bacteriuria
Treatment for UTIs in pregnant women
-Augmentin
-Cephalexin
-5-7 days (complicated UTI)
Consider when treating pregnant women
-Avoid Nitrofurantoin (jaundice)
-AVOID FQ
-Avoid Bactrim in the 3rd trimester (weeks 27-40)
Recurrent UTIs
-often seen in the elderly females
-2 or more infections within 6 months
-3 or more in 1 year
-can be relapse (same organism) or reinfection (after 2-3 weeks, by a different organism)
How to treat recurrent UTI
-mostly behavioral changes: drinking fluids, avoiding spermicides/diaphragm, avoiding delaying urination, urination after intercourse, wiping front to back
-antibiotics is controversial - reduce recurrence but increase resistance and ADEs
->Nitrofurantoin 50mg daily (low dose) -> avoid long-term
->bactrim 1/2 SS tablet daily (low dose)
Other treatments for recurrent UTI
-topical estrogen (lactobacillus and pH)
-post-coital antibiotic if infection occurs after coitus
-Methenamine hippurate - not lot of evidence
Why should long-term use of Nitrofurantoin be avoided?
-causes pulmonary fibrosis and hepatoxicity
Hematuria is a symptom in which type of UTI?
-Cystitis
-Pyelonephritis
-Catheter-associated UTI
Which drug should be avoided in CrCl < 30 ml/min
Nitrofurantoin
What to consider in patients with signs of Pyelonephritis?
-Admission to the hospital? Y/N
-admit if a comorbid condition is present (renal dysfunction, urologic disorder, diabetes, liver or cardiac disease, immunocompromised)
-dehydrated
-hemodynamic instability: hypotension
-male sex
-severe flank and abdominal pain
-sepsis
-high fever >103°F
What are the biggest indications for a UTI on a Urinalysis?
Nitrite (+)
elevated leukocytes
