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Flashcards in Urinary Tract Infections Deck (23)
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Cystitis vs pyelonephritis

- lower UTI or inflammation of the bladder
- presents with: hematuria, frequency/urgency, dysuria, pyuria, suprapubic pain
- DOESN’T usually present with systemic signs
- WBCs, nitrates and leukocyte esterase are all-found in the urine as well , but the CBC will look normal

- upper UTI or inflammation of the kidney itself
- presents with: all cystitis symptoms + fever/chills, lower flank pain (CVA junction), N/V, hypotension
- infection counts in urine are present but WBCs are also elevated in the CBC (different from cystitis)
- also may show hyaline or WBC casts

**both are 10x more common in females


Risk factors for both cystitis and pyelonephritis

Being a women
- have shorter urethras and also receive urethral Trauma during sex

Frequent sexual intercourse (cystitis only)
- “honeymoon” cystitis in women and is usually staph saph

Kidney procedures

Catheterization *(#1 risk factor)*

Enlarged prostate

Obstruction of the tract

- causes higher pH

- causes higher pH

Congenital defects

Frequent Post-void residuals

Having urethra bypass or indwelling catheter


What are the major UTI-causing pathogens?

E. Coli (#1)

Serratus marcescens

Proteus mirabilis

Pseudomonas aeruginosa

Klebsiella pneumoniae

Enterococcus species

**staphylococcus saprophyticus is only in women, but accounts for (5-15%)


ORENUC phenotype classification

**you give the UTI one of these letters based on the patient **

O: No risk factors
- patient is healthy and premenopausal

R: risk of recurrent UTIs
- patient has risky sexual behavior/uses spermicide, hormonal deficiencies (postmenopausal), well controlled diabetes

E: extra-urogenital risk factors are present
- premature new born, currently pregnant, male gender, poorly controlled DM, is immunosupressed

N: nephropathic diseases present with likely severe outcomes
- renal insufficiency, polycystic kidney disease, interstitial nephritis

U: resolvable/urological risk factors are present
- ureteral obstruction, asymptomatic bacteria, short-term external urinary catheter present, asymptomatic bacteremia

C: permanent external catheter is present or in resolvable urological risk factors
- irreversible neurogenic bladder


How are symptomatic UTIs classified?

By severity

The most severe = febrile UTI (urosepsis syndrome)


Guidelines for catheter care

**note that because catheterization is the #1 risk factor for UTIs, it is essential to keep a patient on a catheter as little as possible**

**also bacteria that infect a catheter often produce biofilms which make antiseptic techniques not work as well**

Avoid catheterization when possible

Keep duration to minimum
- each day on a catheter = Increases 3-10% chance

Use intermittent catheter rather than permanent whenever possible

Maintain a gravity drain

Use topical antiseptics around the meatus in women

Must use closed drain systems whenever possible


Common Bacterial virulence factors amoung UTIs

# Fimbria/pill
- allow for adherence and increased hemolysin
- **bacteria that possess P fimbriae are far more likely to cause pyelonephritis
- **very common in e. Coli

# Capsular polysaccharide
- K antigens and other antigens allows for anti-phagocytic properties

- almost all have them and increases risks of kidney stones
- also allows them to live since urine is often toxic

IgA protease


- used to decrease ureteral peristalsis which allows easier time to retrograde migrate into the kidney

# = most important and common virulence factors in UTIs


Acute lower UTI’s

Poorly understood immune response
-IgA and IgG are present but unknown why
- low serological response

Acute onset of dysuria/urgency and frequency will be present, usually no flank pain though and not severe suprapubic pain (but does show suprapubic pain)
- **elderly patients can be asymptomatic

Almost always shows pyuria and bacteriuria
- (+/-) hematuria
- usually labs dont show increased WBCs, but the urine dipstick will suggest UTI

Recurrent often causes fibrosis and metaplasia in the bladder


What are the two most common bacteria that can cause a UTI but NOT show up on UA cultures initially?

TB and chylamida
- both are rare causes of UTIs, but these two specifically dont show up well on UA cultures

**also gonorrhoeae can cause this but is more rare**


Acute upper UTIs

Difficult to distinguish from UTIs
- lower UTI symptoms + fever/chills and flank pain is the msot common method
- CBC = elevated WBC
- dipstick = signs of infection

Recurrent = loss of renal function
- leads to HTN and **chronic interstital nephritis (most dangerous)

Staph is more common in Upper UTIs, but still e.coli is #1


What populations are at risk for asymptomatic UTIs

Pregnant women

Young children



**will show hematuria with no symptoms**


What is the cutoff for significant bacteriuria based on bacterial counts

10^5 (100,000 CFUs) or greater = significant bacteriuria

10^3 = not infected

In between = could have been contaminated but unknown


What is the cutoff for normal amounts of WBCs in urine?



Common oral antibacterials used for UTIs

1) Trimethoprim
- good to use but has elevated resistance in some strains
- because of this often combined with sulphamethoxazole which combats the resistance

2) nitrofurantoin
- used in uncomplicated UTIs caused by E.coli add staph
- DONT use for urease positive organisms, it doesnt work (if the patients urine is alkaline = dont use)

3) fluroquinolones
- very broad spectrum and often a first line treatment
- doesnt work well against enterococcus however (use TMP-SMX if can)

**usually use best guess until culture is obtained for specific organism**


Most important pseudomonas aeruginosa virulence factors pertaining to UTIs

Exotoxins A:
- MOA = ADP-ribosylation of EF-2
- inhibits host cell protein synthesis

- MOA = hydrolysis of phospholipids and Eukaroytic membranes
- casues tissue damage

- MOA = adherence and protection from immune system and dehydration

- MOA = protects against complement and allow induces sepsis via (O and lipid A antigens)


Stress and pseudomonas aeruginosa

Studies have shown that stress-induced opioid formation in hosts leads to increased Pseudomonas quorum sensing (increases chances of invasion of cells)
- this activates at a greater magnitude the virulence factors and pathogenesis of the disease

**P. Aeruginosa is much more deadly in stressed patients and weakened immune systems**


What is the gold standard for confirmation of a UTI

Urine culture = 10^5 (100,000 CFUs)
- still can mean your infected if below this, however if you hit this level, you HAVE an infection


What is the most common lab results for urethritis?

Patient is positive for pyuria but negative for a urine culture
- **sterile pyuria**
- can be gonorrhea and Chlamydia infections or just general inflammation

**this is how you differentiate urethritis from cystitis (both will present will very similar symptoms)**


What is a VCUG?

Voiding cystourethrogram
- injects radiocontrast up the uric nary tract to the kidney and monitor with imagining while it comes back down
- not first line unless severe UTIs or complicated UTIs (increases risks of scarring of the kidney)


Which bacteria causes ammonia smelling urine?

Proteus species


What is the most common UTI in elderly males?

- is almost always complication UTI since it is highly resistant to antibiotics

Risk factors (other than being an elderly male)
- catheters
- prolonged hospitalization
- use of broad-spectrum antibiotics


What is the #1 bacteria most common in alcoholics and diabetics?

Klebsiella pneumoniae
- is the only UTI that shows a very prominent capsule around its cell

shows “current jelly” sputum and highly antibiotic resistant


What are the only enterobacteriacae species that ferment lactose?

E. Coli and enterobacter
*will look pink on macconkey*