Chapter 55 Infections of the Urinary Tract

Question 1

What is a UTI?

Answer 1

A UTI (Urinary Tract Infection) is an inflammatory response of the urothelium to bacterial invasion, typically associated with bacteriuria and pyuria.

Question 2

What does bacteriuria refer to?

Answer 2

Bacteriuria is the presence of bacteria in the urine, indicating either bacterial colonization or infection of the urinary tract.

Question 3

What does pyuria refer to?

Answer 3

Pyuria is the presence of white blood cells (WBCs) in the urine, generally indicative of infection and/or an inflammatory response of the urothelium.

Question 4

Can bacteriuria occur without an actual urinary tract infection? If so, what might it indicate?

Answer 4

Yes, bacteriuria can occur without an actual urinary tract infection, potentially indicating bacterial colonization without overt infection or contamination of a sample during collection.

Question 5

What conditions can contribute to pyuria besides UTIs?

Answer 5

Conditions that can contribute to pyuria include bacteria, stones, indwelling foreign bodies, and other conditions that can cause inflammation of the urothelium.

Question 6

What is the clinical syndrome described by cystitis?

Answer 6

Cystitis is a clinical syndrome described by dysuria, frequency, urgency, and occasionally suprapubic pain.

Question 7

What can cause symptoms similar to bacterial cystitis apart from a bacterial infection?

Answer 7

Symptoms similar to bacterial cystitis can be caused by urethral or vaginal infections, noninfectious conditions such as interstitial cystitis/painful bladder syndrome, bladder carcinoma, or calculi.

Question 8

What defines acute pyelonephritis?

Answer 8

Acute pyelonephritis is defined as a clinical syndrome of chills, fever, and flank pain, accompanied by bacteriuria and pyuria, specific for an acute bacterial infection of the kidney.

Question 9

Why might diagnosing acute pyelonephritis be difficult in spinal cord–injured and elderly patients?

Answer 9

Diagnosing acute pyelonephritis might be difficult in spinal cord–injured and elderly patients because they may be unable to localize the site of their discomfort.

Question 10

What does chronic pyelonephritis describe?

Answer 10

Chronic pyelonephritis describes a shrunken, fibrosed kidney, diagnosed by morphologic, radiologic, or functional evidence of renal disease, often postinfectious but not necessarily associated with current UTI.

Question 11

What are the radiographic changes associated with bacterial infection of the kidney?

Answer 11

Radiographic changes associated with bacterial infection of the kidney can include focal, coarse scarring in the renal cortex overlying a calyx, often accompanied by calyceal distortion, which can result from vesicoureteral reflux (VUR) or calyceal stone disease.

Question 12

What is xanthogranulomatous pyelonephritis (XGP) and what is it associated with?

Answer 12

Xanthogranulomatous pyelonephritis (XGP) is a rare form of chronic pyelonephritis often associated with stone disease, characterized by destructive replacement of normal renal parenchyma with granulomatous inflammation, and associated with ipsilateral loss of renal function.

Question 13

What is demonstrated by an excretory urogram in the case of a young patient with a history of recurrent urinary tract infections and vesicoureteral reflux?

Answer 13

An excretory urogram can demonstrate focal, coarse scarring in the kidney, blunted calyces, and calyces extending to the capsule due to atrophy of the overlying cortex, particularly in patients with a history of recurrent urinary tract infections and vesicoureteral reflux.

Question 14

What does pyelonephritic atrophy suggestive of postobstructive atrophy indicate in a patient with spina bifida and a history of neurogenic bladder?

Answer 14

Pyelonephritic atrophy suggestive of postobstructive atrophy indicates uniform, regular atrophy of the renal cortex, likely due to the reflux of bacteria simultaneously into virtually all nephrons. This condition is uncommon and characteristic of obstruction with superimposed infection, especially in patients with underlying conditions like spina bifida and neurogenic bladder.

Question 15

How is an uncomplicated UTI defined?

Answer 15

An uncomplicated UTI is defined as an infection in a healthy patient with a structurally and functionally normal urinary tract, often referring to the absence of obstruction to any part of the urinary tract. It typically includes cases of isolated or recurrent bacterial cystitis or acute pyelonephritis, with pathogens that are susceptible to and eradicated by a short course of oral antimicrobial therapy.

Question 16

What distinguishes a complicated UTI from an uncomplicated UTI?

Answer 16

A complicated UTI is distinguished by factors that increase the chance of acquiring bacteria and decrease the efficacy of therapy. These include a urinary tract that is structurally or functionally abnormal, a compromised host, and/or bacteria that have increased virulence or antimicrobial resistance.

Question 17

What factors suggest a complicated urinary tract infection (UTI)?

Answer 17

• Functional or anatomic abnormality of the urinary tract
• Male gender
• Pregnancy
• Elderly patient
• Diabetes
• Immunosuppression
• Childhood urinary tract infection
• Recent antimicrobial agent use
• Indwelling urinary catheter
• Urinary tract instrumentation
• Hospital-acquired infection
• Symptoms for more than 7 days at presentation

“FEMME DI CUSHI”:
- Functional/anatomic abnormality
- Elderly
- Male
- Medication (recent antimicrobial use)
- Equipment (indwelling catheter, instrumentation)
- Diabetes
- Immunosuppression
- Childhood infection
- Urinary tract symptoms >7 days
- Symptoms in pregnancy
- Hospital-acquired
- Infection (recurrent)

Question 18

“What are common functional abnormalities encountered in UTIs?”

Answer 18

“Functional abnormalities commonly encountered in UTIs include those that reduce the concentrating ability of the kidney or voiding dysfunction that alters bladder-emptying capabilities.”

“Remember: Functional abnormalities in the kidney can affect either ‘concentrating power’ or ‘bladder-emptying’ – think of a ‘faulty sink’ for concentration issues and a ‘clogged drain’ for voiding problems.”

Question 19

“What renal diseases mainly affect the tubulointerstitial compartment?”

Answer 19

“Renal diseases that mainly affect the tubulointerstitial compartment include postobstructive nephropathy, sickle cell nephropathy, lithium nephropathy, chronic tubulointerstitial nephritis, and inherited diseases such as medullary cystic kidney disease.”

“Remember the ‘Tubular Troupe’: Postobstructive, Sickle cell, Lithium, Chronic interstitial nephritis, and Medullary cystic diseases. They all crash the ‘Tubulo-interstitial party’.”

Question 20

“What are examples of anatomic abnormalities in renal diseases?”

Answer 20

“Examples of anatomic abnormalities in renal diseases include enlargement of the prostate or congenital or acquired sites of residual urine, such as calyceal or urethral or bladder diverticula.”

“Remember: Anatomic abnormalities creating urinary problems can be remembered as ‘PACE’ - Prostate enlargement, Acquired or Congenital abnormalities, and Enlargements like diverticula.”

Question 21

“What conditions contribute to functional abnormalities in the urinary tract?”

Answer 21

“Conditions that contribute to functional abnormalities in the urinary tract include bladder outlet obstruction, neurogenic bladder, and detrusor underactivity.”

“Remember BOND for bladder issues: Bladder Outlet obstruction, Neurogenic bladder, and Detrusor underactivity. Like James Bond, they’re all under cover in the urinary system.”

Question 22

“What often causes a complicated urinary tract infection (UTI)?”

Answer 22

“A complicated urinary tract infection (UTI) is frequently caused by multidrug-resistant bacteria.”

“Memory aid: Think of ‘complicated UTIs’ as ‘complicated villains’ – they often resist the usual tactics, much like multidrug-resistant bacteria resist standard antibiotics.”

Question 23

“What does the term ‘chronic’ imply in the context of urinary tract infections (UTIs), and when should it be avoided?”

Answer 23

“Memory aid: In UTI terminology, ‘chronic’ is a ‘chronic confusion’ – avoid it unless it’s specifically about chronic pyelonephritis or bacterial prostatitis.”
“Memory aid: In UTI terminology, ‘chronic’ is a ‘chronic confusion’ – avoid it unless it’s specifically about chronic pyelonephritis or bacterial prostatitis.”

Question 24

“What defines a first or isolated urinary tract infection (UTI)?”

Answer 24

“A first or isolated urinary tract infection (UTI) occurs in an individual who has never had a UTI or has had one remote infection from a previous UTI.”
“Memory aid: Think of a ‘first or isolated UTI’ like a ‘first-time visitor’ – new to the area or hasn’t been around for a long time.”

Question 25

“What defines an unresolved urinary tract infection (UTI)?”

Answer 25

“An unresolved urinary tract infection (UTI) is one that has not responded to antimicrobial therapy and is documented to be the same organism with a similar resistance profile.”
“Memory aid: Think of an ‘unresolved UTI’ as an ‘unfinished story’ where the bacteria are the stubborn characters who refuse to leave the plot despite efforts.”

Question 26

“What defines a recurrent urinary tract infection (UTI)?”

Answer 26

“A recurrent urinary tract infection (UTI) is one that occurs after documented, successful resolution of an antecedent infection.”
“Memory aid: ‘Recurrent UTI’ is like a ‘boomerang’ – it comes back after you thought it was gone for good.”

Question 27

“What is the difference between reinfection and bacterial persistence in the context of recurrent urinary tract infections (UTIs)?”

Answer 27

“Reinfection in recurrent UTIs describes a new event associated with reintroduction of bacteria into the urinary tract. Bacterial persistence refers to a recurrent UTI caused by the same bacteria reemerging from a focus within the urinary tract, such as an infectious stone or the prostate.”
“Memory aid: ‘Reinfection’ is like an ‘unwelcome visitor returning’, while ‘bacterial persistence’ is like the ‘persistent squatter hiding inside’ – one comes from outside, the other never really left.”

Question 28

“What is antimicrobial prophylaxis (AP) in the context of urinary tract infections (UTIs)?”

Answer 28

“Antimicrobial prophylaxis (AP) in the context of urinary tract infections (UTIs) is the attempted prevention of reinfections by the administration of antimicrobial drugs, assuming that bacteria have been eliminated before prophylaxis begins.”
“Memory aid: Think of ‘Antimicrobial prophylaxis’ as ‘bacterial shields up’ – preventing future invasions after the battlefield (urinary tract) has been cleared.”

Question 29

“What is antimicrobial suppression in the context of urinary tract infections (UTIs)?”

Answer 29

“Antimicrobial suppression in the context of urinary tract infections (UTIs) is the attempted prevention of growth of a focus of bacterial persistence that cannot be eradicated.”
“Memory aid: Think of ‘antimicrobial suppression’ as ‘keeping the bacterial beast at bay’ – it can’t be kicked out, but it can be kept under control.”

Question 30

“What defines domiciliary or outpatient urinary tract infections (UTIs)?”

Answer 30

“Domiciliary or outpatient urinary tract infections (UTIs) occur in patients who are not hospitalized or institutionalized at the time they become infected.”
“Memory aid: ‘Domiciliary or outpatient UTIs’ can be remembered as ‘home-based or walk-in UTIs’ – they happen to those living their everyday life, not in a hospital.”

Question 31

“What defines nosocomial or health care–associated urinary tract infections (UTIs)?”

Answer 31

“Nosocomial or health care–associated urinary tract infections (UTIs) occur in patients who are hospitalized or institutionalized.”
“Memory aid: ‘Nosocomial or health care–associated UTIs’ are like ‘hospital souvenirs’ – unfortunately, they’re acquired during a stay.”

Question 32

“What are catheter-associated urinary tract infections (CAUTIs) and their common risk factors?”

Answer 32

“Catheter-associated urinary tract infections (CAUTIs) occur in patients with indwelling bladder drainage catheters. Common risk factors include prolonged catheter

Question 33

Bacteriuria and pyuria are not synonymous with which medical condition?

Answer 33

Bacteriuria and pyuria are not synonymous with a urinary tract infection (UTI).
Memory Aid: Think of Bacteriuria as “Bacteria presence” and Pyuria as “Pus presence”. They can occur independently without indicating a UTI. Imagine them as two separate visitors who don’t always come together to the ‘UTI party’.

Question 34

UTIs are classified based on what criteria?

Answer 34

Urinary tract infections (UTIs) are classified based on their presumed site of origin.
Memory Aid: Think of UTIs as tourists deciding where to visit: some choose the lower urinary tract (cystitis) and others the upper urinary tract (pyelonephritis). The classification is like picking a travel destination.

Question 35

What distinguishes uncomplicated UTIs from complicated UTIs?

Answer 35

Uncomplicated UTIs occur in healthy patients with normal urinary tracts, while complicated UTIs are associated with factors that increase the likelihood of bacteriuria and decrease the efficacy of therapy.
Memory Aid: Think of an ‘uncomplicated UTI’ like a straightforward road trip in perfect weather, versus a ‘complicated UTI’ like navigating through a storm with roadblocks. The journey (treatment) is harder with complications. ​

Question 36

What are UTI-related complaints ranked among primary diagnoses for women visiting the emergency department in the United States?

Answer 36

UTI-related complaints are among the most common primary diagnoses for women visiting the emergency department in the United States.Memory Aid: Remember “UTC” as “UTI-Top Complaint” for easy recall that UTIs are among the top complaints in emergency departments for women.

Question 37

How many office visits were there for UTI-related complaints in the United States in 2007, and what percentage of all ambulatory visits did this represent?

Answer 37

In 2007 in the United States, there were an estimated 10.5 million office visits for UTI-related complaints, representing 0.9% of all ambulatory visits.
Memory Aid: Think of “UTI Ten Point Five” rhyming with “Office Live” to remember the 10.5 million office visits for UTIs in 2007.

Question 38

By what age have nearly 30% of women had a symptomatic UTI requiring antimicrobial therapy?

Answer 38

Nearly 30% of women have had a symptomatic UTI requiring antimicrobial therapy by age 24.
Memory Aid: Remember “UTI at 24” like a 24-hour clock, indicating a round-the-clock risk of UTIs by this age.

Question 39

What percentage of women will experience a UTI during their lifetime?

Answer 39

Almost half of all women will experience a UTI during their lifetime.
Memory Aid: Recall “Half-Women-Half-UTI” to remember that nearly 50% (half) of all women experience a UTI at some point.

Question 40

What percentage of women over the age of 18 have at least one UTI annually?

Answer 40

11% of women over the age of 18 have one UTI annually.
Memory Aid: Remember “11% annual UTI” as “One in Eleven”, similar to one in a dozen but for UTI incidence.

Question 41

What was the estimated annual cost for the treatment of UTIs in the United States in 2010?

Answer 41

The estimated annual cost for the treatment of UTIs in the United States was $2.3 billion in 2010.
Memory Aid: Think of “UTI costs a 2.3 Billion Fortune” to remember the staggering annual cost.

Question 42

How does the cost differ in treating UTIs caused by antimicrobial-resistant organisms compared to susceptible bacterial counterparts?

Answer 42

The cost in treating UTIs caused by antimicrobial-resistant organisms is greater than treating susceptible bacterial counterparts.
Memory Aid: Recall “Resistant = More Expensive” to remember that antimicrobial-resistant UTIs are costlier to treat.

Question 43

What were the estimated direct and indirect costs for the treatment of acute pyelonephritis in the United States in 2000 and projected for 2013?

Answer 43

The estimated direct and indirect costs for the treatment of acute pyelonephritis were $2.14 billion in 2000 and projected to be $2.9 billion in 2013 in the United States.
Memory Aid: Think “Pyelonephritis Billions Rise” from $2.14 billion to $2.9 billion to remember the increasing cost from 2000 to 2013.

Question 44

Which are the most common nosocomial infections and what percentage do they constitute of nosocomial UTIs?

Answer 44

Catheter-associated urinary tract infections (CAUTIs) are the most common nosocomial infections, constituting more than 80% of nosocomial UTIs.Memory Aid: Recall “CAUTIs Top 80%” to remember that CAUTIs are the majority of nosocomial UTIs.

Question 45

What increases the incidence of bacteriuria?

Answer 45

The incidence of bacteriuria increases with institutionalization or hospitalization and concurrent conditions.
Memory Aid: Use “Hospital increases Bugs” to recall how hospitalization or being in an institution raises bacteriuria rates.

Question 46

What is the risk of UTI recurrence after the first infection in young, sexually active women according to the prospective trial following 285 college women?

Answer 46

In a prospective trial following 285 college women after their first UTI, the risk of a second infection was 24% within the 6-month follow-up period.
Memory Aid: Remember “1 in 4 chance in 6 months” to recall the 24% risk of a second UTI in young women post-first infection.

Question 47

In the context of UTI recurrences, what was found regarding women with a history of 2 or more previous UTIs compared to those with fewer previous infections?

Answer 47

Women with a history of 2 or more previous UTIs had 2 to 5 times the risk of recurrence at 1 year compared to counterparts who only had 1 or no previous infections. Memory Aid: Think “2 or more times trouble” to remember that a history of 2+ UTIs multiplies the risk of recurrence by 2 to 5 times.

Question 48

What was the percentage of recurrence in the antibiotic vs. probiotics group among postmenopausal women in the study by Beerepoot et al.?

Answer 48

In the study by Beerepoot et al., 69.3% recurred in the antibiotic arm compared with 79.1% in the probiotics group among postmenopausal women.
Memory Aid: Recall “70% antibiotics vs. 80% probiotics” to remember the approximate recurrence rates in Beerepoot et al.’s study.

Question 49

What was the risk of UTI recurrence at 30 days among men treated in an ambulatory setting within the Veteran Affairs system?

Answer 49

Among men treated in an ambulatory setting for a UTI within the Veteran Affairs system, the risk of recurrence at 30 days was 4.1%.
Memory Aid: Remember “4 in 100 chance in 30 days” to recall the 4.1% recurrence risk in men treated for UTI in the Veteran Affairs system.

Question 50

What factors can lead to progressive renal damage in adults with UTIs?

Answer 50

Progressive renal damage in adults with UTIs can result from the presence of obstruction, infection stones, diabetes mellitus, and other risk factors.
Memory Aid: Use the mnemonic “O.I.D.” for “Obstruction, Infection stones, Diabetes” to recall factors leading to renal damage in UTIs.

Question 51

What is the rank of UTIs among bacterial infections in terms of commonality?

Answer 51

UTIs are the most common bacterial infection.
Memory Aid: Remember “UTI = #1 Bacteria” to recall that UTIs are at the top of the list for bacterial infections.

Question 52

What factors increase the incidence of bacteriuria?

Answer 52

The incidence of bacteriuria increases with institutionalization/hospitalization, pregnancy, and certain comorbidities that alter lower urinary tract function or cause immunosuppression.
Memory Aid: Think of “H.I.P. factors for bacteriuria: Hospitalization, Institutionalization, Pregnancy and comorbidities” to recall the factors increasing bacteriuria incidence.

Question 53

Is there a clear association between recurrent uncomplicated UTIs and renal sequelae such as scarring, hypertension, or progressive renal insufficiency?

Answer 53

No clear association has been described between recurrent uncomplicated UTIs and renal sequelae such as scarring, hypertension, or progressive renal insufficiency.
Memory Aid: Remember “Uncomplicated UTIs usually don’t Complicate Kidneys” to recall the lack of association with severe renal outcomes.

Question 54

What are the key factors determining the successful infection of the urinary tract in UTIs?

Answer 54

Successful infection of the urinary tract in UTIs is determined by the virulence factors of the bacteria, the inoculum size, and the inadequacy of host defense mechanisms.
Memory Aid: Use “VIP of UTI” to remember “Virulence, Inoculum size, and Poor host defenses” as the key factors for UTI success.

Question 55

How do bacterial virulence and host resistance interact in the context of urinary tract infections?

Answer 55

In urinary tract infections, increased bacterial virulence is necessary to overcome strong host resistance, whereas bacteria with minimal virulence factors can infect patients who are significantly compromised.
Memory Aid: Think of it as a “Battle of Strengths”: high bacterial virulence versus strong host resistance, and weak bacteria versus compromised hosts.

Question 56

What is the most common route by which bacteria enter the urinary tract?

Answer 56

The most common route by which bacteria enter the urinary tract is the ascending route, from the bowel and skin reservoir through the urethra into the bladder.
Memory Aid: Think “A for Ascending” to remember the primary way bacteria enter the urinary tract is by moving upward.

Question 57

What factors enhance the risk of ascending infections in the urinary tract?

Answer 57

Factors that enhance the risk of ascending infections in the urinary tract include significant soilage of the perineum with feces, use of spermicidal agents, and the presence of intermittent or indwelling catheters.
Memory Aid: Remember “SFC - Soilage, Femicides, Catheters” to recall risk enhancers for ascending UTIs.

Question 58

What is the typical cause of most episodes of pyelonephritis?

Answer 58

Most episodes of pyelonephritis are caused by the retrograde ascent of bacteria from the bladder through the ureter to the renal pelvis and parenchyma.
Memory Aid: Recall “Pye-lo-ne-phri-tis: Pathway Leading North” to remember the retrograde ascent from bladder to kidney.

Question 59

Is urine reflux required for ascending urinary tract infections?

Answer 59

Although urine reflux is probably not required for ascending infections, edema associated with cystitis may cause sufficient changes in the ureterovesical junction to permit reflux.
Memory Aid: Think “Cystitis can unlock the door for reflux, but it’s not always needed for the party.”

Question 60

What effects do gram-negative bacteria and their endotoxins have on the ureteral peristaltic function?

Answer 60

Gram-negative bacteria and their endotoxins, as well as other factors such as pregnancy, ureteral obstruction, and high lower tract pressures, have a significant antiperistaltic effect on the ureteral peristaltic function.
Memory Aid: Recall “Negative on the Move” to remember that gram-negative bacteria slow down ureteral peristalsis.

Question 61

How do bacteria reach the renal parenchyma from the renal pelvis?

Answer 61

Bacteria that reach the renal pelvis can enter the renal parenchyma via the collecting ducts at the papillary tips and then ascend within the collecting tubules.
Memory Aid: Think “Rental Pelvis Doorway” to remember the route bacteria take from the renal pelvis to the parenchyma.

Question 62

What conditions exacerbate the process by which bacteria ascend within the collecting tubules?

Answer 62

The process by which bacteria ascend within the collecting tubules is hastened and exacerbated by increased intrapelvic pressure from ureteral obstruction or vesicoureteral reflux (VUR), especially when associated with intrarenal reflux.
Memory Aid: Remember “Pressure Pushes Pelvis Particles” to recall how increased intrapelvic pressure speeds up bacterial ascent in the kidneys.

Question 63

What role does E. coli play in the pathogenesis of ascending urinary tract infections according to the diagram?

Answer 63

E. coli plays a central role in the pathogenesis of ascending urinary tract infections by adhering to and ascending the urinary tract, from colonization in the bowel, invasion in the bladder, and up to inducing damage in the kidneys.

Memory Aid: Think “E. coli Elevator” for how it ascends from the bladder to the kidneys, causing damage along the way.

Question 64

How does E. coli adhere to the bladder and kidney tissues?

Answer 64

E. coli adheres to bladder and kidney tissues through Type 1 fimbriae binding to the bladder’s epithelial cells and P. fimbriae binding to renal tubular epithelial cells.
Memory Aid: Picture “E. coli’s Fingers” (fimbriae) as it grabs onto bladder and kidney cells.

Question 65

What effects do haemolysin and cytokine induction have in the context of UTIs?

Answer 65

Haemolysin damages epithelial cells, facilitating bacterial invasion, while cytokine induction contributes to the inflammatory response in the kidneys during UTIs.
Memory Aid: Remember “Haemolysin Hammer & Cytokine Call” to recall haemolysin breaking down barriers and cytokines calling for an immune response.

Question 66

What conditions select for the invasion of type 1 fimbriated E. coli in the bladder?

Answer 66

Type 1 fimbriated E. coli are selected for invasion in the bladder at high CFU (colony-forming units) and low O2 (oxygen) conditions.
Memory Aid: Think “High Crowd, Low Oxygen” for the conditions that favor E. coli invasion in the bladder.