It is slide on urinary tract infection with recent updated definition and management

1. Urinary Tract Infection
Dr. Navin Adhikari
IM Resident, NAMS

2. CONTENT
• Epidemiology
• Terminology
• Etiopathogenesis
• Microorganism
• Risk Factors
• Innate Host Response
• Clinical Features
• Acute Simple Cystitis
• Pyelonephritis
• Protatitis
• Diagnosis
• Treatment
• Complications

3. UTI
UTI is inflammation of urinary tract due to infectious agent,
comprises of variety of clinical entities, from subclinical infection
asymptomatic bacteriuria to disease like cystitis, prostatitis, and
pyelonephritis.
The most common manifestation of UTI is acute cystitis and
Acute cystitis is far more prevalent among women than
among men.

4. Epidemiology
• Between 1 year and ~50 years of age, UTI and recurrent UTI
are predominantly diseases of females.
• As many as 50–80% of women in the general population
acquire at least one UTI during their lifetime - uncomplicated
cystitis in most cases.
• About 20–30% of women who have had one episode of UTI
will have recurrent episodes.
• Approximately 3% of non-pregnant adult women and 5% of
pregnant women have asymptomatic bacteriuria.

5. TERMINOLOGY
1. Lower tract UTI – involvement of urinary bladder, urethra
and/or prostate.
a. Cystitis
b. Urethritis
c. Protatitis
2. Upper tract UTI – involvement of ureter, collecting ducts
and/or renal parenchyma
a. Ureteritis
b.Pyelitis
c. Pyelonephritis

6. • Traditionally uncomplicated urinary tract infection refers to
acute cystitis or pyelonephritis in nonpregnant outpatient
women without anatomic abnormalities or instrumentation of
the urinary tract.
• Complicated UTI has been defined as cystitis or pyelonephritis
in a patient with underlying urologic abnormalities.Individuals
who do not fit into either category have often been treated as
having a complicated UTI by default.

7. Defination According to Uptodate
Acute complicated urinary tract infection (UTI) to refer to an acute
UTI with any of the following features, which suggest that the
infection extends beyond the bladder.
• Fever >99.9°F/37.7°C.
• Other signs or symptoms of systemic illness (including chills or
rigors, significant fatigue or malaise beyond baseline).
• Flank pain.
• Costovertebral angle tenderness.
• Pelvic or perineal pain in men, which can suggest accompanying
prostatitis.
By this definition, pyelonephritis is a complicated UTI, regardless of
patient characteristics. In the absence of any of above symptoms,
patients with UTI to have acute simple cystitis(uncomplicated UTI).

8. ETIOPATHOGENESIS

9. MICROORGANISMS

10. VIRULENCE
• Ability to adhere to epithelial cells determines the degree of
virulence of the organism.
• For E. coli, virulent factors include
a. flagellae (for motility),
b. aerobactin (for iron acquisition in the iron-poor
environment of the urinary tract),
c. haemolysin (for pore forming) and
d. adhesins on the bacterial fimbriae and on the cell surface.
• There are two types of E. coli: those with type 1 fimbriae
(with adhesin known as FimH) associated with cystitis; and
those with type P fimbriae (with adhesin known as PapG)
commonly responsible for pyelonephritis.

11. RISK FACTORS
• Previous UTI
• Lack of circumcision (children and young adults)
• Urologic instrumentation or surgery
• Urethral catheterization
• Urinary tract obstruction, including calculi
• Neurogenic bladder
• Renal transplantation
• Sexual intercourse
• New sex partner
• Insertive rectal intercourse
• Lack of urination after intercourse

12. • Spermicidal contraceptive jellies
• Diaphragm use
• Pregnancy
• Lower socioeconomic group
• Diabetes
• sickle cell trait in pregnancy
• Functional or mental impairment
• Estrogen deficiency (loss of vaginal lactobacilli)
• Prostatic enlargement
• Condom catheter drainage
• Bladder prolapse

13. ROUTE OF INVASION
1. Ascending Route
In the majority of UTIs, bacteria establish infection by ascending
from the urethra to the bladder. Continuing ascent up the ureter
to the kidney is the pathway for most renal parenchymal
infections. Most common route of invasion.
2. Hematogenous Route
Accounts for less than 2 % of documented UTIs and usually
results from bacteremia caused by relatively virulent organisms,
such as Salmonella and S. aureus.
3. Lymphatic route

14. INNATE HOST DEFENCES
1. Neutrophils – adhesins activate receptors, e.g. Toll
receptor 4, on the mucosal surface, phagocytosis
2. Urine osmolality and pH – urinary osmolality >800
mOsm/kg and low or high pH reduce bacterial survival
3. Complement – complement activation with IgA production
by uroepithelium
4. Commensal organisms – such as lactobacilli,
corynebacteria, streptococci and bacteroides
5. Urine flow – urine flow and normal micturition wash out
bacteria. Urine stasis promotes UTI
6. Uroepithelium – mannosylated proteins , have
antibacterial properties, interfere with bacterial binding to
uroepithelium, Disruption of this uroepithelium by trauma
(e.g. sexual intercourse or catheterization) predisposes to
UTI. Cranberry juicecontain a large-molecular-weight
factor (proanthrocyanidins) that prevents binding of E.
coli to the uroepithelium

15. EPIDEMIOLOGICAL TRIAD
• The interplay of host, pathogen, and environmental factors
determines whether tissue invasion and symptomatic
infection will ensue.
• For example, bacteria often enter the bladder after sexual
intercourse, but normal voiding and innate host defense
mechanisms in the bladder eliminate these organisms. Any
foreign body in the urinary tract, such as a urinary catheter or
stone, provides an inert surface for bacterial colonization.
Abnormal micturition and/or significant residual urine volume
promotes infection.

17. CLINICAL FEATURES

18. ACUTE SIMPLE CYSTITIS
• The typical symptoms of cystitis are dysuria, urinary
frequency, and urgency. Nocturia, hesitancy, suprapubic
discomfort, and gross hematuria are often noted as well.
• The probability of cystitis is greater than 50 percent in
women with any of these symptoms and greater than 90
percent inwomen without vaginal discharge or irritation.
• The differential diagnosis includes urethritis due to
sexually transmitted disease, urethritis associated with
reactive arthritis, urethritis and cystitis but no
bacteria are cultured from the urine (the ‘urethral
syndrome’).

19. DIAGNOSTIC APPROACH

20. PYELONEPHRITIS
• Mild pyelonephritis can present as low-grade fever with or
without lower-back or costovertebral-angle pain.
• Severe pyelonephritis can manifest as high fever, rigors,
nausea, vomiting, and flank and/or loin pain. Symptoms are
generally acute in onset, and symptoms of cystitis may not be
present. The fever of pyelonephritis typically exhibits a high
spiking “picket-fence” pattern and resolves over 72 h of
therapy.
• The differential diagnosis of acute pyelonephritis includes
pyelonephrosis, acute appendicitis, diverticulitis, cholecystitis,
salpingitis, ruptured ovarian cyst or ectopic pregnancy.

21. PROSTATITIS
• Acute bacterial prostatitis presents as dysuria, frequency,
and pain in the prostatic pelvic or perineal area. Fever and
chills are usually present, and symptoms of bladder outlet
obstruction are common.
• The presence of typical symptoms of prostatitis should
prompt digital rectal exam, and the finding of an edematous
and tender prostate on physical exam in this setting usually
establishes the diagnosis of acute bacterial prostatitis.
• Chronic bacterial prostatitis presents more insidiously as
recurrent episodes of cystitis, sometimes with associated
pelvic and perineal pain.
• Prostadynia (prostatic pain in the absence of active infection)
may be a very persistent sequel to bacterial prostatitis.

22. DIAGNOSIS

24. URINALYSIS
URINE SAMPLE- Collection of a midstream urine, with or without
cleaning of the urethral meatus, at the time of clinical evaluation
likely produces a reasonable specimen for analysis.
MICROSCROPY
Pyuria- Number of leukocytes >10/microL is significant.
Sterile Pyuria- Pyuria in the absence of apparent bacterial
infection.
Causes of sterile pyuria include: use of antimicrobial,
urine sample with vaginal leukocytes from vaginal secretions,
Chronic interstitial nephritis, Nephrolithiasis , Uroepithelial
tumor, Infection with atypical organisms, such as Chlamydia,
Ureaplasma urealyticum, or tuberculosis, Intra-abdominal
inflammatory process adjacent to the bladder.

25. White blood cell casts in the urine are indicative of kidney
inflammation, which may reflect pyelonephritis or other renal
conditions.
DIPSTICK
Detects the presence of leukocyte esterase and nitrite in the
urine. Leukocyte esterase corresponds to pyuria and nitrite
reflects the presence of Enterobacteriaceae, which convert
urinary nitrate to nitrite. Leukocyte esterase may be used to
detect >10 leukocytes per high power field (sensitivity of 75 to
96 percent; specificity of 94 to 98 percent) . A positive nitrite
test is a reliable index of significant bacteriuria, although a
negative test does not exclude bacteriuria.

26. URINE CULTURE
• The detection of bacteria in a urine culture is the
diagnostic gold standard for UTI.
• should not be performed in nonpregnant patients
without any symptoms consistent with a UTI, as bacteriuria
does not indicate a UTI in an asymptomatic patient

27. TREATMENT

28. INDICATIONS FOR HOSPITALIZATION
FOR COMPLICATED UTI
• Septic or critically ill patient
• persistently high fever (eg, >38.4°C/>101°F) or pain
• marked debility,
• inability to maintain oral hydration or take oral medications.
• suspected urinary tract obstruction
• concerns regarding patient adherence.
Other patient with uncomplicated UTI and acute complicated
UTI of mild to moderate severity who can be stabilized can be
managed in outpatient basis or emergency department and
discharged on oral antimicrobials with close follow-up.
Empiric antimicrobial therapy should be initiated promptly.
taking into account risk factors for drug resistance.

32. Antimicrobial For Uncomplicated UTI

33. Antimicrobial in Other Conditions
• PREGNANCY
Nitrofurantoin, ampicillin, and the cephalosporins are
considered relatively safe in early pregnancy.
Sulfonamides should clearly be avoided both in the first
trimester (because of possible teratogenic effects) and near
term (because of a possible role in the development of
kernicterus).
Fluoroquinolones are avoided because of possible adverse
effects on fetal cartilage development.
Pregnant women with ASB are treated for 4–7 days . With
overt pyelonephritis, parenteral β-lactam therapy with or
without aminoglycosides is the standard of care.

34. PROSTATITIS
• A 7- to 14-day course of a fluoroquinolone or TMP
SMX is recommended if the uropathogen is susceptible.
• Therapy can be tailored to urine culture results and should
be continued for 2–4 weeks.
• For documented chronic bacterial prostatitis, a 4- to 6-week
course of antibiotics is often necessary. Recurrences, which
are not uncommon in chronic prostatitis, often warrant a 12-
week course of treatment.

35. RESPONSE TO THERAPY
• If therapy is appropriate, clinical response should occur
within 24 hours with treatment of cystitis.
• With pyelonephritis, response should occur by 48 to 96
hours.
• Lack of response by 72 hours should be an indication for
imaging studies.
• Four patterns of response of bacteriuria to antimicrobial
therapy—cure, persistence, relapse, and reinfection
• Bacteriologic Cure is defined as negative urine cultures on
chemotherapy and during the follow-up period, usually 1 to 2
weeks.
• Bacteriologic Persistence- It is persistence of significant
bacteriuria after 48 hours of treatment.Causes are the
urinary levels of the drug are inordinately low (i.e., from
not taking the agent, insufficient dosage, poor intestinal
absorption, or poor renal excretion, as in renal
insufficiency or resistent strain.

36. RELAPSE AND REINFECTION
• If UTI is recurrent it is necessary to distinguish between
relapse and reinfection.
• Relapse is diagnosed by recurrence of bacteriuria with the
same organism within 7 days of completion of antibacterial
treatment and implies failure to eradicate infection usually in
conditions such as stones, scarred kidneys, polycystic disease
or bacterial prostatitis.
• Reinfection is when bacteriuria is absent after treatment for
at least 14 days, usually longer, followed by recurrence of
infection with the same or different organisms. This is the
result of reinvasion of a susceptible tract with new organisms.
Approximately 80% of recurrent infections are due to
reinfection

38. NONANTIMICROBIAL THERAPY
• A high (2 L daily) fluid intake is encouraged during treatment.
Increased fluid intake has some disadvantages of increased
vesicoureteral reflux and possibly cause acute urinary
retention in the partially obstructed bladder. The larger urine
output results in dilution of antibacterial substances normally
present in the urine and may make symptoms of dysuria
worse.
• To acidify the urine, it is often necessary to modify the diet
by restriction of agents that tend to alkalinize the urine (e.g.,
milk, fruit juices [except cranberry juice], sodium bicarbonate)
• Use of Canberry juice - disable the ability of E. coli to adhere
to the epithelial cells of the urethra.
• Analgesics can be used if flank pain or dysuria is severe.

39. Prophylactic Measures For Recurrent
UTI
• 2 L daily fluid intake .
• Voiding at 2- to 3-hour intervals with double micturition if
reflux is present .
• Voiding before bedtime and after intercourse
• avoidance of spermicidal jellies and bubble baths and other
chemicals in bathwater.
• avoidance of constipation, which may impair bladder
emptying.
• Nitrofurontoin 50-100mg at bedtime daily.

40. ASB
• The presence of bacteriuria (≥105 colony-forming units/mL of a
uropathogen) with or without pyuria in the absence of any
symptom that could be attributable to a UTI is called asymptomatic
bacteriuria and generally does not warrant treatment in
nonpregnant patients who are not undergoing urologic surgery.
• Asymptomatic bacteriuria during pregnancy has been
associated with adverse pregnancy outcomes, increased risk of
preterm birth, low birth weight, and perinatal mortality. It is also
assossiated with risk of progression to pyelonephritis because of
pressure on the bladder and ureters from the enlarging uterus.
• ASB is treated in pregnancy, urological surgery and renal
transpant patient.

41. Approach in ASB

42. CATHETER-ASSOCIATED UTI
• It is bacteriuria with symptoms of UTI in a catheterized patient.
• Accepted threshold for bacteriuria to meet the definition of
CAUTI is ≥103 CFU/mL of urine.
• The etiology of CAUTI is diverse, and urine culture results are
essential to guide treatment.
• Treatment is usually avoided in asymptomatic patients, as this
may promote antibiotic resistance.
• Evidence supports the practice of catheter change during
treatment for CAUTI. The goal is to remove biofilm-associated
organisms that could serve as a nidus for reinfection.
• Antimicrobial catheters impregnated with silver or
nitrofurazone have not been shown to provide significant
clinical benefit.

43. COMPLICATIONS
Acute Complicated UTI
• Sepsis
• Multiple organ system dysfunction
• Shock
• Acute renal failure.
Acute Pyelonephritis
• Renal corticomedullary abscess
• Perinephric abscess
• Emphysematous pyelonephritis
• Papillary necrosis
• Xanthogranulomatous pyelonephritis

44. EMPHYSEMATOUS PYELONEPHRITIS
• Emphysematous pyelonephritis is a gas-producing,
necrotizing infection involving the renal parenchyma and, in
some cases, perirenal tissue.
• Diabetes mellitus and urinary tract obstruction are the major
risk factors.
• These infections are usually due to Escherichia coli or
Klebsiella pneumoniae , other causative organisms include
Proteus, Enterococcus, Pseudomonas, Clostridium, and, rarely,
Candida spp.
• Diagnosis by plain films of the abdomen and/or computed
tomography (CT). Such radiographs reveal air in the renal
parenchyma, bladder, or surrounding tissue in 50 to 85
percent of cases

45. • Clinical features are fevers, chills, flank or abdominal pain,
nausea, and vomiting.
• Treatment includes nephrectomy or open drainage along
with systemic antibiotics.

46. XANTHOGRANULOMATOUS
PYELONEPHRITIS
• This is an uncommon chronic interstitial infection of the
kidney
• most often caused by Proteus
• Clinically presents with fever, weight loss, loin pain and a
palpable enlarged kidney.
• It is usually unilateral and associated with staghorn calculi.
• CT scanning shows up intrarenal abscesses as lucent areas
within the kidney.
• Nephrectomy is the treatment of choice; antibacterial
treatment rarely, if ever, eradicates the infection.

47. REFLUX NEPHROPATHY
• This was called chronic
pyelonephritis or atrophic
pyelonephritis, and it results
from vesicoureteric reflux,
infection acquired in infancy
or early childhood. There is
papillary damage,
tubulointerstitial nephritis
and cortical scarring in areas
adjacent to ‘clubbed calyces’.
• Diagnosis based on CT of
kidney
• Meticulous early detection
and control of infection, with
or without ureteral
reimplantation to create a
competent valve, can prevent
further scarring and allow
normal growth of the kidneys

48. URETHRAL SYNDROME
• It is abacteriuric frequency or dysuria.
• Common causes are postcoital bladder trauma, vaginitis,
atrophic vaginitis or urethritis in the elderly, and interstitial
cystitis (Hunner’s ulcer).
• Interstitial cystitis is an uncommon condition affecting
women over the age of 40 years. It presents with frequency,
dysuria and often severe suprapubic pain. Cystoscopy shows
typical inflammatory changes with ulceration of the bladder
base.Treatment include oral prednisolone therapy, bladder
instillation of sodium cromoglicate or dimethyl sulphoxide and
bladder stretching under anaesthesia.
• Predominant frequency and passage of small volumes of urine
(‘irritable bladder’) is possibly consequent on previous UTI or
conditioned by psychosexual factors.

49. References
• Uptodate 2021
• Harrison's Principles of Internal Medicine, 20th
Edition.
• Davidson Principles and Practice of medicine 23rd
Edition.
• Kumar & Clark's Clinical Medicine, 7th Edition
• Mandell, Douglas, and Bennett's Principles and
Practice of Infectious Disease, Eight Edition

50. Thank You