UTI Flashcards
Introduction
A Urinary Tract Infection (UTI) is an infection that can occur in any part of the urinary system, including the kidneys, ureters, bladder, or urethra. UTIs are particularly common medical issues, especially among women. Women aged between 20 to 50 years are approximately 50 times more likely to experience a UTI compared to men
. In women, most UTIs manifest as ___ or ____. In men, UTIs commonly present as ____or____
cystitis (infection of the bladder) or pyelonephritis (infection of the kidneys).
urethritis (infection of the urethra) or prostatitis (infection of the prostate).
What are the classification of UTI
Classification
- Lower UTI:
- Urethritis: Infection of the urethra.
- Cystitis: Infection of the bladder.
- Prostatitis: Infection of the prostate gland (in men).
- Upper UTI:
- Pyelonephritis: Infection of the kidneys.
- Complicated UTI: Occurs in individuals with structural or functional abnormalities in the urinary tract, or in individuals with other health conditions (such as diabetes or an immunocompromised state) that make infections more severe or difficult to treat.
- Uncomplicated UTI: Occurs in otherwise healthy individuals with a normal urinary tract, usually in women.
- Asymptomatic bacteriuria: The presence of bacteria in the urine without clinical symptoms or signs of infection.
What are the risk factors of developing UTI?
Risk Factors
UTIs can develop due to various risk factors, which can be categorized as:
- Anatomic/Physiological Factors:
- Vesicoureteral reflux (backward flow of urine from the bladder into the kidneys).
- Pregnancy.
- Female sex: Shorter urethra in women makes it easier for bacteria to enter the urinary tract.
- Genetics:
- Familial tendency: Some people are more genetically predisposed to UTIs.
- Susceptible uroepithelial cells.
- Vaginal mucus properties.
- Behavioral Factors:
- Voiding dysfunction (difficulty in emptying the bladder).
- Frequent or recent sexual intercourse.
- Iatrogenic Factors:
- Indwelling catheters (long-term catheter use).
- Antibiotic misuse.
- Use of spermicides.
What are the causes of UTI?
Causes
The organisms responsible for UTIs are usually bacteria, most commonly originating from the intestines. UTIs are generally classified by their causative pathogens:
- Enteric Gram-Negative Aerobic Bacteria:
- Escherichia coli: Accounts for 75-95% of UTI cases.
- Klebsiella.
- Proteus mirabilis.
- Pseudomonas aeruginosa.
- Gram-Positive Bacteria:
- Staphylococcus saprophyticus: Responsible for 5-10% of bacterial UTIs.
- Enterococcus faecalis.
- Streptococcus agalactiae.
In hospitalized patients, the organisms commonly causing UTIs include:
- E. coli (50% of cases).
- Klebsiella, Proteus, Enterobacter, Serratia, and Pseudomonas (40% of cases).
- S. saprophyticus, E. faecalis, and Staphylococcus aureus (10% of cases).
Pathogenesis of UTI is?
UTIs typically develop by two main routes: which are?
- Ascending Infection:
- Type 1 fimbriae: Binds to mannose residues on the surface of uroepithelial cells, allowing bacteria like E. coli to adhere and invade.
- Type 2 or P fimbriae: Binds to glycolipids on the apical surface of renal epithelial cells, contributing to kidney infections (pyelonephritis).
- Hematogenous Spread:
- Rare in healthy individuals, but certain pathogens like Staphylococcus aureus, Salmonella, Candida, and Mycobacterium tuberculosis can infect the kidneys through the bloodstream, especially if there is urinary obstruction
Asymptomatic Bacteriuria
Asymptomatic bacteriuria is the presence of bacteria in the urine without any clinical symptoms or signs of infection. Common risk factors include:
- Indwelling catheters.
- Neurogenic bladder (bladder dysfunction due to neurological conditions).
- Cognitive impairment.
E. coli is the most common organism, though Klebsiella, Enterococcus, and coagulase-negative staphylococci may also be involved. Mixed infections are common in patients with catheters and may involve organisms like Morganella morganii, Providencia spp., and Proteus spp..
How’s diagnosis made?
Diagnosis is made by detecting the presence of the same organism in two consecutive urine samples with counts > 10⁵ CFU/mL.
Treatment
Treatment is not typically required, except in:
- Pregnant women (due to the risk of fetal complications).
- Patients undergoing indwelling instrumentation (e.g., during surgery).
Acute Uncomplicated Cystitis
Epidemiology
Acute uncomplicated cystitis is more common in women, with an incidence of 0.5-0.7 episodes per woman per year. About 10% of women experience at least one episode of cystitis per year, and 50% of all women will have at least one episode of cystitis during their lifetime
The most common causative organisms of acute uncomplicated cystitis are:
.
Etiology
- Escherichia coli (E. coli): Responsible for 75% to 95% of cases.
- Staphylococcus saprophyticus: Accounts for 5-10% of cases.
- Other bacteria include Proteus spp. and Klebsiella spp.
Clinical features of us cute uncomplicated cystitis
Clinical Features
Symptoms of acute uncomplicated cystitis include:
- Dysuria: Pain or burning sensation during urination.
- Frequency: Increased frequency of urination.
- Suprapubic pain: Pain or discomfort in the lower abdomen.
- Urgency: A sudden, strong urge to urinate.
- Hematuria: Presence of blood in the urine.
- Foul-smelling urine.
- Nocturia: Need to urinate frequently at night
How’s it’s diagnosis made?
Diagnosis
Diagnosis is based on urinalysis and urine microscopy, culture, and sensitivity (m/c/s):
- Urinalysis:
- Positive for nitrites: Indicates the presence of bacteria that reduce nitrate to nitrite, most commonly E. coli.
- Positive for leukocyte esterase: Indicates the presence of white blood cells (pyuria), a sign of infection or inflammation.
Treatment if cystitis
Treatment
The choice of antibiotic is guided by the sensitivity pattern of the causative organism. Common antibiotics include:
- Trimethoprim: 200 mg every 12 hours.
- Nitrofurantoin: 100 mg twice daily.
- Co-amoxiclav: Particularly useful in women.
- Trimethoprim-Sulfamethoxazole (TMP-SMX).
- Fluoroquinolones: Reserved for cases where first-line antibiotics fail or in resistant infections.
Prostatitis and Urethritis
Types of Prostatitis:
- Type 1: Acute Prostatitis
- Acute bacterial infection of the prostate.
- Type 2: Chronic Prostatitis
- Chronic bacterial infection lasting for more than 3 months.
- Type 3: Chronic Abacterial Prostatitis or Chronic Pelvic Pain Syndrome (CPPS)
- Type 3A: Inflammatory CPPS (with white blood cells in prostate secretions but no bacteria).
- Type 3B: Non-inflammatory CPPS (no white blood cells or bacteria in prostate secretions).
- Type 4: Asymptomatic Inflammatory Prostatitis
- No symptoms, but inflammation is detected during prostate biopsies or other evaluations.
What’s the most common cause of Prostatitis
- Escherichia coli (E. coli): The most common cause, responsible for 80% of prostatitis cases.
- Other gram-negative organisms (Pseudomonas aeruginosa, Serratia spp., Klebsiella spp., Enterobacter spp.) account for 10-15% of cases.
- Gram-positive bacteria, including Enterococci, cause 5-10% of cases.
- Others: Corynebacterium spp., Chlamydia trachomatis, and Ureaplasma urealyticum.
Clinical Features of Prostatitis
- Acute onset pain: Severe, localized pain in the perineum, scrotum, or rectum.
- Discomfort: Can also be felt in the penis, bladder, or lower back.
- Lower urinary tract symptoms (LUTS):
- Urinary frequency.
- Urinary urgency.
- Dysuria (painful urination).
- Voiding symptoms like hesitancy, poor urinary stream, and less commonly urinary retention.
- Systemic symptoms:
- Fever, chills, malaise, nausea, and signs of generalized sepsis.
Approximately 5% of acute prostatitis cases progress to chronic bacterial prostatitis, which is characterized by recurrent, culture-positive UTIs and distinguishes it from chronic abacterial prostatitis.
- Digital Rectal Examination (DRE):
- Findings include prostatic tenderness, abscesses, or a normal examination.
Diagnosis and Management
- Diagnosis is primarily clinical, supported by laboratory tests (urine culture) to identify the causative organism.
- Treatment typically includes antibiotics tailored to the pathogen, along with supportive measures such as pain management.
What are the Investigations you will like to do for Prostatitis
Prostatitis
- Midstream urine (MSU) microscopy, culture, and sensitivity (m/c/s):
- The test typically shows a significant number of white blood cells and bacteria, which indicates infection. Specific uropathogens (e.g., E. coli, Klebsiella) or other bacteria can be identified through culture.
- Prostatic massage:
- Painful procedure that may exacerbate symptoms. Used for chronic prostatitis to evaluate the presence of infection, but it’s typically avoided in acute prostatitis due to the risk of worsening the clinical scenario.
- Blood culture:
- Performed in cases where there are features of systemic illness (e.g., fever, chills) to rule out bacteremia or sepsis.
- Prostatic biopsy:
- Rarely done for routine prostatitis. It can be difficult to culture microorganisms from biopsy material.
- Prostate ultrasound (USS):
- Used to detect complications like prostatic abscess, prostatic calcification, or seminal vesicle dilation. It is not widely used in acute or chronic prostatitis but can be useful for identifying severe complications.
- Prostate-specific antigen (PSA):
- PSA levels rise in acute bacterial prostatitis and many UTIs but remain normal in abacterial prostatitis. PSA levels should be interpreted carefully because of the overlap with other conditions.
- Urine microscopy after prostatic massage (for chronic bacterial prostatitis):
- The key investigation for chronic bacterial prostatitis is quantitative bacteriological localization cultures, where urine samples taken before and after a prostatic massage are analyzed.
What are the Investigations you will like to do for urethritis
- Urethral swab m/c/s:
- A swab from the urethra is sent for microscopy, culture, and sensitivity. This helps to identify the specific pathogen responsible for the infection (e.g., N. gonorrhoeae, C. trachomatis).
- High vaginal swab m/c/s (in females):
- Used to identify infections in women, particularly in cases of urethritis caused by sexually transmitted infections (STIs).
- MSU m/c/s:
- Similar to prostatitis, this test is used to identify significant bacteriuria or the presence of white blood cells, indicating infection.
Treatments for Prostatitis
Prostatitis
- Antibiotics for Acute Bacterial Prostatitis:
- Fluoroquinolones (e.g., ciprofloxacin): Given for 10 days. They have good bioavailability, penetrate the prostate well, and are effective against gram-negative organisms (e.g., E. coli, Pseudomonas) as well as some gram-positive and atypical organisms (e.g., Chlamydia, Mycoplasma).
- Intravenous antibiotics: Broad-spectrum penicillins, third-generation cephalosporins, or fluoroquinolones can be used, often in combination with aminoglycosides for severe infections.
- Antibiotics for Chronic Bacterial Prostatitis:
- Treatment lasts 4-6 weeks. Options include:
- Fluoroquinolones: As described above, they are highly effective.
- TMP-SMX (Trimethoprim-Sulfamethoxazole): Inexpensive but has no activity against Pseudomonas, some enterococci, and some Enterobacteriaceae.
- Tetracyclines: Effective for Chlamydia and Mycoplasma, but less effective against E. coli, enterococci, staphylococci, and Pseudomonas.
- Surgical Treatment:
- Acute urinary retention: Treated with temporary catheter drainage.
- Prostatic abscess drainage: May require surgical drainage through a transperineal or transrectal route.
Treatments for Urethritis
Urethritis
- Treatment for Gonorrheal Urethritis:
- Ceftriaxone 500 mg IM (intramuscular) plus Azithromycin 1g stat: This combination is used to cover both Neisseria gonorrhoeae and co-infections like Chlamydia.
- Cefixime 400 mg: An alternative to ceftriaxone.
- Quinolones: These are used as a single dose but are becoming less effective due to high resistance rates (over 25%).
- Treatment for Non-Gonococcal Urethritis:
- Azithromycin 1g (single dose) or Doxycycline 100 mg twice daily for 7 days.
- Alternatives include Ofloxacin, Levofloxacin, or Erythromycin for 7 days, particularly if there is resistance or intolerance to first-line drugs
Pathogenesis of Urethritis
- Gonorrheal urethritis caused by Neisseria gonorrhoeae and non-gonococcal urethritis caused by Chlamydia trachomatis are both sexually transmitted infections (STIs). These organisms penetrate the urethral epithelium and cause a pyogenic (pus-forming) infection.
- In men, infection can spread to involve the epididymis.
- In women, infections can lead to cervicitis, endometritis, and salpingitis.
- Mycoplasma genitalium can also cause cervicitis and pelvic inflammatory disease (PID) in women
Clinical Features of Urethritis
- Mucopurulent or purulent discharge: Urethral discharge that may be clear, yellow, or green.
- Dysuria: Painful urination.
- Orchalgia: Testicular pain.
- Urethral or glans pruritus: Itching in the urethra or around the glans penis.
- Women often have minimal symptoms, making diagnosis harder.
Examination for Urethritis in males & female
- Males:
- Inspect the distal urethra for redness.
- Examine the penis and testicles for tenderness or swelling.
- Perform a digital rectal examination (DRE) to assess prostatic tenderness, especially if prostatitis is suspected.
- Females:
- Perform a vaginal examination (VE) to check for discharge and signs of cervical inflammation or tenderness (CET).