UTIs, VU Reflux and Urinalysis interpretation

Question 1

Define UTIs

Answer 1

• A urinary tract infection is an infection of the kidneys, bladder or urethra.
  * Infection cystitis
  * most common type of UTI, which is caused by a bacterial infection of the bladder

  * Pyelonephritis
     * infection that spreads from the bladder to the kidneys
  
  * Urethritis
     * infection causing inflammation of the urethra.

Question 2

Classify UTIs

Answer 2

• uncomplicated
  * mainly occur in adult nonpregnant women
  * lower urinary tract infection in a setting offunctionally and structurally normal urinary tract
  • complicated
    
    • pyelonephritis and/or structural/functional abnormality
  • unresolved bacteriuria
    
    • urinary tract is not sterilized during therapy (most commonly due to resistant organisms or noncompliance)
  • recurrent UTI
    
    • bacterial persistence = urine cultures become sterile during therapy but resultant reinfection of the urine by the same organisms
    • reinfection = new infection with new pathogen (80% of recurrent UTis)

Question 3

UTI Aetiology

Answer 3

• ascending (most common) - GI organisms
  
  • hematogenous (TB, perinephric abscess)
  • lymphatic
  • direct (inflammatory bowel disease, diverticulitis)

Question 4

UTI Risk Factors

Answer 4

• stasis and obstruction:
  
  • foreign body:
    
    • e.g. catheter, instrumentation
  • decreased resistance to organisms:
    
    • DM, malignancy, immunosuppression
  • other factors:
    
    • trauma,
    • anatomic variance (congenital),
    • female (short urethra),
    • sexual intercourse

Question 5

UTI Clinical Features

Answer 5

• storage symptoms (frequency, urgency, dysuria)
  
  • voiding symptoms (hesitancy, post-void dribbling, dysuria)
  • haematuria
  • pyelonephritis: more severe symptoms (including fever/chills, CV A/flank pain

Question 6

UTI Organisms

Answer 6

• KEEPS
  * Klebsiella spp
  * E. coli (90% in uncomplicated, 20-30) and other Gram negatives
  * Enterococci
  * Proteus mirabilis, Pseudomonas
  * Strep. saprophyticus

Question 7

UTI Investigations

Answer 7

• midstream urine MCS
  * dipstick:
  * leukocytes ± nitrites ± hematuria
  * microscopy
  * Gram stain
  * culture and sensitivity
  • haematuria workup
    
    • urine cytology, ultrasound, cystoscopy
  • CT scan if indicated
  • BGL

Question 8

MSU Interpretation

- Bacteria

Answer 8

Bacteria

• Normal = absent
• Indicates infection when:
• – any detected
• Accuracy - high SPE

Question 9

MSU Interpretation

- Leukocyte esterase

Answer 9

• Normal = absent
• Indicates infection when:
• – Positive = pyuria, presence of WBCs in urine
• Accuracy - high SEN

Question 10

MSU Interpretation

- WBC

Answer 10

• Normal = < 5
• Indicates infection when:
• – Pyuria: WBC > 10
• Accuracy - high SEN

Question 11

MSU Interpretation

- Nitrite

Answer 11

• Normal = absent
• Indicates infection when:
• – Positive = Gram negative bacteria
• – Convert nitrates to nitrites
• Accuracy - high SPE

Question 12

MSU Interpretation

- RBC

Answer 12

• Normal = < 5
• Indicates infection when:
• – Haematuria common in infection
• Accuracy - high SPE

Question 13

MSU Interpretation

- Epithelial cells

Answer 13

• Normal = <5 = good sample
• – high indicates contamination of skin flora
• Accuracy - N/A

Question 14

MSU Interpretation

- pH

Answer 14

• Normal = 4.5-8
• Indicates infection when:
• – pH increase if urea-splitting organism is present
• – ie Proteus mirabilis
• Accuracy - Low SPE - many causes of high pH

Question 15

Uncomplicated UTI Treatment

Answer 15

• Uncomplicated (incl pregnant, men, children & pyelonephritis) (one of)
  * Trimethoprim
  * Cephalexin (A)
  * Augmentin (B1) (amoxycillin and clavulanate)
  * Nitrofurantoin (A)

Question 16

Recurrent UTI Treatment

Answer 16

• Recurrent (one of)
  * Cranberry juice (first line)
  * Trimethoprim PO
  * Cephalexin PO

Question 17

Complicated/Severe UTI Treatment

Answer 17

• Complicate/Severe (acute pyelonephritis or in children)
  * Gentamicin
  * or Cetriaxone IV or Cefotaxime IV
  * Amoxy/ampicillin

Question 18

Define Vesicoureteral Reflux

Answer 18

• retrograde passage of urine from the bladder, through the ureterovesicular junction (UVJ), into the ureter

Question 19

VUJ Risk Factors

Answer 19

• race (white> black),
  
  • female gender, age (<2 yrs),
  • genetic predisposition

Question 20

VUJ Causes

Answer 20

• primary reflux:
  * incompetent or inadequate closure of UVJ
  * trigonal weakness,
  * lateral ureteral insertion,
  * short submucosal segment
  • secondary reflux:
    
    • abnormally high vesicular pressure resulting in failure of UVJ closure
      
      • associated with anatomic (PUV)
      • or functional (neurogenic) bladder obstruction

Question 21

VUJ Investigations

Answer 21

• Blood and urine tests
  * BUN - blood
  * Creatinine - blood
  * Creatinine clearance – urine and blood
  * Urinalysis or 24-hour urine studies
  * Urine culture
  • Imaging tests that may be done include:
    
    • Abdominal CT scan
    • Bladder ultrasound
    • Intravenous pyelogram (IVP)
    • Kidney ultrasound

Question 22

VUJ Management

Answer 22

• Spontaneous resolution in 60% of primary reflux
  * in lower grades (I-III), goal is to prevent infection or renal damage via medical treatment and monitoring
  • medical treatment:
    
    • long-term antibiotic prophylaxis
  • surgical treatment:
    
    • ureteral reimplantation ± ureteroplasty,