Urinary Tract Infections Flashcards
What causes UTI?
colonic bacteria
E. coli (54-67%)
Klebsiella and Proteus spp.
Enterococcus and Pseudomonas
What are the symptoms of Pyelonephritis?
abdominal pain or flank pain
FEVER, malaise, nausea, vomiting, occ diarrhea
Fever may be the only manifestation
>39C without another source lasting more than 24hrs for males, more than 48hrs for females
What are usual locations of renal abscess?
hematogenous spread with S. aureus
most are unilateral and right sided
Type of abscess that occur secondary to contiguous infection in perirenal area or pyelonephritis that dissects renal capsule
Perinephric abscess
only bladder involvement
Cystitis
What are the symptoms of Cystitis?
dysuria, urgency, frequency, suprapubic pain, incontinence, malodorous urine
Does not cause fever and does not result in renal injury
Highest risk of acute pyelonephritis and subsequent renal scarring
patients younger than 2yrs
What are the risk factors for UTI?
female gender uncircumcised male VUR toilet training voiding dysfunction obstructive uropathy urethral instrumentation constipation anatomic abnormality (labial adhesion) neuropathic bladder sexual activity pregancy
What are the difference between Type I and II fimbrae?
Type 1: most strains of E.coli, mannose sensitive, no role in pyelonephritis
Type 2: glycosphingolipid, can cause pyelonephritis
necessary for confirmation and appropriate therapy
Urine culture
How to obtain urine sample?
Toilet trained: midstream urine
uncircumcised males: retract prepuce
Children 2 to 24 months not toilet trained: catheterized or suprapubic aspirate
When is the “bag” collection useful?
only if the urinalysis or culture is negative
What are usually positive in infected urine specimen?
nitrites and leukocyte esterase
high sensitivity and specificity for UTI?
in febrile infants less than 60 days old, with pyuria, nitrites and leukocyte esterase
Urine culture findings in patients with UTI?
> 50,000 CFU/ml of a SINGLE pathogen (suprapubic or catheter) with pyuria or bacteriuria in a symptomatic child
What is the first line of imaging for screening patients suspected to have UTI?
Ultrasound
Treatment for acute cystitis
if mild or diagnosis is doubtful, treatment can be delayed until results of culture are known
If severe, start presumptive treatment
3-5 day course of therapy with TMP-SMX (6-12mg TMP/kg/day in 2 divided doses)
Nitrofurantoin also effective against Klebsiella and Enterobacter.
Amoxicillin can also be used but has high rate of resistance
What is treatment for acute febrile UTI?
7-14 days course of antibiotics
For hospitalized, Ceftriaxone (50mg/kg/24hr) or Cefepime (100mg/kg/24hr q12) or Cefotaxime (100-150mg/kg/24hr in 3-4 divided doses)
for outpatient: Cefixime is treatment of choice
Cephalexin may also be considered
What is the treatment for acute lobar nephronia?
duration of 14-21 days same antibiotics with pyelonephritis
What is the treatment for renal abscess?
larger than 3-5cm: immediate percutaneous drainage
Small less than 3cm: may be treated with antibiotics alone
10-14 days IV antibiotics followed by 2-4wk oral antibiotics
What is “bottom up” approach?
renal sonogram plus VCUG to identify upper and lower urinary tract abnormalities including VUR, bladder-bowel dysfunction and bladder abnormalities
What is the “top down” approach?
intended to reduce the number of VCUG
begins with DMSA scan to identify acute pyelonephritis
If DMSA is positive then proceed to VCUG
AAP recommendation for children 2-24months with first episode of UTI
do initial ultrasound
VCUG if with recurrent febrile UTI, patients younger than 6mos with atypical features (non-Ecoli, sig family history)
AAP recommendation for pas with 1st episode of pyelonephritis with normal urinary tract
does not recommend routine use of antibiotics
bag sample, urine culture positive, symptomatic or single organism >100,000
presumed UTI
