UTI and Pylonephritis (PN): Sarah Eisenschenk
URI
PN
Terminology/defin
itions
Organisms
Microbial
colonization of
urine and tissue
invasion of any
structure of the
urinary tract is
broadly called
UTI.
Clinically, UTI
usually refers to
involvement of
lower tract
structures while
pyelonephritis
refers to
involvement of
upper tract
structures
Bacteria: E.
coli > 90%
cases.
Proteus
(produces
urease, NH3+),
Klebsiella,
Staph
saprophyticus,
Pseudomonas,
Enterobacter,
Enterococci
Yeast Candida,
especially in
diabetics or
OTHER (IC)
patients
Fungi – IC
patients
Viruses
Body’s
Defense
Mechanis
m
Urine: the
following
inhibit
bacterial
replicatio
n: Acid
pH, ↑
urea, ↑
osmolality
Dynamics
of urinary
flow –
wash out
Risk Factors
Clinical Presentation
Laboratory Evaluation
Females >>> males due to
short urethra which results
in easier ascension and
migration of perineal/large
bowel bacteria to bladder
where infection may occur.
↑ urinary frequency, Dysuria,
Suprapubic discomfort/pressure,
Cloudy & malodorous urine,
Fever: not as common, but can
occur (even rigors),
Flank pain: not often, but can
occur,
Hematuria: usually not gross
CBC: usually see leukocytosis. Much more likely to see
significant ↑ of WBC in pyelonephritis
*Clinical pearl: Beware elderly patients and
immunocompromised patients who may not mount this
response
Urinalysis - How to obtain:
1. Clean-catch midstream sample
2. Catheterization
3. Suprapubic aspirate (mostly infants)
4. Laboratory Evaluation (cont’d)
Urinalysis – Positive findings for UTI and pyelonephritis
include: Nitrites: surrogate marker for bacteriuria;
Leukocyte esterase: reflects presence of WBCs;
Proteinuria: more commonly in pyelonephritis; Pyuria: >
10 WBC/hpf on centrifuged specimen: important number;
Hematuria: few RBCs to gross hematuria depending on
body’s response, degree of tissue invasion/inflammation
and organism; Bacteriuria on light microscopy with or
without Gram staining
Culture: Helps to define organism, antibiotic sensitivity
- Should be done routinely on all men, children, and
patients with risk factors in addition to female status
- If first episode for a female, culture not required but if
patient has history of recurrent infections or is pregnant or
has immunosuppression, including diabetes, culture should
be done
- Positive culture usually defined as ≥ 10,000 cfu of bacteria
per ml of urine obtained on clean-catch midstream
specimen
- Catheterized or suprapubic specimen may be considered
positive if > 100 cfu are found due to fewer contaminants
- Radiology: Ultrasound, CT, IVP, MRI; usually done if
patient not responding to treatment in 2-3 days
Instrumentation: cystoscopy,
catheterization (short-term
and long-term)
Structural or anatomical
anomalies of GU tract, i.e.,
posterior urethral valves,
medullary sponge kidney,
polycystic kidney, benign
prostatic hyperplasia (BPH),
stones, cystocele, etc.
Functional anomalies:
Vesicoureteral reflux (often
seen in children) &
Neurogenic bladder
Intercourse: “Honeymoon
cystitis”; void immediately
after intercourse
Pregnancy = ↑ incidence of
bacteriuria
Age: Elderly = ↑ rates of
bacteriuria
Up to 40% of elderly patients
- Usually patient has many similar
symptoms as UTI but often
significant fever (38.9 to 40º C.)
- Often see nausea, vomiting
- Commonly CVAT, flank pain
- Abdominal pain (upper/lower),
altered GI function (diarrhea,
ileus) and fatigue may be seen
*Clinical Pearl*
UTI, pyelonephritis, and urethritis
share many similar symptoms.
The more toxically ill the patient
appears, the more likely it is that
he/she has pyelonephritis.
UTI and Pylonephritis (PN): Sarah Eisenschenk
Treatment:

Antibiotics - po vs. parenteral

Empiric: TMP/SMX is still first-line therapy (E. coli resistance may be up to
20% in some areas)

Quinolones (≥18 yrs)

Nitrofurontoin (resistance rates generally low for E. coli)

Cephalosporins

Amoxicillin (not used very often)
When To Refer (to Urology, Nephrology, Infectious Disease)

Renal papillary necrosis

diabetics with significant vascular disease and severe pyelonephritis

analgesic abusers

patients with rapidly decompensating course due to ischemic necrosis of papilla and
medulla

diagnosis made by pyelogram and/or urinary sediment examination for papillary tissue

Antifungals (in immunocompromised.)

Symptomatic: Pyridium (In will cause urine to turn orange and will stain contact lenses.)

Often occurs as extension of pyelonephritis process

Fluids po or IV important: Remember dynamic urinary flow  washout principle. Water
and juice are best.

Consider staph spread hematogenously from a distant source (endocarditis)

Prophylaxis: indicated for patients with recurrent infections (defined as 3 or more UTIs
documented by urine culture within one year).

Imaging studies such as CT, US, and IVP helpful

Surgical drainage usually needed

Treatment strategies are as follows:

Acute self-treatment with 3-day course of standard therapy

Post-coital dosing with TMP/SMX

Continuous daily prophylaxis with low dose nitrofurantin, trimethoprim, or
TMP/SMX for 6 months

Renal abscess

When To Refer (cont’d)

Perinephric abscess

Often difficult to diagnose

Most patients have diabetes mellitus or stone disease and have had recent UTI

Uncomplicated UTI with no previous history = may treat with 3 days antibiotics

Patients present with fever and unilateral flank pain

UTI in pregnancy: 7 days recommended

Usually the perinephric abscess occurs secondary to the rupture of an intrarenal abscess

UTI in complicated cases (i.e., sx > 1 week, diabetic, immunosuppressed): 7 days
recommended

Surgical drainage is needed

Nephrolithiasis with infection
Treatment- Pylonephritis





Staghorn calculus or struvite calculus is formed by a rapidly growing stone which tends to fill
the pelvocalyceal system. Stones are composed of magnesium ammonium phosphate
(struvite) which represents a common sequela of urinary tract infections

Proteus mirabilis is the most common organism associated with urolithiasis, but organisms
such as Pseudomonas aeruginosa, Klebsiella species, Escherichia coli, and Staphylococcus
aureus are also known to promote stone formation

May have obstruction of ureter with high grade hydronephrosis

Surgical intervention may be necessary
Uncomplicated, outpatient: 7 days of Cipro has higher success rate than 14 days
TMP/SMX (JAMA 283:1583, 2000)
He treats with 10 days and has close follow-up to ensure their symptoms are
improving.
Hospitalized: IV Abx - FQ usually, but Amp/Gent and AM/SB are alternatives. Treat until
afebrile 24-48º, then switch to po and treat for total of 2 weeks
Complicated pyelo: usually cath-related

Treat for 2-3 weeks total with combination IV and po Abx

Atypical organisms, usually in immunocompromised patients

Candida

Fungi