Biology Reference
In-Depth Information
CLINICAL MANIFESTATIONS
Transmission
Host factors predisposing women to recurrent UTI and upper UTI
Several host-associated factors predispose women to recurrent UTI. Frequent
sexual intercourse (>9 times/month) is the factor with the strongest correlation
to recurrent UTI (
Kodner and Thomas Gupton, 2010
). Other factors that can
predispose otherwise healthy women to UTI include choice of contraceptive,
anatomical factors, local pH fluctuations and the antibody titers in the vaginal
tract (
Kodner and Thomas Gupton, 2010
). Development of upper UTI, such as
pyelonephritis, is associated with diabetes, immunosuppression, and anatomical
urinary tract obstructions (
Tseng et al., 2002
).
Clinical features and diagnosis
Urinary tract infection clinical features
UTI is categorized by the site within the urinary tract to which the infection is
localized and the severity of disease: bacteriuria (the urine, otherwise unspeci-
fied), cystitis (the bladder), pyelonephritis (the kidneys), and urosepsis (often,
but not always blood). Cystitis, infection of the bladder, is characterized by
inflammation of the lower urinary tract and presents with symptoms such as
dysuria, increased frequency of urination, and suprapubic pain. Bacteriuria is
present and a urinary dipstick test is often positive for leukocyte esterase and
nitrates (
Kodner and Thomas Gupton, 2010
;
Norinder et al., 2012
). Diagno-
sis of cystitis is confirmed when ≥10
3
bacteria/ml in a midstream clean-catch
urine sample from a patient with symptoms of UTI is observed, although the
diagnosis can be made without culture confirmation in women with typical
features and a prior history. Acute pyelonephritis-associated features include
flank pain, pyuria with casts, costovertebral angle tenderness, rigors, bacteriuria
with or without diaphoresis, nausea,vomiting, abdominal or groin pain, and fever
(
Kodner and Thomas Gupton, 2010
).
Complications
Intense inflammation caused by UPEC in the kidneys occurs in wedge-shaped
areas from papillae to renal cortex, and tubules are filled with polymorpho-
nuclear leukocytes (PMNs). Renal abscesses may form in areas of localized
inflammation, and bacteria may travel to the bloodstream causing bacteremia. In
fact, 12% of patients with acute pyelonephritis have bacteremia. This increases
the severity of disease, and when untreated, can be fatal. Complications from
pyelonephritis result in a 25% mortality rate with 36 000 deaths per annum in
the USA (
Stamm and Norrby, 2001
). Pyelonephritis can also lead to scarring of
the kidneys, reduced renal concentrating ability, and renal failure.
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