Acute pn
Transcript of Acute pn
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ACUTE PYELONEPHRITIS
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Acute pyelonephritis is a potentially organ- and/or life-
threatening infection that characteristically causes
scarring of the kidney.An episode of acute pyelonephritis may lead to:
kidney failure;
abscess formation (eg, nephric, perinephric);
sepsis
septic shock,
multiorgan system failure.
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PathophysiologyAcute pyelonephritis results from bacter ia l invasion of the
renal parenchym a.
Bacteria usually reach the kidney by ascending from the
lower urinary tract.
In all age groups, episodes of bacteriuria occur commonly,
but most are asymptomatic and do not lead to infection.
The development of infection is influenced by bacterial
factors and host factors. Bacteria may also reach the kidney via the
bloodstreamMost bacterial data are derived from research with
Escherichia coli, which accounts for 70-90% of
uncomplicated UTIs and 21-54% of complicated UTIs
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Pathogen
s
Staphylococcus
saprophyticus
Klebsiella pneumoniae
Proteus mirabilis
Enterococci
S aureus
Pseudomonas aeruginosa
Enterobacter s ecies
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Complicated infection
Complicated UTI is an infection of the urinary tract in
which the efficacy of antibiotics is reduced because ofthe presence of one or more of the following:
Structural abnormalities of the urinary tract
Functional abnormalities of the urinary tract
Metabolic abnormalities predisposing to UTIs
Unusual pathogens
Recent antibiotic use
Recent urinary tract instrumentation
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Obstruction is the most important factor.
It negates the flushing effect of urine flow; allows
urine to pool (urinary stasis)=>providing bacteriaa medium in which to multiply;
=>changes intrarenal blood
flow, affecting neutrophil delivery.
Obstruction may be extrinsic or intrinsic.
Extrinsic obstruction : chronic constipation ,
prostatic swelling/mass (eg, hypertrophy, infection,cancer), and retroperitoneal mass.
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Intrinsic obstruction occurs with bladder outlet
obstruction, cystocele, fungus ball, papillary necrosis,
stricture, and urinary stones.
Atrophic vaginal mucosa in postmenopausalwomen predisposes to the colonization of urinary
tract pathogens and UTIs because of the higher pH
(5.5 vs 3.8) and the absence of lactobacilli.
Bacterial prostatitis (acute or chronic) produces
bacteriuria,
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Pregnancy produces hormonal and mechanical
changes that predispose the woman to upper urinary
traction infections.
Hydroureter of pregnancy, secondary to both
hormonal and mechanical factors, manifests
as dilatation of the renal pelvis and ureters(greater on the left than on the right), with the
ureters containing up to 200 mL of urine.
Progesterone decreases ureteral peristalsisand increases bladder capacity.
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Diabetes mellitus produces autonomic bladder neuropathy,
glucosuria, leukocyte dysfunction, microangiopathy, and
nephrosclerosis.
Complicated UTIs in patients who have diabetes mellitus
include the following:
Renal and perirenal abscess
Emphysematous pyelonephritis
Emphysematous cystitis
Fungal infections
Xanthogranulomatous pyelonephritis
Papillary necrosis
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Bacteria % Uncomplicated % Complicated
Gram negative
Escherichia coli 70-95 21-54
Proteus mirabilis 1-2 1-10
Klebsiella spp 1-2 2-17
Citrobacter spp < 1. 5
Enterobacter spp < 1 2-10Pseudomonas aeruginosa < 1 2-19
Other < 1 6-20
Gram positive
Coagulase-negative staphylococci 5-10 1-4Enterococci 1-2 1-23
Group B streptococci < 1 1-4
Staphylococcus aureus < 1 1-23
Other < 1 2
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History
The classic presentation =triad : fever, costovertebral
angle pain, and nausea and/or vomiting.
Symptoms may be minimal to severe and usuallydevelop over hours or over the course of a day.
symptoms develop over several days and may even
be present for a few weeks before the patient seeks
medical care.
Symptoms of cystitis : urinary frequency, hesitancy,
lower abdominal pain, and urgency.
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Gross hematuria (hemorrhagic cystitis) is present in
30-40% of pyelonephritis cases in females, most often
young women.
Gross hematuria is unusual in males and should
prompt consideration of a more serious cause.
Pain may be :
mild, moderate, or severe
unilateral /bilateral.
in the back (lower or middle) and/or the suprapubicarea. Patients may describe suprapubic symptoms as
discomfort, heaviness, pain, or pressure.
Upper abdominal pain is unusual, and radiation of pain
to the groin is suggestive of a ureteral stone.
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Fever
is not always present.
it is not unusual for the temperature to exceed 103F
(39.4C).
Gastrointestinal symptoms.
Anorexia is common.
Nausea and vomiting vary in frequency and intensity
from absent to severe.
Diarrhea occurs infrequently.
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Elderly patients may present with typical manifestations of
pyelonephritis, or they may experience fever, mental status
change, decompensation in another organ system, orgeneralized deterioration.
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Complicated pyelonephritis
A history of the following indicates an increased r iskof
complicated pyelonephritis:
Structural abnormalities of the urinary tract
Functional abnormalities of the urinary tract
Metabolic abnormalities predisposing to UTIs
Recent antibiotic use
Recent urinary tract instrumentation
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abdominal examination:
suprapubic tenderness usually ranges from mild tomoderate without rebound.
Abdominal tenderness other than in the suprapubic
area suggests another diagnosis.
Patients usually do not have rigidity or guarding, and
bowel sounds are often normally active.
Flank or costovertebral angle (CVA) tenderness is mostcommonly unilateral over the involved kidney, although
bilateral discomfort may be present.
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In women: a pelvic examination should be performed.
Tenderness of the cervix, uterus, and adnexa should be
absent. Any positive finding suggests an additional or
alternative diagnosis
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Complications
Complications occur more often in patients with diabetes
mellitus, chronic renal disease, sickle cell disease, renal
transplant (particularly during the first 3 months), AIDS,
and other immunocompromised states.
Complications may involve any of the following:
Acute renal failure
Chronic renal damage leading to hypertension and renal
failure
Sepsis syndromes
Renal papillary
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Acute Abdomen and
Pregnancy
Acute Bacterial Prostatitis
Appendicitis
Cervicitis
Chronic Bacterial Prostatitis
Chronic Pyelonephritis
Cystitis in Females
Endometritis
Pelvic Inflammatory Disease
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Approach Considerations
In the outpatient setting, pyelonephritis is usuallysuggested by the history and physical examination
and supported by urinalysis results, which should
include microscopic analysis.
Other laboratory studies are used to identifycomplicating conditions and to assist in determining
whether the patient should be admitted.
Easily diagnosed cases typically occur in women,both pregnant and nonpregnant.
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Collection of Urine Specimens
Urine specimens obtained for urinalysis and culture
should approximate the urine contained in the bladderas closely as possible.
The 3 procedures for collecting such a urine specimen
are:
clean catch,
urethral catheterization,
suprapubic needle aspiration.
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Urinalysis
Pyuria is defined as more than 5-10 WBCs per high-power field (hpf)on a specimen spun at 2000 rpm for 5 minutes. Almost all patients with
pyelonephritis have significant pyuria (>20 WBCs/hpf).
The dipstick leukocyte esterase test (LET) helps screen for pyuria.
LET results have a sensitivity of 75-96% and a specificity of 94-98% fordetecting more than 10 WBC/hpf.
The nitrite production test (NPT) for bacteriuria has 92-100%
sensitivity and 35-85% specificity.
Combined, the LET-NPT has a sensitivity of 79.2% and a specificity of
81%, which is too low for it to be used as the only screening study for
bacteriuria.
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Gross hematuria occurs infrequently with pyelonephritis
and is more common with cystitis (hemorrhagic cystitis).
When gross hematuria is present, the differential should
include calculi, cancer, glomerulonephritis, tuberculosis,trauma, and vasculitis.
Microscopic hematuria may be present in patients with
uncomplicated acute pyelonephritis, but other causes
should be considered, particularly calculi
Microscopic hematuria may be present in patients with
uncomplicated acute pyelonephritis, but other causes should
be considered, particularly calculi.White cell casts are suggestive of pyelonephritis
Proteinuria is expected (up to 2 g/day). When it exceeds 3
g/day, glomerulonephritis should be considered.
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Urine and Blood CulturesUrine culture is indicated in any patient with pyelonephritis,
whether treated in an inpatient or an outpatient setting,
because of the possibility of antibiotic resistance.
Blood cultures are indicated in any patient who is beingadmitted or who has already been admitted. Approximately
12-20% of patients have cultures that are positive for
infection
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Indications for Imaging Studies
Imaging may be required to make the diagnosis in infants
and children in whom pyelonephritis presents insidiously.
Imaging is warranted at the time of admission in patients
with the following conditions:
AIDSPoorly controlled diabetes
Organ transplant (particularly renal)
Other immunocompromised state
Sepsis syndromeSeptic shock
Indications for imaging studies are as follows:
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Indications for imaging studies are as follows:
Fever or positive blood culture results that persist for
longer than 48 hours
Sudden worsening of the patients condition
Toxicity persisting for longer than 72 hours
Complicated UTI
Computed Tomography
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Computed Tomography
Contrast-enhanced helical/spiral computed
tomography (CECT) is the imaging study of choice,
both in adults and in children with acute
pyelonephritis.CECT is more sensitive than ultrasonography and
intravenous pyelography (which has only 25%
sensitivity), and it can more readily identify alterations
in renal parenchymal perfusion, alterations in contrastexcretion, perinephric fluid, and nonrenal disease.
Ultrasonography
Ultrasonography (US) can sometimes detect acutepyelonephritis, but a negative study does not exclude
the possibility.
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CT and MR Urography
CT urography and MR urography are evolving modalities
that surpass intravenous urography, which was the prior
mainstay of urinary tract imaging.
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Approach Considerations
Ambulatory younger women who present with signsand symptoms of uncomplicated acute pyelonephritis
may be candidates for outpatient therapy. (They must
be otherwise healthy and must not be pregnant.)
In addition, they must be treated initially in theemergency department (ED) with vigorous oral or IV
fluids, antipyretic pain medication, and a dose of
parenteral antibiotics.
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Admission is usually appropriate for :
patients who are severely ill,
pregnant,
elderly
who have comorbid disorders that increase the
complexity of management or the complication rate
(eg, diabetes mellitus, chronic lung disease, congenital
or acquired immunodeficiency).
Admission may also be advisable for patients whosesocial situation is unstable, because of the possibility of
poor compliance or poor follow-up.
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Antibiotic Selection
Antibiotic selection is typically empirical, because the
results of blood or urine cultures are rarely available by
the time a decision must be made.Initial selection should be guided by local antibiotic
resistance patterns.
Culture results from specimens collected before the
initiation of therapy should be checked in 48 hours todetermine antibiotic efficacy.E coli or other Enterobacteriaceae => Acceptable
regimens may include fluoroquinolones, cephalosporins,
penicillins, extended-spectrum penicillins, carbapenems,
and aminoglycosides.
enterococci => ampicillin or vancomycin can replace the
fluoroquinolone. If any doubt exists as to the diagnosis,
coverage of both Enterobacteriaceae and enterococci is
acceptable.
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Regimens for complicated cases
With complicated acute pyelonephritis, treat patients
parenterally until defervescence and improvement in the clinicondition warrants changing to oral antibiotics. Complete the
course of therapy with an oral agent selected on the basis of
culture results
Acceptable regimens include the following:
Ampicillin and an aminoglycoside
Cefepime
Imipenem
Meropenem
Piperacillin-tazobactam
Ticarcillin-clavulanate
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Outpatient Treatment
Antibiotic therapy
Patients presenting with acute pyelonephritis can be
treated with a single dose of a parenteral antibioticfollowed by oral therapy, provided they are monitored
within the first 48 hours.
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First-line therapy
ciprofloxacin (Cipro) 500 mg PO BID for 7d orciprofloxacin extended-release (Cipro XR) 1000 mg PO da
for 7d or
levofloxacin (Levaquin) 750 mg PO daily for 5d
If fluoroquinolone resistance is thought to be >10%, administa single dose of ceftriaxone (Rocephin) 1g IV or a consolidat
24-hour dose of an aminoglycoside (gentamicin 7 mg/kg IV o
tobramycin 7 mg/kg IV or amikacin 20 mg/kg IV)
cefaclor 500 mg PO TID for 7d
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Second-line therapy
trimethoprim/sulfamethoxazole* 160 mg/800 mg(Bactrim DS, Septra DS) 1 tablet PO BID for 14d
If trimethoprim/sulfamethoxazole is used when the
susceptibility is not known, an initial single IV dose of
the following may also be given: ceftriaxone (Rocephin)1 g IV or a consolidated 24-h dose of an
aminoglycoside (gentamicin 7 mg/kg IV or tobramycin 7
mg/kg IV or amikacin 20 mg/kg IV)
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Alternative therapy
Oral beta-lactams are not as effective for treating
pyelonephritis; however, if they are used, administerwith a single dose of ceftriaxone (Rocephin) 1 g IV or a
consolidated 24-h dose of an aminoglycoside
(gentamicin 7 mg/kg IV or tobramycin 7 mg/kg IV or
amikacin 20 mg/kg IV)amoxicillin-clavulanate (Augmentin) 500 mg/125 mg
PO BID for 14d or
amoxicillin-clavulanate (Augmentin) 250 mg/125 mg
PO TID for 3-7d orcefaclor 500 mg PO TID for 7d