Diagnosis and management of acute pyelonephritis in adults

American Family Physician,  March 1, 2005  by Kalyanakrishnan Ramakrishnan,  Dewey C. Scheid

• E-mail
• Print
• Link

TABLE 1
Risk Factors for Complicated Acute Pyelonephritis

Age
  Infants
  Elderly (> 60 years of age)
Anatomic/functional abnormality
  Polycystic kidney disease
  Horseshoe kidney
  Double ureter
  Ureterocele
  Vesicoureteric ref lux
Foreign body
  Urinary, ureteric, or
    nephrostomy catheters
  Calculus
Immunosuppressed state
  Diabetes mellitus
  Sickle cell disease
  Transplantation
  Malignancy
  Chemoradiation
  HIV infections
  Corticosteroid use
Male sex
  Anatomic abnormalities
  Prostatic obstruction
Obstruction
  Foreign body
  Calculi
  Bladder neck obstruction
  Posterior urethral valve
  Benign prostatic hypertrophy
  Neurogenic bladder
Pregnancy
Miscellaneous
  Inappropriate antibiotics
  Resistant organisms
  Instrumentation

HIV = human immunodeficiency virus.

Information from references 1 and 2.

TABLE 2
Microbial Organisms Causing Specific Types of Urinary Tract Infections

                     Acute            Acute
                     uncomplicated    uncomplicated
Microbial organism   cystitis (%) *   pyelonephritis (%)

Escherichia coli     68               89
Staphylococcus       8                0
  saprophyticus
Proteus              6                4
Klebsiella           4                4
Enterococci          3                0
Pseudomonas          0                0
Mixed                3                5
Yeast                0                0

                     Complicated   Catheter-associated
Microbial organism   UTI (%)       UTI (%)

Escherichia coli     32            24
Staphylococcus       1             0
  saprophyticus
Proteus              4             6
Klebsiella           5             8
Enterococci          22            7
Pseudomonas          20            9
Mixed                10            11
Yeast                15            8

UTI = urinary tract infection.

*--One study (9) showed that 25 percent of E. coli isolates were
resistant to ampicillin, 24 percent to tetracyclines, and 11 percent
to trimethoprim-sulfamethoxazole (TMP-SMX, Bactrim, Septra).

Adapted with permission from The Johns Hopkins Ambulatory Clerkship in
Medicine. Dysuria. Accessed online December 5, 2004, at.
http://deptmed.med.som.jhmi.edu/ambclerk/dysuria.html, with additional
information from reference 9.

TABLE 3
Laboratory Diagnosis of Urinary Tract Infection

Test                          Finding                 Sensitivity (%) *

Urinalysis (16,17)            > 5 WBCs/HPF            72 to 95
                              > 10 WBCs/HPF           58 to 82
Leukocyte esterase test (3)   Positive                74 to 96
Nitrite test (18)             Positive                92 to 100
Leukocyte esterase and        Either test positive    75 to 84
  nitrite tests's (19)
Dipstick hematuria (20)       Positive                44
Gram stain of uncentrifuged   > 1 bacterium per HPF   93
  urine (21)

Test                          Specificity (%)

Urinalysis (16, 17)           48 to 82
                              65 to 86
Leukocyte esterase test (3)   94 to 98
Nitrite test (18)             35 to 85
Leukocyte esterase and        82 to 98
  nitrite tests's (19)
Dipstick hematuria (20)       88
Gram stain of uncentrifuged   95
  urine (21)

WBCs/HPF = white blood cells per high-power field.

*--For identification of > 100,000 colony-forming units per
[mm.sup.3].

Information from references 3 and 15 through 21.

TABLE 4
Indications for Hospitalization
in Patients with Acute
Pyelonephritis

Absolute indications

Persistent vomiting

Progression of uncomplicated UTI

Suspected sepsis

Uncertain diagnosis

Urinary tract obstruction

Relative indications

Age > 60 years

Anatomic urinary tract abnormality

Immunocompromised (diabetes mellitus,
cancer, sickle cell disease, organ
transplant)

Inadequate access to follow-up

Frailty, poor social support

UTI = urinary tract infection.
Information from reference 1.

TABLE 5
Antimicrobial Agents Used in the Treatment of Acute Pyelonephritis

                                                 Oral dose
Agent                      Dosing schedule       (mg)

Penicillins

Amoxicillin                Every 8 to 12 hours   500
Amoxicillin- clavulanate   Every 8 to 12 hours   500/125
  potassium (Augmentin)
Ampicillin-sulbactam       Every 4 to 6 hours    --
  (Unasyn)
Aztreonam (Azactam)        Every 6 to 8 hours    --
Imipenem (Primaxin I.V.)   Every 6 hours         --
Piperacillin (Pipracil)    Every 6 hours         --
Piperacillin-tazobactam    Every 6 to 8 hours    --
  (Zosyn)
Ticarcillin-clavulanate    Every 4 to 6 hours    --
  (Timentin)

Cephalosporins

Cefotaxime (Claforan)      Every 8 to 12 hours   --
Ceftriaxone (Rocephin)     Once  in 24 hours     --
Cephalexin (Keflex)        Every 6 hours         500

Fluoroquinolones

Ciprofloxacin (Cipro)      Every 12 hours        500
Enoxacin (Penetrex)        Every 24 hours        400
Gatifloxacin (Tequin)      Every 24 hours        --
Levofloxacin (Levaquin)    Every 24 hours        250 to 750
Lomefloxacin (Maxaquin)    Every 24 hours        400
Norfloxacin (Noroxin)      Every 12 hours        400
Ofloxacin (Floxin)         Every 12 hours        200 to 400

Aminoglycosides

Amikacin (Amikin)          Every 12 hours        --
Gentamicin (Garamycin)     Every 24 hours        --
Tobramycin (Nebcin)        Every 24 hours        --

Other antibiotics

TMP-SMX (Bactrim;          Every 12 hours        160/800
  Septra)

Agent                      IV dose

Penicillins

Amoxicillin                --
Amoxicillin- clavulanate   --
  potassium (Augmentin)
Ampicillin-sulbactam       150 to 200 mg
  (Unasyn)                   per kg per day
Aztreonam (Azactam)        1 to 2 g
Imipenem (Primaxin I.V.)   0.5 g
Piperacillin (Pipracil)    3 g
Piperacillin-tazobactam    3.375 g/4.5 g
  (Zosyn)
Ticarcillin-clavulanate    3.1 g
  (Timentin)

Cephalosporins

Cefotaxime (Claforan)      1 to 2 g
Ceftriaxone (Rocephin)     1 to 2 g
Cephalexin (Keflex)        --

Fluoroquinolones

Ciprofloxacin (Cipro)      400 mg
Enoxacin (Penetrex)        --
Gatifloxacin (Tequin)      400 mg
Levofloxacin (Levaquin)    250 to 750 mg
Lomefloxacin (Maxaquin)    --
Norfloxacin (Noroxin)      --
Ofloxacin (Floxin)         400 mg

Aminoglycosides

Amikacin (Amikin)          7.5 mg per kg
Gentamicin (Garamycin)     5 to 7 mg per kg
Tobramycin (Nebcin)        5 to 7 mg per kg

Other antibiotics

TMP-SMX (Bactrim;          8 to 10 mg per kg
  Septra)                    (TMP)

Agent                      Comments

Penicillins

Amoxicillin                None
Amoxicillin- clavulanate   GI side effects *
  potassium (Augmentin)
Ampicillin-sulbactam       GI side effects *
  (Unasyn)
Aztreonam (Azactam)        Phlebitis; GI side effects *
Imipenem (Primaxin I.V.)   None
Piperacillin (Pipracil)    GI side effects *; phlebitis
Piperacillin-tazobactam    GI side effects *; rash;
  (Zosyn)                    headaches; insomnia
Ticarcillin-clavulanate    GI side effects*; rash; phlebitis
  (Timentin)

Cephalosporins

Cefotaxime (Claforan)      Thrombophlebitis
Ceftriaxone (Rocephin)     Leukopenia; elevated BUN
                             and liver enzyme levels
Cephalexin (Keflex)        GI side effects *

Fluoroquinolones

Ciprofloxacin (Cipro)      Nausea; headache; photosensitivity;
                             pregnancy category C
Enoxacin (Penetrex)        Pregnancy category C
Gatifloxacin (Tequin)      Pregnancy category C
Levofloxacin (Levaquin)    ECG QT prolongation;
                             pregnancy category C
Lomefloxacin (Maxaquin)    Pregnancy category C
Norfloxacin (Noroxin)      Pregnancy category C
Ofloxacin (Floxin)         Pregnancy category C

Aminoglycosides

Amikacin (Amikin)          Ototoxicity; nephrotoxicity
Gentamicin (Garamycin)     Ototoxicity; nephrotoxicity
Tobramycin (Nebcin)        Ototoxicity; nephrotoxicity

Other antibiotics

TMP-SMX (Bactrim;          G6PD deficiency; sulfa allergy;
  Septra)                    do not use in third trimester

IV = intravenous, GI = gastrointestinal, BUN = blood urea nitrogen,
ECG = electrocardiogram; TMP-SMX = trimethoprim-sulfamethoxazole,
G6PD = glucose-6-phosphate dehydrogenase.

*--GI side effects include nausea, vomiting, and diarrhea.

Strength of Recommendations

Key clinical recommendation                            Label  References

Blood cultures should be obtained in patients with     C      24, 25
acute pyelonephritis only if there is diagnostic
uncertainty, the patient is immunosuppressed, or a
hematogenous source is suspected.

Outpatient oral therapy is successful in 90 percent    B      27, 28
of selected patients with uncomplicated acute
pyelonephritis who can tolerate oral intake, will be
compliant with the treatment regimen, will return for
early follow-up, and have adequate social support.

Patients hospitalized with acute pyelonephritis        B      29
should be treated with one of three initial
intravenous therapies: a fluoroquinolone; an
aminoglycoside with or without ampicillin; or an
extended-spectrum cephalosporin with or without an
aminoglycoside.

A = consistent, good-quality patient-oriented evidence, B =
inconsistent or limited-quality patient-oriented evidence,
C = consensus, disease-oriented evidence, usual practice,
opinion, or case series. See page 835 for more information.