Acute Pyelonephritis Treatment & Management

Updated: May 31, 2023
  • Author: Tibor Fulop, MD, PhD, FACP, FASN; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Approach Considerations

Ambulatory younger women who present with signs and 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 the emergency department (ED) with vigorous oral or intravenous (IV) fluids, antipyretic pain medication, and a dose of parenteral antibiotics. Studies have shown that outpatient therapy for selected patients is as safe as inpatient therapy for a comparable group of patients and is much less expensive.

Use analgesics as needed. Early in the course of the illness, parenteral analgesics are often necessary to reduce morbidity from symptoms. Nonsteroidal anti-inflammatory drugs and narcotics are complementary; do not assume that one class is better than the other.

Admission is usually appropriate for patients who are severely ill, pregnant, or elderly or 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 whose social situation is unstable, because of the possibility of poor compliance or poor follow-up.

Emergency surgery may be indicated in a patient with fever or positive blood culture results persisting longer than 48 hours; in a patient whose condition deteriorates; or in a patient who appears toxic for longer than 72 hours. These patients may have an abscess, emphysematous pyelonephritis, or an obstructing calculus. The etiology may not be immediately evident, but an unexpected change in the clinical picture warrants immediate evaluation for potential surgical intervention.

After recovery from the acute infection, patients may be candidates for elective surgery to reverse conditions that predispose to recurrent kidney infections and damage, such as the following:

  • Congenital anomalies
  • Fistulae involving the urogenital tract
  • Prostatic hyperplasia
  • Kidney calculi
  • Vesicoureteral reflux

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 to determine antibiotic efficacy.

The pathogen in community-acquired infections is usually Escherichia coli or other Enterobacteriaceae. Acceptable regimens may include fluoroquinolones, cephalosporins, penicillins, extended-spectrum penicillins, carbapenems, and aminoglycosides. [25, 3] If enterococci are suggested on the basis of Gram stain results, ampicillin or vancomycin can replace the fluoroquinolone. If any doubt exists as to the diagnosis, coverage of both Enterobacteriaceae and enterococci is acceptable.

There is a higher incidence of enterococcal infections in hospitalized and other institutionalized patients. Ampicillin or amoxicillin should be included in the regimen. If the patient is allergic to penicillin, vancomycin should be substituted.

In choosing an empirical antibiotic regimen, consideration should include the local antibiogram and drug-resistance rates. For example, in a community with growing fluoroquinolone resistance, agents in that class may not be an ideal first-line choice. In light of increasing resistance, short courses of treatment are preferred. In one clinical trial, a 7-day course of oral ciprofloxacin was shown to be a safe and successful treatment for acute pyelonephritis in women, including older women and those with more severe infection. [26]

For uncomplicated pyelonephritis, the American College of Physicians (ACP) recommends administering a short course of fluoroquinolones (5 to 7 days) or trimethoprim-sulfamethoxazole (TMP-SMX; 14 days), based on antibiotic susceptibility. [27]

Patient characteristics should also be considered. For example, patients who have been frequently exposed to antibiotics (eg, solid-organ transplant and hematopoietic transplant patients) or are from institutional facilities are at a greater risk for infection with drug-resistant pathogens, such as extended-spectrum beta-lactamase–producing or carbapenemase-producing organisms.

For more information, see Pyelonephritis Empiric Therapy and Pyelonephritis Organism-Specific Therapy

Oral versus parenteral administration

Growing data suggest that oral antibiotic therapy, parenteral antibiotic therapy, and initial parenteral antibiotic therapy followed by oral antibiotic therapy are equally effective regimens, although most of the studies have been small. [28, 29] Some clinicians believe that initiating therapy with an intravenous or intramuscular dose of medication reduces the risk of therapeutic failure; other clinicians believe that a completely oral course is sufficient. Data exist to support both assertions.

One conventional regimen comprises levofloxacin, 500 mg/day, given intravenously and then orally for 7-14 days. A short-course regimen of intravenous levofloxacin at 750 mg/day for 5 days proved non-inferior to that conventional regimen in a prospective, open-label, randomized, controlled clinical trial in 317 Chinese patients with complicated urinary tract infections and acute pyelonephritis. [30]

To be considered for oral therapy, patients must meet several prerequisites. They must, of course, be able to tolerate oral medication. In addition, they must have no indication for admission, and close monitoring to ensure good compliance must be possible.

One prospective study supports using oral therapy alone in patients who can tolerate oral intake, lack signs of sepsis, and do not show signs of obstruction or kidney suppuration on urinary tract ultrasonography. Another study (prospective, randomized, unblinded) in a controlled hospital setting found no difference in efficacy between oral and intravenous ciprofloxacin for the initial management of severe pyelonephritis.

The 2010 guidelines from the Infectious Diseases Society of America (IDSA) recommend that women with pyelonephritis who require hospitalization be treated initially with an intravenous antimicrobial regimen. The choice of antimicrobial agents should be based on local resistance data, with the regimen tailored on the basis of susceptibility results. [3]

Although the guidelines recommend either 14 days of TMP-SMX or 7 days of ciprofloxacin for the treatment of pyelonephritis, a study in 272 women with susceptible E coli pyelonephritis reported similar clinical outcomes with 7 days of TMP-SMX therapy compared with 7 days of ciprofloxacin. [31]

Because of the high rate of resistance of E coli, the empirical use of TMP-SMX should be avoided in patients who require hospitalization. If beta-lactam drugs and fluoroquinolones are contraindicated, administer aztreonam parenterally. As such, the patient will need to be admitted.

Regimens for complicated cases

With complicated acute pyelonephritis, treat patients parenterally until defervescence and improvement in the clinical condition warrants changing to oral antibiotics. Complete the course of therapy with an oral agent selected on the basis of culture results. [29] Acceptable regimens include the following:

  • Ampicillin and an aminoglycoside
  • Cefepime
  • Imipenem
  • Meropenem
  • Piperacillin-tazobactam
  • Ticarcillin-clavulanate
  • Ceftazidime-avibactam [32, 33]
  • Meropenem-vaborbactam

If the patient is allergic to penicillin, vancomycin should be substituted. Vancomycin or linezolid are options if enterococci are a consideration.

Meropenem-vaborbactam (Vabomere) is a combination of the carbapenem antibiotic meropenem with the beta-lactamase inhibitor vaborbactam. Specifically, vaborbactam inhibits bacterial production of the Klebsiella pneumoniae carbapenemase (KPC) enzyme, which confers resistance to carbapenems. The US Food and Drug Administration (FDA) has approved meropenem-vaborbactam for adults aged 18 years and older with pyelonephritis and other complicated urinary tract infections (UTIs) caused by designated susceptible Enterobacteriaceae: Escherichia coli, K pneumoniae, and Enterobacter cloacae species complex. [34]

The safety and efficacy of meropenem-vaborbactam were demonstrated in a study of more than 500 adults with complicated UTI, including pyelonephritis, in which cure or improvement in symptoms and a negative urine culture were seen in about 98% of patients treated with meropenem-vaborbactam, versus about 94% of patients treated with piperacillin–tazobactam. Approximately 7 days after completing treatment, about 77% of patients treated with meropenem-vaborbactam demonstrated resolution of symptoms and a negative urine culture, compared with about 73% of patients treated with piperacillin–tazobactam. [34]


Outpatient Treatment

Antibiotic therapy

Patients presenting with acute pyelonephritis can be treated with a single dose of a parenteral antibiotic followed by oral therapy, provided they are monitored within the first 48 hours. In a study of febrile, nonpregnant women presenting with symptoms of acute pyelonephritis, 25% were hospitalized; of nonhospitalized patients, 80% were treated with a single parenteral dose of ceftriaxone or gentamicin, followed by oral therapy (usually TMP-SMX). Twelve percent returned with persistent symptoms, most in the first day; most of those patients were admitted. [5]

Acute pyelonephritis has customarily been treated with 14 days of antibiotics, and the IDSA guidelines maintain this recommendation for TMP-SMX and beta-lactam agents. However, evidence suggests that in young, healthy women who are receiving a fluoroquinolone, including ciprofloxacin, the course of treatment can be shortened to 7 days. Levofloxacin, 750 mg/day, can be given for 5 days. [35, 36] Young, healthy males should complete a 14-day course. [3]

Outpatient treatment is appropriate for patients who have an uncomplicated infection that does not warrant hospitalization. Oral antibiotics are used to treat patients with mild to moderate illness. (See Table 2, below, for a description of outpatient treatments for pyelonephritis.)

Table 2. Outpatient Treatment for Pyelonephritis (Open Table in a new window)

First-line therapy

  • Ciprofloxacin (Cipro) 500 mg PO BID for 7d or

  • Ciprofloxacin extended-release (Cipro XR) 1000 mg PO daily for 7d or

  • Levofloxacin (Levaquin) 750 mg PO daily for 5d

  • If fluoroquinolone resistance is thought to be > 10%, administer a single dose of ceftriaxone (Rocephin) 1g IV or  a consolidated 24-hour dose of an aminoglycoside (gentamicin 7 mg/kg IV or  tobramycin 7 mg/kg IV or amikacin 20 mg/kg IV)

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 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)

Alternative therapy

  • Oral beta-lactams are not as effective for treating pyelonephritis; however, if they are used, administer a single dose of ceftriaxone 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 250 mg/125 mg PO TID for 3-7d or

  • Cefaclor 500 mg PO TID for 7d

*Should generally be avoided in elderly patients because of the risk of affecting kidney function.

For female patients suspected of having acute pyelonephritis, the IDSA guidelines recommend sending urine for culture and susceptibility testing and then starting empirical antibiotic therapy. [3]

The fluoroquinolones are well tolerated and quite effective. They are probably the outpatient antibiotic treatment of choice for pyelonephritis. They (along with TMP-SMX) do not eradicate the protective lactobacilli from the vagina. An important caveat for the use of fluoroquinolones in the elderly is their potential to cause aortic aneurysm or dissection; hypoglycemia; and a variety of neuropsychiatric symptoms, ranging from seizures to worsening of dementia. [37]

In communities where the prevalence of resistance in uropathogens to fluoroquinolones is not known to be greater than 10%, the IDSA guidelines advise that patients who do not require hospitalization be treated with oral ciprofloxacin, 500 mg twice daily for 7 days, with or without an initial 400-mg dose of intravenous ciprofloxacin. If the uropathogen’s fluoroquinolone resistance is greater than 10%, an initial intravenous dose of a long-acting parenteral antimicrobial (eg, ceftriaxone, 1 g) is recommended. [3]

On an individual basis, for persons with community-onset UTI and fever, a case-control study found that the risk of fluoroquinolone-resistant E coli infection increased if the patient had undergone recent hospitalization or urinary catheterization or if the patient had used a fluoroquinolone within the past 6 months. [28]

Intravenous fluids

If oral intake is not tolerated, intravenous hydration is warranted. Intravenous fluids should include 1 L of 5% dextrose in saline to reverse any existing ketosis, regardless of whether ketones are detected in the urine. Additional intravenous hydration is accomplished with normal saline. Exercise caution regarding conditions that might be adversely affected by improper amounts of fluid, saline, or glucose.


If the patient is not admitted at the time of diagnosis, follow-up reevaluation is important in 1-2 days to be sure the patient is progressing properly. A good rule based on common sense is that if the managing clinician is concerned that the patient may not respond well to outpatient management but still thinks the patient deserves a trial at home, the initial follow-up visit should take place in 24 hours. If the clinician thinks that the patient will do quite well with outpatient management, the initial follow-up visit can take place in 48 hours.

If the patient thinks that he or she is not progressing well or is getting worse, the patient should be evaluated emergently for consideration for admission and intravenous antibiotics.

Continue supportive care by prescribing antiemetics, antipyretics, analgesics, and urinary tract analgesics as needed. Have the patient complete a 14-day course of oral antibiotics. Evidence suggests that when treating a young, healthy female, the course of treatment can be shortened to 7 days from 14 days, if the antibiotic being used is a fluoroquinolone. Healthy young males should complete a 14-day course.

Obtain follow-up urine culture results in any patient with a complicated UTI, a complicated course, or increased risk of infection. Urine cultures are generally not indicated in healthy, nonpregnant women with resolved symptoms. [14] All patients with a complicated UTI should be considered for outpatient follow-up imaging of the urinary tract to identify abnormalities that predispose to further infections.

Rest is essential for recovery. Activity should be minimal. The patient should not return to work for 2 weeks, so as to allow time for the infection to be eliminated and for the patient to recover physical strength. Temper this recommendation depending on the physical condition of the patient and the presence of comorbid conditions.


Inpatient Treatment

The decision regarding admission of a patient with acute pyelonephritis depends on age; host factors, such as immunocompromising chemotherapy or chronic diseases, known urinary tract structural abnormalities, renal calculi, recent hospitalization, or urinary tract instrumentation; and the patient's response to ED therapy.

Admit all patients with complicated UTI. Complicating factors include the following:

  • Structural urinary tract abnormalities (eg, calculi, tract anomalies, indwelling catheter, obstruction)
  • Metabolic disease (eg, diabetes, kidney insufficiency)
  • Impaired host defenses (eg, HIV, current chemotherapy, underlying active cancer)
  • Pregnancy

Admission is also indicated for patients with apparent clinically uncomplicated pyelonephritis who have any of the following:

  • Inability to maintain adequate oral hydration
  • Evidence of vasomotor instability
  • Unrelenting fever despite antipyretic therapy
  • Debilitating pain or dehydration that cannot be corrected promptly in the ED
  • Inadequate home care or resources to fill prescriptions or comply with the medical regimen (eg, homeless patients, adolescents, elderly patients in an acute illness setting who are at risk for clouded judgment, patients with substance abuse issues or other issues that will prevent adequate compliance)

Inpatient care includes the following:

  • Continue supportive care
  • Monitor urine and blood culture results
  • Monitor comorbid conditions for deterioration
  • Maintain hydration status with IV fluids until hydration can be maintained with oral intake
  • Continue IV antibiotics until defervescence and significant symptomatic improvement occur; convert to an oral regimen tailored to urine or blood culture results

In patients with acute pyelonephritis who require hospitalization, treatment begins with IV antibiotics. IV therapy should be given for 24-48 hours or until severe symptoms improve. A systematic review of 8 randomized, controlled trials in hospitalized patients with acute pyelonephritis found that early switching to oral antibiotic treatment appears to be as effective and safe as exclusively IV regimens. [38]

Selection of a regimen should be based on local resistance data, and the regimen should be tailored on the basis of susceptibility results. Recommended regimens are listed in Table 3, below. However, a multinational study in 184 patients found that cefazolin is non-inferior to ceftriaxone for the empirical treatment of acute pyelonephritis in hospitalized patients. At 72 hours, defervescence or normalization of white blood cell count had occurred in 87.0% of the cefazolin group versus 85.9% of the ceftriaxone group; in addition, no difference was observed between the two groups for length of stay or 30-day readmission for cystitis or pyelonephritis. [39]

Table 3. Inpatient Treatment for Acute Pyelonephritis (Open Table in a new window)

First-line therapy

  • Ciprofloxacin (Cipro) 400 mg IV q12h for 10-14d or

  • Levofloxacin (Levaquin) 250 mg IV q24h for 10d or

  • Levofloxacin (Levaquin) 750 mg IV q24h for 5d

Second-line therapy

Extended-spectrum cephalosporins or penicillins:

  • Ampicillin-sulbactam (Unasyn) 1.5 g IV q6h or

  • Piperacillin-tazobactam (Zosyn) 3.375 g IV q6h or

  • Ticarcillin-clavulanate (Timentin) 3.1 g IV 4-6h or

  • Cefotaxime (Claforan) 1-2 g IV q8h or

  • Ceftriaxone (Rocephin) 1 g IV q24h or

  • Ceftazidime (Fortaz, Tazicef) 2 g IV q8h

  • All of the above can be administered with or without an aminoglycoside (except in pregnant patients); see Aminoglycosides, below


  • Meropenem (Merrem) 500 mg IV q8h or

  • Ertapenem (Invanz) 1 g IV q24h or

  • Doripenem (Doribax) 500 mg IV q8h

Monobactam (for patients with penicillin allergy):

  • Aztreonam (Azactam) 1 g IV q8-12h

Alternative therapy

Aminoglycosides (because of their potential nephrotoxicity, aminoglycoside antibiotics should be reserved for patients with serious and potentially life-threatening infections, and the dosage and blood levels should be carefully monitored to minimize the risk of nephrotoxicity):

  • Gentamicin 3 mg/kg/day IV/IM in 3 divided doses or 7 mg/kg/day pulsed dosing or

  • Tobramycin 3 mg/kg/day IV/IM in 3 divided doses or 7 mg/kg/day pulsed dosing or

  • Amikacin 10 mg/kg/day IV/IM in 3 divided doses or 20 mg/kg/day pulsed dosing or

  • Plazomicin 15 mg/kg IV q24hr infused over 30 minutes

However, an Israeli medical center that instituted a program of initial empirical treatment of pyelonephritis with aminoglycosides reported higher rates of in vitro activity and lower overall mortality than with non-aminoglycoside antibiotic therapy, without excess nephrotoxicity. In the study, which included 2026 patients, 715 treated with aminoglycosides and 1311 treated with non-aminoglycoside drugs, aminoglycosides were more likely to have in vitro activity against clinical isolates (odds ratio 2.0; P < 0.001); death at 30 days occurred in 55 (7.6%) versus 145 (11%) patients treated with aminoglycosides and non-aminoglycoside drugs, respectively (adjusted hazard ratio 0.78; P = 0.013). The incidence of acute kidney injury was 2.5% versus 2.9%, respectively; P = 0.6). [40]

Duration of therapy

Duration of therapy should be at least 10-14 days, inclusive of initial IV therapy. Patient circumstances may warrant more prolonged therapy.

The PROGRESS (Procalcitonin-guided Antimicrobial Therapy to Reduce Long-Term Sequelae of Infections) study found that in septic patients, procalcitonin levels can be used to guide discontinuation of antibiotics. This multicenter randomized trial in 266 patients, 95 of whom had acute pyelonephritis, used an ≥80% reduction in procalcitonin level or any procalcitonin level of ≤0.5 μg/L at Day 5 or later as a criterion for discontinuing antibiotics. [41]

In PROGRESS, procalcitonin-guided discontinuation, compared with standard of care, resulted in a shorter median length of antibiotic therapy (5 versus 10 days), a lower rate of infection-associated adverse events such as infections by multidrug-resistant organisms and Clostridioides difficile (7.2% versus 15.3%), and lower 28-day mortality (15.2% versus 28.2%). The cost of hospitalization was also reduced in the procalcitonin arm. [41]



For renal cortical abscesses (renal carbuncles), surgical drainage was once the only treatment. However, modern antibiotics alone often are curative. A semisynthetic penicillin, cephalosporin, fluoroquinolone, or vancomycin is recommended. Generally, parenteral antibiotics should be administered for 10-14 days, followed by oral therapy for 2-4 weeks. Fever should resolve within 5-6 days, and pain should resolve within 24 hours. If parenteral antibiotic therapy is successful, oral therapy is instituted for an additional 2-4 weeks.

If patients do not respond within 48 hours, percutaneous (or open) drainage should be performed. Other surgical options are enucleation of the carbuncle or nephrectomy.

Treatment of renal corticomedullary abscess includes parenteral antibiotics for 48 hours (usually successful), incision and drainage, and nephrectomy. If antibiotic therapy is successful, oral therapy is instituted for an additional 2 weeks.

Mortality associated with perinephric abscesses is 20-50%, but this rate can be decreased with early recognition, surgical drainage, and antimicrobial therapy (not adequate alone). Antibiotics should include an aminoglycoside and an antistaphylococcal agent. If Pseudomonas species are considered or demonstrated, an antipseudomonal beta-lactam antibiotic should be added. For enterococci, an aminoglycoside and ampicillin are recommended. Other organisms that have been reported include tuberculosis and fungi. Nephrectomy may be necessary.


Calculi-Related Infections

A major challenge with calculi-related UTI is that the organisms can survive within the calculus. In the presence of acute infection, calculi must be removed immediately using cystoscopy or open surgical procedure. In a review of adult patients with obstructive pyelonephritis due to a ureteral stone or kidney stone with hydronephrosis (n=311,100), delayed decompression (2 or more days after admission) increased the odds of in-hospital death by 29% (odds ratio 1.29, 95% confidence interval 1.03-1.63, P=0.032). [42]

The preferred method of treatment is surgical. Options include extracorporeal shockwave lithotripsy (ESWL), endoscopic methods, percutaneous methods, and open surgery. For staghorn calculus, the treatment of choice is to remove the whole stone. Fragments left behind remain infected and will grow again. Antibiotic therapy should be used in conjunction.

Although food and vitamin supplements that are rich in phosphorus and magnesium are advisable, remember that magnesium (and other divalent cations) can chelate fluoroquinolones, preventing their absorption from the gut.

Acidifying agents have been used. Ascorbic acid does not significantly decrease urinary pH, and ammonium chloride provides only temporary acidification. This approach is of little clinical usefulness. Urease inhibitors are effective in reducing stone formation, but long-term use is fraught with neurosensory, hematologic, and dermatologic adverse effects.


Other Complicated Infections

Treatment for renal papillary necrosis is admission for intravenous antibiotic therapy. The agents chosen should cover E coli and Enterobacter, Proteus, and Klebsiella species. Treatment for more serious infections also should cover Pseudomonas and Enterococcus species.

Parenteral agents that may be used empirically pending the result of a urine culture include the following:

  • Gentamicin
  • Cefotaxime
  • Ceftriaxone
  • Ceftazidime
  • Cefepime
  • Piperacillin-tazobactam
  • Imipenem-cilastatin
  • Meropenem
  • Ciprofloxacin

Parenteral therapy should be continued until the fever and other symptoms resolve. Duration of therapy generally is 14 days. If the response is not good, CT-guided drainage or surgical drainage with debridement is indicated.

The treatment of choice for xanthogranulomatous pyelonephritis is nephrectomy after the patient is stabilized. See Xanthogranulomatous Pyelonephritis for more information.


Pregnant Patients

Physiologic changes in the urinary tract predispose pregnant women to an increased risk of cystitis and pyelonephritis, which may lead to preterm labor and kidney damage. Hydroureter of pregnancy develops around the seventh week and progresses throughout the remainder of pregnancy; it resolves by 8 weeks post partum. The ureters may dilate sufficiently to contain 200 mL or more of urine. In addition, the kidneys enlarge and bladder capacity may double. The left kidney is more affected than the right.

The prevalence of bacteriuria in pregnancy is 2-25%, depending on the study criteria. Symptomatic UTI occurs in 1-3% of all pregnancies and leads to premature labor in 20-50% of cases.

The recommendation is that all pregnant women have a screening urine culture at 16 weeks' gestation. If the results are negative for a UTI, no additional cultures are indicated. If the patient has a history of recurrent UTIs, further cultures and other screening techniques (eg, nitrite dipstick or urine Gram stain) may be needed to detect the development of asymptomatic bacteriuria.

Successful treatment of bacteriuria prevents pyelonephritis. Fluoroquinolones and aminoglycosides should be avoided in pregnancy. Accepted regimens for treating asymptomatic bacteriuria include the following:

  • Amoxicillin 250 mg orally 3 times a day for 3 or 7 days; or 3 g in a single dose
  • Cephalexin 2 or 3 g in a single dose
  • Nitrofurantoin 200 mg in a single dose; or 100 mg 4 times a day for 3 or 7 days

Inpatient admission is warranted for any pregnant patient with pyelonephritis. The treatment of choice during pregnancy includes the use of beta-lactam antibiotics. Intravenous antibiotics should be administered until the patient is afebrile for 24 hours and symptomatically improved. It is recommended to avoid fluoroquinolones in pregnant patients. Aminoglycosides should also be avoided due to potential risk of ototoxicity following prolonged fetal exposure. See Table 4, below, for regimens for pyelonephritis in pregnant patients.

Table 4. Treatment of Pyelonephritis During Pregnancy (Open Table in a new window)

Mild to moderate pyelonephritis

  • Ceftriaxone (Rocephin) 1 g IV q24h or

  • Cefepime (Maxipime) 1 g IV q12h or

  • Cefotaxime (Claforan) 1-2 g IV q8h or

  • Ceftazidime (Fortaz, Tazicef) 2 g IV q8h or

  • Ampicillin 1-2 g IV q6h plus gentamicin IV 1.5 mg/kg q8h

Severe pyelonephritis

If patient is immunocompromised and/or has incomplete urinary drainage:

  • Ticarcillin-clavulanate (Timentin) 3.1 g IV q6h or

  • Ampicillin-sulbactam (Unasyn) 1.5 g IV q6h or

  • Piperacillin-tazobactam (Zosyn) 3.375 g IV q6h

Once patients are afebrile for at least 48 hours, they can be switched to oral antibiotics, with the regimen choice guided by results from susceptibility studies, and discharged to complete 10-14 days of treatment. Obtain an additional urine culture 1-2 weeks after the completion of therapy to verify eradication of the infection. Obtain monthly urine cultures until delivery to monitor the urine for recurrent infection.

Postcoital therapy with cephalexin or nitrofurantoin is recommended for prophylaxis against recurrent infection. If the initial infection requires a second agent for clearing the infection or a recurrent infection occurs, suppressive therapy until delivery is indicated with nitrofurantoin (50 mg or 100 mg at bedtime). Recurrent infection or persistent bacteriuria is an indication for urological evaluation 3-6 months after delivery.

Caution should be used when prescribing nitrofurantoin for prophylaxis, as adverse effects of this medication include peripheral neuropathy, pulmonary toxicity, and hepatotoxicity. Nitrofurantoin-induced liver injury and death have been reported. Hepatotoxicity is reversible if recognized early and nitrofurantoin is stopped, so hepatic enzymes should be monitored in women at higher doses or with prolonged use. [43]


Pediatric Patients

In pediatric patients with acute pyelonephritis, indications for immediate urologic referral include the following:

  • Abnormal electrolyte values associated with acidosis
  • Elevated blood urea nitrogen level
  • Hypertension
  • A palpable bladder
  • Voiding difficulty (dribbling, poor stream, straining)

Aside from the effects of acute infection, the overriding concern is progressive deterioration in function of an already compromised kidney (hypoplastic or dysplastic) secondary to scarring from recurrent pyelonephritis with or without associated obstruction. Infants and preschool-aged children are at greatest risk. Initial management varies with patient age and presentation.

Close follow-up, regardless of whether the patient is initially admitted, is essential to ensure recovery. Immediate reevaluation is encouraged for any recurrence of symptoms. Neither treatment of asymptomatic bacteriuria nor long-term suppressive therapy has been found to be effective.

Urologic evaluation is necessary to establish the presence of any urologic abnormality. The preferred imaging study for the diagnosis of acute pyelonephritis is technetium-99m dimercaptosuccinic acid (99m Tc-DMSA) scintigraphy. Ultrasonography is the imaging study of choice for the diagnosis of urinary tract structural abnormalities. (See Workup/Scintigraphy).

Age-related data adapted from Harwood-Nuss and colleagues and Hansson and colleagues are presented below in Table 5. [44, 45]

Table 5. Pediatric Urinary Tract Infections (Open Table in a new window)



Infants 6 weeks to 3 years of age

Children 3-6 years of age

Children 6-11 years of age

UTI frequency (%)





Female-to-male ratio





Route of infection





Signs and symptoms

Failure to thrive, fever, hypothermia, irritability, jaundice, poor feeding, sepsis, vomiting

Diarrhea, failure to thrive, fever, irritability, poor feeding, strong-smelling urine, vomiting

Abdominal pain, dysuria, enuresis, fever, gross hematuria, meningismus, strong-smelling urine, urinary urgency, urinary frequency, vomiting

Dysuria, enuresis, fever, flank pain or tenderness, urinary urgency, urinary frequency

Predominant organism

Klebsiella species

E coli

E coli, Proteus species in older boys

E coli


Admit for intravenous ampicillin and gentamicin and further evaluation

Admit for intravenous ampicillin and gentamicin and further evaluation

Follow adult guidelines, but avoid fluoroquinolones, which are theoretically contraindicated due to potential effects on the musculoskeletal system

Follow adult guidelines, but avoid fluoroquinolones, which are theoretically contraindicated due to potential effects on the musculoskeletal system




Consultation is indicated if the infection is complicated. Most cases of acute pyelonephritis occur in adult women and are readily managed without consultation. The following are reasons for consulting various subspecialists:

  • A urologist may be consulted regarding patients with ureteral or urethral obstruction, urinary stones, urogenital abnormality, or recurrent pyelonephritis, or for the first episode of pyelonephritis in an infant or child.
  • A nephrologist may be consulted regarding patients with acute kidney injury or advanced chronic kidney disease or for neonates or infants.
  • An infectious disease specialist may be consulted regarding patients with an unusual or resistant pathogen, those who are immunocompromised, patients with persisting fever (> 48 hours) or toxicity (> 72 hours), or patients whose blood culture results are positive for more than 48 hours.
  • An obstetrician may be consulted for patients who are pregnant.


A regular diet is permitted as tolerated. Special diets, such as those for patients with diabetes mellitus, should be honored. Maintaining hydration is very important. If admission is not indicated and the patient will be monitored in an outpatient setting, hydration status should be normalized with intravenous fluids; the physician should not assume that the patient can or will accomplish this with oral hydration alone.




Rest is essential for recovery. Activity should be minimized. Patients who are treated in an outpatient setting should not return to work for 2 weeks in order to allow time for the infection to be eliminated. This time also allows the patient to recover physical strength. This recommendation can be tempered in special circumstances as warranted by the clinician.



Prevention of pyelonephritis involves identifying clinical situations that could lead to pyelonephritis and developing a strategy to decrease that likelihood. These strategies may include a change in contraceptive behavior, administration of prophylactic antibiotics, or early identification and treatment of cystitis.

If these strategies do not eliminate infection, recurrence of infection, or relapse (reinfection less than 14 days after completing an appropriate regimen), the patient needs to undergo systematic evaluation for predispositional anatomic, functional, or structural abnormalities.

For more information, see Prevention of Urinary Tract Infection (UTI).