This is a 2011 review from the official journal of the AAFP, American Family Physician:
Acute pyelonephritis is a bacterial infection of the renal pelvis and kidney most often seen in young women.
Symptoms of acute pyelonephritis
Most patients have fever, although it may be absent early in the illness. Flank pain is nearly universal.
Tests for acute pyelonephritis
A positive urinalysis confirms the diagnosis.
Urine culture should be obtained in all patients to guide antibiotic therapy if the patient does not respond to initial empiric antibiotic regimens.
Escherichia coli is the most common pathogen in acute pyelonephritis. In the past decade, there has been an increasing rate of E. coli resistance to extended-spectrum beta-lactam antibiotics.
Imaging, usually with contrast-enhanced CT is not necessary unless there is:
- no improvement in the patient's symptoms
- symptom recurrence after initial improvement
Treatment of acute pyelonephritis
Outpatient treatment is appropriate for most patients.
Oral fluoroquinolone is the initial outpatient therapy if the rate of fluoroquinolone resistance in the community is less than 10%. If the resistance rate exceeds 10%, an initial IV dose of ceftriaxone or gentamicin should be given, followed by an oral fluoroquinolone regimen.
Oral beta-lactam antibiotics and trimethoprim/sulfamethoxazole (TMP-SMX (Bactrim) are inappropriate for therapy because of high resistance rates.
Diagnosis and treatment of acute pyelonephritis in women. Colgan R, Williams M, Johnson JR. Am Fam Physician. 2011 Sep 1;84(5):519-26.