Bilateral Pyelonephritis Causes and Risk Factors

Microbial Causes

Escherichia coli is the most common cause of bilateral pyelonephritis, accounting for approximately 75% of all cases of recurrent urinary tract infections and pyelonephritis, according to the American College of Radiology 1
Other common bacterial pathogens include Enterococcus faecalis, as reported by the American College of Radiology 1
Serratia marcescens is also a common pathogen, as noted by the American College of Radiology 1
Staphylococcus saprophyticus is a common pathogen, particularly in patients with risk factors for complicated UTIs, as reported by the American College of Radiology 1

Vesicoureteral reflux (VUR) is a significant risk factor, particularly in bilateral cases, according to the American College of Radiology 2
Congenital urinary tract anomalies increase the risk of bilateral pyelonephritis, as reported by the American College of Radiology 2
Renal calculi (kidney stones) are a risk factor for bilateral pyelonephritis, as noted by the American College of Radiology 2
Mechanical obstruction of urinary flow and altered bladder function are also risk factors, according to the American College of Radiology 2

Urethral or bladder diverticula increase the risk of bilateral pyelonephritis, as reported by the American College of Radiology 1
Infected urachal cyst is a risk factor, as noted by the American College of Radiology 1
Postoperative changes, such as remaining urethral stump that retains urine, increase the risk of bilateral pyelonephritis, according to the American College of Radiology 1
High postvoid residuals of urine and cystocele in postmenopausal women are also risk factors, as reported by the American College of Radiology 1

Diabetes mellitus is a risk factor for bilateral pyelonephritis, as noted by the American College of Radiology 2
Pregnancy increases the risk of bilateral pyelonephritis, according to the American College of Radiology 2
Genetic predisposition is a risk factor, as reported by the American College of Radiology 2
Prior history of pyelonephritis increases the risk of recurrent episodes, as noted by the American College of Radiology 2
Postmenopausal status with atrophic vaginitis is a risk factor, as reported by the American College of Radiology 1

Use of spermicidal-containing contraceptives increases the risk of bilateral pyelonephritis, as noted by the American College of Radiology 1
Urinary incontinence in postmenopausal women is a risk factor, as reported by the American College of Radiology 1
Personal or maternal history of UTIs increases the risk of bilateral pyelonephritis, according to the American College of Radiology 2

Bacterial persistence can occur with calculi (stones), foreign bodies, and anatomical abnormalities that cause urinary stasis, as reported by the American College of Radiology 1

In children, bilateral pyelonephritis is often associated with congenital anomalies, particularly vesicoureteral reflux, as noted by the American College of Radiology 3
In neonates and young infants, there is a high incidence of urinary anomalies with UTI, with VUR being the most common, according to the American College of Radiology 4
Bilateral pyelonephritis carries a higher risk of complications, including renal scarring, which can lead to hypertension and chronic renal failure, as reported by the American College of Radiology 3

Bilateral pyelonephritis should raise suspicion for underlying structural or functional abnormalities of the urinary tract, as noted by the American College of Radiology 2
Not all patients with pyelonephritis present with fever - absence of fever does not exclude the diagnosis, according to the American College of Radiology 5
Imaging studies are indicated in bilateral pyelonephritis to detect treatable conditions and monitor progress, as reported by the American College of Radiology 1