Priority Topic: Urinary Tract Infection

Key Feature 1: Take an appropriate history and do the required testing to exclude serious complications of urinary tract infection (UTI) (ex: sepsis, pyelonephritis, impacted infected stones).
Skill: Clinical Reasoning
Phase: Hypothesis generation, Investigation

Key Feature 2: Appropriately investigate all boys with urinary tract infections, and young girls with recurrences (ex: ultrasound).
Skill: Clinical Reasoning
Phase: Investigation

Key Feature 3: In diagnosing urinary tract infections, search for and/or recognize high-risk factors on history (ex: pregnancy, immune compromise, neonate, a young male, or an elderly male with prostatic hypertrophy).
Skill: Clinical Reasoning
Phase: Hypothesis generation, History

Urinary tract infections are extremely common, and most of the time they aren't complicated. When someone presents to my clinic with symptoms in keeping with a UTI (dysuria, urinary frequency and urgency +/- hematuria +/- suprapubic pain), it's my job to ensure that they don't have symptoms and signs suggesting a more complicated picture. The following features on clinical assessment take a UTI from simple to complicated:

• The patient has constitutional symptoms or  is febrile on exam
• The patient has flank pain or costovertebral tenderness

All patients with features suggesting a complicated UTI warrant referral to the nearest ED for further workup. Beyond routine and microscopic urinalysis as well as urine culture and sensitivity, blood cultures are warranted if you are thinking about possible sepsis. In terms of imaging, if you are thinking about pyelonephritis, obtain a CT abdo/pelvis with contrast, and if you are thinking about infected kidney stones, obtain a non-contrast CT abdo/pelvis. If you wish to avoid contrast and have the option, consider starting with a renal ultrasound instead. 

Speaking of renal ultrasound, besides its utility in looking for pyelonephritis or nephrolithiasis, it is also useful to look for urinary tract malformations in pediatric patients when indicated. As in the adult population, UTIs are much more common in females as their urethral tract is much shorter and they are therefore at greater risk of bacteria finding their way up and into the bladder. However, recurrent UTIs in prepubertal females are not common, and any UTIs in prepubertal males are unusual. UpToDate recommends obtaining renal and bladder ultrasonography if the following indications are met: 

• Children younger than two years of age with a first febrile UTI
• Children of any age with recurrent febrile UTIs
• Children of any age with a UTI who have a family history of renal or urologic disease, poor growth, or hypertension
• Children who do not respond as expected to appropriate antimicrobial therapy

As well, for any children with suspected UTI, obtain urinalysis as well as urine culture and sensitivity (by catheter for children who are not toilet-trained).

Children should also be sent for a voiding cystourethrogram to look for vesicoureteral reflux if the following indications are met: 

• Children of any age with two or more febrile UTIs, or
• Children of any age with a first febrile UTI and:
  • Any anomalies on renal ultrasound, or
  • The combination of temperature ≥39°C and a pathogen other than E. coli, or
  • Poor growth or hypertension 

So now I've singled out two groups to be weary of with suspected UTI: those who have features suggestive of a complicated UTI and children with suspected UTI. Other groups that require special considerations, and the considerations they warrant, are as follows. Note that any patients with a suspected complicated UTI, recurrent UTI, or any features below warrant at the very least a urinalysis and urine culture & sensitivity.

• Women who are pregnant: Although standard of care is not to test for cure after a course of antibiotics if the patient improves symptomatically, doing so with culture and sensitivity is recommended in women who are pregnant. Any infection in pregnancy poses risk of infection in the developing child, and high temperature (ex: from hot weather, hot tubs, hot yoga, or fever) can be teratogenic. 
• Patients who are immunocompromised: Although these patients may present with signs and symptoms of uncomplicated UTI, it is important to follow these patients closely if they are being treated for an uncomplicated UTI to ensure they improve as expected. If there is any doubt as to whether there is a smidge of complication to the UTI, it is best to err on the side of caution and treat them with suspicion for a complicated UTI.
• Neonates: If they have a UTI, they are at increased risk for bacteremia, so any neonate with a suspected UTI should be sent to the ED for blood cultures. If ill-appearing or febrile, an LP is also warranted. Treatment is with parenteral antibiotics. All neonates diagnosed with UTI also warrant at least a renal ultrasound as far as imaging is concerned. 
• Young men: As mentioned above, UTIs are more uncommon in boys, as they are in men of all ages. All males of any age with suspected UTI warrant at least a urinalysis and urine culture & sensitivity. If they have a tender prostate on examination, they should be treated for prostatitis rather than acute uncomplicated cystitis.
• Elderly men with BPH: Enlargement of the prostate can result in urinary retention, and urinary retention increases the risk for UTI. In elderly men with a UTI, obtain a genitourinary ultrasound to rule out urinary obstruction as a contributing factor.