19.1 UTI, Enuresis, Hydronephrosis & Acute Scrotum

Urology and nephrology are clinical category #15 on the PNCB CPNP-PC outline. Domain II wants a urinary complaint named by specimen, fever, and which side of the scrotum hurts. Domain III wants an AAP-aligned plan: treat true infection, image the right child, stop calling every wet night a character problem, and do not watch a torsed testis overnight. You are not running a pediatric urology OR. You are deciding whose bag urine is contamination, who needs a voiding cystourethrogram, and who leaves in an ambulance.

Quick Answer: Culture infants by catheter (or SPA) and older children by clean catch. Treat pyelonephritis as upper-tract disease and cystitis as lower-tract disease. After a first febrile UTI at 2–24 months, obtain renal and bladder ultrasound; VCUG is not routine unless that ultrasound is abnormal or infection recurs. Uncircumcised boys have higher infant UTI risk. Primary nocturnal enuresis after age 5–6: UA, constipation treatment, education, alarm, selected desmopressin. Daytime wetting is a different problem. Sudden high-riding testis with absent cremasteric: ED now.

Clinic opening. An 8-month-old uncircumcised boy has had fever of 39.1°C for 36 hours, no cough, and a mildly red tympanic membrane. A bag UA shows leukocyte esterase. If you start nitrofurantoin from the bag and skip imaging after a confirmed febrile UTI, you missed both the specimen rule and AAP 2011/2016.

UTI: the specimen is the diagnosis

Urinary tract infection is bacteria in the urinary tract with symptoms or fever — not a bag that grew mixed skin flora. Culture is the gold standard. UA (leukocyte esterase, nitrite, pyuria, bacteria) is a rapid screen that supports starting therapy after a proper specimen, not a substitute for culture. Nitrite is specific but insensitive in infants who void often. A little tympanic redness is not an adequate source that lets you skip urine in a febrile young child.

Pyelonephritis versus cystitis is the treatment fork. Fever, ill appearance, flank or CVA tenderness, and vomiting mean upper tract until proven otherwise. Young febrile infants with UTI are treated as pyelonephritis. They need a full course (commonly 7–14 days), close follow-up, and admission if they are neonates, toxic, dehydrated, or vomiting oral medicine. Well-appearing older children with cystitis (dysuria, frequency, urgency, no fever) can often complete a short oral course aimed at local E. coli susceptibility — not nitrofurantoin for a febrile bacteremic infant, and not a 14-day parenteral course for an afebrile school-age girl with isolated dysuria. Asymptomatic bacteriuria in an otherwise well toilet-trained child is not an automatic antibiotic.

Start empiric therapy in a febrile infant after the catheter specimen is obtained, then adjust to culture. Recheck if the child is not improving in 48 hours. Recurrence, unusual organisms, or poor response raise obstruction, reflux, and adherence questions.

AAP 2011/2016 imaging — and circumcision risk

The 2011 AAP UTI guideline, reaffirmed in 2016, still drives CPNP-PC teaching for febrile UTI in infants 2–24 months:

• Obtain a renal and bladder ultrasound after the first febrile UTI, looking for hydronephrosis, scarring, anatomic abnormality, or obstruction.
• VCUG is not routine after the first febrile UTI. Add VCUG if the ultrasound is abnormal, if the clinical course is atypical (poor response, unusual pathogen, mass, elevated creatinine), or if febrile UTIs recur.
• You are not obligated to fluoroscope every first infection “to be complete.” You are also not allowed to skip the ultrasound.

Infants outside 2–24 months, children with known urologic disease, and atypical courses still need an individualized plan — often urology. Do not invent a third imaging test the guideline does not require.

Circumcision and UTI risk. Uncircumcised boys, especially in the first year, have a substantially higher UTI risk than circumcised boys (order-of-magnitude teaching, not a license to quote a fake percentage). That is one medical benefit discussed in AAP circumcision counseling. It is shared decision-making, not a mandate, not a punishment for a febrile UTI, and not a substitute for a proper culture. Teach foreskin hygiene; do not forcibly retract.

Clinic vignette. A 14-month-old girl completes treatment for her first febrile E. coli UTI. Ultrasound is normal. Grandmother wants a VCUG “like her cousin had in 2004.” You obtain the ultrasound, explain that VCUG is not routine after a first febrile UTI when imaging is normal, and teach recurrence precautions. You do not bag-diagnose the next fever.

Enuresis is not one disease

Primary nocturnal enuresis is nighttime wetting in a child who has never had a sustained dry period (often six months). It is common, often familial, and usually not kidney failure. Evaluation belongs once the child is about 5–6 years and the family wants help — or sooner if there are red flags. Always obtain a urinalysis (glucose, infection, concentrating clues). Treat constipation; encopresis and enuresis share a full rectum that irritates the bladder (see the gastroenterology chapter). Examine the spine, gait, and ankle reflexes; occult spinal dysraphism is uncommon and must not be missed. Ask about snoring and sleep apnea. Do not punish. Do not shame.

Treatment after age 5–6, once UA and constipation are addressed:

1. Education — bladder capacity, evening fluids, void before bed, calendars, no humiliation.
2. Enuresis alarm — first-line when the family can use it; best chance of sustained dryness.
3. Desmopressin — selected use (sleepovers, travel, alarm not feasible or not yet successful). Evening fluid restriction is mandatory; hyponatremia is the harm. Hold during intercurrent illness with high fluid intake. It is a tool, not a character grade.

Daytime wetting is a red flag, not “primary nocturnal enuresis that also happens after lunch.” Think constipation, UTI, voiding dysfunction, giggle incontinence, ectopic ureter (constant dampness in a girl who never had a dry day), diabetes mellitus, diabetes insipidus, and, when the story is wrong, sexual abuse. Secondary enuresis (was dry, now wet) is UTI, new diabetes, constipation, OSA, and stress until you look.

Prenatal hydronephrosis, phimosis, hydrocele, hernia

Antenatal hydronephrosis is common. Postnatal renal ultrasound is the follow-up; for most unilateral mild–moderate dilatation, obtain it after about 48 hours of life so transitional newborn oliguria does not falsely reassure you. Bilateral disease, a solitary kidney, oligohydramnios, or suspected obstruction may need earlier imaging and neonatology/urology, not a two-week well-visit stall. Repeat ultrasound and specialist referral scale with grade, laterality, and UTI. Prophylactic antibiotics are not automatic for every extra-renal pelvis; they are a urology decision for higher-grade dilatation or suspected reflux. Circumcision may be discussed again in boys with high-grade dilatation because of UTI risk.

Physiologic phimosis is a nonretractile foreskin in infants and many young boys. It is normal. Do not force the foreskin. Do not diagnose disease because a 2-year-old is not retractile. Pathologic phimosis is scarring, ballooning with infection, or balanitis xerotica obliterans — topical corticosteroid or urology, not shame. Paraphimosis (foreskin trapped behind the glans) is an emergency reduction.

Acute scrotum: torsion does not wait for radiology

Testicular torsion is ischemia on a clock. Classic: sudden severe pain, nausea or vomiting, a high-riding testis, horizontal lie, and absent cremasteric reflex. Adolescents and the perinatal extravaginal form both count. ED and urology NOW. If suspicion is high, do not delay for ultrasound. Imaging is for equivocal cases the receiving team orders, not a primary-care appointment slot that burns the salvage window.

Torsion of the appendix testis is more subacute, the child is less toxic, and a blue-dot sign may appear on the scrotal skin. You still have to rule out spermatic-cord torsion; when you cannot, it is torsion until urology says otherwise.

Epididymitis is more gradual, with scrotal swelling and tenderness of the epididymis. Prehn’s sign is unreliable in children. Younger children: think UTI and urinary anomalies. Adolescents: consider STI (gonorrhea/chlamydia) as well as urine pathogens. UA and culture (and NAAT when sexually active) guide antibiotics. An afebrile adolescent with isolated epididymal tenderness is not permission to send a vomiting 13-year-old with a high-riding testis home on ceftriaxone.

Clinic vignette. A 14-year-old woke with left scrotal pain and vomited. The testis is high, cremasteric reflex is absent. Do not book an outpatient Doppler for 4 p.m. Send to the ED for immediate urology. Time is the testicle.

Exam traps

1. Treating a positive bag as culture-proven UTI.
2. Automatic VCUG after every first febrile UTI despite a normal ultrasound (that is not AAP 2011/2016).
3. Skipping ultrasound entirely after a febrile UTI at 2–24 months.
4. Calling daytime wetting primary nocturnal enuresis.
5. Starting desmopressin at age 3, or using it without fluid counseling.
6. Forcing a physiologic foreskin.
7. Delaying torsion for ultrasound when the exam already screams ischemia.
8. Calling every scrotal swelling a hydrocele without asking whether it reduces.

Clinic close. Catheter the infant; clean-catch the older child; bag is a screen. Pyelo is not cystitis. First febrile UTI at 2–24 months: ultrasound yes, routine VCUG no. Wet nights after five: UA, constipation, alarm, selected desmopressin. Daytime wet: hunt. Prenatal hydronephrosis: postnatal ultrasound, not a shrug. Sudden high-riding testis: ED, not Doppler-in-the-morning.