Urinary tract infection (peds)

Background

• After 1yr of age occult UTI w/ nl UA extremely rare
• After 2yr of age UTI remains common in girls (but a/w symptoms)
• Associated w/ bacteremia in up to 30% of infants between 4-8wk of age

Diagnosis

Clinical Presentation

• Infants/young children: Fever without other source
• Older children: Urinary complaints, abd/back pain

Labs

• UA
  • Obtain clean catch specimen OR cath UA
  • Neg UA = neg LE, nit, GS & <5 WBC
  • Bag urine results in 83% false pos; only useful if negative
• UCx
  • Send on all pts except for:
    • 1. Low-risk pts w/ normal UA and another explanation for sx
    • 2. Older adolescent females w/ very high post-test probability w/o severe illness
  • 20% of +Ucx will have negative UA

Test Characteristic Ranges				Post-test Probability (%) of UTI in Different Patients
Test	Sensitivity (%)	Specificity (%)	Test Result	LR	Patient A	Patient B	Patient C	Patient D	Patient E
Leukocyte esterase	67–85	81–92	+	3.5–10.6	21–45	2–5	23–49	20–43	26–52
			–	0.16–0.41	1–3	<1	1–3	1–3	2–4
Nitrite*	21–69	95–99	+	4.2–69	24–84	2–26	26–86	22–83	29–87
			–	0.31–0.83	2–6	<1	3–7	2–5	3–8
Leukocytes on microscopy	51–91	45–91	+	0.90–10.1	6–43	0–5	7–47	6–41	8–50
			–	0.10–1.09	1–8	0–1	1–9	1–7	1–10
Bacteria on microscopy	46–96	11–96	+	0.5–24.0	4–64	0–11	4–68	3–63	5–70
			–	0.04–4.91	<1–27	<1–2	<1–30	<1–25	<1–33
Bacteria on Gram stain	80–97	87–99	+	6.2–97	32–88	3–33	35–89	30–87	38–91
			–	0.03–0.23	<1–2	<1	<1–2	<1–2	<1–2
Combined tests
Any positive test on dipstick	99–100	63–70	+	2.7–3.3	13–20	1–2	19–22	16–19	21–25
			–	0.00–0.02	<1	<1	<1	<1	<1

Patient A: Female patient in ED, <1 year old, fever with no definitive source on examination, pretest probability of UTI is 7%.

Patient B: Male patient in ED, <1 year old, circumcised, fever with no definitive source on examination, pretest probability of UTI is 0.5%.

Patient C: Male patient in ED, <1 year old, uncircumcised, fever with no definitive source on examination, pretest probability of UTI is 8%.

Patient D: Female patient in ED, 2–6 years old, no fever but GU symptoms, pretest probability of UTI is 6.5%.

Patient E: Female patient in ED, adolescent age range, no fever but urinary symptoms, pretest probability of UTI is 9%

Treatment

Cephalexin or cefixime x 10-14 days for infants, x 7 days for children

Disposition

Admit all pyelo <3 mo or if vomiting