Bacterial meningitis in febrile young infants acutely assessed for presumed urinary tract infection: a systematic review

Urinary tract infections, the most common severe bacterial infections in young infants, may be associated with co-existing meningitis. There is no consensus on when to perform a lumbar puncture in these infants. Our aim was to quantify the frequency of co-existing bacterial meningitis in febrile young infants acutely assessed for presumed urinary tract infections. We systematically reviewed PubMed, EMBASE, and the Cochrane Library for studies including infants ≤ 3 months with suspected/confirmed urinary tract infections, who underwent a lumbar puncture. Two investigators independently reviewed articles for inclusion and extracted relevant data. Our outcomes were culture-confirmed meningitis and identification of low-/high-risk criteria of meningitis. Overall 20/2079 studies, including 4191 infants, met inclusion criteria. A total of 11 infants had bacterial meningitis (frequency between 0 and 2.1% across studies) and were mostly neonates. Of 253 infants meeting the low-risk criteria (well-appearing, age > 21 days, procalcitonin ≤ 0.5 ng/ml, and C reactive protein ≤ 20 mg/L) none developed meningitis, but only 15 underwent lumbar puncture.Conclusion: Co-existing bacterial meningitis in febrile young infants with urinary tract infection is rare. In those meeting low-risk criteria, a lumbar puncture may not be indicated. A case by case assessment should be made in infants not meeting low-risk criteria.Trial registration: CRD42018105339 What is known: • When caring for febrile infants ≤ 3 months with urinary tract infections, clinicians may have uncertainty on whether to perform a lumbar puncture (LP) for possible co-existing meningitis What is new: • An up-to-date systematic review of 20 studies found the frequency of co-existing meningitis in this population to be between 0 and 2.1% • Despite limited data, an LP may not be indicated in infants meeting low-risk criteria (being well-appearing, age > 21 days, procalcitonin ≤ 0.5 ng/ml, C reactive protein ≤ 20 mg/L). Ill-appearance and neonatal age appear to be significant risk factors of co-existing meningitis.