<p><strong>BACKGROUND: </strong>Nearly one-third of patients with neurofibromatosis type 1-associated optic pathway glioma (NF1-OPG) fail frontline chemotherapy; however, little is known about risk factors for treatment failure.</p>

<p><strong>METHODS: </strong>We performed a retrospective multi-institutional cohort study to identify baseline risk factors for treatment-refractory/relapsed disease and poor visual outcome in children with NF1-OPG. Refractory/relapsed NF1-OPG was defined as requirement of two or more treatment regimens due to progression or relapse.</p>

<p><strong>RESULTS: </strong>Of 111 subjects eligible for inclusion, adequate clinical and visual data were available for 103 subjects from 7 institutions. Median follow-up from initiation of first chemotherapy regimen was 95 months (range 13-185). Eighty-four (82%) subjects received carboplatin-based frontline chemotherapy. Forty-five subjects (44%) experienced refractory/relapsed disease, with median time of 21.5 months (range 2-149) from initiation of first treatment to start of second treatment. The proportion of patients without refractory/relapsed disease at 2 and 5 years was 78% and 60%. In multivariable analyses, age less than 24 months at initial treatment, posterior tumor location, and familial inheritance were associated with refractory/relapsed NF1-OPG by 2 years. Both age less than 24 months and posterior tumor location were associated with refractory/relapsed NF1-OPG by 5 years. Subjects with moderate to severe vision loss at last follow-up were more likely to have posterior tumor location, optic disc abnormalities, or abnormal visual acuity at initial treatment.</p>

<p><strong>CONCLUSION: </strong>Young age, posterior tumor location, and optic disc abnormalities may identify patients with the greatest likelihood of refractory/relapsed NF1-OPG and poor visual outcomes, and who may benefit from newer treatment strategies.</p>

<p><b>BACKGROUND: </b>The Rule of 7's classifies children as low-risk for Lyme meningitis with the absence of the following: ≥7 days of headache, any cranial neuritis or ≥70% cerebrospinal fluid mononuclear cells. We sought to broadly validate this clinical prediction rule in children with meningitis undergoing evaluation for Lyme disease.</p><p><b>METHODS: </b>We performed a patient-level data meta-analysis of 2 prospective and 2 retrospective cohorts of children ≤21 years of age with cerebrospinal fluid pleocytosis who underwent evaluation for Lyme disease. We defined a case of Lyme meningitis with a positive 2-tier serology result (positive or equivocal first-tier enzyme immunoassay followed by a positive supplemental immunoblot). We applied the Rule of 7's and report the accuracy for the identification of Lyme meningitis.</p><p><b>RESULTS: </b>Of 721 included children with meningitis, 178 had Lyme meningitis (24.7%) and 543 had aseptic meningitis (75.3%). The pooled data from the 4 studies showed the Rule of 7's has a sensitivity of 98% [95% confidence interval (CI): 89%-100%, I2 = 71%], specificity 40% (95% CI: 30%-50%, I2 = 75%), and a negative predictive value of 100% (95% CI: 95%-100%, I2 = 55%).</p><p><b>CONCLUSIONS: </b>The Rule of 7's accurately identified children with meningitis at low-risk for Lyme meningitis for whom clinicians should consider outpatient management while awaiting Lyme disease test results.</p>