Acute transverse myelitis (ATM) in children is a rare and often severe disease for which there are few known prognostic factors, particularly the subsequent risk of multiple sclerosis (MS) diagnosis.

To determine the clinical course and prognostic factors after a first episode of ATM in children.

Thirty children below 16 years of age diagnosed with a first neurological episode of ATM were included retrospectively. Clinical evaluation, treatment, laboratory, and MRI data were collected.

Median age at onset was 11 years (range 3–15 years). Follow-up data were available for a median of 4 years (range 0.5–16.7 years). Five patients subsequently had a diagnosis of MS (17%), which was associated with acute partial transverse myelitis (odds ratio 5; 95% confidence interval 2.3–11), with a 60% probability of having a relapse at five years (p < 0.01). The 2011 Verhey criteria correctly identified MS in children with the highest specificity (96%) and sensitivity (80%).

Acute partial transverse myelitis and brain MRI abnormalities at initial presentation are significantly predictive of a subsequent diagnosis of MS in children with ATM. These findings suggest that closer brain MRI monitoring after acute partial transverse myelitis might make the earlier introduction of disease-modifying therapies possible.