Acetylcholine receptor antibody positivity rate in ocular myasthenia gravis: a matter of age?

Journal of Neurology - Anti-acetylcholine receptor antibodies (AChR Abs) are detected in 85% of myasthenia gravis (MG) patients, at higher rates in patients with late-onset disease. AChR Ab...     

A score that predicts aquaporin-4 IgG positivity in patients with longitudinally extensive transverse myelitis

Background and purpose

Longitudinally extensive transverse myelitis (LETM) associated with aquaporin-4 autoantibodies (AQP4-IgG) can cause severe disability. Early diagnosis and prompt treatment are critical to prevent relapses. A novel score is described based on clinical and neuroimaging characteristics that predicts AQP4-IgG positivity in patients with LETM.

Methods

Patients were enrolled both retrospectively and prospectively from multiple Italian centers. Clinical and neuroimaging characteristics of AQP4-IgG positive and negative patients were compared through univariate and multivariate analysis.

Results

Sixty-six patients were included. Twenty-seven (41%) were AQP4-IgG positive and median age at onset was 45.5 years (range 19–81, interquartile range 24). Female sex (odds ratio [OR] 17.9, 95% confidence interval [CI] 2.6–381.9; p = 0.014), tonic spasms (OR 45.6, 95% CI 3.1–2197; p = 0.017) and lesion hypointensity on T1-weighted images (OR 52.9, 95% CI 6.8–1375; p = 0.002) were independently associated with AQP4-IgG positivity. The AQP4-IgG positivity in myelitis (AIM) score predicted AQP4-IgG positivity with 85% sensitivity and 95% specificity. Positive and negative likelihood ratios were 16.6 and 0.2 respectively. The inter-rater and intra-rater agreement in the score application were both excellent.

Conclusions

The AIM score predicts AQP4-IgG positivity with good sensitivity and specificity in patients with a first episode of LETM. The score may assist clinicians in early diagnosis and treatment of AQP4-IgG positive LETM.