Asymmetric Guillain-Barré Syndrome as a Stroke Mimic.

BACKGROUND

Guillain-Barré syndrome (GBS) typically presents with symmetric weakness, but marked asymmetry can mimic stroke and delay diagnosis, especially when unilateral onset progresses to bilateral asymmetric involvement. We aimed to characterize this phenotype and identify features that facilitate early recognition.

METHODS

We retrospectively analyzed 611 consecutive patients with GBS over 10 years. Asymmetry was defined as a difference of ≥ 2 points on the Medical Research Council (MRC) scale between contralateral limbs. Clinical features, electrophysiological subtypes, and diagnostic timelines were compared between asymmetric and symmetric cases.

RESULTS

Thirty-two patients (5.2%) exhibited asymmetric onset. Compared with symmetric cases, asymmetric GBS had fewer antecedent respiratory infections (12.5% vs. 32.1%; p = 0.02) and no facial weakness (0% vs. 13.6%; p = 0.049). Twenty-two patients progressed to symmetric weakness; among 10 patients with persistent asymmetry, 6 unilateral onset cases evolved into bilateral asymmetric involvement, all initially misdiagnosed as stroke. Of these 10, 6 (60%) lacked sensory involvement, 7 (70%) had axonal GBS, and 4/7 (57%) were anti-ganglioside antibody positive. Asymmetric GBS was associated with longer diagnostic delays (median 3 vs. 2 days; p < 0.001), longer admission-to-immunotherapy intervals (median 4 vs. 3 days; p < 0.001), and greater disability at nadir (median 4 vs. 3; p = 0.01).

CONCLUSIONS

Within asymmetric GBS, unilateral-onset cases that evolve into bilateral asymmetric involvement are the subgroup most likely to mimic stroke. The absence of facial weakness, few antecedent respiratory infections, axonal electrophysiologic subtype, and positive anti-ganglioside antibodies may aid recognition and timely immunotherapy.