208. Isolated Unilateral Blepharoptosis Associated with Influenza Infection

Article type: Letter to Editor
Article title: Isolated Unilateral Blepharoptosis Associated with Influenza Infection

Journal: Neurology India
Year: 2026
Authors: Jamir Pitton Rissardo and Ana Leticia Fornari Caprara

ABSTRACT
Blepharoptosis can arise from neurogenic, myogenic, aponeurotic, mechanical, or traumatic causes, with Horner syndrome representing a classic neurogenic etiology due to disruption of the oculosympathetic pathway. Although influenza A infection is known to trigger immune-mediated neurological complications, isolated autonomic manifestations such as ptosis are exceedingly rare. We report a case of a 63-year-old male who developed isolated right upper eyelid ptosis three days after experiencing flu-like symptoms. Neurological and ophthalmologic evaluations revealed preserved levator function, no anisocoria, and no other cranial nerve deficits. Imaging studies including cranial CT, CT angiography, brain and orbital MRI were unremarkable, and laboratory investigations ruled out myasthenia gravis, thyroid dysfunction, and giant cell arteritis. Apraclonidine testing suggested incomplete Horner syndrome. The patient tested positive for influenza A but declined antiviral therapy, and the ptosis resolved spontaneously within 30 days. A literature review revealed no prior reports of isolated ptosis directly linked to influenza infection, though similar cases have been described post-vaccination or with additional neurological findings. This case highlights influenza A as a potential, albeit rare, cause of transient autonomic dysfunction manifesting as isolated ptosis, and underscores the importance of considering recent viral infections in the differential diagnosis of unexplained eyelid drooping, especially when imaging and laboratory findings are inconclusive.
Keywords: blepharoptosis, influenza, aponeurotic. 

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DOI

Citation
Rissardo JP, Caprara AL. Isolated Unilateral Blepharoptosis Associated with Influenza Infection. Neurol India 2026;74:343-4.
Figure 1. Isolated right eyelid ptosis. (a) Primary gaze demonstrating right upper eyelid ptosis with a normal left eyelid position. (b) Activation of the levator palpebrae superioris muscle reveals a reduced margin reflex distance 1 (MRD1) in the right eye. The contralateral eyelid appears slightly retracted due to Hering’s law of equal innervation, leading to apparent pseudo-ptosis of the left eye. Notably, the patient exhibits frontalis muscle activation even in primary gaze, likely as a compensatory effort to maintain eyelid elevation and prevent complete eye closure.
Video 1. Neuro-ophthalmological assessment of pupillary reflexes and accommodation: No miosis is observed, and accommodation remains intact.