Acute Unilateral Ptosis and Myositis Following the H1N1 Influenza Vaccine.

The authors present a rare case of sudden onset unilateral complete ptosis occurring hours after administration of the H1N1 influenza vaccine. A complete workup for autoimmune and neurological disease was negative. MRI of the orbits demonstrated unilateral orbital myositis involving the left superior rectus/levator complex, superior oblique, and medial rectus muscles. Ptosis resolved spontaneously over 2 months without intervention. An autoimmune mechanism may explain rare cases of orbital myositis following administration of the H1N1 influenza vaccination.A case of acute onset and spontaneous resolution of complete unilateral ptosis and orbital myositis post H1N1 influenza vaccination.