Transient oculomotor palsy; This literature case was received on 15-Feb-2021 and concerned a 23-year-old, male patient.  The patient's concurrent condition included inflammatory bowel disease ulcerative colitis. The patient had no medical history of diabetes mellitus, hypertension, glucose intolerance, systemic vasculitis, hyperlipidaemia, smoking, or obesity. The patient had no significant family history of neurological disorders. The patient's concomitant medication included sulfasalazine for ulcerative colitis.  On an unspecified date, the patient was vaccinated with influenza virus vaccine polyvalent (brand name not specified; route of administration, anatomical location, dose, indication: not reported). The batch number reported was not reported.  On the same day, immediately after receiving influenza virus vaccine polyvalent, the patient experienced blurry vision.   On an unspecified date, five days after receiving influenza virus vaccine polyvalent vaccine, the patient presented to the hospital with a complaint of blurry vision. He denied smoking cigarettes, drinking alcohol, using intravenous drugs and was sexually active with one female partner only. On a general physical exam, his blood pressure revealed 122/67. The ophthalmic exam revealed a dilated pupil in the right eye, mild ptosis, and diplopia with reduced adduction, elevation, and depression of the right eye but abduction and intorsion were fine. No abnormality was detected in other cranial nerve exams. Neurological and other system examinations revealed normal. On blood work, the complete blood count, comprehensive metabolic panel, erythrocyte sedimentation rate, lipid panel, and haemoglobin a1c (HbA1c) revealed unremarkable. Imaging of the brain that included computed tomography (CT) of the head without contrast, magnetic resonance imaging (MRI) of the brain with and without intravenous (IV) contrast, and magnetic resonance angiography (MRA) of the head and neck with and without IV contrast revealed unremarkable. The cerebrospinal fluid analysis was normal. The patient was diagnosed with transient oculomotor nerve palsy and was treated conservatively with lubricating eye drops.  On an unspecified date, the patient recovered from the event since his symptoms resolved in two weeks.  The reporters assessed the event as related to influenza virus vaccine polyvalent vaccine. Most of the possible causes of oculomotor nerve palsy, such as stroke, intracranial space occupying lesions, aneurysms, and infections, were ruled out by history, physical exam, blood work, and imaging studies, thus leading to the influenza vaccine as the most likely cause. The fact that this happened immediately after an influenza vaccination made this a plausible cause, and the rapid improvement of the symptoms in patient supported the rationale of demyelination for the pathogenesis of transient nerve palsy.  The event of 'oculomotor nerve paralysis' was considered to be medically significant by a Physician within Seqirus' Pharmacovigilance and Risk Management Department.   Company Comment: A 23-year-old male patient developed IIIrd nerve paralysis on the same day after vaccination with the suspect product influenza virus vaccine polyvalent. The patient had no significant medical history. Comprehensive laboratory findings were unremarkable. Investigations included imaging of the brain with computed tomography (CT) and magnetic resonance imaging (with and without intravenous (IV) contrast), and magnetic resonance angiography (MRA) of the head and neck with and without IV contrast. All results were unremarkable. Based on lack of alternative aetiology and due to plausible time relationship, causality for the reported event is assessed as possibly related.; Reporter's Comments: The fact that this happened immediately after an influenza vaccination made this a plausible cause, and the rapid improvement of the symptoms in patient supported the rationale of demyelination for the pathogenesis of transient nerve palsy.; Sender's Comments: A 23-year-old male patient developed IIIrd nerve paralysis on the same day after vaccination with the suspect product influenza virus vaccine polyvalent. The patient had no significant medical history. Comprehensive laboratory findings were unremarkable. Investigations included imaging of the brain with computed tomography (CT) and magnetic resonance imaging (with and without intravenous (IV) contrast), and magnetic resonance angiography (MRA) of the head and neck with and without IV contrast. All results were unremarkable. Based on lack of alternative aetiology and due to plausible time relationship, causality for the reported event is assessed as possibly related.