Miller Fisher syndrome (MFS); fatigue; excessive sleepiness; paresthesia of both hands; moderate ptosis of upper eyelids bilaterally.; Pupils were mid-dilated; Pupils were nonreactive; tachycardia; increased somnolence/Hypersomnolence,; Initial information received on 03-Oct-2019 regarding an unsolicited valid serious case issued from a literature article.  This case involves a 50 years old female patient who experienced miller fisher syndrome (Miller Fisher syndrome), while she received vaccine DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE [ADACEL].  The patient's past medical treatment included citalopram, citalopram and citalopram. The patient's past medical history, vaccination(s) and family history were not provided. At the time of the event, the patient had ongoing Vision blurred, Diplopia, Gait disturbance and Skin laceration.  On an unknown date, the patient received a dose of suspect DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE lot number not reported.  On an unknown date, The patient developed a serious miller fisher syndrome (mfs) (miller fisher syndrome) with associated symptoms fatigue, excessive sleepiness (hypersomnia), paresthesia of both hands (paraesthesia), moderate ptosis of upper eyelids bilaterally. (eyelid ptosis), pupils were mid??'dilated (mydriasis), pupils were nonreactive (pupillary reflex impaired), tachycardia (tachycardia), increased somnolence/hypersomnolence, (hypersomnia) 5 days following the administration of DIPHTHERIA-2/TETANUS/5 AC PERTUSSIS VACCINE. These events were assessed as medically significant. The patient was hospitalized for these events. It was reported Fundus examination revealed sharp disc margins. There was no pallor or edema. The remainder of the cranial nerve examination was normal except for impaired hearing bilaterally. Motor strength was normal. Vibratory sensation was reduced over toes. Deep tendon reflexes were absent in upper extremities and at knees. Ankle reflexes were hypoactive. Gait was unsteady and she was unable to tandem walk. Cranial magnetic resonance imaging (MRI) did not demonstrate any abnormality. Hematological and biochemical workup was unremarkable. Tensilon test failed to improve ptosis or ocular dysmotility. Cerebrospinal fluid (CSF) studies revealed elevated proteins without pleocytosis. There were no oligoclonal bands in CSF. Serum anti??'GQ1b IgG antibody was detected in high titers of 299 (Ref range: 0-50). Serum anti??'GD1b and anti??'GM1 antibodies were negative.  Relevant laboratory test results included: Inhibiting antibodies positive (0 - 50) - On an unknown date: 299 [299]  Final diagnosis was miller fisher syndrome (mfs).  As corrective treatment patient received plasmapheresis.  The patient outcome is reported as Unknown for miller fisher syndrome (mfs), as Unknown for fatigue, as Unknown for excessive sleepiness, as Unknown for paresthesia of both hands, as Unknown for moderate ptosis of upper eyelids bilaterally., as Unknown for pupils were mid??'dilated, as Unknown for pupils were nonreactive, as Unknown for ocular motility was profoundly impaired, as Recovered / Resolved on an unknown date for tachycardia and as Recovered / Resolved on an unknown date for increased somnolence/hypersomnolence.  There will be no information available on the batch number for this case.; Sender's Comments: Patient experienced Miller Fisher syndrome 5 days after vaccination. Time to onset is compatible with the role of vaccine. However, further information including patient's other medical history, concomitant medications, previous vaccination and tolerance, laboratory investigations excluding other etiology would be needed to fully assess this case. Based on available information the role of vaccine cannot be assessed.