One in a million

Author: Helen Johnson-Kolb / Editor: Sarah Edwards / Codes: NeuC10, NeuC5, NeuP4, NeuP6, NeuP7, SLO1 / Published: 05/09/2025

A 39-year-old male who is normally fit and well presents to the emergency department (ED) with a two-week history of feeling unwell with a sore throat and a non-productive cough.

He was started on Penicillin V (Phenoxymethylpenicillin) for suspected tonsillitis by his GP 4 days prior to attending ED.  24 hours after starting antibiotics he developed pins and needles in both hands, blurred vision, difficulty swallowing and described feeling off balance. He called for an ambulance but was not conveyed to hospital. Instead, he was advised to stay at home and stop taking the penicillin antibiotics as the paramedics suspected that his symptoms were due to an adverse reaction. 

The patient’s symptoms progressed so he is brought to the ED by his wife the next day.  He requires a wheelchair to travel the short distance from the car to the waiting room as he feels too unsteady to mobilize independently.

On examination he is alert and orientated and all observations are within normal limits. His voice is slightly horse but normal volume. He has no stridor and no apparent swallowing difficulties.

CNS exam:

The patient’s pupils are equal and reactive. He has bilateral ptosis and bilateral ophthalmoplegia, most obviously affecting the right eye where he has a complete failure of abduction. Visual fields are normal.  He has bilateral facial muscle weakness involving the forehead which is more pronounced on the right. He has normal power and light touch sensation to all 4 limbs but is areflexic. There is bilateral past-pointing and dysdiadochokinesia.  He is very ataxic on attempting to walk.

ENT exam:

Normal appearance of the oropharynx.

The rest of his examination is unremarkable. He is admitted for neurology review and investigations including electromyography, MRI brain and lumbar puncture confirm the diagnosis of Miller-Fisher syndrome, a rare variant of Guillain-Barré syndrome.