Why does paresthesia progress in post-polio syndrome?

Hi doctor,

The patient is a 50-year-old woman with a history of polio in childhood and has complained of paresthesia for a year. It started suddenly from the toes on both sides, and it progressed to the upper back (T4) in 20 days. She was hospitalized with post-polio syndrome and treated with intravenous immunoglobulin (IV Ig).

She complained of bilateral tinnitus and seeing some flashes of light in her central vision after IV Ig therapy. She had paresthesia in her fingers and both hands after two months. She was hospitalized again and treated. She lost movement in her left leg during hospitalization, which progressed to hemiplegia. She denies any trauma, fever or incontinence.

Her medication includes Gabapentin, Vitamin D and B1, Duloxetine and Chlordiazepoxide. Past medical history includes polio and migraine. Family history includes father with Alzheimer's, mother with hypertension (HTN) and heart failure. She is married, monogamous with her husband and has adopted one child.

On physical examination, the pupil was normal and no nystagmus. Laboratory tests showed complete blood count (CBC) and differential nil, erythrocyte sedimentation rate (ESR) 40, and CRP 25. Also, I have attached her magnetic resonance imaging (MRI) report.

Kindly guide.