Hi there, This is Dr Basu, Experienced Specialist. I am here to address your concerns and provide great service.
Sorry to hear about your son.
His symptoms are consistent with transverse myelitis which can cause lg weakness, tingling, numbness, change bowel and bladder function.
Arachnoid cyst is too small to cause symptoms.
Also signs of inflammation in the brain does suggest autoimmune nature of the problem
That means his immune system is reacting against his neural tissues.
This needs to be treated with immuno suppressive regimen.
The first line of treatment is intravenous corticosteroid in high doses like Methyl prednisolone 1000 mg daily for 5 days.
Plasma exchange also combined in case of worsening symptoms to relieve the motor symptoms mainly weakness.
Then a chronic maintenance therapy is considered with any of the following medications:
1. Azathioprine 150 to 250 mg daily.
2. Methotrexate 15 to 20 mg weekly
3. Mycophentolate 2 to 3 gram daily.
An experienced neurologist should be consulted at the earliest to start the above treatment regimen.
This will bring about rapid improvement in his condition.
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