<s>[INST] Hey doctor so my twin has been having this arm ache in her left arm for 2 days now and she says when she bends it it feels like she is losing the circulation of blood to her lower arm I fear she may have MS please please get back to me I am only really worried about her [/INST] Hello Thanks for writing to us, There are various patterns of presentation of MS If your symptoms are progressive and repeated then you should consult your doctor again and do require investigation. You can do the Spinal Tap Spinal fluid analysis holds important clues in diagnosis. You can do Evoked Potential Tests for Multiple SclerosisThis painless test measures electrical activity in the brain to help diagnose MS. THIS CAN ALSO BE DUE TO CERVICAL SPINE DISC BULGE LEADING TO ARM SYMPTOMS. Hope this answers your query. If you have additional questions or follow-up queries then please do not hesitate in writing to us. I will be happy to answer your queries. Wishing you good health. Take care. </s>