Hello, Thanks for writing to Health Care magic, I am Dr , Muhammad Ahmad , I have read your question closely, I understand your concern and will be helping you with your health related problem. You are having complicated diabetes, with compromise of kidneys, eyes, and nervous system. This means that your muscles would alos be weak and this can be the reason of cramps. Other reason in some people is the abrupt decrease in sugar levels which cause cramps. Thirdly insuline causes decrease in potassium level quite quickly this causes muscles to get cramped up in some people. In some people the cause is not known. I would sugges you to discuss this with your doctor you can start physiotherapy and this should improve your muscle endurance. This is common in many people not an extraordinary thing in your scenario. I hope this answered your question, If you have more queries I am happy to answer you. Regards. Dr.Muhammad Ahmad