Monofilament test being carried out on the foot of a 50 year old male patient to test for nerve damage (neuropathy). Damage to nerves and blood vessels is one of the side effects of diabetes. Tests on the level of feeling in the feet (here, whether the pressure applied is felt) helps assess the risk of foot ulcers. Diabetes mellitus affects glucose sugar metabolism. Blood sugar is not oxidised due to a lack of the pancreatic hormone insulin. Treatment is based on a strict diet and insulin injections to maintain the blood-sugar balance.