Hyperglycemia is a condition that is related to diabetes. It can be a symptom or a cause for diabetes. Hyperglycemia is defined as an increase in the blood sugar levels. It is mainly caused due to improper intake of insulin, illness or infections, stress and also due to side effects of certain medicines. Sometimes, over eating also causes hyperglycemia. If left untreated, it can lead to various complications related to eyes, kidneys and heart which require emergency medical services.Hyperglycemia has certain initial symptoms such as: headache, frequent hunger, frequent urination, increased thirst and fatigue. The latter symptoms are: loss of weight, dry and itchy skin, mouth dryness, hindered healing of wounds, blurred vision, nausea, vomiting, shortness of breath and dizziness. It can also result in impotency in males and recurrent infections such as vaginal yeast infections in women.