The classic symptoms of diabetes are weight loss, polyuria, polydipsia, and polyphagia. Symptoms may be produced gradually, developing over a period of time as seen in type 2 diabetes mellitus, while they are more rapid in type 1 diabetes mellitus.
Polyuria: Polyuria is the passage of large volumes of urine with an increase in urinary frequency. A normal adult excretes about one to two liters of urine per day. Polyuria is a daily urine output of more than 2.5 liters.
Polyuria presents much less frequently than urinary frequency which is frequent passage of small amounts of urine. Before coming to a conclusion about the cause of polyuria it is essential that the frequency of urination and amount of urine is assessed. Increased frequency during nights is also called nocturia which is common in diabetes.
Polyuria in osmotic cases is due to increased flow of urine in the distal nephron, where the rate of flow is usually very low. Increased pressures in the distal nephron are responsible for the increased amount of urine in diabetes with high blood sugar level that increases the osmolality of blood.
Any person presenting to the hospital with polyuria has to be assessed for signs of significant dehydration is admitted in the hospital, Fluid balance and electrolyte disturbance will need to be corrected. Desmopressin can be considered for nocturnal polyuria, if other medical treatments have failed.
Polydipsia: Chronic excessive intake of water is called as polydipsia. Excessive intake of water is a manifestation of excessive thirst. It is a characteristic feature of diabetes mellitus. It may also occur in many other diseases like diabetes insipidus and psychogenic diseases like schizophrenia. In diabetes mellitus, it occurs because the blood sugar levels are usually high when diabetes is not treated well or when the disease is unidentified or not under control or otherwise in any patient compared to a healthy individual, the excess sugar in the blood increases the osmolality of the extra cellular fluids, which in turn causes the kidneys to excrete excess amounts of urine in an attempt to remove the excess glucose. Hence in diabetes, excessive consumption of water is in turn a manifestation of excess excretion of water by the kidneys. It is one f the earliest symptoms of diabetes mellitus.
Polyphagia: it is a medical sign meaning excessive hunger and abnormally large intake of food. In diabetics, though there is an excessive amount of glucose available for the cells in the body, they cannot take up the sugars present in the blood either because of deficiency of insulin or due to development of resistance to insulin, which is essential for the uptake of glucose by the cells to produce energy. This leads to excessive hunger which can lead to polyphagia. Taking small and more frequent meals helps in controlling the condition.
Fatigue: fatigue is defined as extreme tiredness and exhaustion that does not disappear with sleep or rest. It occurs in diabetes as a result of low availability of glucose to the cells causing low energy level.
Loss of weight: a significant decrease in the body weight that occurs unintentionally is called as unexplained weight loss. In diabetes, as a result of deficiency or resistance to insulin, body cannot utilize glucose to produce energy, then starts breaking down fats to contribute for the energy requirements which leads to persistent decrease in the body stores of fat and loss of weight. Treating the cause will rectify the problem.
Blurry vision: inability to see the fine details in sight and loss of sharpness of vision. It occurs due to swelling of the eyeball in diabetes because of high glucose level.
Headache, dizziness, nausea: because of the frequent rise and fall of blood glucose level, the body's metabolism can get interrupted and confused which can lead to a mixed feeling of nausea.
Slow healing of cuts: in diabetes, high blood sugar levels over a long period of time can cause poor blood circulation, making it difficult for the skin to repair and the wound to heal. This can cause non healing wounds more prone to fungal infections, bacterial infections, gangrene.
Itchy skin: In diabetes, blood glucose levels can go abnormally high, which can therefore provide ideal conditions for naturally present yeast to grow and also diminishes the body’s ability to fight infection.