Diabetes mellitus presentation

Type 1 diabetes

The severity of the insulin deficiency and the acute­ness with which the catabolic state develops deter­mine the intensity of the metabolic derangements. An ab­solute deficiency of insulin results in excessive accu­mulation of circulating glucose and fatty acids, with consequent hyperosmolality and hyperketonemia. Weight loss despite normal or increased appetite is a common feature of type 1 diabetes when it develops subacutely over a period of weeks. The weight loss is initially due to depletion of water, glycogen, and triglyceride stores. Chronic weight loss due to re­duced muscle mass occurs as amino acids are di­verted to form glucose and ketone bodies. Increased urination is a conse­quence of osmotic diuresis secondary to sustained hyperglycemia. Thirst is a conse­quence of the hyperosmolar state, as is blurred vision, which often develops as the lens and retina are ex­posed to hyperosmolar fluids. Lowered plasma volume produces dizziness and weakness due to postural hypotension when sitting or standing. Total body potassium loss and the general catabolism of muscle protein contribute to the weak­ness. Ketoacidosis occurs when insulin deficiency is severe and of acute onset.  It exacerbates the dehydration and hyperosmolality by producing anorexia, nausea, and vomiting, thus interfering with oral fluid replace­ment. As plasma osmolality exceeds 330 mosm/kg, impaired consciousness ensues. With progression of acidosis to a pH of 7.1 or less, deep breathing with a rapid ventilatory rate (Kussmaul respiration) occurs and progresses to se­vere circulatory collapse with pH 7.0 or less.

Type 2 diabetes

Many patients with type 2 diabetes have an insidious onset of hyperglycemia and may be relatively asymptomatic initially. This is particularly true in obese patients, whose diabetes may be detected only after glycosuria or hyper­glycemia is noted during routine laboratory studies. The classic symptoms of polyuria, thirst, recurrent blurred vision, paresthesias, and fatigue are manifestations of hyperglycemia and osmotic diuresis and are therefore present late in the course of disease. Chronic skin infections are common. Generalized pruritus and symptoms of vaginitis are frequently the initial complaints of women with type 2 diabetes. Di­abetes should be suspected in women with chronic candidal vulvovaginitis as well as in those who have delivered large infants (4.1 kg) or have had polyhydramnios, pre-eclampsia, or unexplained fetal losses. Occasionally, a man with previously undiag­nosed diabetes may present with impotence.