Patients with type 1 diabetes have a characteristic symptom complex. An absolute deficiency of insulin results in accumulation of circulating glucose and fatty acids, with consequent hyperosmolality and hyperketonemia.
Patients with type 2 diabetes may or may not have characteristic features. The presence of obesity or a strongly positive family history for mild diabetes suggests a high risk for the development of type 2 diabetes.
A. SYMPTOMS AND SIGNS
1. Type 1 diabetes - Increased urination is a consequence of osmotic diuresis secondary to sustained hyperglycemia. This results in a loss of glucose as well as free water and electrolytes in the urine. Thirst is a consequence of the hyperosmolar state, as is blurred vision, which often develops as the lenses are exposed to hyperosmolar fluids.
Weight loss despite normal or increased appetite is a common feature of type 1 when it develops subacutely. The weight loss is initially due to depletion of water, glycogen, and triglycerides; thereafter, reduced muscle mass occurs as amino acids are diverted to form glucose and ketone bodies.
Lowered plasma volume produces symptoms of postural hypotension. Total body potassium loss and the general catabolism of muscle protein contribute to the weakness.
Paresthesias may be present at the time of diagnosis, particularly when the onset is subacute. They reflect a temporary dysfunction of peripheral sensory nerves, which clears as insulin replacement restores glycemic levels closer to normal, suggesting neurotoxicity from sustained hyperglycemia.
When absolute insulin deficiency is of acute onset, the above symptoms develop abruptly. Ketoacidosis exacerbates the dehydration and hyperosmolality by producing anorexia and nausea and vomiting, interfering with oral fluid replacement.
The patient’s level of consciousness can vary depending on the degree of hyperosmolality. When insulin deficiency develops relatively slowly and sufficient water intake is maintained, patients remain relatively alert and physical findings may be minimal. When vomiting occurs in response to worsening ketoacidosis, dehydration progresses and compensatory mechanisms become inadequate to keep serum osmolality below 320-330 mosm/L. Under these circumstances, stupor or even coma may occur. The fruity breath odor of acetone further suggests the diagnosis of diabetic ketoacidosis.
Hypotension in the recumbent position is a serious prognostic sign. Loss of subcutaneous fat and muscle wasting are features of more slowly developing insulin deficiency. In occasional patients with slow, insidious onset of insulin deficiency, subcutaneous fat may be considerably depleted.
2. Type 2 diabetes - While many patients with type 2 diabetes present with increased urination and thirst, many others have an insidious onset of hyperglycemia and are 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. Occasionally, type 2 patients may present with evidence of neuropathic or cardiovascular complications because of occult disease present for some time prior to diagnosis. Chronic skin infections are common. Generalized pruritus and symptoms of vaginitis are frequently the initial complaints of women. Diabetes should be suspected in women with chronic candidal vulvovaginitis as well as in those who have delivered large babies (> 9 lb, or 4.1 kg) or have had polyhydramnios, preeclampsia, or unexplained fetal losses.
Obese diabetics may have any variety of fat distribution; however, diabetes seems to be more often associated in both men and women with localization of fat deposits on the upper segment of the body (particularly the abdomen, chest, neck, and face) and relatively less fat on the appendages, which may be quite muscular. Standardized tables of waist-to-hip ratio indicate that ratios of “greater than 0.9” in men and “greater than 0.8” in women are associated with an increased risk of diabetes in obese subjects. Mild hypertension is often present in obese diabetics. Eruptive xanthomas on the flexor surface of the limbs and on the buttocks and lipemia retinalis due to hyperchylomicronemia can occur in patients with uncontrolled type 2 diabetes who also have a familial form of hypertriglyceridemia.