In persons exposed to frequent hypoglycemic episodes during tight glycemic control, autonomic warning signals of hypoglycemia are less common or even absent. This dangerous acquired condition is termed hypoglycemic unawareness. When patients lack the early warning signs of low blood glucose, they may not take corrective measures in time. In patients with persistent, untreated hypoglycemia, the manifestations of insulin excess may develop— confusion, weakness, bizarre behavior, coma, seizures—at which point they may not be able to procure or safely swallow glucose-containing foods. Hypoglycemic awareness may be restored by preventing frequent hypoglycemic episodes. An identification bracelet, necklace, or card in the wallet or purse, as well as some form of rapidly absorbed glucose, should be carried by every dia betic person who is receiving hypoglycemic drug therapy.
All the manifestations of hypoglycemia are relieved by glu cose administration. To expedite absorption, simple sugar or glucose should be given, preferably in liquid form. To treat mild hypoglycemia in a patient who is conscious and able to swallow, dextrose tablets, glucose gel, or any sugar-containing beverage or food may be given. If more severe hypoglycemia has produced unconsciousness or stupor, the treatment of choice is 1 mg of glucagon injected either subcutaneously or intramuscularly. This may restore consciousness within 15 minutes to permit ingestion of sugar. Emergency medical services should be called in the event of loss of consciousness. The emergency personnel can restore consciousness by giving 20–50 mL of 50% glucose solution by intravenous bolus over a period of 2–3 minutes.
B. Diabetic Coma 1. Diabetic ketoacidosis—Diabetic ketoacidosis (DKA) is a life-threatening medical emergency caused by inadequate or absent insulin replacement, which occurs in people with type 1 diabetes and infrequently in those with type 2 diabetes. It typically occurs in newly diagnosed type 1 patients or in those who have experienced interrupted insulin replacement, and rarely in people with type 2 diabetes who have concurrent unusually stressful conditions such as sepsis or pancreatitis or are on high-dose steroid therapy. DKA occurs more frequently in patients on insulin pumps. Poor compliance—either for psychological reasons or because of inadequate education—is one of the most common causes of DKA, particularly when episodes are recurrent.
Signs and symptoms include nausea, vomiting, abdominal pain, deep slow (Kussmaul) breathing, change in mental status (including coma), elevated blood and urinary ketones and glucose, an arterial blood pH lower than 7.3, and low bicarbonate (15 mmol/L).
The fundamental treatment for DKA includes aggressive intravenous hydration and insulin therapy and maintenance of potassium and other electrolyte levels. Fluid and insulin therapy is based on the patient’s individual needs and requires frequent reevaluation and modification. Close attention must be given to hydration and renal status, sodium and potassium levels, and the rate of correction of plasma glucose and plasma osmolality. Fluid therapy generally begins with normal saline. Regular human insulin should be used for intravenous therapy with a usual starting dosage of about 0.1 U/kg/h.