Hyperosmolar diabetic coma

A specific complication of the use of large amounts of insulin during hyperosmolar diabetic coma is rhabdomyo-lysis (123). Low intramuscular phosphate and potassium concentrations, often masked by relatively high blood glucose concentrations, may be important contributory factors. 

Hyperosmolar diabetic coma occms chiefly in noninsulin-dependent diabetics who fail to compensate for their continuing, osmotic glucose diuresis. It is characterised by severe dehydration, a very high blood sugar (> 33 mmol/1 600 mg/100 ml) and lack of ketosis and acidosis. Treatment is with isotonic (0.9%) saline, at half the rate recommended for ketoacidotic coma, and with less potassium than in severe ketoacidosis. Insulin requirements are less than in ketoacidosis, where the acidosis causes resistance to the actions of insuhn, and should generally be half those shown in Table 35.2. Patients are more liable to thrombosis and prophylactic heparin is used. 

Azam H, Newton RW, Morris AD, Thompson CJ. Hyperosmolar nonketotic coma precipitated by lithium-induced nephrogenic diabetes insipidus. Postgrad Med J 1998 74(867) 39 11. 

In diabetic ketoacidosis, hyperosmolar nonketotic coma, and hypoglycemia, the clinical laboratory has an essential role in both diagnosis and monitoring of therapy Several analytes are frequently measured to guide clinicians in treatment regimens to restore euglycemia and correct other metabolic disturbances. The metabolic abnormalities of these conditions are beyond the scope of this book, and interested readers are referred to a standard textbook of medicine. The NACB guidelines also provide information on the tests that are used. 

Features Diabetic ketoacidosis (OKA) Hyperosmolar nonketotic coma (HONK) Lactic acidosis... 

Hepatic encephalopathy Hyperbilirubinemia Hypocalcemia Hypercalcemia Hyperparathyroidism Hypoparathyroidism Thiamine deficiency (Wernicke s) encephalopathy Diabetic ketoacidosis Nonketotic hyperosmolar coma Phosphate depletion Hypoglycemia Hypoxemia Hypercapnia... 

Hyperglycemia and diabetes mellitus Hyperglycemia, in some cases extreme and associated with ketoacidosis or hyperosmolar coma or death, has been reported in patients treated with atypical antipsychotics. 

Acute complications of diabetes include diabetic ketoacidosis, hyperglycaemic non-ketotic hyperosmolar coma, lactic acidosis and hypoglycaemia. 

Type II diabetics are less prone to develop ketone bodies or diabetic ketoacidosis but may develop hyperosmolar coma, a condition characterized by severe hyperglycemia and dehydration. Both diabetic ketoacidosis and hyperosmolar coma are medical emergencies that require prompt insulin administration and intravenous fluids. 

When a 45-year-old man with severe lithium-induced diabetes insipidus developed hyperosmolar, nonketotic hyperglycemia, it was suggested that poorly controlled diabetes mellitus may have contributed to the polyuria (684). Prior contact with a female patient who had developed hyperosmolar coma secondary to lithium-induced diabetes insipidus (685) allowed physicians 4 years later to treat her safely after a drug overdose and a surgical procedure, by avoiding intravenous replacement fluids with a high dextrose content (despite stopping lithium several years earlier, the patient continued to put out 10 liters of urine daily) (686). 

MacGregor DA, Baker AM, Appel RG, Ober KP, Zaloga GP. Hyperosmolar coma due to lithium-induced diabetes insipidus. Lancet 1995 346(8972) 413-7. 

Two other forms of severe metabolic decompensation may occur in diabetics. These are hyperosmolar non-ketotic (HONK) coma and lactic acidosis. Table I shows the principal features of these conditions in comparison with DKA. 

A client with Type 1 diabetes will experience diabetic ketoacidosis a client with Type 2 diabetes will experience hyperosmolar, hyperglycemic, nonketotic coma. 

A hyperosmolar non-ketotic coma developed in a 29-year-oId diabetic patient with chronic renal failure after repeated oral use of 120 ml 50% glycerol solution, given every 12 hours for a neovascular glaucoma, in addition to 250 mg Diamox per os every 6 hours for 24 hours. Hyperosmolar non-ketotic coma is a serious disorder having a mortality rate between 20 and 70%. By applying i.v. hypotonic saline, albumin, packed red blood cells together with insulin and bicarbonate, the coma could be treated successfully (47 ). 

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