Hypoglycemia hypoglycemic coma

Biguanides cause hypoglycemia in 0.24 cases per 100 patient-years and it is more common when they are used in combination with a sulfonylurea (44). In 102 consecutive patients with drug-induced hospital-related hypoglycemic coma, 13 were taking metformin + glibenclamide and 3 were taking metformin + insulin (45). 

Of 20 patients with severe hypoglycemic coma and 20 with no or light coma, those with hypoglycemia had chronic depression and anxiety and performed persistently more poorly in several cognitive tests (74). 

Frequent attacks of hypoglycemia can result in encephalopathy, and after withdrawal of the hypoglycemic drug cerebral injury can persist. It is not exceptional for prolonged hypoglycemic coma to end fatally (43,44). In 494 cases of severe hypoglycemia, 10% of the patients died and 9% had permanent sequelae (45). 

Fig. 3.1 Altered metabolism of excitatory amino acids during hypoglycemic coma. Oxaloacetate and a-ketoglutarate are the corresponding a-keto-acids to aspartate and glutamate, respectively. During hypoglycemia the aspartate—glutamate transaminase reaction is driven to the left...

Fig. 3.3 Krebs cycle in hypoglycemia. This fundamental metabolic pathway is altered during hypoglycemic coma. The Krebs cycle continues to turn, however short the glucose supply from Embden—Myerhof glycolysis is, due to a short circuit of metabolites across the circle by amino acid transamination...

Rapid development of hypoglycemia in persons with intact hypoglycemic awareness causes signs of autonomic hyperactivity—both sympathetic (tachycardia, palpitations, sweating, tremulousness) and parasympathetic (nausea, hunger)—and may progress to convulsions and coma if untreated. 

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