Psychobehavioral Metabolic Parameters of Severe Hypoglycemic Episodes

Investigators have discussed the incidence of severe hypoglycemia (1,2) and its consequences in terms of skeletal muscle damage (3) and both transient (4) and long-term (5) cognitive impairments. We (6) and others (7,8) have presented retrospective data that indicate the aversive consequences and subsequent fear of hypoglycemia that may promote a phobia toward hypoglycemia and in turn prompt avoidance behaviors that attempt to maintain elevated blood glucose (BG) to avoid future hypoglycemia. Trauma-fear-avoidance behavior can then be responsible for significant metabolic disruption. This case report presents prospective data that illustrate this phenomenon and suggests additional concerns associated with hypoglycemia and a new focus of intervention. A 37-yr-old 210-lb large-frame White married male realtor of above-average intelligence participated in a study investigating the therapeutic effects of continuous subcutaneous insulin infusion (CSII) therapy. The protocol for this study involved counterregulation testing before and after CSII and psychological testing including the Hypoglycemic Fear Survey (6-8). On 22 September 1988, the patient was admitted to the Clinical Research Center, and at 2200, he was placed on overnight variable intravenous infusion of human regular insulin to sustain euglycemia. At 0900 the next morning, a standard 120-min continuous infusion of human regular insulin (0.67 mU • kg" • min") was begun to determine ability to counterregulate (9). The patient's BG counterregulated at 50 mg/dl 60 min into the protocol. Epinephrine rose from 240 to 1090 pg/dl between 40 and 60 min, and pancreatic polypeptide similarly rose from 55 to 740 pg/dl. These data clearly indicate that the patient counterregulated to hypoglycemia. Four months later (15 January 1989), the patient was hospitalized to be trained and placed on CSII with a basal insulin rate of 0.7 U • kg" • day". He returned monthly for follow-up and glycosylated hemoglobin (HbA,) determinations. After 3 mo of CSII (25 March 1989), he unexpectedly learned that his wife was pregnant and subsequently had several low (<70 mg/dl) self-monitoring of blood glucose readings throughout the day. Despite a BG of 50 mg/dl at bedtime, he failed to reduce his basal insulin rate. At -0400, he experienced a severe hypoglycemic seizure, during which he shattered his left clavicle, which required reconstructive surgery. His BG level was recorded as 2 mg/dl in the emergency room. A subsequent computerized axial tomography scan was negative. Total medical expenses resulting from this hypoglycemic episode were $22,000. The patient returned to work 3 days postseizure. The first four HbA, readings before this seizure were 10.5, 11.8, 11.4, and 9.8. Eight, 12, and 18 wk after the seizure, HoA, rose to 13.8, 14.9, and 13.8, respectively. His score on the worry scale of the Hypoglycemic Fear Survey (6-8), a scale that quantifies to what extent a patient is preoccupied with concerns about hypoglycemia, rose by nearly 40% after his hypoglycemic experience, compared with his three previous scores (worry scale = 23, 26, 24 for 3 mo before seizure, and 36 after seizure). Item analysis of the worry scale indicated increased concern over 7) having a hypoglycemic episode while asleep, 2) having a seizure, and 3) losing control. During an interview 3 mo after the seizure, the patient reported that he had been extremely frightened by the hypoglycemic seizure. Because of the fear that a similar episode would recur, he attempted to maintain his BG in a "safer" and higher range than previously. The patient said he thought that he "needed a little padding" in case his BG fell again. The patient also noted that his HbA, measurements had been affected by these changes in his self-treatment and reported trying very hard to return to his previous pattern of intensive treatment. Additionally, he reported that his wife was even more intimidated by the hypoglycemic episode than he was, and she encouraged him to maintain elevated BGs. A counterregulation test repeated at this time (22 June 1989) demonstrated that the patient's BG again counterregulated 80 min into the insulin infusion at 40 mg/dl, in which epinephrine rose from 71 to 471 pg/dl between 60 and 80 min, and pancreatic polypeptide similarly rose from 40 to 980 pg/dl. This case study illustrates that, although the ability to counterregulate during standardized insulin infusion protocols is associated with reduced risk of severe hypoglycemia (9), the ability to counterregulate does not preclude severe hypoglycemic episodes. Secondly, although the acute physical and cognitive effects may resolve quickly, the psychobehavioral effects of severe hypoglycemia may linger for a long period and possibly contribute to continued metabolic dysregulation. Clinicians should routinely look for such psychological sequelae to hypoglycemia and its behavioral metabolic consequences, possibly with the Hypoglycemic Fear Survey. Subsequent efforts to reestablish metabolic control should then focus on eliminating this psychological barrier to appropriate self-care behaviors and readjusting the insulin-diet regimen.