Case Study: Marked Hyperglycemia Followed by Marked Hypoglycemia

R.P. is a 13-year-old Hispanic girl with type 1 diabetes diagnosed a number of years ago. Her disease was well controlled for at least a year on a three-injection regimen of 70/30 NPH/regular insulin before breakfast, regular insulin before supper, and NPH at bedtime. During the following 2 years, her glucose control deteriorated, and she required hospital admission twice (April and July of the second year) for re-regulation(Table 1). After the second admission, she was referred to a diabetes specialist.

During her hospitalizations, R.P. was evaluated for the Somogyi or rebound effect (hypoglycemia followed by hyperglycemia due to counterregulatory hormone release), and she was also assessed for the development of insulin antibodies, which were not demonstrated. During the second hospital stay, she was placed on a continuous glucose monitor for 3 days. Her blood glucose patterns were noted (Table 2)and reported later to her family at the time of her first outpatient visit to the specialist.

The patient's medical history revealed that she was the larger of fraternal twins, weighing 7 lb, 10 oz at birth. The pregnancy had been complicated by toxemia, but the delivery was uneventful. The child grew and developed normally. There were no major medical problems until of onset of diabetes. Her only surgical procedure was a tonsillectomy at the age of 6 years for enlarged tonsils that were obstructing her airway. The patient had no known allergies and took no medications other than insulin. There was a positive family history for diabetes (an aunt with type 2 diabetes on her father's side and a grandmother with type 1 diabetes on her mother's side).

Review of systems was essentially negative, with the exception of some emotional problems apparently related to the remarriage of her father. The father had been separated from the family for several years, but the remarriage had occurred the previous February. This had resulted in some acting out on the part of the patient and subsequent behavior problems at home and at school.

Physical examination revealed a well developed and nourished girl in no acute distress. Her weight was within the expected range for her height. Her head was normocephalic; pupils were equal and reactive to light; fundi were benign; ear, nose, and throat exams were within normal limits; and her neck was supple, without masses, adenopathy, bruits, or thyromegaly. Her chest was clear to auscultation and percussion, and her heart was normal in tone and intensity. There was a 2/6 holosystolic murmur, previously believed to be a benign flow murmur, that had remained unchanged from infancy. Her genitourinary system was normal for a pubertal girl. Examination of the extremities revealed full range of motion and normal strength, volume, and tone of all muscle groups. No vascular abnormalities were noted. The neurological exam was within normal limits.

Laboratory values at the time of the second hospital admission were hemoglobin 10.5 g/dl; hematocrit 32.3% with hypochromic, microcytic indices;and white blood count 6.2 k/cmm with normal differentiation. Other laboratory findings were normal, except the alkaline phosphatase was 395 g/dl, the phosphate was 4.8 U/l, and the urine analysis was negative except for 5%glucose in the urine. The blood glucose level was 494 mg/dl, and the A1C was 14.1%.

R.P. was placed on a continuous glucose monitor on day 2 of her second hospitalization, using her home regimen of 24 units of 70/30 NPH/regular insulin before breakfast, 12 units of regular insulin before supper, and 12 units of NPH insulin at bedtime plus a 2,000-calorie meal plan that included three meals and three snacks. During the subsequent 3 days, she exhibited occasional swings from hypoglycemia to hyperglycemia. Her blood glucose values remained high throughout most of this time(Table 2).

On analysis of the continuous glucose monitoring results, R.P.'s insulin regimen was changed to four injections per day of regular insulin, with three meals and three snacks. The total dose of insulin was 60 units, with 25%before breakfast, 25% before lunch, 25% before supper, and 25% at midnight. Simple sugars were excluded from her meal plan. Her blood glucose levels were monitored before each meal and at bedtime.

During this most recent regimen, R.P. demonstrated marked postprandial hyperglycemia for 2–3 hours and then marked hypoglycemia, i.e., glucose(in mg/dl) in the 40s to 50s (Table 3). Further dietary modifications were attempted, including the avoidance of simple carbohydrates and increasing the protein and fiber foods. She was placed on daily iron capsules for anemia.

Blood glucose levels (in mg/dl) at the time of R.P.'s discharge ranged from the 40s to the 300s. A referral was made to the diabetes specialist at the time of discharge.

1. Why were high blood glucose levels after meals and hypoglycemic episodes still occurring?

2. How would rapid-acting insulin aid in alleviating such wide swings in blood glucose levels?

3. What other factors might contribute to the widely fluctuating blood glucose levels?

4. What other considerations may be helpful when planning the patient's future program?

R.P. was at an age when hormonally related emotional issues might be occurring. This was a time when specific emotions were being challenged (the father leaving the family), along with growth and development issues related to the normal maturation process. Either or both could have resulted in the elevation of blood glucose levels.

Although it is unusual to observe type 1 diabetes in a person of Hispanic origin, the genetic history revealed a white grandmother with type 1 diabetes.

Because of some of the emotional pressures at home, supervision was found lacking at a number of times when the patient self-administered injections of insulin. She admitted later that she had omitted a number of injections because she was afraid that the increased insulin dosage prescribed by her family physician was going to result in insulin reactions. As the family physician tried to overcome the hyperglycemia noted before meals, the peak of the regular insulin plus the patient's reluctance to take a mid-morning snack when “no one else was eating” apparently led to the pre-meal hypoglycemia.

The diabetes specialist received much information, both from the continuous glucose monitoring (which could have been done on an outpatient basis) and from the assessment in the diabetes center clinic related to the psychosocial and physical issues needing to be addressed at this age and stage of maturation.

R.P. was quickly changed to rapid-acting insulin (50% of her total insulin dose, divided among the three meals) and an extended, long-acting insulin (the other 50% of her total daily dose). Within a few days, this resulted in a decrease in the total amount of insulin.⁴  The rapid-acting insulin covered the more rapid increase in absorption of food without subsequent hypoglycemic episodes.

The family chose to use the calorie point system (75 calories = 1 point)rather than the carbohydrate counting system. This was because of concern about the total caloric intake needed for growth (30 kcal/lb in prepubescence,based on activity levels; 15 kcal/lb postpubescence, based on activity levels)and recognition of the possibility that obesity might occur in her teenage years (based on a family history of obesity).

The family learned to use the food-to-insulin ratio approach, which is based on good nutrition with ∼ 50% of each meal from carbohydrate. The food intake for each meal was kept relatively stable during four days of assessment. Once the 2-hour postprandial blood glucose levels were within an acceptable range (90–180 mg/dl), the average points of food eaten at the time of meals were divided into the previous insulin dose to determine how much insulin covered how many points of food. Flexibility was given to administer insulin either after a meal based on the points eaten or before a meal if R.P. knew what she would be eating. Nutrition education was provided,including types of foods, use of fiber, the need for whole grains, fruits, and vegetables, and the importance of selecting low-fat meats.

Concurrently, the family attended an intensive education program while this initial assessment was being conducted. R.P. learned how to use the flexibility of her care regimen and came to understand how her self-care activities affected her results.⁵  After the baseline needs were determined with insulin and food, the bedtime long-acting insulin was later self-administered, with supervision, at her evening meal. This change was made for two reasons: convenience and the occurrence of higher blood glucose levels in the evening because the bedtime insulin did not effectively cover late-evening insulin needs the next day.

Her regimen also included family therapy for 6 weeks to assist her in adjusting to her father's recent remarriage and the stressors of family life when visiting her father on weekends. She was also assessed at that time for any neuropsychological problems that had not surfaced from the earlier verbal assessment.⁶  R.P.'s father and his new wife also completed the education program. By the end of the 6 weeks, R.P.'s father and mother had worked out their differences relating to R.P.'s diabetes care. They agreed to document glucose levels,adjustments in calories and insulin doses, and any unusual events that occurred at either parents home. One record book would be shared between homes.

• It is possible to increase the duration of action of an insulin dose by increasing the number of units administered, but then hypoglycemia is more likely to occur during the higher peak action of the insulin, especially when food is not present.

• Any diabetes management program must mimic nature as much of the time as possible.

• On long- versus rapid-acting insulin, pre-meal blood glucose levels reflect the dosage of the extended, long-acting insulin. Two-hour postprandial blood glucose levels reflect the rapid-acting insulin responses.

Subsequent visits to a nurse practitioner at the diabetes center have documented better outcomes (Table 4). R.P.'s A1C results are now 7.8%, and her blood glucose levels(in mg/dl) range from the 70s to a few 200s. Other laboratory values remain normal.