When glucose is given orally, the patient experiences a greater release of insulin than when glucose is administered IV, even though the same blood glucose concentrations are given. In physiological and hormonal terms, explain the difference in insulin release when given IV.
When glucose is given orally, the patient experiences a greater release of insulin than when glucose is administered IV, even though the same blood glucose concentrations are given. In physiological and hormonal terms, explain the difference in insulin release when given IV.
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Carol, an 8-year-old girl inpreviously good health, has noticed that, in the past month, she isincreasingly thirsty. She gets up several times a night to urinate,and finds herself gulping down glasses of water. At the dinnertable, she seems to be eating twice as much as she used to, yet shehas lost 5 pounds in the past month. In the past three days, shehas become nauseated, vomiting on three occasions, prompting avisit to her pediatrician.
At the doctor's office, she is breathing rapidly during herphysical examination. Blood and urine samples are taken. Thefollowing lab results are noted:
| Blood glucose level = 545 mg/dl Blood pH level = 7.23 | (normal = 50 - 170 mg/dl) (normal = 7.35 - 7.45) |
Urine = tested positive for glucose and for acetone /acetoacetate (i.e. ketone bodies) (normally urine is free ofglucose and ketone bodies) | |
Following her visit to the pediatrician, Carol undergoes adiabetic care training program, learning how to self-inject insulinsubcutaneously and check her blood-glucose level at home withchemstrips. In addition, she learns the importance of carryingcandy and glucagon with her at all times as well as eating theright amounts of food at the right times each day. Sheis started on the following schedule of insulin dosing: â¨
morning dose = 8 units of NPH insulin and 4 units of regularinsulin
supper dose = 4 units of regular insulin
bedtime dose = 5 units of NPH insulin
total dose per day = 21 units
Note: regular insulin is a fast-acting insulin, while NPHinsulin has a slower onset of action and a longer duration ofaction.
Three days later, she returns to the doctor's office for areview of her blood-glucose readings and a measurement of herfasting blood-glucose level, which is found to be 95 mg/dl. Most ofher glucose readings during the day have been in the low- tomid-100 range. Her glucose levels before supper, however, are inthe upper 200s. The dosage of insulin is adjusted. Carol returns toher pediatrician three months later for a re-check, and is found tohave a glycosylated hemoglobin level (Hb A1C) of 9.5%.
1. Why is her glucose level elevated? What is the primarydiagnosis and what are the key lab results that confirm it?
2. Why is her blood pH level decreased? Why are there ketonebodies in her urine?
3. Carol is breathing rapidly. What physiological purpose doesthis serve?
4. What is the name for frequent urination and why is ithappening to Carol? What is osmotic diuresis and what causesit?
5. What is the name for constant hunger and why is it happeningto Carol? Use the role of glucagon in your answer.
6. What are the concerns about Carol giving herself insulin on adaily basis? Why does she need to carry both candy and glucagonwith her at all times?
7. How would you adjust Carolâs insulin-dosing schedule to bringher pre-supper glucose levels down?
8. What is glycolsylated hemoglobin? What is the normal rangefor glycosylated hemoglobin?
9. What does Carol's Hb A1C level indicate that a one-timedirect measurement of blood glucose doesn't indicate?
10. What are the possible long-term complications of herdisease?
