Excess Insulin

Question 1

Insulinoma

Answer 1

unregulated production of insulin with HYPOGLYCEMIA as classic manifestation

Question 2

Causes of hypoglycemia (5)

*Common in sick/hospitalized patients

Answer 2

1. Drugs, including insulin
2. Hepatic failure; not enough glycogen
3. Chronic renal failure
4. Sepsis
5. Malnutrition

Question 3

Causes of hypoglycemia (3)

*Uncommon in healthy/non hospitalized outpatients

Answer 3

1. Drugs, including insulin
2. Hormonal deficiencies
   - Adrenal insufficiency (lack of cortisol)
   - Hypothyroidism
   - Growth hormone deficiency
   - Hypopituitarism
3. Hormonal excess: insulinoma
   - Islet cell hypertrophy

Question 4

Drugs that can cause hypoglycemia (5)

*not all listed

Answer 4

1. Insulin
2. Sulfonylureas & meglitinides (oral diabetes meds)-acts on ATP sensitive K channel
3. alcohol
4. beta-adrenergic antagonists
5. Angiotensin-converting enzymes’ inhibitors

Question 5

Hormal response to Hypolgycemia @

1. <60mg/dl

Answer 5

1. insulin secretion decreases
2. glucagon and epinephrine secretion increases
3. growth hormone secretion increases
4. cortisol secretion increases

Question 6

Adrenergic symptoms of hypoglycemia (8)
<55mg/dl blood glucose

*Non-specific symptoms

Answer 6

1. sweating
2. feeling warm
3. anxiety
4. tremor
5. nausea
6. palpitations
7. tachycardia
8. hunger

Question 7

Neuroglycopenic symptoms of hypoglycemia (11)

<50mg/dl

Answer 7

1. fatigue
2. dizziness
3. headache
4. visual disturbances
5. drowsiness
6. difficulty speaking
7. inability to concentrate
8. unusual behavior
9. confusion; loss of memory
10. loss of consciousness
11. seizures

Question 8

Whipple’s triad

Answer 8

Evaluation of hypoglycemia

1. serum glucose <50mg/dl
2. neuroglycopenic symptoms
3. relief of symptoms by raising glucose level

Question 9

Process of determining cause of hypoglycemia

Answer 9

1. Exclude medications
2. Rule out hormonal deficiencies (cortisol, TH)
3. Rule out hormonal excesses (insulin): 72 hour fast

Question 10

72 hour fast: evaluation of hypoglycemia

Answer 10

1. Patient is hospitalized and can drink calorie-free and caffeine-free beverages
2. when blood glucose <45mg/dl check levels of proonsulin, insulin, and C peptide
3. screen for presence of sulfonylureas or meglitinides

Question 11

Insulinoma localization

Answer 11

1. All are islet-cell tumors
2. Pancreatic imaging: CT, MRI, transabdominal ultrasound, endoscopic ultrasound
3. Surgical resection
   - Laparoscopy
   - small tumor can be enucleated
   - Whipple procedure (part of duodenom taken out too)
4. Transient post-operative hyperglycemia common; resolved by 48-72 hours

Question 12

Medical management of insulinoma

Answer 12

1. used only for those who are not surgical candidates due to other health issues
2. Octreotide (somatostatin analogue) via subcutaneous injects, act on beta cell receptor to inhibit insulin secretion
3. Also diazoxide, interferon-alfa, and verapamil