Diabetes mellitus, 250.00
Type 1 diabetes mellitus, 250.01
Type 2 diabetes mellitus, 250.02
I. Definition
A. A group of metabolic diseases resulting from a breakdown in the body’s ability to produce and/or to use insulin
B. Characterized by hyperglycemia and associated with numerous acute and chronic complications
1. Acute complications
a. Diabetic ketoacidosis
b. Hyperglycemic hyperosmolar nonketotic coma
2. Chronic complications
a. Neuropathy
b. Nephropathy
c. Retinopathy
d. Cardiovascular disease
e. Peripheral vascular disease
II. Incidence/predisposing factors
A. Approximately 14 million Americans have diabetes.
B. Affects approximately 5% to 7% of the U.S. population
C. Affects approximately one fifth (18%) of individuals aged 65 to 74 years
D. In approximately 50% of all individuals with diabetes mellitus, the condition is undiagnosed.
E. Ethnic minorities, with Native Americans at highest risk
F. Others with a family history of diabetes mellitus
III. Classifications of diabetes mellitus and other forms of glucose intolerance
A. Type 1 (previously, insulin-dependent or juvenile-onset diabetes)—See p. 451.
B. Type 2 (previously, non–insulin-dependent or adult-onset diabetes mellitus)—See p. 455.
C. Secondary diabetes related to the following:
1. Hormonal excess
a. Cushing’s syndrome
b. Acromegaly
c. Hyperthyroidism
d. Pheochromocytoma
2. Medications
a. Glucocorticoids
b. Diuretics
c. Phenytoin (Dilantin)
d. Oral contraceptives
3. Pancreatic disease
a. Pancreatitis
b. Pancreatectomy
4. Other genetic factors
a. Beta-cell defects
b. Neoplasia
c. Other genetic syndromes
i. Down syndrome
ii. Turner’s syndrome
D. Gestational diabetes
E. Impaired glucose homeostasis
1. Impaired fasting glucose
2. Impaired glucose tolerance
3. Pre-diabetes
IV. Laboratory/diagnostic testing
A. According to the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus, the diagnosis of diabetes mellitus and/or impaired glucose homeostasis may be made from positive findings from any two of the following tests on different days:
1. Symptoms of diabetes mellitus
a. Polyuria
b. Polydipsia
c. Unexplained weight loss plus
2. Random or casual (any time of day without regard to time since the last meal) plasma glucose concentration 200 mg/dl (11 mmol/L) or above, or
3. Fasting plasma glucose (FPG) = 126 mg/dl (7.0 mmol/L) or above
C. Urinalysis: Although this test is less used today because of the wide availability of glucose meters, it can be used to monitor for the following:
1. Glycosuria—easily detected by Diastix or Clinistix paper strip testing
2. Ketonuria—quantitatively evident in patients with type 1 diabetes via nitroprusside tests such as Acetest or Ketostix
D. BUN and urinary creatinine
1. Baseline
2. To rule out dehydration (i.e., elevated)
E. Glycosylated hemoglobin (HbA1c)
1. Elevated before diagnosis in approximately 85% of patients with diabetes
2. Indicative of a patient’s glycemic control over the past 2 to 3 months
3. Not used for the initial diagnosis of diabetes mellitus because of the low sensitivity of the test
4. Although it has low sensitivity, the test is highly specific; therefore, measurements are conducted in known diabetic patients approximately every 3 months so that therapy can be adjusted as needed.
5. Normal values are approximately 5.5% to 7%; higher levels indicate higher blood glucose levels and thus, poorer glucose control; most clinicians strive for less than 6% as the goal.
V. Management: diet, exercise, and foot care for diabetic patients
Note: Treatment plans for all diabetic patients must be highly individualized. The following points provide general guidelines that may be tailored to the needs of each patient:
A. Teach patients about the benefits of diet therapy:
1. American Diabetes Association (ADA) diets found at www.eatright.org or at www.ada.org
2. Refer patient to a dietitian, as appropriate.
3. Total carbohydrate intake should be 55% to 60% of total caloric intake.
4. Fiber intake should be 25 g/1000 calories.
5. Fats should account for 25% to 35% of total calories (individualized according to serum lipid levels).
6. Protein should make up 15% to 20% of total calories.
7. Meal schedules for diabetic patients:
a. Patients with type 1 diabetes should be encouraged to have three meals each day and three snacks on a consistent schedule, consistent with insulin regimen.
b. Patients with type 2 diabetes should be taught to have meals 5 hours apart, with few or no snacks.
c. Teach patients who are on insulin how to use the Diabetic Exchange List.
9. Alcohol intake should be limited to modest use (e.g., two drinks or fewer per day).
10. Optimal glycemic control and weight reduction, as needed, are both important goals of therapy.
B. Encourage exercise—an essential component of care for all diabetic patients
1. Encourage at least 30 minutes of exercise every other day; allow for periods of warm-up (5 to 10 minutes) and cool-down (5 to 10 minutes).
2. Teach the patient to use silica gel or air midsoles and polyester or cotton blend socks to keep feet as dry as possible; wearing proper footwear and monitoring for blisters is of paramount importance.
3. Monitor patient for dehydration; encourage intake of extra fluids.
4. Teach the patient to inject insulin at a body site far from that being exercised, if possible (e.g., abdomen instead of legs or arms).
5. Additional carbohydrates should be ingested prior to exercise.
6. Teach that exercise diminishes the need for insulin.
C. Foot care: Patients should be taught the importance of foot care in preventing infection, gangrene, and/or the need for amputation.
1. The most important prevention strategy for foot complications is to examine the feet for injuries each day with a mirror, including the bottoms of the feet and between the toes.
2. Report immediately any new problems such as broken skin, ulcers, or blisters—that is, tell the patient not to wait until his or her next appointment.
3. Have nails trimmed regularly by an experienced health care provider.
4. Wash feet daily with lukewarm water and a mild soap; pat feet dry with a soft cloth; apply lotion after washing.
5. Wear only shoes prescribed by a health care professional.
6. Always wear protective shoes and socks; do not wear socks alone.
7. Stop smoking.
VI. Complications
A. Diabetic retinopathy
1. Occurs in approximately 15% of diabetic patients after 15 years; increases by 1% each year after diagnosis
2. The most common cause of all blindness
3. Annual ophthalmology examinations are indicated.
B. Cardiovascular disease
1. Diabetes adds an independent risk factor to atherosclerotic development.
2. The prevalence of hypertension is 2 times greater in patients with type 2 diabetes than in the general population.
C. Cataracts—increased incidence among diabetic patients
D. Glaucoma—occurs in approximately 6% of diabetic patients
F. Nephropathy—End-stage renal disease has a 40% incidence in patients with type 1 diabetes and a less than 20% incidence in patients with type 2 diabetes.
G. Infections
1. Chronically common in diabetic patients
2. Watch for necrobiosis lipoidica diabeticorum lesions over the anterior legs and dorsal surfaces of the ankles; these may predispose patients to infection.
3. Yeast infections are also common.
H. Gangrene of the feet—Incidence is 20 times higher among diabetic patients.
I. Diabetic ketoacidosis (type 1 patients)—See Chapter 47.
J. Hyperosmolar hyperglycemic nonketosis (HHNK)—See Chapter 47.
TYPE 1 DIABETES MELLITUS
I. Predisposing factors/general comments: type 1 diabetes
A. Each year, in 15 per 100,000 individuals with diabetes, type 1 diabetes is diagnosed.
B. Most commonly seen in whites
C. African Americans have the lowest incidence of this type in the U.S.
D. Males and females are affected equally.
E. Genetic predisposition
F. Approximately 70% acquire type 1 before age 20.
G. Virtual absence of circulating insulin
H. Islet cell antibodies may be found in approximately 90% of patients within the first year of diagnosis.
I. Development of this type of diabetes is strongly associated with the presence of human leukocyte antigens HLA-DR3 and HLA-DR4.
J. Absence of C-peptide
K. Ketone development usually occurs.
L. Usually develops acutely over a period of days to weeks
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