Diabetes Mellitus
Michael Ostapchuk and Michael B. Foster
Diabetes mellitus (DM) is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both (1). There are two types of DM: type 1 and type 2. Approximately 7.8 million people in the United States have DM (2). Of these, 10% to 15% have type 1. The prevalence of type 1 DM is 1/400 individuals aged 18 years or less. Approximately 20% of those with type 1 DM present after 18 years of age.
Approach
The initial goal is to determine which type of diabetes the patient has.
A. Type 1 diabetes. Type 1 DM is thought to be caused by a gradual autoimmune destruction of pancreatic beta cells (3). This leads to a critical deficiency in the production of insulin that often leaves the patient dependent on insulin throughout life. Type 1 DM has no seasonal variation and the gender-based differences are not clinically significant. The genetics of type 1 DM remains unclear. Early institution of insulin therapy may help to preserve pancreatic secretory reserve, which enhances the ability of the patient to maintain stable blood glucose control.
B. Type 2 diabetes. In type 2 DM is found a combination of resistance to insulin action and an inadequate secretory response. Risk factors for type 2 DM include (a) a family history of type 2 DM, (b) prior gestational diabetes, (c) advanced age, (d) sedentary lifestyle, (e) upper body obesity, and (f) African-American, Hispanic, or native American ethnicity (1). These individuals often do not need insulin to survive. Because type 2 DM can go unrecognized, patients are at increased risk for developing microvascular and macrovascular complications.
History
The initial presentation of DM can vary. Either type may present with the insidious onset of the symptoms associated with hyperglycemia (polyuria, polydipsia, and polyphagia) or with the abrupt onset of an acute complication [diabetic ketoacidosis (in type 1 DM) or nonketotic hyperglycemic-hyperosmolar coma (in type 2 DM)].
A. Type 1 diabetes. Patients with type 1 DM typically present before the age of 18 years. The symptoms heralding the disease emerge gradually as hyperglycemia appears and becomes more frequent and profound. Physiologic stress (e.g., an acute illness or trauma), which increases the requirement for insulin, can unmask the insulinopenia and give the impression that the problem is acute. Enuresis may be a clue for polyuria in a child who was previously toilet-trained. Lethargy, weakness, and weight loss are other common features.
B. Type 2 diabetes. Patients with type 2 DM usually present after the age of 40 years. The diagnosis is often made in an asymptomatic patient as a result of routine blood tests that reveal an elevation of plasma glucose. Other patients may present with the symptoms of hyperglycemia. The patient may have a history of recurrent skin infections or persistent vulvovaginitis. Other common symptoms include altered sensations in the extremities, nocturia, erectile dysfunction, and visual disturbances (Chapters 4.6, 5.1, 10.3, and 10.4). The use of glucocorticoids, β-adrenergic agonists, or thiazides can precipitate the symptoms of type 2 DM.
Physical examination
Patients often present with similar physical findings in both type 1 and type 2 DM, owing to hyperglycemia. In the young child, failure to grow and gain weight can occur with type 1 DM. The child may be ill appearing, lethargic, and often have signs of dehydration (tachypnea, tachycardia, and low blood pressure). Ketone production will produce a fruity odor on the patient’s breath. The patient with type 2 DM tends to be obese (especially upper body obesity) and may appear fatigued and have muscle weakness or decreased vision. The neurologic examination may reveal painful feet and numbness. Monilial infections may be found in the vagina and pubic areas.
Testing
A. Type 1 diabetes. Not all children with hyperglycemia have diabetes. Some children with a severe illness (e.g., severe dehydration from diarrhea or asthma treated with corticosteroids) may have elevated serum glucose and ketosis. If the diagnosis is uncertain, a low serum insulin level along with hyperglycemia supports the diagnosis of DM and excludes all other diagnoses. Elevated glycosylated hemoglobin provides a strong circumstantial case for the diagnosis of DM, but it is not used alone for the diagnosis. Performing a glucose tolerance test is rarely necessary. However, it is imperative to obtain insulin levels along with the blood glucose values when it is performed.
B. Type 2 diabetes. The American Diabetes Association (ADA) diagnostic criteria for type 2 DM are either (a) symptoms of diabetes and a casual plasma glucose level of 200 mg/dl or greater, (b) a fasting plasma glucose level of 126 mg/dl or greater, or (c) a plasma glucose level of 200 mg/dl or greater 2 hours after an oral glucose load (75 g). A “casual” plasma blood glucose level is obtained at any time of the day without regard to the time of the last meal, and a “fasting” level is obtained after a fast of at least 8 hours. If the only criterion is hyperglycemia, confirmation should be made on a different day (1).
Diagnostic assessment
The presence of polyuria, polydipsia, polyphagia, and weight loss along with hyperglycemia and ketosis are sufficient to establish the diagnosis of type 1 DM. This provides an ample basis for beginning insulin therapy. Hyperglycemia can also occur during a severe illness. Therefore, the diagnosis of type 1 DM is not always clear. Low insulin levels may be needed to make the diagnosis. The key to the diagnosis of type 2 DM is the detection of hyperglycemia. Patients with symptoms of diabetes should have testing according to the ADA recommendations. Once the diagnosis is made, formulate a treatment program with the patient.
References
1. American Diabetes Association. Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Diabetes Care 1997;20:1183–1197.
2. National Diabetes Data Group. Diabetes in America, 2nd ed. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases, 1995. NIH publication 1468-1995.
3. Baker JR. Autoimmune endocrine disease. JAMA 1997;278:1931–1937.
Book Source Details
- Book Title: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter
- Author(s): Robert B. Taylor (editor)
- Year of Publication: 2000
- Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2000 Lippincott Williams & Wilkins.
Other Book Chapters Related to Diabetes-like symptoms
Read excerpts from these other book chapters related to Diabetes-like symptoms:
Medical Books Excerpts
- GLYCOSURIA
- "Algorithmic Diagnosis of Symptoms and Signs" (2003)
- [ read ]
- POLYDIPSIA
- "Algorithmic Diagnosis of Symptoms and Signs" (2003)
- [ read ]
- Polydipsia
- "Handbook of Signs & Symptoms (Third Edition)" (2006)
- [ read ]
- Polydipsia
- "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
- [ read ]
- Polydipsia
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
- Diabetes Mellitus
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
- Polydipsia
- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
- [ read ]
Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2008 Williams & Wilkins.
More About Causes of Diabetes-like symptoms
» Next page: Diabetic complications during pregnancy (Handbook of Diseases)
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