Diabetes mellitus is a metabolic disorder in which the basic defect is an absolute or relative lack of insulin, resulting in impairment of carbohydrate, fat and protein metabolism.

• Primary diabetes mellitus is typically classified according to the following types:

  • Type 1 termed insulin-dependent diabetes mellitus (IDDM) is characterized by an absolute insulin deficiency, and a high disposition toward ketosis since the pancreas produces little or no insulin. The condition is most often diagnosed in childhood or adolescence, and thus labeled as juvenile IDDM.

  • Type 2 termed non-insulin-dependent diabetes mellitus (NIDDM) is characterized by partial or relative insulin deficiency, resistance to ketosis and, in most patients, resistance to insulin at target tissues. The condition usually occurs in older, obese patients. However, it can be seen in youth, and is referred to as maturity-onset diabetes of youth (MODY).

• Secondary diabetes mellitus can develop as result of destructive lesions or surgical removal of the pancreas, hypersecretion of hormones that antagonize the effect of insulin or interfere with its secretion. Features common to virtually all forms of endocrine-associated diabetes mellitus is reversibility with correction of the underlying disorder, and absence of ketosis. Examples of secondary forms of diabetes mellitus are seen in the following conditions:

  • Surgical removal of more than two-thirds of the pancreas

  • Chronic relapsing pancreatitis

  • Hemachromatosis

  • Cushing's syndrome (see Diagnostic Code: 7907 Cushing's Syndrome)

  • Pheochromocytoma (see Diagnostic Code: 7918 Pheochromacytoma)

  • Primary aldosteronism (see Diagnostic Code: 7917 Hyperaldosteronism)

  • Glucagonoma and somatostatinoma

  • Isolated growth hormone deficiency

  • Multiple autoimmune endocrine deficiency syndromes e.g., Addison's disease (see Diagnostic Code: 7911 Addison's Disease), Hashimoto's thyroiditis, Graves' disease (see diagnostic code 7900 Hyperthyroidism, including, but not limited to, Graves' disease)

Etiologic factors related to the two types are as follows:

• Type 1 is an autoimmune disorder triggered by a viral infection that stimulates the pancreatic beta cells to produce abnormal cells. This process continues until all the insulin producing beta cells are destroyed. The disorder is thought to be due to a combination of genetic and environmental factors with concordance in twins at about 50%.

• Type 2 is termed non-insulin-dependent diabetes mellitus (NIDDM) and results from: altered insulin secretion in response to glucose, a decreased resistance in which insulin is not effective in stimulating the skeletal muscle to take up glucose, and an increase in liver glucose production. Contributing factors are obesity, use of oral contraceptives, and pregnancy. Genetic susceptibility is strong with twin concordance at almost 100%.

The principal symptoms of the two types are as follows:

• Type 1 includes hyperglycemia, polyuria, polydipsia, weight loss, glycosuria, nausea, fatigue, and various infections and boils. In addition, diabetic ketoacidosis (DKA) can occur as a result of excess ketone bodies in the blood. DKA has a distinguishing fruity breath odor and, if left untreated, coma and death are possible.

• Type 2 includes more subtle symptoms. High glucose levels result in polyuria, polydipsia, blurred vision, itching (pruritis), glycosuria, and increased frequency of recurrent infections (carbuncles, furuncles, urinary tract infections (UTI), monilial vaginitis in women, and balanitis in men).

Two fasting (overnight) plasma glucose levels over 126mg/dl are considered diagnostic according the American Diabetes Association (1999). Urine tests are run for glucose and acetone findings.

Conventional treatment is with diet, exercise, and glucose-lowering agents. Type 1 diabetics must take insulin daily. Type 2 patients may take insulin if glucose levels cannot be maintained, or use oral glucose-lowering agents. The goal is to keep the patient's glucose level below 140 mg/dl. Patient education is a vital component of the treatment plan.

If the patient adheres strictly to prescribed therapy, management, and proper treatment, then a near normal life expectancy can be expected. However, there are many potential complications of diabetes mellitus related to the following body areas:

• Eyes presenting with retinopathy, glaucoma, and blindness (0.2%), more so in non-insulin-dependent diabetes mellitus (NIDDM).

• Renal presenting with nephropathy.

• Vascular presenting with atherosclerosis leading to symptomatic coronary artery disease, claudication, and gangrene which commonly occurs due to severe peripheral vascular disease. Amputation of the lower limbs may be an end result.

• Neurological representing a loss of sensory feeling in the peripheral nerves leading to possible injury due to absence of pain sensation. Neuropathy of the autonomic nervous system can produce impotence, postural hypotension, and dysfunctional bladder.

• Consider service connection on a presumptive basis as a chronic condition (38 CFR§3.307; §3.309 (a)).

• Consider service connection on a presumptive basis as a condition associated with herbicide exposure (38 CFR §3.307 (a) (6); §3.307 (d); §3.309 (e)).

• If there is an amputation or blindness as a result of diabetes, consider additional entitlement under 38 CFR 3.350 [Special monthly compensation] 

• Evaluate compensable complications of diabetes separately unless they are part of the criteria used to support a 100-percent evaluation. Noncompensable complications are considered part of the diabetic process under DC 7913.

• When diabetes mellitus has been conclusively diagnosed, do not request a glucose tolerance test solely for rating purposes.