1. Can the initial appearance of retinal microangiopathy at its diagnosis be attributed to diabetes?
Upon the diagnosis of type II diabetes, the estimated duration of abnormal glucose levels consistent with the diagnosis of diabetes (fasting plasma glucose over 140 mg/dl, or 2 hours GTT values of 200 mg/dl or higher), precede the diagnosis by an average of 7 years.
Consequently, retinal microangiopathy or background retinopathy are present in about 25% of patients on diagnosis.
There is a direct correlation between duration of diabetes and progression of diabetic retinopathy. (Depending on method of assessment of retinopathy, progression is from 3 to 10% a year.)
A
yearly ophthalmologic examination is a standard of care for all patients
with diabetes.
2. What is the most important risk factor that should be treated first?
The patient's fasting glucose and HbA1c, although abnormal, are at levels of near maximum benefit of glucose control.
His serum cholesterol is well below target treatment levels and does not demand separate management.
On the other hand, the patient has hypertension, an important macrovascular risk factor, which is also associated with progression of retinopathy and nephropathy.
Hypertension should be the main
target of treatment at this point.
3. Is treatment of glycemia adequate, or should additional hypoglycemic treatment be postulated?
Although many authorities would consider glycemic control adequate for this patient, there is no reason why, once oral sulfonylureas are initiated, an objective other than normal HbA1c should not be pursued as long as the patient tolerates the medication well without hypoglycemic side effects.
As long as this patient is over the ideal body
weight of 159 pounds (calculated as 105 pounds per 5 feet of height, plus 6
pounds per additional inch), he has an indication for a prescription of an
oral agent that decreases peripheral insulin resistance, decreases appetite,
and does not increase endogenous insulin: Metformin is then an ideal
first-line oral agent, that might or might not have to be combined with
sulfonylurea for optimal glycemic control. Another useful agent is Acarbose,
which slows carbohydrate absorption and improves post-prandial serum glucose
levels.
4. Is management of hypertension in diabetes different from that in non-diabetic patients?
The management of hypertension in diabetic patients is the same as that of non-diabetic patients in terms of non-pharmacological therapy: weight reduction, moderate exercise, restriction of alcohol and salt consumption, elimination of cigarette smoking.
For pharmacological therapy, although diuretics in small doses and beta blockers are also employed when needed, they may cause metabolic deregulation and dyslipidemia.
Furthermore, beta blockers in doses that block beta 2 receptors during hypoglycemia, may cause hypoglycemia unawareness and impairment of glycogen breakdown, which might interfere with correction of hypoglycemia.
Calcium channel blockers and angiotensin converting enzyme inhibitors are generally not associated with adverse metabolic side effects and are often preferred as first-line agents.
Alpha-adrenergic blocking agents will not adversely affect insulin action or lipid metabolism, and do not generally cause sexual dysfunction (Doxazosin, Prazosin).