|
Page 6 of 12
Chronic diabetic complications:
All the chronic diabetic complications develop faster in the elderly with poor glycemic control. A reduced insulin secretion is associated with a longer duration of diabetes and a greater prevalence of microvascular complications, while higher insulin levels are associated with the components of the metabolic syndrome.
Ocular Complications:
Frequent complications include diabetic retinopathy, cataracts, and glaucoma. As most of the elder persons have cataracts, the assessment of diabetic retinopathy also becomes difficult. The prevalence of retinopathy tends to rise with age, with more than 25% of patients over 75 years presenting with retinopathy. Retinopathy, however, has not been correlated with age per se but with the duration of diabetes.
Neuropathy:
Neuropathy is the most common symptomatic chronic complication in diabetic patients and accounts for substantial morbidity in the elderly diabetic population. It is predominantly a disease of the older diabetic population, and shows a progressive course with limb amputation due to trophic ulceration as the final end-point of the disease.
The mechanisms underlying the development of diabetic neuropathy involve hyperglycemia induced metabolic abnormalities involving polyol pathway of peripheral nerve fibers and the supporting nutritive vascular supply. Since clinical diagnosis is often difficult due to age related changes in the peripheral and autonomic nervous system, diagnosis is based on nerve conduction studies, and autonomic function tests. Absence of ankle jerk may not be a good indicator of the presence of neuropathy in the elderly as it is absent in many non-diabetic elderly also.
Complications related to neuropathy are also common in the elderly diabetics. Falls are more frequent as a result of muscle weakness due to neuropathy and postural hypotension due to autonomic neuropathy. In symptomatic neuropathic patients, including those with painful neuropathy, symptomatic and palliative measures are often effective. Stepwise addition of antidepressants to simple analgesics has proven to be effective in patients with troublesome pain. However, the side effects caused by tricyclic antidepressants like sedation leading to falls, urinary retention in BPH, confusion and delirium must be carefully monitored for in the elderly. Other metabolic approaches like anti-oxidants and gamma-linolenic acid appear promising. During recent years a class of drugs has been developed that inhibits the activation of the polyol pathway in diabetic nerves. These so-called aldose reductase inhibitors hold promise for a targeted treatment regimen in the near future.
Bladder dysfunction as a result of autonomic neuropathy is quite common and has to be differentiated from benign prostatic hyperplasia in males. Both these conditions are responsible for the increased incidence of urinary tract infections in the elderly diabetics.
Nephropathy:
Advancing age and gradually falling creatinine clearance with contribution from co-existing hypertension and atherosclerosis lead to a high prevalence of nephropathy in the elderly diabetics. ACE inhibitors may be started at the stage of microalbuminuria to prevent progression to overt nephropathy. Improved metabolic control with diet and drugs has been demonstrated to reduce urinary protein excretion.
Coronary Heart Disease (CHD):
Patients with type-2 diabetes have a 2- to 4-fold risk of developing cardiovascular disease. CHD is one of the major causes of death in elderly diabetics. In a study at Hospital Universiti Kebangsaan Malaysia, it was found that 45% of all elderly patients who underwent CABG had diabetes. In the presence of dyslipidemia, obesity and hypertension, elderly diabetics exhibit a dramatic acceleration of atherosclerosis, with resulting CHD (Syndrome X). Hyperinsulinaemia is also an important risk factor for CHD. The presentation of CHD in these subjects is also atypical. They may have asymptomatic CHD that ends in painless myocardial infarction (MI) and acute left ventricular failure or sudden cardiac death. As a rule, every elderly diabetic presenting with acute onset of breathlessness must have an ECG done to rule out MI, even in the absence of chest pain. Furthermore, chronic breathlessness and loss of cardiac reserve may manifest in the elderly diabetic due to diabetic cardiomyopathy. Angina equivalents such as dyspnea and tiredness on exertion may replace classical anginal pain due to advanced autonomic neuropathy.
Long-term instability of fasting plasma glucose has been found to be a novel predictor of cardiovascular mortality in elderly diabetics.
Infectious Complications:
Older diabetic patients often fail to mount a fever in response to infections, thereby delaying the recognition of serious infections. They are also at a high risk of developing tuberculosis. The presentation of tuberculosis may also be atypical with lower lobe tuberculosis or fulminant tubercular pneumonia, especially in high prevalence areas like our country. Infections are common in diabetics due to hyperglycemia and reduced leukocyte function with impaired chemotaxis, which is more pronounced in the elderly. As mentioned earlier, UTI is quite common. Other common infections include necrotizing fasciitis, candidiasis and malignant external otitis media. Astute recognition and appropriate treatment is essential.
|
