Long-standing diabetes mellitus is associated with an increased prevalence of microvascular and macrovascular diseases. With the rising prevalence of diabetes, the number suffering from the vascular complications of diabetes will also increase.
In 1999 a study conducted by Dr.A.Ramachandan1 showed a prevalence of 23.7% of Retinopathy, 5.5% of Nephropathy and 27.5 % of Peri-neuropathy. The recent prevalence of microvascular complication was 16.6% of Retinopathy, 21.1% of Nephropathy and 5.1% of patients have foot ulcer.2
The specific eye complication seen in diabetes is called Diabetic Retinopathy, which affects the retina. Approximately 50% of patients with diabetes will develop some degree of diabetic retinopathy after 10 years of diabetes, and 80% of diabetics have retinopathy after 15 years of the disease. Retina is the nervous sheet at the back of the eyes which is sensitive to the light and carries the images of the objective to the brain. Diabetic Retinopathy is characterized by micro dilatation of arteries, white deposits, bleeding, formation of new blood vessels and finally vitreous hemorrhage and retinal detachment. The early stage is called “non-proliferative diabetic retinopathy, which can easily be arrested by proper control of diabetes and other risk factors. This is asymptomatic and the patient is usually not aware of the condition. This can be detected by a proper examination after full dilatation. Therefore, regular checkup of the eyes at periodic intervals is absolutely mandatory for people with diabetes.
When hard exudates occur in the center of the retina, there will be a marked reduction in the vision and this is called diabetic maculopathy and if not treated properly can produce severe loss of vision. Once new blood vessels are formed the condition is called proliferative diabetic retinopathy and can produce severe bleeding resulting in severe visual loss. In these cases retinal photocoagulation with laser treatment is necessary to arrest the progress of the disease.
It is important to remember that once sever damage to retina has already occurred, there is no treatment for restoration of vision. But visual loss can be prevented by early diagnosis and treatment. This reiterates the importance of regular eye examination in people with diabetes.
The good news is that proper control of blood sugar and blood pressure can go a long way in preventing retinopathy as well as in arresting the progress of early changes.
Diabetes affects kidneys and diabetic nephropathy is one of the important specific complications of diabetes. It is estimated that 30-50% of individuals with kidney failure are diabetics.
Uncontrolled blood glucose for a long period of time produces functional and later structural changes in the kidney. The unfortunate truth is that changes occurring in kidneys are not clinically obvious to the treating doctor. Neither the patient feels any symptoms until the kidney is severely affected and the disease have reached an irreversible stage.
Diabetic Nephropathy(DN) is one of the dreaded complications of diabetes mellitus and can cause severe morbidity to the patient and heavy financial burden to the family, if it is not prevented or detected and properly treated in the early stage of the disease.
Routine laboratory tests to assess renal functions are urine analysis, blood urea and serum creatinine estimations. The results are generally abnormal only till nearly 60 percent or more of normal kidney functions are affected by DN. To detect and prevent DN, test for microalbuminuria is necessary. In normal individuals albumin excretion is less than 30mg in 24 hours and this is called normoalbuminuria. Albumin excretion of more than 30mg/24 hour and less than 300 mg/24 hours is called microalbuminuria. Microalbuminuria cannot be detected by the usual dipstick method and has to be classified by a special test. Based on albuminuria, DN classified as incipient or silent DN, early overt DN, advanced DN and end stage renal disease.
Risk factors for DN include duration of diabetes, poor blood glucose control, hypertension, genetic predisposition and smoking.
Screening for DN is necessary in all diabetic patients. In type 1 diabetes mellitus, DN occurs nearly after 5 years of onset of diabetes. In type 2 diabetes, DN may be present at diagnosis as type 2 diabetes mellitus may remain without symptoms for a number of years. So screening for DN is essential in the long term management of diabetes.
Almost 50% of people with diabetes would be affected with some form of neuropathy. The most common neuropathy is the dysfunction of the nerves of the legs resulting in lack of sensation, numbness, pricking pain, tingling sensation and sometimes lacerating unbearable pain.
People with lack of sensation must be careful to avoid injuries and also take prompt treatment of wound infections. Walking over hot sand or pavement in summer without proper footwear or barefoot (especially in temples) could be detrimental producing thermal injury due to lack of temperature sensation.
Diabetes can also affect muscle power and produce weakness of muscle, either in the limbs or in the girdles. Fortunately muscle weakness due to diabetic neuropathy is largely reversible. Painful diabetic neuropathy is largely reversible. Painful diabetic neuropathy is less common but could be very disturbing and in some patients can cause severe pain in the feet especially in the night.
The pain in diabetic neuropathy some times may be devastating and patients get severely depressed. This will even lead to suicidal tendencies among some and treatment with antidepressants become necessary in such cases.
Another form of diabetic neuropathy is the involvement of the cranial nerves. The commonest is paralysis of the nerves responsible for eye movements and the clinical presentation is usually double vision. This type of neuropathy can affect the face resulting in facial palsy or Bell’s palsy. These types of diabetic cranial neuropathies recover completely.
All the above discussed nerve dysfunction are related to the systemic nerves but diabetes can also affect the autonomic nervous system supplying the muscles of the heart, gut, bladder and genitalia. The most disturbing symptom especially in men is called erectile dysfunction producing sexual incompetence in them. There are very effective treatments for these conditions.
The symptoms of neuropathy can be treated and will subside by good control of blood glucose and by using other therapeutic agents. The good news of course is that proper control of diabetes will help to delay or prevent the onset of neurological complications of diabetes.
- Ramachandran A, Snehalatha C, Satyavani K, Latha E, Sasikala R, Vijay V. Prevalence of vascular complications and their risk factors in type 2 diabetes. J Assoc Phy India 1999;47:1152-1156.
- Viswanathan Mohan, Siddharth Shah, Banshi Saboo; Current Glycemic Status and Diabetes Related Complications Among Type 2 Diabetes Patients in India: Data from the A1 chieve Study; SUPPLEMENT TO JAPI; january 2013; VOL. 61; 12-14.