Complications Of Diabetes
Diabetic Nephropathy
This type of kidney damage is due to small blood vessel disease from uncontrolled diabetes, which leads to decreased kidney function. Diabetic nephropathy develops when the hemoglobin A1C level has been more than 7% for a number of years. When diabetes control has been poor, irreparable kidney damage is caused in the filtration units, called glomeruli. Eventually this will result in the need for kidney dialysis or a kidney transplant. On the other hand tight diabetes control with a hemoglobin A1C of less than 7% will usually prevent this from happening. Also, the ACE inhibitor drugs captopril (brand name: Capoten) and enalapril (brand name: Vasotec) can be used to repair some of the glomeruli micro-damage to a large extend and also help reduce high blood pressure.
Diabetic Retinopathy
The eye damage from uncontrolled diabetes is called diabetic retinopathy. The retina of the eyes is another area where changes to the blood vessels are immediately detectable. The eye-specialist can see changes in the blood vessels long before they lead to complications such as swelling of the retina (= macular edema), proliferative changes, retinal detachment or retinal hemorrhage. Diabetic retinopathy from uncontrolled diabetes is one of the many causes of blindness. Again, it cannot be emphasized enough how important it is to control the blood sugars tightly with hemoglobin A1C values of less than 7%, as blindness from diabetes is preventable.
Diabetic Neuropathy
Nerve damage from diabetes is called diabetic neuropathy. When the small nutritional arteries that supply the nerves in the body with nutrients, get damaged from arteriosclerotic disease due to uncontrolled diabetes, neuropathy damage is noted in various parts of the nervous system:
- polyneuropathy: when sensory nerves are affected there is often a glove stocking distribution of loss of feeling in both hands and both feet. This can lead to such things as unexpected burns or pressure ulcers, because the patient did not feel a pebble in the shoe. However, when the diabetic foot ulcer is being treated, it becomes often apparent that there is poor foot circulation because of severe occlusive arterial disease beyond repair and a foot amputation may have to be considered. Another manifestation of polyneuropathy may be shooting pains or severe deep seated gnawing pains in an affected extremity.
- mononeuropathy: this is an acute, painful condition where the blood supply to a nerve is suddenly interrupted due to a nerve infarction. This happens more often one of the 12 cranial nerves
in the head area and in the femoral nerve of the leg.
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autonomic neuropathy: the autonomic nervous system (the sympathetic and parasympathetic nerve fibers throughout the body) is very sensitive to elevated blood sugars from diabetes and damage to it is called autonomic neuropathy. When the autonomic nervous system is affected by a neuropathy, then a variety of body functions such as the heart rate and digestive system function, which normally are automatically regulated, are in disarray.
The complaints span from impotence in males to sudden low blood pressure with dizziness on standing up, to delayed emptying of the stomach and bladder dysfunction. Bowel activity can be changed with development of diarrhea or change to constipation. Nocturnal diarrhea can be very frustrating and interfere with a normal sleeping pattern. The cardiovascular system can also be affected.
Vascular Complications
Diabetes also affects the blood vessels. As already discussed small blood vessels are damaged by poor control of blood sugars. But the larger blood vessels are also affected by diabetes and a severe acceleration of arteriosclerosis occurs in diabetics who do not control their blood sugars. Doctors call this"macrovascular disease".
This leads to circulation problems in the brain (strokes) and in the heart (heart attacks, serious arrhythmias and congestive heart failure). Unfortunately serious circulation problems result from this usually in the lower extremities, where circulation normally is not as good as in the upper extremities due to gravity (Ref. 7). The worst combination of circumstances exists in a person who is a heavy smoker and who also had uncontrolled diabetes for a number of years. Such a person has a high probability of developing Buerger's disease (narrowing of the smaller and midsize arteries of both legs from smoking) and superimposed severe arteriosclerosis of the larger vessels in both legs as well due to the uncontrolled diabetes. Frequently this leads to amputations of a part or of the whole lower extremity on one or both sides.
Treatment Of Diabetic Neuropathy
Apart from tight control of the hemoglobin A1C level with a combination of diet change, increase in exercise and oral diabetic medications and/or insulintherapy the pain can be directly treated with gabapentin (brand name: Neurontin). This medication, which was approved by the FDA in the early 1990's for resistant partial epilepsy, has also been found useful for chronic pain issues such as neuropathic pain following trauma, shingles pain and diabetic neuropathy pain.
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The advantage of this medication is that it is not metabolized by the liver and that it is mostly excreted by the kidneys. This way there is no drug interaction with other drugs and the side effect profile is very safe. More than 90% of patients tolerate this medication at high doses like 3600 mg per day. Usually the medication is started low at 300 to 600 mg per day and slowly increased (titrated) with regard to the response in treating the pain symptoms, if tolerated. It can be combined with low doses of anti-depressants, which often allows the physician to reduce both the Neurontin and the anti-depressant doses and still treat the pain effectively. Side effects include tiredness (15%) and dizziness (11%). Even very high doses taken with suicidal intentions did not lead to deaths making it one of the safest drugs. Dr. Stephen Clarke, Clinical Assistant Professor in the Div. of Neurology of the University of BC/Vancouver/Canada, reviewed the use of gabapentin at a conference in Vancouver/BC (Ref. 10). He said that it is a "widely loved drug" because of the perceived safety and tolerability. The mechanism of action, he summed up, is an increase of the relaxing brain hormone, called gamma amino butyric acid (=GABA neurotransmitter), in some brain regions. It also inhibits N-methyl-D-aspartate (the NMDA receptor) and calcium channel blockers in the brain, the spinal cord and in nerves in the body. The NMDA receptor is important in perception of pain and transmitting pain through the spinal cord pathways. Neurontin inhibits the transmission of these pain stimuli and dampens pain perception. This is called a "pain modulating" effect. It takes only 38 patients to treat to get a 50% decrease of the pain score in 10 patients, in other words the "number needed to treat" (or NNT) is only 3.8, which in the evidence based literature is considered a good drug. Ask your physician about more details.
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