Neuropathy usually refers to the disorders associated with the peripheral nervous system. Although there are several causes leading to neuropathy, diabetes seems to be the most influential as well as most prevalent.
As you know, diabetes is a chronic disease process, which still can only be prevented. Due to the fact that, diabetic neuropathy can progress slowly and undetected, its occurrence is almost inevitable in persons who are suffering from long standing and poorly controlled diabetes mellitus.
Based on several factors such as metabolism, susceptibility and blood supply, researchers have produced several theories which can co-exist in answering the question ‘what causes diabetic neuropathy?’.
Following are some of these theories leading to neuronal damage.
1. Microvascular damage
Each nerve, whether small or large will require a blood supply to maintain its need for oxygen as well as nutrients. It’s been found that the increased blood sugar levels will promote thickening of the vascular walls and thereby impair the flow of blood towards the nerves thus depriving the nerve of its source of oxygen and nutrients. If these supplies are impaired, it’s possible for certain sections of the nerve to suffer damage, especially ischemic neuronal damage.
It should be remembered that micro vascular damage will occur elsewhere in the body as well.
2. Impairment of cellular proteins
High blood sugar levels will promote glycosylation of cellular proteins and alter their structure as well as function. This impairment is true for the nerves as well.
3. Increased levels of sorbitol
Sorbitol is a product of a specific metabolic pathway known as ‘aldose reductase pathway’ and will be hyper stimulated at high blood sugar levels. The accumulated sorbitol will itself create a concentration gradient between the cell and the extra cellular fluid and thus shift fluid within the cell to outside. This will inevitably damage the cell and most likely to occur within nerve cells as well.
Apart from the increased levels of sorbitol, it further gives rise to the production of oxygen free radicals. These radicals would be able to harm the nerve and its conduction velocity thus generating diabetic related neuropathy.
4. Protein kinase C pathway
Protein kinase C seems to be constricting the blood vessels supplying towards the nerves and thus depriving the nerve with nutrients and oxygen as seen in microvascular damage. The activation of this protein is by the build up of diacylglycerol following increased amounts of blood glucose levels.
As you can see, many complicated mechanisms can give rise to diabetic neuropathy and thus lead to a potentially serious statistics which goes on to say that almost 60 – 70 % of all diabetics has some sort of diabetic neuropathy. Therefore, knowing what causes diabetic neuropathy will facilitate both patients as well as health professionals to approach the problem with understanding.