In this post lets discuss about diabetic neuropathy. Diabetes is one of the most common causes of neuropathy. Neuropathy is a general term which refers to any condition which involves the nerves of the body. Diabetes involves the peripheral nerves of the body and can also involve the cranial nerves. The damage to the peripheral nerves is thought to be mediated by the increased levels of glucose and other metabolic factors in diabetic patients.
As I have stated in my earlier posts (see by my website http://braindiseases.info) neuropathies can be of different types. One may have a motor neuropathy in which only the motor nerves of the body are involved (hence patients present with weakness), one may have a predominantly sensory neuropathy in which the sensory nerves of the body are involved ( patients present with sensory complaints of numbness, tingling, pins and needles sensation) or one have a mixed sensory motor neuropathy (patients have a combination of motor and sensory findings in varying proportion).
Diabetes usually causes a mixed sensory motor neuropathy.
Clinical presentation: So how do patients with diabetic neuropathy present clinically? Well most patients seek medical help when they are bothered by dysesthesias (dysesthesias refers to uncomfortable sensations like feeling a part of the body usually the feet and hands are numb or “dead”, patients may also complain of feeling pins and needles sensation, tingling, burning etc). Patients with diabetic neuropathy have allodynia ( a condition in which a non-painful stimulus feels painful. Let me explain with an example. Suppose I touch your feet with a feather, you are not going to feel that as a painful stimulus. Now if I do the same to a patient with diabetic neuropathy, he may perceive that as a painful stimulus). They also have hyperpathia ( a condition in which the patient experiences a greatly exaggerated pain sensation to painful stimuli. Let me explain this with an example. I touch the same diabetic patient’s leg with a sharp pin. Now any healthy person shall perceive this as a painful stimuli but to a patient with diabetic neuropathy, the pain may be so intense that it might be unbearable).
We sometimes divide these sensations experienced by patients with neuropathy into positive and negative symptoms.
Postitive symptoms include sensations of burning, pins and needles, pain etc while negative symptoms include sensations of feeling a part is numb or “dead”. It is easier to treat and control the positive symptoms while negative symptoms are more hard to treat.
The neuropathy in diabetes is length dependent (by that I mean, the longest nerves are the first to get involved). Hence symptoms first start in the feet (numbness in the toes etc and then proceed upwards. As the neuropathy progresses patients complain of numbness in the feet, then ankles, then shin, finger tips and so on).
Diagnosis of diabetic neuropathy: so now we come to the question of how do we diagnose diabetic neuropathy. The diagnosis of neuropathy is mostly clinical. If you are a diabetic patient presenting to a neurologist with compliants of numbness and tingling in the hands and feet, the diagnosis is readily apparent. Your doctor may test with with a tuning fork (to dtermine how well you perceive vibration), a disposable pin (pain sensation) and shall be able to determine if you clinically have an evidence of neuropathy or not. If the diagnosis is not apparent, he may order other tests like a Nerve Conduction Velocity test (we call this a NCV). During a NCV study, we check for the conduction of a nerve and whether it is delayed or not (this is done by giving a short electrical stimulus and then recording the response as it travels down the length of the nerve. As we are applying a short electrical current as stimulus, patients at times are not very comfortable during the test. The NCV study also helps in grading the severity of the neuropathy and helps in following the response to treatment.
Management of diabetic neuropathy: the management of diabetic neuropathy is twofold. One is the treatment of the underlying disease process (in this case the diabetes which is the cause of the neuropathy in the first case) and the other is the treatment of the neuropathy itself (how to control its symptoms so patients are not bothered by the sensations of numbness, tingling etc).
First and foremost in the managment of diabetic neuropathy, one should ensure good control of the blood sugar. Studies have shown that neuropathy develops in those diabetics who have uncontrolled or poorly controlled blood sugars. Hence aiming for euglycemia is essential (euglycemia means normal or near normal blood sugars). There are oral medications as well as insulin which can be used to achieve euglycemia and your doctor shall guide you in this. It is also essential to follow the blood sugars on a periodic basis so that one is sure that the blood sugar is well controlled.
There are many medications available to treat neuropathic symptoms. Some anti-depressants and anti-convulsants group of drugs are used for this purpose. The role of complimentary therapies like acupuncture, acupressure is not clearly determined as there are not many scientific studies to determine whether these are truly beneficial.
Patients should be advised about the importance of skin and foot care. Patients with diabetic neuropathy are prone to ulcers and infections in the foot, hence the feet should be kept clean and dry, avoid wearing ill fitting shoes and always always do wear clean pair of socks.
I hope this is useful to some of you.
Nitin Sethi, MD