The Disability Handbook on Peripheral Neuropathy
Peripheral Neuropathy of Diabetes Mellitus
15.5.1 The term peripheral neuropathy refers to damage to a nerve or nerves outside the brain and spinal cord. There are a wide variety of causes leading to variable degrees of loss of power and sensation in the area(s) of the body supplied by the damaged nerve(s).
15.5.2 Peripheral neuropathies can be divided into two broad categories depending on the distribution of involvement. The first group comprises damage to single peripheral nerves. Their effects alone are not likely to give rise to significant care or mobility needs. Secondly, there may be a diffuse and symmetrical disturbance of function due to the involvement of several nerves which can be called polyneuropathy (poly=many). In general, this results from causes that act diffusely, such as metabolic disturbances (ie. diabetes mellitus), toxins (poisons), deficiencies of certain vitamins etc. There are also hereditary polyneuropathies such as peroneal muscular atrophy. Because their effects are more widespread, polyneuropathies can cause significantly more disability and so the question of care and mobility needs is more likely to arise.
15.5.3 There are two polyneuropathies seen commonly. These are Guillain-Barre syndrome and the peripheral neuropathy that complicates diabetes mellitus. These are dealt with here.
15.6 Guillain-Barre Syndrome
15.6.1 Introduction
(i) This is an important form of peripheral neuropathy that affects many peripheral nerves simultaneously. It usually develops suddenly. Often there is a history of a flu-like illness in the weeks before the onset of the neuropathy. Most cases recover satisfactorily within a few weeks or months. Very rarely it may lead to rapid and profound disability. Although the vast majority of people with this condition recover completely, a small percentage are left with a widely variable degree of permanent paralysis.
(ii) The condition usually affects the nerves that control muscles, causing muscle weakness. The distribution and severity of the weakness is variable and gives rise to differing types of disability. For example, if the nerves supplying the muscles of the hands are affected a person will have problems with activities needing good manual dexterity. On the other hand, a person in whom the nerves supplying the muscles of the trunk and legs are affected will have difficulty getting up from a chair and getting about and is therefore likely to need considerably more help in day to day activities. In the rare severe case the respiratory muscles are affected and the person may well need mechanical support for breathing for some time while the nerves recover.
15.6.2. Care Needs and Mobility Considerations
(i) In most cases complete or almost complete recovery will occur quickly and any care or mobility needs are unlikely to occur for more than a few weeks or months. In those cases where there is persisting weakness, the degree of disability is very variable indeed. This may range from some help being needed for a few minutes morning and evening when dressing to, very rarely, severe disability not unlike that of a person with paraplegia or tetraplegia. [Chapter 18]. As the intellect is not affected in cases of peripheral neuropathy, it is unlikely that there will be a need for supervision.
(ii) As with care needs, mobility problems will be very variable. The majority will need no help of significance but a few will have great difficulty walking for some several months or more after the onset of the condition.
15.6.3 Duration of Need
As most cases recover quickly it is unlikely that significant disability will persist for more than six months. However, in the small number of cases where it is clear that severe disability is persisting it is possible that a degree of further recovery may occur in a year or so. The chance of further recovery is then remote.
15.6.4 Further Evidence
Most people with severe Guillain Barre syndrome will have been seen at hospital where the diagnosis should have been made. A factual report from the hospital will help to establish the severity of the original illness and the likely duration of disability if this is not clear. If there has not been a hospital admission this may raise doubt about the exact diagnosis and an EMP report should be helpful.
15.7 Peripheral Neuropathy of Diabetes Mellitus
15.7.1 Introduction
(i) About 15% of people with diabetes develop a significant degree of peripheral neuropathy. This is usually a symmetrical sensory polyneuropathy which can have important consequences since the loss of sensation leads to injury and the diabetes causes problems with healing. Commonly, the sensory neuropathy is mild, giving rise to numbness and tingling in the toes and feet and, less commonly, in the fingers. This does not normally give rise to significant problems. More rarely a severe sensory neuropathy develops which is associated with the loss of pain sense. Damage to the joints of the toes and the ankles can occur, leading to degeneration of these joints. Minor injuries go unnoticed and because of poor healing small cuts can develop into large ulcers which become infected. In many cases the situation is complicated by peripheral vascular disease and often the only successful treatment is amputation of the foot or even the leg.
15.7.2 Care Needs and Mobility Considerations
With the mild degree of sensory impairment usually seen there should be no significant increase in care and mobility needs on account of the neuropathy. With the more severe form there will be obvious problems with mobility and, depending on the age and capabilities of the individual, there may also be care needs. If there are significant needs these are likely to be permanent.
15.7.3 Further Evidence
The degree of disability caused by the neuropathy should be fairly clear. If it is not, a factual report from the doctor taking care of the person (GP or hospital doctor) should provide the additional information needed.