Chronic painful neuropathy
Chronic painful neuropathy can occur with other forms of neuropathy. It is therefore important to be thorough in the diagnosis and assessment of this condition.
A comprehensive patient history is required to identify risk factors for the neuropathy and any other potential aetiological factors (Boulton et al, 1998).
Assessment
The patient presenting with chronic painful neuropathy will often complain of two outstanding symptoms, namely pain and paraesthesias. The pain may vary from dull or aching to cramp-like, burning, lancinating, or crushing, and usually has a root type of distribution (Ellenberg, 1976). There is often an exacerbation of pain at night, which may be relieved by pacing the floor. This finding aids the differentiation from peripheral vascular disease (where pain may be relieved by standing or taking a few steps only). There may be absent sensation to several modalities and reduced or absent reflexes (Boulton et al, 1998).
Management
The management of this condition is best described in the Guidelines for the Diagnosis and Outpatient Management of Diabetic Peripheral Neuropathy (Boulton et al, 1998). The fundamental management involves the maintenance of optimal glycaemic control and the use of tricyclic drugs (e.g. imipramine) for the chronic pain (low dose at night, increasing as necessary).
Acute painful neuropathy
Acute painful neuropathy can occur with other forms of neuropathy. It is important to refer all patients with painful neuro pathy to the consultant diabetologist or neurologist with an interest in diabetes.
Assessment
The patient presenting with acute painful neuropathy may have similar symptoms to the patient with the chronic type. The neuropathy is characterised by pain produced by innocuous skin stimulation, e.g. with a cotton wisp (allodynia). Patients with allodynia may find light touch, clothing and wind very painful (Foster et al, 1994). Patients may suffer these symptoms following insulin therapy following poorly controlled diabetes.
Management
Refer to the Guidelines document (Boulton et al, 1998). The pain may be treated with simple analgesic drugs, progressing to NSAIDs or tricyclic drugs. Patients suffering from allodynia may find relief with the use of the topical analgesic, Axsain (capsaicin 0.075%; Elan Pharma). The use of Opsite film (Smith and Nephew) has also been reported as having beneficial effects (Foster et al, 1994).
Conclusion
It is important to recognise these painful forms of neuropathy and refer affected patients to the diabetologist or neurologist accordingly. Many of the patients may be depressed, and could benefit from additional counselling. They will require assurance that the painful neuropathy may disappear within 3 months or so. Unfortunately, in some cases, the symptoms may take up to and beyond one year to subside. The patients will, however, benefit from maintaining optimal glycaemic control, where possible. It is also very important to emphasize the importance of footcare education for the patients who have peripheral neuropathy and to utilise the most appropriate teaching and learning strategies, which are well described in the literature (Rettig et al, 1986; Bloomgarden et al, 1987; Malone et al, 1989). This may help to prevent the onset of foot ulceration and thus remove the threat of amputation.
