Peripheral nerve dysfunction in scleroderma.
Peripheral neuropathy in patients with scleroderma is thought to be rare. We have undertaken a quantitative assessment of peripheral nerve function in 29 patients with either limited cutaneous scleroderma or progressive systemic sclerosis. Tactile thresholds were raised in the fingers in 28 per cent of patients and in the foot in 50 per cent. Two-point discrimination was abnormal in 10 patients, thermal thresholds were abnormal in five and vibration thresholds were abnormal in one. Nerve conduction studies showed abnormalities in six patients, five of whom had clinical signs of a mild peripheral neuropathy: the mean duration of disease in these six patients was 10 years longer than that in the remainder of the patients. There was electrophysiological evidence of a subclinical carpal tunnel syndrome in two patients. The sympathetic skin response was recorded in 16 patients who had not been subjected to sympathectomy for Raynaud's phenomenon, and was abnormal in four. These results indicate that peripheral nerve dysfunction in scleroderma, though mild, is not as uncommon as previously thought. The abnormal cutaneous sensory thresholds may be partly due to altered viscoelastic properties of the skin, but abnormal responses in the lower limbs to tests of tactile sensitivity, the clinical findings and the disturbances of nerve conduction argue in favour of an additional neuropathic process in some patients. Low grade distal nerve trunk ischaemia may be responsible.