In order to learn more on the occurrence of pains and motor deficit in severe diabetic polyneuropathy we reviewed the data
of a series of 30 diabetic patients with an uncommonly severe length-dependent diabetic polyneuropathy (LDDP). Extensive sensory
loss predominated with pains and temperature sensations and affected all four limb extremities, anterior trunk in all, plus
the top of the scalp in 9 patients and the
cauda equina territory in 2. Twenty patients had neuropathic pains. Symptomatic autonomic dysfunction was present in 28/30 patients, mild
distal motor deficit in 12 patients, severe in only one. Vibratory sensation was impaired in the lower limbs in 18 patients;
position sense in 8. In the 10 nerve biopsy specimens, the density of myelinated axons was reduced to 23 % and that of unmyelinated
axons to 8.5 % of control values. Regenerating axons accounted for 32.4 ± 19.8 % of the myelinated fibres. On teased fibre
preparations 13.9 % of fibres were undergoing axonal degeneration, while 29.4 % of fibres showed focal abnormalities of the
myelin sheath.
We conclude that distal motor deficit occurs only after major loss of sensory fibres in LDDP; the unmyelinated axons are predominantly
affected; absence of clinical improvement contrasts with the high proportion of regenerating axons; detection of alteration
of pain and temperature sensation in the feet seems the best method for neuropathy screening in diabetic patients.
Key words diabetic polyneuropathy - pains - nerve biopsy - axonal regeneration - neuropathy screening