This condition is uncommon in childhood and increases with age.
Peripheral nerve damage is related to poor control of diabetes. This is more common in insulin-dependent patients. Damage results from either metabolic disturbance with sorbitol and fructose accumulation in axons and Schwann cells or an occlusion of the nutrient vessels supplying nerves (vasa vasorum). The frequent occurrence of neuropathy with other vascular complications - retinopathy and nephropathy - suggests that the latter is the more usual mechanism. Neurological complications correlate with levels of glycosylated haemoglobin A1C, an indicator of the long-term control of hyperglycaemia.
Polyneuropa thy /
Present in 30% of all diabetics, but only 10% are symptomatic. Distal weakness and sensory loss is usual. Two forms of sensory neuropathy occur - large fibre, causing ataxia and small fibre causing a painful anaesthesia.
Autonomic neuropathy In most patients with peripheral neuropathy, some degree of autonomic disturbance is present. Occasionally this predominates:
- pupil abnormalities
- loss of sweating
- orthostatic hypotension
- resting tachycardia.
- gastroparesis and diarrhoea
- hypotonic dilated bladder
Diabetic amyotrophy -Much less common than polyneuropathy. Pain and weakness rapidly develop. The anterior thigh is preferentially affected with wasting of the quadriceps, loss of the knee jerk and minimal sensory loss. The condition is due to anterior spinal root or plexus disease. Imaging the lumbar roots and plexus excludes other causes. Functional recovery is good.
Cranial nerve palsy
An oculomotor palsy, usually without pain, may occur with pupillary sparing, which helps to differentiate from an aneurysmal cause. The 6th and 7th cranial nerves may also be involved in diabetes. Complete recovery is the rule.
Improved control of diabetes is essential.
Carbamazepine, antidepressants or x-adrenergic blockers, e.g. phenoxybenzene, help control pain.
Drugs which reduce aldose reductase and halt accumulation of sorbitol and fructose in nerves are being evaluated.
Management of autonomic neuropathy - see page 444.
Asymmetrical neuropathies usually spontaneously recover, whereas prognosis for symmetric neuropathies is less certain.
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Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...