Diabetic Amyotrophy

Diabetic amyotrophy (diabetic lumbosacral radiculoplexus neuropathy) is an ischaemic, immune mediated neuropathy of the lumbosacral plexus.

• Typically older men with type 2 diabetes (50 to 60 years) and modest control, often with recent weight loss.
• Subacute onset, usually unilateral at first and often bilateral later.
• Pathology: microvasculitis with ischaemic injury of nerve.
• Spontaneous recovery over 12 to 24 months, often incomplete.

• Severe thigh, hip or buttock pain, worse at night.
• Proximal leg weakness (quadriceps, iliopsoas), wasting, absent knee jerk.
• Weight loss of 10 kg or more, cachexia.
• Distal symmetric neuropathy often coexists.

• Electromyography: asymmetric lumbosacral denervation with paraspinal involvement.
• MRI lumbosacral spine and plexus to exclude compression, tumour, psoas abscess.
• CSF protein often raised.
• Exclude CIDP, malignancy, radiculopathy, retroperitoneal haematoma, monoclonal gammopathy.

• Glycaemic optimisation (insulin if needed), avoid rapid swings.
• Pain: duloxetine, pregabalin, amitriptyline, opioids short term.
• Immunotherapy in rapidly progressive, severe disease: methylprednisolone 1 g IV daily for 3 to 5 days then oral prednisolone taper, or IVIG 0.4 g/kg for 5 days; evidence limited.
• Physiotherapy, orthoses, fall prevention.
• Reassure regarding gradual recovery; recurrence is uncommon.