diabetic amyotrophy/lumbar polyradiculopathy; diabetic lumbosacral radiculoplexus neuropathy (DLRPN)

Etiology

• diabetes mellitus
• may follow a period of weight loss due to illness

Pathology

• subacute lumbosacral plexopathy
• involvement of L2, L3, L4 nerve roots
• primarily affects muscles of the thigh
• inflammation suggested by nerve & muscle biopsy
  • immune complex & complement deposition
  • vasculitis
  • neutrophil infiltration

Clinical manifestations

• severe thigh pain is usual presentation
• proximal muscle weakness & numbness develop over weeks to months
• may be bilateral with symptoms in contralateral leg occuring days to months to years later
• with or without proximal sensory loss
• no involvement of the upper extremities
• no diffuse areflexia
• symptoms stabilize (but may persist) after 6 months
• recovery in 6 months to 2 years

Diagnostic procedures

• electromyography after a period of 3 weeks
  • may reveal denervation & axonal loss
• nerve conduction studies
  • no diffuse motor nerve abnormalities

Radiology

• MRI of lumbar spine to rule out cauda equina syndrome
• CT of abdomen to rule out retroperitoneal hematoma

Differential diagnosis

• chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)
• Guillain-Barre syndrome
• statin myopathy

Management

• intravenous immune globulin may be of benefit
• prednisone may be of benefit
• plasma exchange may be of benefit

More general terms

• lumbosacral radiculoplexus neuropathy
• neurogenic muscle atrophy; denervation atrophy
• diabetic neuropathy

More specific terms

• painless diabetic motor neuropathy

Additional terms

• diabetic polyneuropathy