Case of the Month #5: Thoracoabdominal Neuropathic Pain

Published: 16/04/2021

Differential diagnoses and investigations

  • Painful neuropathy related to diabetes mellitus
  • Bilateral postherpetic neuralgia
  • Spinal cord lesion
  • Multiple sclerosis
  • Abdominal cutaneous nerve entrapment syndrome (ACNES)
  • Fibromyalgia

This gentleman reports high blood sugars. A HbA1c would give an index of his diabetic control. On examination it would be helpful to test the truncal muscles to establish if there is any paresis of the muscles leading to weakness or bulging of the abdominal wall. A history of abdominal or thoracic surgery may help identify a reason in some cases.

Bilateral postherpetic neuralgia is rare, especially in a symmetrical area covering such a large area. A history of a rash should be sort. A history of bilateral shingles may be due to immunosuppression and a referral for specialist review should be considered. The incidence of postherpetic neuralgia in those over 60.

The absence of ankle reflexes is most likely due to diabetes. Imaging of the whole spine and brain is essential to exclude pathology. Nerve conduction studies 

The allodynia may be a feature of a more widespread pain presentation. A history exploring sleep, fatigue and other pain symptoms should be sort.

An initial plan was agreed as follows

  • MRI whole spine
  • MRI brain
  • HbA1c
  • Nerve conduction studies
  • Trial of other antineuropathics: gabapentinoids, duloxetine
  • Neurology opinion