Isolated Ulnar Neuropathy After Acute Angioedema.

Area of Science:

• Neurology
• Allergology
• Musculoskeletal Medicine

Background:

• Ulnar neuropathy, characterized by hand paresthesia, typically results from mechanical compression or repetitive movements.
• While rare, ulnar nerve injury from rapid compression without trauma has been documented.
• The association between angioedema and neuropathy is sparsely reported, with no prior cases of acute allergic angioedema linked to neuropathy.

Observation:

• A 30-year-old male experienced bilateral hand/forearm swelling, numbness, and pain post-allergic reaction treatment with epinephrine and steroids.
• Despite initial swelling improvement, persistent paresthesia and weakness were noted.
• Electrodiagnostic studies revealed severe left proximal wrist ulnar neuropathy with denervation and reinnervation signs, alongside an acute flexor pollicis longus tear on MRI.

Findings:

• The patient's ulnar neuropathy and acute muscle tear were attributed to rapid-onset angioedema secondary to the allergic reaction.
• Diagnostic findings included severe ulnar neuropathy at the left proximal wrist and a flexor pollicis longus tear.
• Electrodiagnostic studies indicated acute/subacute denervation and active reinnervation in specific forearm muscles.

Implications:

• This case suggests a potential link between acute allergic angioedema and nerve compression syndromes like ulnar neuropathy.
• Further research is warranted to elucidate the pathophysiology of nerve compression caused by acute angioedema.
• Understanding this relationship can inform treatment strategies for neuropathy following allergic reactions and angioedema episodes.