The pathology of median neuropathy in acromegaly

Background: Median neuropathy is commonly associated with acromegaly, altho ugh its pathology is uncertain. Objective: To study the pathology of median neuropathy in acromegaly by usi ng magnetic resonance imaging (MRI). Design: Case series. Setting: Outpatient clinic and MRI unit. Patients: Nine patients with acromegaly, four of whom had clinical symptoms of neuropathy. Measurements: At presentation and 6 months after treatment, median nerve si ze, its signal intensity, and the volume of the carpal tunnel contents were measured. Results: At presentation, patients with symptoms of neuropathy had increase d nerve size and signal intensity compared with asymptomatic patients, but the two groups did not differ in volume of carpal tunnel contents. These me asures improved with treatment of acromegaly in symptomatic patients; asymp tomatic patients experienced no change or worsening. Conclusion: The predominant pathology of median neuropathy in acromegaly se ems to be increased edema of the median nerve within the carpal tunnel rath er than extrinsic compression from increased volume of the carpal tunnel co ntents.