Context: Acromegalic patients may complain of sensory disturbances in their hands.

Objective: To examine median and ulnar nerves of acromegalic patients with ultrasound (US) and to determine whether nerve abnormalities correlate with clinical parameters and nerve conduction studies (NCS).

Patients: We prospectively examined the median and ulnar nerves in 34 non-diabetic, acromegalic patients (18 f and 16 m; age range, 18–79 yr) and 34 sex-, age-, and BMI-matched controls with 17–5 MHz US.

Intervention: The median nerve was examined at the carpal tunnel (MN-Ct) and at the mid-forearm (MN-f) level; the ulnar nerve was examined at the mid-forearm (UN-f) and at distal arm (UN-a). A total of 272 nerve cross-sectional areas (CSA) were recorded from both patients and controls. In addition, 22 patients underwent NCS.

Results: Nerves of acromegalic patients (MN-Ct = 16.5 ± 4.4 mm²; MN-f = 10.5 ± 2.4 mm²; UN-f = 9.5 ± 3.0 mm²; UN-a = 13.1 ± 3.7 mm²) had significantly (p<0.0001) greater CSA compared with controls (MN-Ct = 7.4 ± 1.7 mm²; MN-f = 5.5 ± 1.4 mm²; UN-f = 5.3 ± 1.4 mm²; UN-a = 6.6 ± 1.7 mm²). NCS displayed at least one abnormality in 59% of patients. Acromegalic patients, grouped according to disease activity (14 controlled; 8 partially controlled; 12 uncontrolled), had significantly (p<0.0001) greater CSA compared with controls. Nerve CSA were significantly greater in uncontrolled patients compared to controlled, both at MN-Ct and at UN-f level (p<0.01). Abnormal NCS were observed in 5/7 uncontrolled patients and 4/9 controlled patients. IGF-I but not GH levels were correlated with CSA (r = 0.34), whereas disease duration with both nerve CSA and NCS (r = 0.33 and r = 0.31).

Conclusion: US identified a significantly increased volume of median and ulnar nerves in acromegalic patients. Peripheral nerve enlargement in acromegaly seems an intrinsic feature of the disease related to clinical control, disease duration, and IGF-I levels.