Thermoregulatory sweating abnormalities in diabetes mellitus

Area of Science:

• Neurology
• Endocrinology
• Clinical Diagnostics

Background:

• Diabetic neuropathy is a common complication of diabetes mellitus.
• Accurate diagnosis of diabetic neuropathy, particularly its subtypes like autonomic neuropathy and radiculopathy, is crucial for patient management.
• Existing diagnostic methods may not fully capture the distribution and severity of neuropathic involvement.

Purpose of the Study:

• To evaluate the diagnostic utility of the thermoregulatory sweat test (TST) in patients suspected of having diabetic neuropathy.
• To determine the patterns and distribution of sweating abnormalities in diabetic neuropathy.
• To correlate TST findings with clinical assessments of dysautonomia and other electrodiagnostic findings.

Main Methods:

• A thermoregulatory sweat test (TST) was performed on 51 patients with suspected diabetic neuropathy.
• Clinical examination and autonomic function tests were conducted.
• Electromyography (EMG) and quantitative sudomotor axon reflex testing were utilized for comparison.

Main Results:

• The TST demonstrated abnormalities in 94% of patients.
• Distal sweating loss was observed in 65%, segmental in 25%, and dermatomal in 25%.
• A strong correlation was found between the extent of anhidrosis and the severity of clinical dysautonomia (r=0.77, P<0.01).
• Discrete anhidrosis zones correlated with thoracic paraspinal muscle fibrillation potentials in radiculopathy patients.
• Distal sweating loss on TST indicated distal axonal neuropathy, confirmed by other tests.

Conclusions:

• The thermoregulatory sweat test (TST) is a reliable tool for diagnosing diabetic neuropathy.
• TST findings provide valuable information on the distribution of neuropathic damage, including autonomic neuropathy and truncal radiculopathy.
• TST is particularly useful in identifying clinically significant autonomic neuropathy and painful diabetic radiculopathy.