Nerve excitability in iron deficiency anemia: a prospective study

Objective: The aim of this study was to evaluate the effects of iron deficiency anemia (IDA) on peripheral nervous system via nerve excitability tests (threshold tracking). Methods: The study was performed on 32 patients (22 patients (69%) with moderate, and 10 patients (31%) with severe IDA. Parenteral iron treatment was administered based on the calculated iron deficiency. Three nerve excitability tests were performed; Test 1: During the pre-treatment period, Test 2: On the 7th day of the post-treatment period, and Test 3: Three months after the correction of anemia. The strength-duration/time constant (tSD), rheobase and supernormality values of motor and sensory axons of the median nerve were recorded. Results: A statistically significant stepwise increase in the supernormality periods of the sensory axons of the median nerve was detected between the tests conducted in three separate times (p<0.01). This increase significantly correlated with hemoglobin levels but not with iron levels. However, there was no significant difference in tSD and rheobase values between the tests on both motor and sensory axons. A significant correlation observed between the increase of sensorial supernormality and hemoglobin levels. Conclusion: The significant increase of supernormality in sensory axons of the peripheral nerves may suggest that chronic ischemia occurring in IDA may have some impacts on fast acting K channels. The causes of the decrease in supernormality of sensory axons can make contribution to the pathogenesis of the patients' complaints, such as abnormal sensation and dysesthesia in their extremities.