Electroneurophysiological evaluation in children and adolescents with collagen diseases

Abstract

Background: Sensorimotor neuropathies have been reported in patients with known or suspected connective tissue disease. It is often difficult to diagnose early neuropathies, and the study of the peripheral neuromuscular system is often made difficult by symptoms resulting from pain in the joints and limitation of movement.
Objective: We aimed to investigate the central and peripheral nervous systems involvement in patients with pediatric- onset SLE and juvenile rheumatoid arthritis through clinical assessment and neurophysiological studies (motor nerve conduction velocity (MNCV) of the tibial nerve bilaterally and somatosensory evoked potentials (SSEPs) of the median nerve bilaterally) and to study their relation to clinical data and laboratory investigations.
Methods: Nineteen patients with SLE (mean age 14.47± 3.94 years)and fifteen JRA patients (mean age 13.39±3.9 years) were included in the study. Ten healthy, matched subjects served as the control group. In addition to clinical assessment, including complete neurological and psychiatric evaluation, different investigative tools needed for diagnosis as well as assessment of systemic involvement and the degree of activity, were implemented. Both patients and control groups were subjected to neurophysiological studies (Motor nerve conduction velocity (MNCV) of tibial nerve bilaterally and Somatosensory evoked potentials (SSEPs) of the median nerve bilaterally).

Results: Definite manifestations of neuropsychiatric involvement attributable to SLE was diagnosed in 37% of SLE patients. Of the SLE patients, 10.5% had abnormal MNCV on the right side, while Erb-N13 interpeak latencies were prolonged in 10.5% and 31.5% of the median nerves studied on the right and left sides, respectively, and N13-N20 was prolonged in 21% and 31.5%, respectively. Neither hypertension nor renal involvement significantly affected the studied parameters; however, SLE patients with cutaneous vasculitis showed slower MNCV of tibial nerve and prolonged Erb-N13 intervals on both sides. Erb-N13 and N13-N20 (on the right side) were positively correlated to the disease activity index (SLE-DAI). Of the JRA patients, 6% had slowed nerve conduction of right tibial nerve, while the interpeak latencies of Erb-N13 were prolonged in 6.6% and 13.3% on the right and left sides, respectively and N13-N20 was prolonged in 6.6% and 20%, respectively. Erb- N13 (on the right side) was negatively correlated to the cumulative dose of steroids.
Conclusion: Our study revealed that sensorimotor neuropathies are often more common than expected in patients with collagen disease. Early subclinical neuropathies may be difficult to diagnose where symptoms from joint pain may mask the diagnosis. Widespread vasculitis including  vasculitis of the vasa nervora may be the underlying pathology, which  stresses the value of steroids in treatment.

Key words: Collagen disease- neuropathy- somatosensory evoked potentials.