ID 309 – Clinical, electrophyisological and serological evaluation of patients with cramp-fasciculation syndrome

Abstract

Objective Cramp-fasciculation syndrome (CFS) is a rare peripheral nerve hyperexcitability syndrome. There is little information on the clinical and serological profile of a CFS cohort followed by a single outpatient clinic. Method Clinical, electrophysiological and serological features of 6 CFS patients (5men/1woman, 27-61years-old) were investigated. Results All patients presented with cramps, fasciculations, muscle pain and autonomic symptoms, while two of them also reported numbness and burning sensation in the limbs which was reminiscent of neuropathic pain. Nerve conduction studies and RR interval variability tests revealed normal results. Sympathetic skin responses were increased in amplitude, and prolonged after-discharges were recorded from the foot muscles after tibial nerve stimulation in all the patients. Antibodies to voltage-gated potassium channel(VGKC)-complex proteins were found in 3patients, one of whom was also positive for contactin-associated protein-like2(CASPR2) antibody. Two patients with neuropathic pain displayed non-CASPR2 VGKC-complex antibodies. None of the patients had a malignancy. Five patients showed favorable response to carbamazepine or pregabalin treatment, whereas one VGKC-antibody positive patient was resistant to carbamazepine and immunosuppressant treatment. Conclusion Autonomic symptoms, neuropathic pain and VGKC-complex antibodies are commonly found in CFS patients. Key message VGKC-complex antibody positivity might be an indicator of neuropathic pain and resistance to treatment in CFS.