Neurology G177 THE CONTINUING ROLE OF TENSILON (EDROPHONIUM) TESTS IN THE DIAGNOSIS OF CHILDHOOD MYASTHENIA

Aim: Myasthenia is a rare paediatric disease. Traditionally, the Tensilon test, neurophysiological (NP) studies and serology have been used in its diagnosis. This first study in children was to clarify the role and safety of the Tensilon test in the initial diagnoses of myasthenia when compared with, and in association with NP studies such as stimulated single fibre EMG (sSFEMG) and repetitive nerve stimulation (RNS). Methods: Retrospective non-comparative case note review of 44 patients who have had Tensilon tests requested in the last 10 years for the diagnosis of myasthenia in a tertiary paediatric neurology centre. Results: 37 Tensilon tests were carried out as per local hospital protocol. Seven of 44 patients did not have the Tensilon test carried out because of a change in clinical status. 34 of 37 children had ocular symptoms at the time of the Tensilon test. 33 of 37 children had Tensilon test and NP studies (sSFEMG or RNS or both). In 26 of 33 the results of Tensilon test and the NP studies were concordant. 13 of 26 patients had both tests suggestive of a defect in the neuromuscular junction. All these patients had a final diagnosis of myasthenia (autoimmune myasthenia (n = 7), congenital myasthenia (n = 5)). The remaining 13 of 26 children had both tests negative and did not have a final diagnosis of myasthenia. Seven of 33 children had discordant results. Five of seven discordant test group had a positive Tensilon test and normal NP studies. The final diagnosis was autoimmune myasthenia (n = 3), seronegative myasthenia (n = 1) and mitochondrial disease (n = 1). Two of seven patients had a negative Tensilon test and positive NP studies. The final diagnosis was congenital myasthenia (n = 1) and seronegative myasthenia (n = 1). Five of 37 children had minor and transient side-effects after Tensilon was injected. None of the children required atropine or had severe adverse effects. Conclusions: The Tensilon test continues to be a safe bedside test (when performed as per standardised protocol) with minimal complications. During initial presentation especially in myasthenia with ocular symptoms, NP studies could be normal and at that stage, a Tensilon test would be advisable. A concordant test with both Tensilon test and NP studies can confidently diagnose or rule out myasthenia.