Neuropediatrics 2012; 43 - WS35_06
DOI: 10.1055/s-0032-1307196

A 16 year-old patient presenting with Lambert-Eaton myasthenic syndrome

A Della Marina 1, S Lutz 1, K Rupprich 2, W Eberhardt 3, J Nagarajah 4, B Kremens 2, U Schara 1
  • 1Pädiatrische Neurologie, Universitätskinderklinik Essen, Essen, Germany
  • 2Pädiatrische Onkologie, Universitätskinderklinik Essen, Essen, Germany
  • 3Innere Medizin (Tumorklinik), Universitätsklinik Essen, Essen, Germany
  • 4Klinik für Nuklearmedizin, Universitätsklinik Essen, Essen, Germany

Aims: Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune presynaptic disorder of the neuromuscular transmission, which is associated by production of antibodies against voltage-gated calcium channels (VGCC, P/Q-Type). About 50% of the cases are paraneoplastic and only few cases have been reported in children/teens.

Methods: We report on a 16 year-old boy presented in our centre by the symptoms of proximal muscle weakness. Prior to the occurrence of symptoms he was a professional rower. The prominent clinical features were lower limb muscles weakness, decreased exercise tolerance and problems in his balance. As additional symptoms hyporeflexia after rest and moderate restrictive respiratory function were present.

Pathologic decrement at low-rate repetitive nerve stimulation test (3Hz), but no increment at high-rate stimulation (20Hz) was detected. The patient developed further decline in his muscular strength under therapy with pyridostigmin bromide. Anti-acetylcholine receptor, anti-muscle specific kinase and titin antibodies were not elevated. Histopathologic findings from his muscular biopsy were normal.

Results: Antibodies against VGCC of P/Q-Type were highly elevated and therapy by 3,4– diaminopyridine was initiated. Under current dosage of 80mg/day the patient showed significant improvement in his muscular strength and endurance (capability of jogging over a distance of 1km). Because of pathologic tracer accumulation in thymus glandula (FDG PET/CT) thymectomia was performed, histopathological findings were normal.

Conclusion: Antibodies against VGCC should be determinate also in young patients presenting with proximal weakness, intermittent hyporeflexia and pathologic decrement at low-rate repetitive nerve stimulation. Our patient showed significant improvement in muscular strength under therapy with 3,4– DAP so no further immunsupression was necessary for now. In this case we assume a non-neoplastic LEMS because no underlying malignancy was found over the period of 1 ½ years.

Lambert-Eaton myasthenic syndrome - 16 year-old patient - 3,4-Diaminopyridine