Isolated sympathetic failure with autoimmune autonomic ganglionopathy.

A 16-year-old boy had a gradual onset of post-exercise myalgia with progressive fatigue and dizziness. He had bradycardia (37 beats/minute) with low supine and normal standing norepinephrine levels (56 and 311 pg/mL, respectively). He had absent sympathetically mediated vasoconstrictor responses during Valsalva maneuver testing. Circulating ganglionic acetylcholine receptor antibodies were identified. Response was gradual to treatment with intravenous immunoglobulin combined with aggressive symptomatic interventions (permanent pacemaker implantation and treatment with pyridostigmine, midodrine, and modafinil). After the intravenous immunoglobulin treatment, his autoantibody levels decreased and the autonomic abnormalities resolved. After a reconditioning exercise program and eventually undetectable antibody titers, he achieved complete recovery. The patient continued to do well after his pacemaker was removed and his medications were discontinued. Thus, severe isolated sympathetic nervous system failure can occur in adolescents with autoimmune autonomic ganglionopathy, and multifaceted treatment can be effective.