Patient is a 16‐year‐old Hispanic male who was transferred to our tertiary‐care center with hypertension that was refractory to antihypertensive medications. He reported a 1‐month history of profuse sweating, itching, and muscle fasciculations that were more pronounced with activity. Evaluation for causes of secondary hypertension including echocardiogram, electrocardiography, and ultrasound with Doppler flow of the kidneys was negative. Hypertension was ultimately controlled with 3 antihyperten‐sive agents. Evaluation of his complaints of muscle fascicu‐lation included electromyograms with nerve conduction studies, yielding normal results on 2 separate occasions, cerebrospinal fluid (CSF) studies, where showed mild pleocytosis and were negative for oligoclonal bands, and neu‐roimaging with MRI, with normal results. During his hospital course, the patient's muscle fasciculations progressed to a point where he could no longer walk or stand for an extended period. A trial of phenytoin for neuromyotonia was unsuccessful. He developed symptoms of insomnia, confusion, anxiety, and slurred speech. Because of the clinical symptoms of neuromyotonia, dysautonomia, and central nervous system (CNS) manifestations, the clinical diagnosis of Morvan syndrome was made. Antibodies for voltage‐gated potassium channels were negative. His mercury level was elevated, at 30 μg/L (reference range < 10 μg/L). Conservative management was initiated with prednisone 1 mg/kg/day for 2 weeks, with significant improvement of symptoms within 48 hours of initiating treatment. He has had no recurrence of symptoms.
There are 14 published reports of Morvan syndrome. Patients present with signs and symptoms of neuromyotonia, including generalized nerve hyperexcitability causing muscle fascicula‐tions, cramps, and pain; dysautonomia with hypertension, tachycardia, hyperhidrosis, constipation, and itching; and CNS manifestations of encephalopathy, anorexia, insomnia, visual hallucinations, and paresthesias. Diagnostic evaluation often yields abnormal nerve conduction studies, elevated creatinine kinase levels, and indications of autoimmune disorders such as oligclonal bands in the CSF or serum voltage‐gated potassium channel antibodies. However, among the 14 cases described in the literature, there are no consistently positive diagnostic findings. Treatment options include immunosuppression via pulse corticosteroids, plasma exchange, or intravenous immunoglobulin. Many of the cases described in the literature have been associated with alterations in the immune system likely secondary to autoimmune disorders, heavy metal exposure, and previous malignancy.
Morvan syndrome is a rare entity, with this the second reported case in a pe‐diatric patient. We report this case to raise awareness of this unusual diagnosis.
K. Janish ‐ none; D. Martin ‐ none; S. Madrid ‐ none; A. Thompson ‐ none; A. Hudgins ‐ none; L. Johnson ‐ none
To cite this abstract:Janish K, Madrid S, Thompson A, Martin D, Hudgins A, Johnson L. A Case of Morvan Syndrome in a 16‐Year‐Old. Abstract published at Hospital Medicine 2011, May 10-13, Dallas, Texas. Abstract 304. Journal of Hospital Medicine. 2011; 6 (suppl 2). https://www.shmabstracts.com/abstract/a-case-of-morvan-syndrome-in-a-16yearold/. Accessed September 16, 2019.