Mild encephalitis/encephalopathy with a reversible splenial lesion associated with systemic Mycoplasma pneumoniae infection in North America: a case report.

BACKGROUND: Mild encephalitis/encephalopathy with reversible splenial lesion is a clinical-radiological entity found to occur in the setting of an acute systemic inflammatory state with isolated lesions of the splenium of the corpus callosum and mild encephalopathy. Mild encephalitis/encephalopathy with reversible splenial lesion is commonly found to occur in children in the setting of viral infections. It has rarely been associated with Mycoplasma pneumoniae in the United States, unlike in Eastern and Southern Asia where this is much more prominent. CASE PRESENTATIONS: A 5-year-old African-American boy with autism spectrum disorder presented to our emergency department with acute onset intractable vomiting, diarrhea, and abnormal tensing movements for 2 days, following a 6-day period of fatigue, fever, and spastic abdominal pain. Emergent work-up in our department ruled out acute gastrointestinal pathologies. Given the high fevers and encephalopathy, there was concern for meningitis or encephalitis. His cerebrospinal fluid profile was concerning for viral meningitis, however extensive infectious workup was negative. Magnetic resonance imaging of his brain demonstrated a T2 fluid-attenuated inversion recovery sequence hyperintensity in the splenium of the corpus callosum, read as postictal changes by radiology. Continuous video electroencephalography demonstrated mild diffuse encephalopathy without electrographic correlate of his tensing episodes. He was determined to have mild encephalitis/encephalopathy with a reversible splenial lesion in the setting of a postinfectious etiology. He was treated with a single pulse-dose of intravenous methylprednisolone, following which he gradually returned to his baseline the next day. Repeat magnetic resonance imaging and cerebrospinal fluid evaluation demonstrated resolution of previous findings. He was ultimately diagnosed with an acute M. pneumoniae infection, which was determined to be the etiology of his mild encephalitis/encephalopathy with a reversible splenial lesion. CONCLUSIONS: The presentation of mild encephalitis/encephalopathy with a reversible splenial lesion is often nonspecific, with behavioral symptoms ranging from irritability to disturbances in consciousness. Its prevalence is higher in the pediatric population, and is thought to be more of an infection-associated encephalopathy syndrome in this group. The infections are typically viral, more so than bacterial. M. pneumoniae, a small, atypical bacterium lacking a peptidoglycan cell wall, is a common respiratory tract pathogen found in children. Despite infection being so rampant in the pediatric community, very few cases of M. pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion in the United States have been reported. In Eastern and Southern Asian countries, however, M. pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion is much more commonly reported. This difference may potentially lie in the prevalence of macrolide-resistant M. pneumoniae, which is significantly higher in Asian countries given more liberal antibiotic use in M. pneumoniae infections. Infections with macrolide-resistant M. pneumoniae are reportedly greater in severity and duration. This amplified state may suggest a correlation between intensity of inflammatory response and the development of mild encephalitis/encephalopathy with a reversible splenial lesion. Given the rarity of M. pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion in the United States, much remains unknown regarding predilection and optimum treatment strategy. As rates of macrolide-resistant M. pneumoniae begin to rise in the United States, maintaining a high level of suspicion remains key in better understanding this unique phenomenon.

Melody valve implantation within freestyle stentless porcine aortic heterograft.

BACKGROUND: The Melody transcatheter pulmonary valve has been implanted successfully worldwide since its first implant in 2000. The vast majority of these valves have been implanted in pulmonary homografts. In our institution, the most common valve used for pulmonary valve replacement is the Medtronic Freestyle stentless porcine aortic heterograft. OBJECTIVE: We describe our experience implanting the Melody valve within the Freestyle heterograft. METHODS: Retrospective chart review was performed. RESULTS: Between June 2012 and June 2015, 19 Melody valves were placed within Freestyle heterografts. The most common indication for intervention was pulmonary stenosis. Following pre-stent and Melody valve implantation, right ventricle-to-pulmonary artery gradient decreased from 38.1 ± 12.1 to 10 ± 4.7 mm Hg (P < 0.001), and right ventricular pressure decreased from 61.7 ± 17.8 to 35.6 ± 10.2 mm Hg (P < 0.001). Two procedural adverse events occurred. At median follow-up of 24 months (range 2-48 months), no patients had mean right ventricular outflow tract gradients >30 mm Hg or worse than mild insufficiency. No valve reinterventions have been necessary and no episodes of endocarditis have been observed. CONCLUSIONS: The Melody valve can be implanted successfully within a stentless aortic bioprosthesis with good short- and intermediate-term longevity. © 2016 Wiley Periodicals, Inc.