Non-bacterial osteomyelitis may coexist with other autoinflammatory diseases. MRI remains a favorable diagnostic tool and genetic testing may have a limited role in selected cases. Infliximab and canakinumab are associated with variable outcomes, and 6-week or less dosing intervals for both medications may be more effective.

Background Anti-NMDA receptor encephalitis, an autoimmune disease associated with antibodies against N-methyl-D-aspartate (NMDA) receptors, is being diagnosed more frequently, especially in children and young adults. Acute neurological and psychiatric manifestations are the common presenting symptoms. Diagnosing anti-NMDA receptor encephalitis is often challenging given the wide range of clinical presentation, and may be further complicated by its overlap of symptoms, brain MRI changes, and CSF findings with other entities affecting the brain. Even though diagnosis can be made by identifying antibodies in immune-mediated encephalitis, the diagnosis may be delayed by weeks to months. Delay in initiation of treatment with immune suppressive therapies is shown to be associated with adverse outcomes. Malignant catatonia is a severe and life-threatening state associated with anti-NMDA receptor encephalitis. It is often inadequately assessed and may not respond to immunosuppressive treatment. Case presentation We present a confirmed case of anti-NMDA receptor encephalitis in a 16 year old girl who had severe critical neurological and psychiatric manifestations, including malignant catatonia and autonomic instability. Our patient continued to manifest malignant catatonia despite the initiation of prompt, aggressive immune suppressive therapies, including corticosteroids, plasmapheresis, intravenous gammaglobulin and rituximab, as well as treatment with high-dose benzodiazepines. Once electroconvulsive therapy (ECT) began, she had a robust response with resolution of her catatonia. Six weeks after treatment with eight ECT cycles, she had returned to her normal baseline cognitive and motor function. Conclusions ECT was an effective and well-tolerated therapy in our patient, and should be considered for the treatment of children with anti-NMDA receptor encephalitis whose catatonia does not respond to immunosuppression and benzodiazepines.

Hyperimmunoglobulinemia D Syndrome (HIDS) has rarely been reported in Arabs. Moreover, the simultaneous presence of mutations in MEFV and MVK segregating in the same family is exceptional. We report an Arabic girl presenting since the age of 8-years with two patterns of recurrent episodes of fever, and associated with a spectrum of clinical features suggestive of overlap between familial Mediterranean fever (FMF) and HIDS. Her 19-year old brother presented since the age of 1 year with prolonged episodes of fever and was diagnosed with HIDS at the age of 7 years based on clinical features and homozygosity for p.V377I mutation in MVK. Shorter episodes of fever and abdominal pain more consistent with FMF ensued since the age of 17 years. Genetic testing done for both patients and all other family members revealed simultaneous presence of mutations in MEFV and MVK but with a variable clinical spectrum ranging from asymptomatic to severe manifestations. Both of our patients are homozygous for p.V377I MVK mutation; the girl is a compound heterozygote for p.E148Q/p.P369S/p.R408G and p.E167D/p.F479L MEFV mutations whereas the brother is a compound heterozygote for p.E148Q/p.P369S/p.R408G and p.M680I MEFV mutations. The clinical implications of having more than one mutation in different genes of monogenic autoinflammatory diseases in the same individual are not clear but may explain atypical clinical manifestations such as the overlap features of both FMF and HIDS in this family.

Immune- mediated encephalitis is the most common cause of encephalitis after infection in children and adults. Although this disease process was identified nearly 20 years ago, the variety of clinical presentations and the lack of specific diagnostic criteria can make the identification of anti-N-methyl-D-aspartate receptors (NMDA-R) encephalitis challenging. Moreover, identifying NMDA-R antibodies in blood or cerebrospinal fluid can take days to weeks, and thus clinicians need to have a high index of suspicion to investigate for this disease in patients who may appear to have an overlap of neurologic and psychiatric symptomatology. In this article, the authors describe three illustrative cases of anti-NMDA-R encephalitis in children age 3 to 16 years. The discussion reviews our current understanding of the clinical presentation, diagnostic criteria, and inpatient therapeutic management of anti-NMDA-R encephalitis, as well as illuminates the unique and often perplexing presentations of this disease process versus other organic and psychiatric causes of altered mental status. [ Pediatr Ann. 2019;48(10):e387–e390.]

Kawasaki disease (KD) is a vasculitis syndrome of unknown etiology, affecting medium-sized vessels and occurring primarily in young children. It is a self-limited illness classically presenting with fever, conjunctivitis, mucocutaneous lesions, and cervical adenopathy. However, vasculitis of coronary arteries with aneurysm formation may occur, leading to morbidity and rarely mortality. Prompt diagnosis of KD is essential as early treatment with intravenous immune globulin (IVIG) decreases the occurrence and severity of coronary vasculitis. This article reviews the clinical characteristics of KD, laboratory assessment, echocardiogram findings, and recommended initial medical therapy. Complications of KD are discussed, including KD refractory to IVIG, the presence of shock or macrophage activation syndrome (MAS), and short/long-term cardiac sequelae. The medical management of these complications is reviewed. Although improved treatment of KD has resulted in a decrease of coronary artery vasculitis over the past 3 decades, KD remains the most common cause of acquired heart disease in children. [ Pediatr Ann. 2019;48(10):e400–e405.]