Prophylactic immunoglobulin therapy for pediatric congenital myotonic dystrophy.

Congenital Myotonic Dystrophy (CMD) is an autosomal dominant hereditary disease caused by mutations in the dystrophia myotonica protein kinase gene. Patients with CMD often exhibit low immunoglobulin (Ig) G levels. While Ig replacement therapy for low IgG levels has been reported in several adult cases, there have been no reports on pediatric patients. This study presents a first pediatric case where Ig replacement therapy effectively eliminated susceptibility to infections. The CMD patient, a 1-year-old Japanese female with a history of premature birth and necrotizing enterocolitis, developed recurrent severe bacterial infections due to hypogammaglobulinemia. Intravenous immunoglobulin (IVIG) (600 mg/kg/month) was administered but failed to maintain sufficient serum trough IgG levels. The dosage was increased to 2 g/kg/month, and later, the treatment shifted to subcutaneous immunoglobulin (SCIG), resulting in a stable serum trough IgG level above 700 mg/dL for one year. The cause of hypogammaglobulinemia in CMD patients remains unclear, but potential mechanisms, including IgG-mediated hypercatabolism by alterations in the neonatal Fc receptor, have been considered. Genetic testing ruled out common variable immunodeficiency, and other potential causes were excluded. The study suggests that higher doses of IVIG or SCIG can effectively prevent severe infections associated with CMD-induced hypogammaglobulinemia in children.

This case report sheds light on the efficacy of immunoglobulin therapy in pediatric congenital myotonic dystrophy (CMD). We anticipate that our findings will have a positive impact on clinical practice by providing insights into the prevention of severe infections associated with CMD-induced hypogammaglobulinemia. This research is of great interest to the readers of the journal as it addresses an unmet need in pediatric CMD management by providing a strategy for successful immunoglobulin therapy for the treatment of pediatric CMD.

Melting temperature mapping method in children: Rapid identification of pathogenic microbes.

INTRODUCTION: The melting temperature (Tm) mapping method (TM) identifies bacterial species by intrinsic patterns of Tm values in the 16S ribosomal RNA gene (16S rDNA) extracted directly from whole blood. We examined potential clinical application of TM in children with bloodstream infection (BSI). METHODS: This was a prospective observational study at a children's hospital in Japan from 2018 to 2021. In patients with diagnosed or suspected BSI, we investigated the match rates of pathogenic bacteria identified by TM and blood culture (BC), the inspection time to identification of TM, and the amount of bacterial DNA in blood samples. RESULTS: The median age of 81 patients (93 samples) was 3.6 years. Of 23 samples identified by TM, 11 samples matched the bacterial species with BC (positive-match rate, 48 %). Of 64 TM-negative samples, 62 samples were negative for BC (negative-match rate, 97 %). Six samples, including one containing two pathogenic bacterial species, were not suitable for TM identification. In total, the matched samples were 73 of 93 samples (match rate, 78 %). There were seven samples identified by TM in BC-negative samples from blood collected after antibiotic therapy. Interestingly, the bacteria were matched with BC before antibiotic administration. These TM samples contained as many 16S rDNA copies as the BC-positive samples. The median inspection time to identification using TM was 4.7 h. CONCLUSIONS: In children with BSI, TM had high negative-match rates with BC, the potential to identify the pathogenic bacteria even in patients on antibiotic therapy, and more rapid identification compared to BC. REGISTERING CLINICAL TRIALS: UMIN000041359https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000047220.

Purulent lymphadenitis due to Halomonas hamiltonii: a case report.

Halomonas hamiltonii is a gram-negative rod bacterium isolated from highly saline environments. H. hamiltonii has rarely been reported as a human pathogen. Herein, we present the first case report of a purulent lymphadenitis caused by H. hamiltonii worldwide. The patient was a previously healthy girl aged 1 year who was referred to our hospital for left axillary lymphadenitis. Although oral amoxicillin was administered, lymphadenitis did not improve, and an abscess developed. After incision and drainage, the abscess was reduced. No recurrence of lymphadenitis was observed. The pus culture was negative. However, the 16S ribosomal DNA was amplified by the melting temperature mapping method. The amplified 16S ribosomal DNA sequence revealed 99.7% identity of H. hamiltonii. To the best of our knowledge, this is the first case of H. hamiltonii infection in a lymph node. This pathogen should be considered when diagnosing purulent lymphadenitis in healthy patients with lymphadenopathy of unknown origin.

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis syndrome: Clinical characteristics and treatment outcomes - a single center study in Japan.

BACKGROUND: Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is an autoinflammatory disease occurring in children. Although PFAPA is the most common periodic fever syndrome found in children, there are only a few studies defining the clinical characteristics and the efficacy of treatment strategies among Japanese children. This study aimed to clarify the demographic characteristics and clinical features of patients with PFAPA syndrome and to evaluate treatment efficacy. METHODS: We retrospectively reviewed the clinical features of children with PFAPA who visited Saitama Children's Medical Center between January and December 2019. We also evaluated treatment strategies and their efficacy; abortive treatment with corticosteroids, prophylaxis with cimetidine or colchicine, and surgical management with tonsillectomy. RESULTS: A total of 100 Japanese children (61% male) with PFAPA were included. Median age of onset was 3 years, median duration of fever episodes was 5 days, and median interval between episodes was 4 weeks. The symptoms (frequencies) were pharyngitis (89%), exudate on tonsils (71%), cervical adenitis (50%), and aphthous stomatitis (49%). Approximately 37% of patients took prednisolone for aborting fever attacks, showing a 100% response; 93% were treated with cimetidine, showing an 79.6% response, and 18% were treated with colchicine, showing a 66.7% response. Only one patient underwent tonsillectomy. CONCLUSIONS: Among Japanese children with PFAPA, 28% of them were ≥5 years with a male predominance. Pharyngitis is the most frequent symptom associated with fever. Cimetidine is suitable for initial therapy because of its safety and efficacy.

Actinomycosis of the Middle Ear in Children: Case Report and Literature Review.

Actinomycosis of the middle ear is a rare infectious disease, characterized by a slowly progressive clinical course. We report the case of a 9-year-old girl with recurrent otitis media, who presented with clinical signs of a cholesteatoma. She underwent tympanoplasty and ossiculoplasty. After surgery, actinomycosis was diagnosed histologically. We also provide a review of 16 published pediatric cases.

Prospective Study of the Detection of Bacterial Pathogens in Pediatric Clinical Specimens Using the Melting Temperature Mapping Method.

The melting temperature (Tm) mapping method is a novel technique that uses seven primer sets without sequencing to detect dominant bacteria. This method can identify pathogenic bacteria in adults within 3 h of blood collection without using conventional culture methods. However, no studies have examined whether pathogenic bacteria can be detected in clinical specimens from pediatric patients with bacterial infections. Here, we designed a new primer set for commercial use, constructed a database with more bacterial species, and examined the agreement rate of bacterial species in vitro. Moreover, we investigated whether our system could detect pathogenic bacteria from pediatric patients using the Tm mapping method and compared the detection rates of the Tm mapping and culture methods. A total of 256 pediatric clinical specimens from 156 patients (94 males and 62 females; median age, 2 years [<18 years of age]) were used. The observed concordance rates between the Tm mapping method and the culture method for both positive and negative samples were 76.4% (126/165) in blood samples and 79.1% (72/91) in other clinical specimens. The Tm mapping detection rate was higher than that of culture using both blood and other clinical specimens. In addition, using the Tm mapping method, we identified causative bacteria in pediatric clinical specimens quicker than when using blood cultures. Hence, the Tm mapping method could be a useful adjunct for diagnosing bacterial infections in pediatric patients and may be valuable in antimicrobial stewardship for patients with bacterial infections, especially in culture-negative cases. IMPORTANCE This study provides novel insights regarding the use of the melting temperature (Tm) mapping method to identify the dominant bacteria in samples collected from pediatric patients. We designed a new set of primers for commercial use and developed a database of different bacteria that can be identified using these primers. We show that the Tm mapping method could identify bacteria from blood samples and other clinical specimens. Moreover, we provide evidence that the Tm mapping method has a higher detection rate than that of the culture-based methods and can achieve a relatively high agreement rate. We believe that our study makes a significant contribution to this field because rapid identification of the source of bacterial infections can drastically improve patient outcomes and impede the development of antibiotic-resistant bacteria.

Infected simple renal cyst due to Streptococcus pneumoniae rapidly diagnosed by the melting temperature mapping method: a case report.

BACKGROUND: Spontaneous infection of preexisting solitary renal cysts has been documented in adults but is extremely rare in children. To date, no cases of simple renal cysts infected with Streptococcus pneumoniae have been described. Recently, reports have described the diagnosis of bacterial infection using the 16 S rRNA gene as well as the accompanying antimicrobial stewardship for microorganisms that are difficult to culture and for culture-negative cases after preceding antibacterial administration. CASE PRESENTATION: A four-year-old Japanese girl who had a pleuroperitoneal shunt inserted to drain a right pleural effusion due to occlusion of the hepatic portion of the inferior vena cava at three years old visited our hospital due to fever and respiratory discomfort. She was incidentally found to have a right simple renal cyst 10 months before admission. The patient was suspected to have pneumonitis or catheter-related blood stream infection on chest X-ray, which showed right-side pleural effusion. She was diagnosed with invasive pneumococcal infection, as Streptococcus pneumoniae was detected from blood culture on admission. Transient improvements in her symptoms and decreases in the white blood cell count and C-reactive protein level were observed after effective antibiotic administration, but her respiratory condition deteriorated. Enhanced CT showed right renal cyst enlargement and enhancement and thickening of the surrounding wall. Using the melting temperature (Tm) mapping method, S. pneumoniae was rapidly detected directly from pus 4.5 hours after drainage. The specimen culture was negative, but the extracted 16 S rDNA sequence revealed 100 % identity for S. pneumoniae from the same specimen the subsequent day. We successfully performed optimal treatment and reduced medical cost based on the positive Tm mapping method result. CONCLUSIONS: We report the first case of a S. pneumoniae-infected simple renal cyst. The drainage culture was negative, but the Tm mapping method rapidly detected S. pneumoniae directly from the drainage. The Tm mapping method may have great impacts on rapid diagnosis and effective antimicrobial stewardship.

Efficacy, safety, and pharmacokinetics of oral valganciclovir in patients with congenital cytomegalovirus infection.

OBJECTIVES: Valganciclovir (VGCV) has been shown to improve sensorineural hearing loss (SNHL) and neurological outcomes in patients with neonatal symptomatic congenital cytomegalovirus (cCMV) infection. However, reports on the pharmacokinetics, efficacy and safety of oral VGCV are limited. The aim of this study is to evaluate the pharmacokinetics of VGCV for use in the treatment of cCMV. METHODS: This was a single-center, retrospective observational study conducted at Saitama Children's Medical Center in Japan between 2012 and 2017. CMV DNA copy number, maximum plasma VGCV concentration (Cmax), and adverse events (ADEs) during treatment were evaluated. RESULTS: A total of 26 patients with cCMV who received VGCV were included in this study. The median age at VGCV initiation was 9.5 months (range 0-46). Twenty-one patients (81%) had SNHL at baseline. Of these, five patients (19%) presented with improved SNHL, and none experienced worsened SNHL during treatment. The mean VGCV Cmax was 3.5 µg/mL (range 2-5.3), with no significant variation among individual values, and the values were maintained during treatment. Furthermore, there were no correlations between the Cmax values and age, sex, SNHL improvement or ADEs. Neutropenia (<1000/mm3) was observed in six patients (23%); however, no serious ADEs occurred. CONCLUSIONS: VGCV prevented the progression of SNHL without serious ADEs due to its stable pharmacokinetics. This study provides safety and tolerability of VGCV for the treatment of cCMV patients.

A case of Mycobacterium bovis Bacillus Calmette-Guérin (BCG) strain meningitis and ventriculitis following BCG vaccination.

The Bacillus Calmette-Guérin (BCG) vaccine is widely used worldwide. Intracranial manifestation as an adverse event of BCG is extremely rare. A previously healthy 16-month-old boy was referred to our hospital for eye contact difficulties and progressive gait disturbance lasting two months. He was inoculated with BCG at seven months of age. Brain magnetic resonance imaging (MRI) revealed hydrocephalus with widespread and disseminated enhancement lesions with thickening of the third ventricle floor, and brain tissue pathologically showed non-caseous granulomatous inflammation. Immunosuppressive therapies were initiated because of a provisional diagnosis of neurosarcoidosis. Three months later, a positive polymerase chain reaction (PCR) result for the Mycobacterium tuberculosis complex was obtained. Eventually, M. bovis (BCG Tokyo 172 strain) was identified in the cerebrospinal fluid (CSF) and shunt tube culture. The prolonged use of antituberculosis drugs and multiple shunt replacement surgeries were needed for recovery. There was no evidence of immunodeficiency. Unfortunately, he had severe neurological sequelae of bilateral blindness and neurodevelopmental delay. Our purpose in this report was to highlight the potential for intracranial manifestations of adverse reactions related to BCG vaccination. We propose that the CSF PCR assay of Mycobacterium tuberculosis (MTB) complex should be applied repeatedly in children suspected of intractable neurosarcoidosis, with a history of BCG vaccination.

Clinical features of macrophage activation syndrome as the onset manifestation of juvenile systemic lupus erythematosus.

OBJECTIVES: Macrophage activation syndrome (MAS) is a severe complication of juvenile systemic lupus erythematosus (jSLE). However, little is known about the association between these conditions, especially in terms of MAS as the initial manifestation of jSLE. The aim of this study was to determine the clinical features of MAS as the initial manifestation of jSLE. METHODS: We carried out a retrospective review of the clinical features of MAS cases diagnosed concomitantly with jSLE from 2004 to 2016. Data from these patients were compared with those from a control group consisting of jSLE patients without MAS. RESULTS: Eleven (23.9%) of the 46 patients recruited for this study were diagnosed with MAS during the initial stage of jSLE. The between-group comparisons demonstrated that fever, leucopenia, hyperferritinaemia and increased aspartate aminotransferase were more frequently observed in jSLE patients with MAS than in controls (P<0.01). Importantly, neurological symptoms were significantly more common in patients with MAS than in controls (P<0.01), with 6 (54.6%) of the 11 MAS patients affected. For treatment, all 11 patients with both jSLE and MAS were administered CSs upon diagnosis, and 7 received immunosuppressants. No patient involved in this study died. CONCLUSION: MAS can develop as the initial manifestation of jSLE. MAS with jSLE should be suspected in patients with fever, hyperferritinaemia, cytopenia and liver disorder. In addition, we found that jSLE patients with MAS had more neurological symptoms than those without. All patients with MAS were successfully treated with CSs. Early diagnosis and intensive therapy are essential in improving clinical outcomes.

Pyogenic liver abscess due to hypervirulent Klebsiella pneumoniae in a 14-year-old boy.

A 14-year-old otherwise healthy boy presented with right-sided back pain following high fever. Abdominal computed tomography scan showed a large liver abscess. Klebsiella pneumoniae (KP) was rapidly identified from peripheral blood using the melting temperature mapping (Tm) method, which enables identification of pathogenic microorganisms within four hours after patient sample collection. He was diagnosed with pyogenic liver abscess (PLA) caused by KP on the day of admission. The KP was the hypervirulent (hv) clinical variant (string test positive, serotype K1, sequence type 23, rmpA and magA positive). After intravenous antibiotic therapy and drainage of the abscess, his condition resolved. The highlights of this case report are a healthy child with hypervirulent Klebsiella pneumoniae liver abscess in Japan and the new Tm mapping method for rapid and accurate identification of the pathogenic microorganism.