2323. Unexpected Pediatric Presentation Patterns of Toxic Shock Syndrome

Background

A subcategory of severe septic shock, toxic shock syndrome (TSS) represents up to 20% of pediatric septic shock in the United States. Diagnostic criteria for streptococcal TSS (STSS) and non-streptococcal TSS (NSTSS) were first published by the CDC in the early 1990s, with updates, respectively, in 2010 and 2011.

Methods

The Nationwide Children’s Hospital electronic medical record was queried for inpatient hospitalizations with ICD-9/10 codes of interest between 1/1/2010 and 8/31/2017. The query returned 579 hospitalizations which were assessed for adherence to STSS and NSTSS criteria published by the CDC. 61 cases of TSS were identified: 27 STSS, 32 NSTSS. The prevalence of organ system involvement was quantified, and organ system involvement unanticipated by CDC criteria was examined for prevalence, quality and chronology.

Results

TSS patients were predominately female (62%) with an average age of 12. The most common presentation of TSS was with hypotension (93%), fever (82%) and rash (72%). Findings unanticipated by CDC criteria include: pyuria in STSS (41%), pulmonary involvement in NSTSS (66%) and coagulation abnormalities in NSTSS (92%). Pyuria in STSS was commonly accompanied by protein (73%) and leukocyte esterase (55%) on urinalysis. Pyuria also commonly presented with hematuria (45%). Radiographic evidence of pulmonary involvement in NSTSS was typically described as bilateral/diffuse airspace disease, presenting simultaneously with pulmonary edema and pleural effusions. Abnormalities in PT/PTT associated with NSTSS were commonly found within the first few hours of admission and began normalizing by the next day; d-dimer assays were abnormal in the six instances in which they were assessed.

Conclusion

This study suggests that early signs and symptoms of pediatric TSS may exist beyond those described by existing guidelines. The organ systems found to be involved in this review are often found early in the clinical course and can be assessed by noninvasive methods. Contextualization of these findings within the narrative of TSS might help clinicians better detect and diagnose a disease associated with significant patient morbidity and mortality. They may also aid in understanding the results of toxic shock surveillance efforts.

Disclosures

All authors: No reported disclosures.

2311. Atypical Cat Scratch Disease Presentations

Background

Cat scratch disease (CSD) is caused by B henselae, a Gram-negative intracellular bacilli which is transmitted to humans via cat bite/scratch. Typical CSD presents as regional lymphadenopathy and fever. However, there are multiple atypical presentations of cat scratch disease that have been reported including prolonged fever, absence of lymphadenopathy and systemic complications such hepatosplenic disease, osteomyelitis, Parinaud oculoglandular syndrome, neuroretinitis, encephalitis, and bacillary angiomatosis among other rare presentations. The aim of this study was to review the frequency, presentation, and treatment outcomes of aytpical CSD presentations at Nationwide Children’s Hospital (Columbus OH).

Methods

This was a retrospective study performed at Nationwide Children’s Hospital, Columbus, OH. EMR of patients were reviewed between January 2010 and March 2017 using ICD9 or ICD 10 codes for CSD. Patients were identified on the basis of compatible clinical presentation and confirmatory serological test or PCR results for B. henselae. Clinical, radiological, and histopathological findings were collected

Results

A total of 204 patients were serologically diagnosed as having cat scratch disease between January 2010 and July 2017. Of the 204 cases, 166 (81%) had typical CSD and 38 (18.6%) had atypical CSD. Of the atypical manifestations, 20 (52%) patients had no lymphadenopathy, 12 (31%) had osteomyelitis, 12 (31%) patients had hepatic and/or splenic microabscesses, 4 (10.5%) had osteomyelitis and hepatic/splenic involvement, 3 (1.5%) had encephalitis, 2 (5.2%) had neuroretinitis, and there was one case each (2.6%) of Parinaud oculoglandular syndrome, uveitis, pulmonary cavitary lesion, myocarditis, and endocarditis. Fever of unknown origin was present in 28 (75.6%) of the atypical CSD cases. The median duration of antibiotic treatment was 25 days (IQR 31) and median duration of illness in patients with atypical CSD was 51 days (IQR 56). The majority of patients were treated with dual antibiotic therapy that included rifampin.

Conclusion

In children with fever of unknown origin, serologic testing for CSD should be performed even in the absence of lymphadenopathy and a search for underlying systemic complications is recommended for prompt diagnosis and appropriate treatment.

Disclosures

All authors: No reported disclosures.

Increased fibrosis: A novel means by which GH influences white adipose tissue function

OBJECTIVE

White adipose tissue (WAT) fibrosis - the buildup of extracellular matrix (ECM) proteins, primarily collagen - is now a recognized hallmark of tissue dysfunction and is increased with obesity and lipodystrophy. While growth hormone (GH) is known to increase collagen in several tissues, no previous research has addressed its effect on ECM in WAT. Thus, the purpose of this study is to determine if GH influences WAT fibrosis.

DESIGN

This study examined WAT from four distinct strains of GH-altered mice (bGH and GHA transgenic mice as well as two tissue specific GH receptor gene disrupted lines, fat growth hormone receptor knockout or FaGHRKO and liver growth hormone receptor knockout or LiGHRKO mice). Collagen content and adipocyte size were studied in all cohorts and compared to littermate controls. In addition, mRNA expression of fibrosis-associated genes was assessed in one cohort (6month old male bovine GH transgenic and WT mice) and cultured 3T3-L1 adipocytes treated with GH.

RESULTS

Collagen stained area was increased in WAT from bGH mice, was depot-dependent, and increased with age. Furthermore, increased collagen content was associated with decreased adipocyte size in all depots but more dramatic changes in the subcutaneous fat pad. Notably, the increase in collagen was not associated with an increase in collagen gene expression or other genes known to promote fibrosis in WAT, but collagen gene expression was increased with acute GH administration in 3T3-LI cells. In contrast, evaluation of 6month old GH antagonist (GHA) male mice showed significantly decreased collagen in the subcutaneous depot. Lastly, to assess if GH induced collagen deposition directly or indirectly (via IGF-1), fat (Fa) and liver (Li) specific GHRKO mice were evaluated. Decreased fibrosis in FaGHRKO and increased fibrosis in LiGHRKO mice suggest GH is primarily responsible for the alterations in collagen.

CONCLUSIONS

Our results show that GH action is positively associated with an increase in WAT collagen content as well as a decrease in adipocyte size, particularly in the subcutaneous depot. This effect appears to be due to GH and not IGF-1 and reveals a novel means by which GH regulates WAT accumulation.

Depot-specific and GH-dependent regulation of IGF binding protein-4, pregnancy-associated plasma protein-A, and stanniocalcin-2 in murine adipose tissue

INTRODUCTION

Pregnancy-associated plasma protein-A (PAPP-A) stimulates insulin-like growth factor (IGF)-I action through proteolytic cleavage of IGF binding protein-4 (IGFBP-4). Recently, stanniocalcin-2 (STC2) was discovered as an inhibitor of PAPP-A. Most members of the IGF system are expressed in adipose tissue (AT), but there is a relative paucity of information on the distribution of IGFBP-4, PAPP-A, and STC2 in different AT depots. Since IGF-I expression in AT is highly GH-dependent, we used bovine GH transgenic (bGH) and GH receptor knockout (GHR-/-) mice to investigate AT depot-specific expression patterns of IGFBP-4, PAPP-A, and STC2, and whether the regulation is GH-dependent.

METHODS

Seven-month-old male bGH, GHR-/- and wild type (WT) control mice were used. Body composition was determined, and subcutaneous, epididymal, retroperitoneal, mesenteric and brown adipose tissue (BAT) depots were collected. RNA expression of Igfbp4, Pappa, and Stc2 was assessed by reverse transcription quantitative PCR and IGFBP-4 protein by Western blotting.

RESULTS

Igfbp4, Pappa, and Stc2 RNA levels were differentially expressed in an AT depot-dependent manner in WT mice. Igfbp4 RNA levels were significantly higher in all white AT depots than in BAT. Pappa was most highly expressed in the mesenteric depot: levels were 7.5-fold higher in mesenteric than in subcutaneous AT (p < .001). Although intraabdominal in origin, epididymal and retroperitoneal Pappa expression levels were 69% and 68% lower, respectively, as compared to mesenteric levels (p < .001). Stc2 RNA expression was significantly higher in all intraabdominal white AT as compared to subcutaneous AT and BAT; levels in epididymal, retroperitoneal, and mesenteric were all more than three-fold higher than in subcutaneous AT (p < .001) and 12-fold higher than in BAT (p < .001). Gene expression patterns in bGH and GHR-/- mice mimicked those in WT mice, suggesting that GH does not affect the transcription of the STC2-PAPP-A-IGFBP-4-axis in AT. However, proteins levels of intact IGFBP-4 were significantly increased in bGH mice and decreased in GHR-/- mice, whereas the PAPP-A-generated IGFBP-4 fragment level was unaltered.

CONCLUSION

Expression of Igfbp4, Pappa, and Stc2 differ between AT depots and is generally higher in white AT than in BAT. The transcription appears to occur in a GH-independent manner, whereas IGFBP-4 protein levels are highly influenced by altered GH activity.

Insulin, IGF-1, and GH Receptors Are Altered in an Adipose Tissue Depot-Specific Manner in Male Mice With Modified GH Action

Growth hormone (GH) is a determinant of glucose homeostasis and adipose tissue (AT) function. Using 7-month-old transgenic mice expressing the bovine growth hormone (bGH) gene and growth hormone receptor knockout (GHR-/-) mice, we examined whether changes in GH action affect glucose, insulin, and pyruvate tolerance and AT expression of proteins involved in the interrelated signaling pathways of GH, insulinlike growth factor 1 (IGF-1), and insulin. Furthermore, we searched for AT depot-specific differences in control mice. Glycated hemoglobin levels were reduced in bGH and GHR-/- mice, and bGH mice displayed impaired gluconeogenesis as judged by pyruvate tolerance testing. Serum IGF-1 was elevated by 90% in bGH mice, whereas IGF-1 and insulin were reduced by 97% and 61% in GHR-/- mice, respectively. Igf1 RNA was increased in subcutaneous, epididymal, retroperitoneal, and brown adipose tissue (BAT) depots in bGH mice (mean increase ± standard error of the mean in all five depots, 153% ± 27%) and decreased in all depots in GHR-/- mice (mean decrease, 62% ± 4%). IGF-1 receptor expression was decreased in all AT depots of bGH mice (mean decrease, 49% ± 6%) and increased in all AT depots of GHR-/- mice (mean increase, 94% ± 8%). Insulin receptor expression was reduced in retroperitoneal, mesenteric, and BAT depots in bGH mice (mean decrease in all depots, 56% ± 4%) and augmented in subcutaneous, retroperitoneal, mesenteric, and BAT depots in GHR-/- mice (mean increase: 51% ± 1%). Collectively, our findings indicate a role for GH in influencing hormone signaling in AT in a depot-dependent manner.

Growth Hormone Receptor Antagonist Transgenic Mice Have Increased Subcutaneous Adipose Tissue Mass, Altered Glucose Homeostasis and No Change in White Adipose Tissue Cellular Senescence

BACKGROUND

Growth hormone (GH)-resistant/deficient mice experience improved glucose homeostasis and substantially increased lifespan. Recent evidence suggests that long-lived GH-resistant/deficient mice are protected from white adipose tissue (WAT) dysfunction, including WAT cellular senescence, impaired adipogenesis and loss of subcutaneous WAT in old age. This preservation of WAT function has been suggested to be a potential mechanism for the extended lifespan of these mice.

OBJECTIVE

The objective of this study was to examine WAT senescence, WAT distribution and glucose homeostasis in dwarf GH receptor antagonist (GHA) transgenic mice, a unique mouse strain having decreased GH action but normal longevity.

METHODS

18-month-old female GHA mice and wild-type (WT) littermate controls were used. Prior to dissection, body composition, fasting blood glucose as well as glucose and insulin tolerance tests were performed. WAT distribution was determined by weighing four distinct WAT depots at the time of dissection. Cellular senescence in four WAT depots was assessed using senescence-associated β-galactosidase staining to quantify the senescent cell burden, and real-time qPCR to quantify gene expression of senescence markers p16 and IL-6.

RESULTS

GHA mice had a 22% reduction in total body weight, a 33% reduction in lean mass and a 10% increase in body fat percentage compared to WT controls. GHA mice had normal fasting blood glucose and improved insulin sensitivity; however, they exhibited impaired glucose tolerance. Moreover, GHA mice displayed enhanced lipid storage in the inguinal subcutaneous WAT depot (p < 0.05) and a 1.7-fold increase in extra-/intraperitoneal WAT ratio compared to controls (p < 0.05). Measurements of WAT cellular senescence showed no difference between GHA mice and WT controls.

CONCLUSIONS

Similar to other mice with decreased GH action, female GHA mice display reduced age-related lipid redistribution and improved insulin sensitivity, but no change in cellular senescence. The similar abundance of WAT senescent cells in GHA and control mice suggests that any protection against generation of senescent cells afforded by decreased GH action, low insulin-like growth factor 1 and/or improved insulin sensitivity in the GHA mice may be offset by their severe adiposity, since obesity is known to increase senescence.

Removal of growth hormone receptor (GHR) in muscle of male mice replicates some of the health benefits seen in global GHR-/- mice

Global disruption of the GH receptor in mice (GHR-/-) produces a large and reproducible extension in lifespan. Since lack of GH action in muscle resulting in improved glucose homeostasis is potentially a mechanism by which GHR-/- mice are long-lived, and since no information on muscle-specific GHR disruption in females is available, we generated and characterized a line of muscle-specific GHR disrupted (MuGHRKO) mice. As expected, male MuGHRKO mice had improved fasting blood glucose, insulin, c-peptide, and glucose tolerance. In contrast, female MuGHRKO mice exhibited normal glucose, insulin, and glucose tolerance. Body weight was mildly but significantly altered in opposite directions in males (decreased) and females (increased) compared to controls. Grip strength and treadmill endurance were unchanged with advanced age in both sexes, suggesting that the direct action of GH on muscle has minimal effect on age-related musculoskeletal frailty. Longevity was unchanged in both sexes at Ohio University and significantly increased for males at University of Michigan. These data suggest that removal of GHR in muscle of male MuGHRKO mice replicates some of the health benefits seen in global GHR-/- mice including improvements to glucose homeostasis and smaller body weight in males, which may explain the trends observed in lifespan.