Negative energy balance is a prevalent feature of cystic fibrosis (CF). Pancreatic insufficiency, elevated energy expenditure, lung disease, and malnutrition, all characteristic of CF, contribute to the negative energy balance causing low body-growth phenotype. As low body weight and body mass index strongly correlate with poor lung health and survival of patients with CF, improving energy balance is an important clinical goal (e.g., high-fat diet). CF mouse models also exhibit negative energy balance (growth retardation and high energy expenditure), independent from exocrine pancreatic insufficiency, lung disease, and malnutrition. To improve energy balance through increased caloric intake and reduced energy expenditure, we disrupted leptin signaling by crossing the db/db leptin receptor allele with mice carrying the R117H Cftr mutation. Compared with db/db mice, absence of leptin signaling in CF mice (CF db/db) resulted in delayed and moderate hyperphagia with lower de novo lipogenesis and lipid deposition, producing only moderately obese CF mice. Greater body length was found in db/db mice but not in CF db/db, suggesting CF-dependent effect on bone growth. The db/db genotype resulted in lower energy expenditure regardless of Cftr genotype leading to obesity. Despite the db/db genotype, the CF genotype exhibited high respiratory quotient indicating elevated carbohydrate oxidation, thus limiting carbohydrates for lipogenesis. In summary, db/db-linked hyperphagia, elevated lipogenesis, and morbid obesity were partially suppressed by reduced CFTR activity. CF mice still accrued large amounts of adipose tissue in contrast to mice fed a high-fat diet, thus highlighting the importance of dietary carbohydrates and not simply fat for energy balance in CF. NEW & NOTEWORTHY We show that cystic fibrosis (CF) mice are able to accrue fat under conditions of carbohydrate overfeeding, increased lipogenesis, and decreased energy expenditure, although length was unaffected. High-fat diet feeding failed to improve growth in CF mice. Morbid db/db-like obesity was reduced in CF double-mutant mice by reduced CFTR activity.

Marfan syndrome is a rare connective tissue disorder with a prevalence of approximately 2 to 3 per 10,000 individuals. There have been some reports of young patients with Marfan syndrome developing arteriovenous thromboembolism. These events were unprovoked and recurrent. Owing to its rarity, hypercoagulopathy and other metabolic derangement in patients with Marfan syndrome remains largely unknown. Herein, we report a case of a young man with Marfan syndrome who had myocardial infarction and pulmonary embolism. We hope that this case adds to the scant body of knowledge about this patient population.

How smart is the chart? Completeness of the medical record in documenting diarrhea in patients tested for Clostridioides difficile infection.

INTRODUCTION: Capnocytophaga species are a collection of fusiform gram-negative rods that are considered part of the oral commensal flora. They are opportunistic pathogens and most often cause periodontal infections. In immunocompromised patients, C. Canimorsus can be transmitted via dog bite and causes severe sepsis, with death as a frequent outcome. CASE PRESENTATION:We present a case of a 36-year-old woman with no known past medical history who presented to outside hospital with acute onset of fevers and malaise as well as subacute polyarthralgia, malar rash, and fatigue. Labs showed severe leukopenia with concern for acute myeloid leukemia prompting her transfer to our institution. Upon arrival, peripheral smear showed toxic appearing neutrophils, thrombocytopenia, and no evidence of blasts with overall smear findings consistent with severe sepsis. Patient was anuric with labs consistent with D.I.C. She had a purpuric rash affecting bilateral distal upper and lower extremities consistent with purpura fulminans. She was started on vancomycin and piperacillin / tazobactam with blood, urine and sputum cultures obtained. On admission day 3 she was intubated for acute hypoxic respiratory failure secondary to volume overload from acute renal failure. Given the high acuity and rapid progression of her illness a broad differential was entertained. Hematology, nephrology, rheumatology, and infectious disease were consulted for aid in diagnosis and treatment. Initially there was higher index of suspicion for hemophagocytic lymphohistiocytosis (HLH) given the cytopenias, ferritin > 5000, and acute inflammatory syndrome. Soluble IL-2 receptor levels were sent and found to be elevated, however not high enough to be specific for HLH. After further history taking, it was revealed that she had sustained a bite from her pet dog with puncture wound on her fingers 3 days before falling ill. Dermatology performed tissue biopsy which did reveal bacterial tissue growth. Pathologist review of the peripheral blood smear revealed the presence of intra-cellular gram-negative organisms in several of the patient's neutrophils consistent with C. canimorsus infection. With supportive care, initiation of RRT and antibiotics she improved. She did require amputation of several digits on her hands and feet and had a prolonged course while inpatient, but eventually was discharged from the hospital. DISCUSSION: Risk factors for severe infection with C. canimorsus include asplenia, alcoholism, and immune compromise. Further discussion revealed that she had been drinking close to 8 beers per day prior to her bite, which is her most likely predisposing factor for this presentation.CONCLUSIONS: This case underlies the importance of maintaining a broad differential and frequently revisiting the differential, history, and exam as more information becomes available.

BackgroundInappropriate testing for Clostridium difficile infection (CDI) may result in diagnosis of CDI in asymptomatic carriers with diarrhea due to other causes such as laxatives. Current guidelines suggest that periodic chart review may be useful to assess the appropriateness of CDI testing, but it is not known how accurate the medical record is in documenting diarrhea.MethodsWe conducted a prospective cohort study of 80 patients tested for CDI to determine the accuracy of diarrhea documentation in the medical record in comparison to patient interviews and to assess the appropriateness of testing.ResultsThirty-five of 80 (44%) CDI tests were deemed inappropriate because patients either did not have clinically significant diarrhea (i.e., 3 or more unformed stools per day) or had an alternative explanation for diarrhea. Seventy-four of 80 (93%) patients stated they had diarrhea, but only 53 (66%) had clinically significant diarrhea based on symptom review. Physician and/or nursing notes documented diarrhea in 67 of 80 (84%) patients, but the number of bowel movements and the consistency of stool were documented for only 36 (45%) and 41 (51%) patients.ConclusionIn our facility, inappropriate CDI testing was common and the accuracy of the medical record in documenting diarrhea was suboptimal. Education of patients and providers may be beneficial in improving the accuracy of diarrhea documentation and the appropriateness of testing.Disclosures All authors: No reported disclosures.