Longitudinal disease-associated gut microbiome differences in infants with food protein-induced allergic proctocolitis.

BACKGROUND: Complex interactions between the gut microbiome and immune cells in infancy are thought to be part of the pathogenesis for the marked rise in pediatric allergic diseases, particularly food allergies. Food protein-induced allergic proctocolitis (FPIAP) is commonly the earliest recognized non-immunoglobulin E (IgE)-mediated food allergy in infancy and is associated with atopic dermatitis and subsequent IgE-mediated food allergy later in childhood. Yet, a large prospective longitudinal study of the microbiome of infants with FPIAP, including samples prior to symptom onset, has not been done. RESULTS: Here, we analyzed 954 longitudinal samples from 160 infants in a nested case-control study (81 who developed FPIAP and 79 matched controls) from 1 week to 1 year of age by 16S rRNA ribosomal gene sequencing as part of the Gastrointestinal Microbiome and Allergic Proctocolitis (GMAP) study. We found key differences in the microbiome of infants with FPIAP, most strongly a higher abundance of a genus of Enterobacteriaceae and a lower abundance of a family of Clostridiales during the symptomatic period. We saw some of these significant taxonomic differences even prior to symptom onset. There were no consistent longitudinal differences in richness or stability diversity metrics between infants with FPIAP and healthy controls. CONCLUSIONS: This study is the first to identify differences in the infant gut microbiome in children who develop FPIAP, some even before they develop symptoms, and provides a foundation for more mechanistic investigation into the pathogenesis of FPIAP and subsequent food allergic diseases in childhood. Video abstract.

An Unusual Case of Neurosyphilis Manifesting as Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH).

BACKGROUND Syphilis has increased in prevalence in the United States by 72.7% from 2013 to 2017, with the highest rates recorded in men who have sex with men. There is an increased incidence of syphilis in patients with a concomitant HIV infection, estimated at a 77-fold increase. CASE REPORT This report documents an unusual case of neurosyphilis manifesting as syndrome of inappropriate antidiuretic hormone secretion (SIADH) in a 56-year-old man with HIV/AIDS. A 56-year-old man who has sex with men with HIV/AIDS presented with a 4-day history of periumbilical abdominal pain, nausea, and constipation. A physical exam revealed slowing of baseline cognition, but was otherwise unremarkable. Urine and serum osmolality studies were consistent with SIADH as defined by the Bartter and Schwartz Criteria: serum osmolality <275 mOsm/kg, urine osmolality >100 mOsm/kg, urine sodium >20-40 mmol/L, euvolemia, and no other cause for hyponatremia identified. He was fluid-restricted, with improvement in laboratory abnormalities, further supporting the diagnosis of SIADH. A diagnostic work-up included a CT abdomen/pelvis with perirectal lymphadenopathy, colonoscopy negative for malignancy, chest CT with lymphadenopathy, and a head MRI negative for intracranial processes. The patient was ultimately found to have positive results on rapid plasma reagin (RPR) and Venereal Disease Research Laboratory (VDRL) tests, and was diagnosed as having neurosyphilis. He underwent penicillin desensitization and received a 14-day course of penicillin G, with recovery of sodium to normal range on discharge. CONCLUSIONS Our case highlights SIADH as an initial presenting sign of neurosyphilis with HIV infection, which has only been documented in 2 prior case reports. Our case highlights the importance of recognizing atypical presentations of neurosyphilis in patients with HIV to prevent long-term complications.