Browsing by Author "Montgomery, Gregory"

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    Association of Antibiotics, Airway Microbiome, and Inflammation in Infants with Cystic Fibrosis
    (American Thoracic Society, 2017-10) Pittman, Jessica E.; Wylie, Kristine M.; Akers, Kathryn; Storch, Gregory A.; Hatch, Joseph; Quante, Jane; Frayman, Katherine B.; Clarke, Nadeene; Davis, Miriam; Stick, Stephen M.; Hall, Graham L.; Montgomery, Gregory; Ranganathan, Sarath; Davis, Stephanie D.; Ferkol, Thomas W.; Pediatrics, School of Medicine
    RATIONALE: The underlying defect in the cystic fibrosis (CF) airway leads to defective mucociliary clearance and impaired bacterial killing, resulting in endobronchial infection and inflammation that contributes to progressive lung disease. Little is known about the respiratory microbiota in the early CF airway and its relationship to inflammation. OBJECTIVES: To examine the bacterial microbiota and inflammatory profiles in bronchoalveolar lavage fluid and oropharyngeal secretions in infants with CF. METHODS: Infants with CF from U.S. and Australian centers were enrolled in a prospective, observational study examining the bacterial microbiota and inflammatory profiles of the respiratory tract. Bacterial diversity and density (load) were measured. Lavage samples were analyzed for inflammatory markers (interleukin 8, unbound neutrophil elastase, and absolute neutrophil count) in the epithelial lining fluid. RESULTS: Thirty-two infants (mean age, 4.7 months) underwent bronchoalveolar lavage and oropharyngeal sampling. Shannon diversity strongly correlated between upper and lower airway samples from a given subject, although community compositions differed. Microbial diversity was lower in younger subjects and in those receiving daily antistaphylococcal antibiotic prophylaxis. In lavage samples, reduced diversity correlated with lower interleukin 8 concentration and absolute neutrophil count. CONCLUSIONS: In infants with CF, reduced bacterial diversity in the upper and lower airways was strongly associated with the use of prophylactic antibiotics and younger age at the time of sampling; less diversity in the lower airway correlated with lower inflammation on bronchoalveolar lavage. Our findings suggest modification of the respiratory microbiome in infants with CF may influence airway inflammation.
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    Chronic Thromboembolic Pulmonary Hypertension Successfully Treated in a Six Year Old with Asthma
    (authorea, 2020) Serrano, Ryan; Montgomery, Gregory; Rao, Rohit; Kivett, Tisha; Johansen, Michael; Pediatrics, School of Medicine
    Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but serious, sequala of acute pulmonary embolism. Symptoms can be subtle and non-specific and the prognosis is poor if severe pulmonary hypertension (PH) and right ventricular dysfunction are present. While PH-targeted therapies are often used, there is only one FDA approved therapy, and only for disease that is deemed inoperable. The greatest chance for potential cure and long-term survival is surgical pulmonary endarterectomy. We report a 6-year-old male with a history of asthma and two unprovoked deep venous thromboses who presented with syncope. Chest x-ray showed cardiomegaly and an echocardiogram showed severe PH with severely decreased right ventricular (RV) function. Ventilation-perfusion scan showed mismatched perfusion defects involving the right lower lobe, and CT of the chest showed right lower lobe subsegmental pulmonary thrombus, suspicious for chronic thromboembolism. Given his clinical presentation and the severity of his right ventricular dysfunction, he was started on ambrisentan, sildenafil and subcutaneous treprostinil. Bilateral pulmonary endarterectomy was performed with resection of level 2 to 3 disease and he was successfully weaned off all PH therapy. Four months post-op, he is clinically asymptomatic and his echo shows normal RV function without PH. In conclusion, CTEPH is a rare but likely underdiagnosed disease process in pediatrics. Clinicians should have a high index of suspicion for at risk patients with unexplained dyspnea. Even if right ventricular dysfunction and severe PH are present, surgical pulmonary endarterectomy can be performed successfully in young children.
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    Wheezing in Preterm Infants and Children
    (Authorea, 2020-11-20) Rhoads, Eli; Montgomery, Gregory; Ren, Clement; Pediatrics, School of Medicine
    Wheezing is a common outcome of preterm birth. This article will review the mechanisms, epidemiology, and treatment of wheezing in preterm children with and without a history of bronchopulmonary dysplasia