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Robinson, John C.

https://orcid.org/0000-0002-3061-2492

Mayo Clinic

Mayo Clinic

Citations 3

Gastric Bypass Associated Hyperammonemia (GaBHA): A Case Study, Scoping Review of the Literature, and Proposed New Pathophysiologic Mechanism
Fenves, Andrew Z. , Hatipoğlu, Dilara , Robinson, John C. , Rothkopf, Michael M.

Metabolites | August 28, 2025 | Volume: 15 | Issue: 9 | Pages: 573

10.3390/metabo15090573 Get It

Background/Objectives: GaBHA syndrome (gastric bypass hyperammonemia) is an emerging new syndrome primarily in women who had prior Roux-en-Y gastric bypass surgery (RYGB) and then developed non-cirrhotic hyperammonemia with a high case–fatality ratio. Genetic and nutritional deficiencies have been implicated in the pathogenesis of this clinical condition, but none has been proven. We present an illustrative case and do a scoping review of the current literature in 58 patients with this diagnosis. Methods: A retrospective scoping literature review was utilized to identify patients who fulfilled 1. RYGB surgery, and 2. Hyperammonemic encephalopathy following the PRISMA extended checklist. We searched PubMed, MedLine, SCOPUS, and Web of Science databases. Results: We described the classic presenting symptoms and laboratory findings of this syndrome. We confirmed the female predominance (93%) and the high case–fatality ratio (32%). We then presented a novel hypothesis contending that arginine deficiency ultimately leads to a functional deficiency of the ornithine transcarbamolyase (OTC) enzyme, leading to the non-cirrhotic life-threatening hyperammonemia. Our hypothesis may also explain the high incidence of hypoglycemia found in these patients as we found in our search. Our proposed hypothesis may also be relevant to the occurrence of hyperammonemia in some solid organ transplant recipients. Conclusions: GaBHA syndrome is emerging as an important potential adverse outcome after RYGB surgery. It has a female predominance and a high case–fatality ratio. Arginine deficiency may explain the emergence of a functional OTC deficiency, which then leads to the severe hyperammonemia, and may also explain the frequent occurrence of hypo-glycemia in these patients.
Pharmacokinetics of Sulbactam/Durlobactam in a Patient With Acute Renal Failure, Severe Obesity, and Carbapenem‐Resistant Acinetobacter baumannii Bacterem
Ilges, Dan , Fu, Yakun , Dickinson, Drew T. , Robinson, John C. , Speiser, Lisa , Nicolau, David P., Speiser, Lisa J , Ilges, Dan , Nicolau, David P.

Pharmacotherapy: The Journal of Human Pharmacology and Drug Therapy | July 18, 2025 | Volume: 45 | Issue: 8 | Pages: 522-528

10.1002/phar.70042 Get It

ABSTRACT Carbapenem‐resistant Acinetobacter baumannii (CRAB) are difficult‐to‐treat pathogens that primarily cause health care‐associated infections. Sulbactam/durlobactam (SUL/DUR) is a novel antibiotic combination that is uniquely formulated to target CRAB isolates. However, investigations of SUL/DUR's pharmacokinetics in obese patients are limited. Here, we report on the successful treatment of CRAB bacteremia in a patient with acute renal failure and severe obesity (weight 273 kg, body mass index 103 kg/m 2 ) with SUL/DUR and meropenem combination therapy. The patient had a calculated creatinine clearance of 25 mL/min and received therapy with intravenous SUL/DUR 1 g/1 g every 8 h over 3 h in combination with intravenous meropenem 500 mg every 8 h to complete 14 days of therapy. Pharmacokinetic analysis revealed target attainment with prolonged half‐life ( T 1/2 ) and volume of distribution (Vd) of 35.3 h and 81.3 L for sulbactam and 30.5 h and 169.1 L for durlobactam, respectively. Susceptibility testing using the broth disk elution test did not show synergy between SUL/DUR and meropenem. No adverse effects were observed, and the patient achieved clinical cure without recurrence of A. baumannii infection.
Impact of Hypoalbuminemia on Clinical Outcomes in Patients Receiving Cefazolin for Methicillin-Susceptible Staphylococcus aureus Bacteremia
Whitenack, Kaylee, Ilges, Dan , Epps, Kevin , McGary, Alyssa , Robinson, John C. , Whitenack, Kaylee M , Ilges, Dan

Annals of Pharmacotherapy | February 20, 2025 | Volume: 59 | Issue: 9 | Pages: 794-800

10.1177/10600280251313874 Get It

Background: Cefazolin is a preferred treatment option for methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. Recent studies have suggested a potential impact on clinical outcomes in patients with hypoalbuminemia treated with highly protein-bound antimicrobials. Objective: The purpose of this study was to determine if there are any differences in clinical outcomes between normoalbuminemic and hypoalbuminemic patients treated with cefazolin for bacteremia. Methods: A retrospective, multicentered cohort study of patients hospitalized between 2019 and 2023 with MSSA bacteremia treated with cefazolin for at least 24 hours prior to culture clearance. Patients were divided into hypoalbuminemia (serum albumin ≤2.5 g/dL) or normoalbuminemia groups. The primary outcome was time to culture clearance. Results: Of 69 patients included (50 in normoalbuminemia group and 19 in hypoalbuminemia group), the most common sources of bacteremia were line-related, osteoarticular, and infective endocarditis. Deep-seated infections were present in 24% of the normoalbuminemia group and 58% of the hypoalbuminemia group. Patients with hypoalbuminemia had a significantly longer mean hospital length of stay (12 vs 7 days, P = 0.016). After adjusting for deep-seated infection, hypoalbuminemia was associated with increased time to culture clearance by 1.2 days ( P = 0.039). In-hospital mortality was significantly higher in the hypoalbuminemia group (26% vs 4%, P = 0.015). Conclusion and Relevance: Limited research is available describing the relationship between serum albumin levels and clinical outcomes. Our study suggests patients with hypoalbuminemia treated with cefazolin for MSSA bacteremia have significantly longer time to culture clearance, increased mortality, and longer length of stay.