Emergency Medicine

Select Active Projects

The EC-ID research program is currently conducting a number of ongoing studies in three primary lines of inquiry, as well as numerous collaborations and consultations.

Cellulitis diagnosis Pneumonia in older adults COVID-19 and antibiotic stewardship

Improving Cellulitis Diagnosis for Emergency Department Patients

Background: Skin and soft tissue infections account for 2% of all emergency department (ED) encounters (2.8 million annual visits).1 Cellulitis is one of the most common indications for antibiotics in the ED, but this condition frequently involves misdiagnosis and inappropriate antibiotic use.2–4

Challenge: Cellulitis is largely a clinical diagnosis, defined by expanding redness, warmth, tenderness and edema. These features are commonly found in inflammatory dermatologic conditions that can mimic infections like cellulitis, such as venous stasis dermatitis, deep venous thrombosis, lymphedema, and gout.5 Studies using dermatology review as the diagnostic gold standard, have identified high rates of cellulitis misdiagnosis in the ED (30%), ambulatory care (67%), and inpatient wards (74%).6–8

To better understand and address this diagnostic dilemma, we are conducting the following studies.

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Characterizing barriers to antibiotic stewardship for skin and soft tissue infections in the ED using a systems engineering framework

We conducted 20 interviews with emergency physicians from across the country to characterize barriers and facilitators to optimal antibiotic use for skin and soft tissue infections (SSTIs) in the emergency department (ED) using a systems engineering framework and matched them with targeted stewardship interventions.

Identified barriers to optimal antibiotic prescribing for SSTIs: Poor access to follow-up (organization), need for definitive diagnostic tools (tools and technology), fear over adverse outcomes related to missed infections (person).

Identified potential interventions: Programs to enhance follow-up care, diagnostic aides (e.g., rapid MRSA assays for purulent infections and surface thermal imaging for cellulitis), and shared decision-making tools.

Funding

  • AHRCQ Mentored Clinical Scientist Career Development Award: K08HS024342 (PI: Michael Pulia), 2016-2021
  • Wisconsin Partnership Program New Investigator Award (PI: Michael Pulia), 2016-2019
  • Central Society for Clinical and Translational Research: New Investigator Award (PI: Michael Pulia), 2019-2020
  • BerbeeWalsh Department of Emergency Medicine Pilot Award (PI: Michael Pulia), 2019-2022

Related Article

Pulia MS, Schwei RJ, Hesse SP, Werner NE. Characterizing barriers to antibiotic stewardship for skin and soft-tissue infections in the emergency department using a systems engineering framework. Antimicrob Steward Healthc Epidemiol. 2022 Nov 7;2(1):e180. doi: 10.1017/ash.2022.316. PMID: 36386011; PMCID: PMC9641503.

Validation of thermal imaging and the ALT-70 prediction model to differentiate cellulitis from pseudocellulitis

We enrolled 204 adult participants in a validation study of surface thermal temperatures as a diagnostic tool to differentiate cellulitis from pseudocellulitis. Participants were eligible to participate if they presented to the ED with an acute dermatologic complaint of the lower extremity. High-definition photographs and thermal images were taken of the participant’s affected and unaffected extremity. Skin surface temperatures (Tmax, Tavg) were obtained for the affected area of skin and exact corresponding area of the unaffected limb. Detailed information about demographics and symptoms were obtained using a patient survey and structured chart review.

All encounters were independently reviewed by a panel of six board certified physicians to determine the majority consensus diagnosis regarding the presence or absence of cellulitis. A majority cellulitis (yes/no) consensus was reached when at least four physicians agreed upon a cellulitis diagnosis.

The expert panel and treating physician disagreed on diagnosis in 27% of cases. This misdiagnosis rate is consistent with other studies, supporting the validity of our expert panel consensus process.6,9

Among patients with cellulitis, the affected skin was 2.9°C warmer than their unaffected skin (paired t-test; 95% CI: 2.5 to 3.4°C; p<0.001). Likewise, the surface skin temperature on the affected skin was significantly warmer in patients with cellulitis than pseudocellulitis (unpaired t-test; 2.0°C; 95% CI: 1.3 to 2.7°C; p<0.001). These findings suggest skin surface temperature can help differentiate cellulitis and pseudocellulitis.

Our future research will investigate what combination of clinical factors and thermal imaging data can best differentiate cellulitis from pseudocellulitis.

Funding

  • AHRCQ Mentored Clinical Scientist Career Development Award: K08HS024342 (PI: Michael Pulia), 2016-2021
  • Wisconsin Partnership Program New Investigator Award (PI: Michael Pulia), 2016-2019
  • Central Society for Clinical and Translational Research: New Investigator Award (PI: Michael Pulia), 2019-2020
  • BerbeeWalsh Department of Emergency Medicine Pilot Award (PI: Michael Pulia), 2019-2022

Related Articles

The Role of Oral Hypofunction, Dysphagia, and the Upper Airway Microbiome on Pneumonia Pathogenesis in Older Adults

Background: Pneumonia is the leading infectious cause of mortality among adults aged 65 or older (>40,000 deaths), with some estimates indicating that pneumonia is a contributing factor in more than 350,000 deaths among older adults annually.11,15 Pneumonia is also the most common cause of sepsis in older adults.

Challenge: After an initial episode of pneumonia, there is a significant risk of recurrence and associated delayed morbidity and mortality for older adults.16,17 Although much less is known about risk factors for recurrent pneumonia compared to incident cases, increasing age and impaired functional status are two independent predictors.17,18 Poor oral health and oropharyngeal dysphagia (swallowing dysfunction) are known risk factors for initial and recurrent pneumonia, but the underlying mechanisms are vastly understudied. It remains unclear why some patients with these conditions will develop pneumonia while others do not.19–24

To clarify the role of oral hypofunction, dysphagia and the upper airway microbiome in the development of pathogenesis we are conducting the following studies.

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Comparative evaluation of bacterial microbiome profiles by dysphagia status

We are enrolling emergency department patients in a research study to identify the prevalence of dysphagia and frailty and malnutrition. We will compare the prevalence between older adults with and without pneumonia.

Comparison of prevalence of dysphagia, frailty and malnutrition between patients with pneumonia and other older adults with a non-infectious concern

18 ED patients with pneumonia had microbiome samples collected from several sites in the oral cavity. The cohort was evenly divided with 50% failing the 3-ounce water swallow dysphagia screen. Bacterial community composition was characterized by PCR amplification of the v3-4 variable region of the 16S rRNA gene. Comparison of alpha rarefactions, between pneumonia participants with or without dysphagia risk, revealed reduced taxa diversity in the dysphagia group at all three sampling sites. Additionally, Analysis of Compositions of Microbiomes with Bias Correction (ANCOM-BC) differential abundance tests identified several bacterial taxa at the genus level as either significantly enriched or depleted, in participants with dysphagia compared to the non-dysphagia group. At least one genus was >2 LFC more abundant in the dysphagia group at each site (saliva = Staphylococcus; buccal = Corynebacterium; tongue = Anaeroglobus and Alloprevotella).

Use of a translational lung on a chip model to catalyze diagnostic and therapeutic advances for aspiration pneumonia

Active from April 2024 to March 2026
Role: Co-PI
Funded by: Wisconsin Partnership Program

Background: This project seeks to develop a novel diagnostic model for aspiration pneumonia (AP) through identification of a unique molecular signature for lung injury due to aspiration. Pneumonia is the leading infectious cause of mortality in older adults and about 15 percent of cases are due to AP, which currently lacks objective diagnostic criteria and methodology for identifying high risk patients. The results of this project could inform identification of effective interventions for AP and promote improved health outcomes for at-risk older adults throughout Wisconsin.

Challenges: Pneumonia, the leading infectious cause of death in United States hospitals across all age groups, includes aspiration pneumonia, where food, saliva or liquid entering the airway causes infection. Conditions like dementia or muscle weakness can lead to difficulty swallowing, increasing the risk of aspiration. Treatment involves antibiotics and rehabilitative interventions to improve swallowing function. However, there are no clear guidelines or tests to distinguish AP from other causes of pneumonia which leads to inappropriate treatment, including overuse of antibiotics. Developing tests to diagnose AP and identify high-risk patients is crucial for effective treatment. Current diagnostic methods rely on clinical suspicion, lacking rigorous evaluation of swallowing function, compounded by limitations in animal models. A new approach is necessary to enhance diagnosis and treatment of AP.

Aims: The overarching goals of this project are to identify noninvasive diagnostic biomarkers for AP, develop objective methods to stratify the risk of infection in patients with aspiration and identify the causes of AP to facilitate the development of precision therapies for the infection.

Impact of COVID-19 on Antibiotic Stewardship

Background: The pandemic represents an unprecedented stress test for hospital-based antibiotic stewardship programs and available reports demonstrate a concerning pattern. Specifically, a series of systematic reviews and meta-analyses have identified high rates of antibiotic use among patients hospitalized with COVID-19, despite low rates of culture confirmed bacterial co-infections.25–29

Challenge: This reflects a continuation of pre-pandemic trends from various healthcare settings, including acute care hospitals, in which 30-50% of antibiotic prescribing for acute respiratory conditions (e.g. asthma, congestive heart failure, influenza) is non-indicated. 30–36

To define the impact of COVID-19 on antibiotic stewardship, we conducted the following studies.

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Quantify the impact of COVID-19 on patient level antibiotic prescribing practices and bacterial resistance patterns in acute care hospitals using a large, diverse and nationally representative sample

We analyzed antibiotic prescribing over time in admissions for symptomatic COVID-19 and non-COVID-19 viral acute respiratory tract infections.

Related Article

Pulia M, Griffin M, Hekman DJ, Schwei R, Pop-Vicas AE, Schulz L, Shieh MS, Pekow P, Lindenauer P. 2269. Inpatient Antibiotic Prescribing for Symptomatic COVID-19 Patients in a Large US Sample, 2020-2022. Open Forum Infect Dis. 2023 Nov 27;10(Suppl 2):ofad500.1891. doi: 10.1093/ofid/ofad500.1891. PMCID: PMC10678375.

Examine the association between antibiotic treatment and a broad set of clinical outcomes among patients hospitalized for COVID-19 in hospitals across the U.S.

Despite low rates of bacterial co-infection, individuals with COVID-19 are frequently prescribed antibiotics. We sought to examine the association between antibiotic treatment and clinical outcomes among patients hospitalized for COVID-19.

Strategies for antimicrobial stewardship program resiliency during the COVID-19 pandemic

The COVID-19 pandemic was an unprecedented stress test for hospital-based antimicrobial stewardship (AMS) programs. The impact of COVID-19 on antimicrobial prescribing has been mixed. The purpose of this study was to characterize strategies for AMS program resiliency during the COVID-19 pandemic.

Strategies to optimize antibiotic stewardship for patients with COVID-19 using a systems engineering framework

The COVID-19 pandemic stressed antimicrobial stewardship programs with increased workloads and lack of guidance on the treatment of COVID-19. Throughout the pandemic, COVID-19 patients have received antibiotics for this viral illness despite reported low rates of confirmed bacterial co-infections. The purpose of this study was to identify challenges to and strategies for successful antibiotic stewardship for COVID-19 inpatients.

EC-ID Research Program

Questions can be directed to Becky Schwei, MPH, at rschwei@medicine.wisc.edu.

References are available here.