Antimicrobial discontinuation in dogs with acute aspiration pneumonia based on clinical improvement and normalization of C‐reactive protein concentration

Abstract

Background: Evidence regarding optimal treatment duration in dogs with aspiration pneumonia (AP) and the role of thoracic radiographs (TXR) and lung ultrasonography (LUS) in the long-term follow-up of affected dogs is lacking. C-reactive protein (CRP) is a reliable acute phase protein to monitor bacterial pneumonia in dogs. Hypothesis: Investigate the safety of antimicrobial discontinuation based on clinical improvement and serum CRP normalization, as well as the usefulness of TXR and LUS for follow-up. Animals: Dogs diagnosed with AP and treated with antimicrobials. Methods: Prospective observational study. Antimicrobials were discontinued based on clinical improvement and serum CRP normalization after 1, 3, or 5 weeks. At each consultation, a quality-of-life questionnaire, physical examination, serum CRP, TXR, and LUS were assessed. Short-(2 weeks) and long-term (>1 month) follow-ups after treatment discontinuation were performed to monitor for possible relapses.Results: Seventeen dogs were included. Antimicrobials were discontinued after 1 week in 12 dogs (70.6%) and 3 weeks in the remaining 5 dogs (29.4%). Short-term relapse was not observed in any dog and long-term relapse was diagnosed in 3 dogs.Thoracic radiographs and LUS were useful for diagnosis, but did not add additional information during follow-up, because image normalization lagged behind clinical improvement and serum CRP normalization. Conclusion and ClinicalImportance: Dogs with AP can be safely and effectively treated using a short-term antimicrobial regimen discontinued after clinical improvement and serum CRP normalization. Imaging might still be useful for complicated cases with a less favorable response to treatment.

Change over time and agreement between clinical markers of disease resolution in dogs with aspiration‐induced lung injury

“…The calculated PE scores were based on the dog's vital signs (body temperature, heart rate and respiratory rate), percentage oxygen saturation in room air, respiratory pattern and pulmonary auscultation adapted from respiratory scoring previously reported in dogs, and a validated acute respiratory infection severity score used in infants and children. 21,[28][29][30] The clinical scoring system used to calculate PE scores is shown in Table 1. A single clinician (M.C.)…”

“…The CS-O scoring was adapted from the recently published respiratory scoring system reported in dogs and validated respiratory scoring used in people, including a published cough frequency/severity score. 21,[31][32][33] For this study, the owner scoring of each dog was simplified for ease of assessment and targeted what owners use to assess their dog's recovery. The focus of the CS-O score included the impact the dog's clinical signs had on disrupting the dog's activity and appetite, estimation of the dog's frequency of coughing and description of respiratory effort (Table 1).…”

“…For example, reported high C-reactive protein (CRP) concentrations in dogs with bacterial pneumonia have led to others investigating CRP normalisation as a marker to guide antibiotic treatment durations. [21][22][23][24][25][26][27] In addition, TXR as a marker of disease resolution in dogs with pneumonia has been challenged, with a recent study suggesting thoracic ultrasound as an alternative imaging tool. 22,24,26 Much of this recent work has focused on dogs with pneumonia of varying aetiologies, with only a few studies focused explicitly on dogs with aspiration pneumonia.…”

“…Of those studies with cohorts of dogs with aspiration pneumonia, the underlying pathology contributing to an aspiration event was not always well described. [21][22][23]26,27 Recently, studies in dogs with aspiration pneumonia have reported that CRP and clinical signs resolved before normalisation of pulmonary imaging, based on assessments at 1, 3 and 5 weeks. 21,22 More research is needed to increase our understanding of temporal changes associated with clinical disease resolution in defined populations of dogs with pneumonia, for example, dogs with A-ILI with an underlying risk factor for a single or repeated aspiration event.…”

“…[21][22][23]26,27 Recently, studies in dogs with aspiration pneumonia have reported that CRP and clinical signs resolved before normalisation of pulmonary imaging, based on assessments at 1, 3 and 5 weeks. 21,22 More research is needed to increase our understanding of temporal changes associated with clinical disease resolution in defined populations of dogs with pneumonia, for example, dogs with A-ILI with an underlying risk factor for a single or repeated aspiration event. Temporal changes of interest include how clinical signs and CRP concentrations evolve with treatment, especially during the first 72 hours after an aspiration event, to determine the dog's early response to treatment, or how to best prioritise clinical signs, CRP concentrations and TXR monitoring to determine disease recovery.…”