Clinical findings and outcome predictors for multinodular pulmonary fibrosis in horses: 46 cases (2009-2019).
Authors: Craven Amanda, Todd-Donato Amy, Stokol Tracy, Liepman Rachel, Glasberg Ilana, Wilkins Pamela, Luethy Daniela, Wong David, Schoster Angelika, van den Brom-Spierenburg Astrid J, Tomlinson Joy E
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Multinodular Pulmonary Fibrosis in Horses — Clinical Features and Prognostic Indicators Equine multinodular pulmonary fibrosis (EMPF) represents a serious interstitial lung disease with poorly understood prognostic markers, prompting this retrospective multicenter analysis of 46 affected horses diagnosed between 2009 and 2019. The research team reviewed diagnostic imaging and bronchoalveolar lavage fluid (BALF) cytology, identifying classical presentation signs including weight loss (78%), increased respiratory effort (72%), tachypnea (70%), and fever (39%), alongside consistent laboratory findings of elevated blood fibrinogen (89% of tested cases) and equine herpesvirus 5 detection (80%), with macrophage atypia appearing significantly more prevalent in EMPF than in equine asthma. Survival to discharge was achieved in 59% of cases, but only 24% survived three months, with longer-term survival correlating strongly with lower respiratory rates at presentation (30 versus 41 breaths per minute), higher BALF lymphocyte:neutrophil ratios (4.7 versus 0.47), and higher circulating lymphocyte counts (1.25 versus 0.90 × 10⁹/L)—notably, corticosteroid treatment and imaging findings failed to predict three-month outcome. For practitioners managing horses with unexplained weight loss, tachypnoea and respiratory distress, this evidence supports aggressive diagnostic investigation and suggests that immunological parameters may offer more reliable prognostic guidance than imaging alone, whilst also indicating that standard corticosteroid protocols warrant reconsideration given their lack of survival benefit in this condition.
Read the full abstract on PubMed
Practical Takeaways
- •Horses presenting with weight loss, increased respiratory effort, and elevated respiratory rate warrant diagnostic investigation for EMPF even without fever; fever alone is an insensitive clinical sign
- •EMPF carries a poor prognosis with only 24% surviving to 3 months post-diagnosis; corticosteroids do not improve outcomes and should be reconsidered as first-line therapy
- •BALF cytology showing macrophage atypia and lymphocyte-dominant patterns may help differentiate EMPF from other respiratory conditions like asthma, improving diagnostic accuracy
Key Findings
- •Primary clinical signs of EMPF include weight loss (78%), increased respiratory effort (72%), tachypnea (70%), and fever (39%)
- •EHV-5 was detected in 80% of EMPF cases and macrophage atypia in BALF was significantly more common in EMPF (67%) than asthma (8%)
- •Three-month survival was only 24% overall, and was associated with lower respiratory rates (30 vs. 41 breaths/min) and higher BALF lymphocyte:neutrophil ratios (4.7 vs. 0.47)
- •Corticosteroid treatment and imaging findings were not associated with improved 3-month survival