Equine multinodular pulmonary fibrosis (EMPF) in a Thoroughbred filly

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1 Equine multinodular pulmonary fibrosis (EMPF) in a Thoroughbred filly Angelique Leone, VMD William Castleman, DVM, PhD, DACVP

2 Presentation to the rdvm 2 year old Thoroughbred filly Fever and abnormal lung sounds Initial diagnostics & treatment

3 Initial diagnostics & treatment CBC & clinical chemistry abnormalities Leukocytosis of 16 X 10 3 /ul (5.5-11) Fibrinogen of 800 mg/dl (0-400) Treatment Naxcel (7 days) Transtracheal wash (TTW) - No abnormalities Post treatment thoracic ultrasound Areas of consolidation in right lung fields

4 At the UF Large Animal Medicine Service Presented: quiet, but bright and alert with tachypnea and tachycardia New CBC/Chem abnormalities: Leukocytosis with a toxic left shift 18 X 10 3 /ul (5.5-11) Thrombocytosis -268 X 10 3 /µl ( ) Elevated ALP 344 U/L (54-176) Thoracic auscultation crackles, most prominent within the caudoventral lungs

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6 Diagnostic plan Repeat TTW Culture - mixed fungal flora including Aspergillus sp. Gram stain no microorganisms Biopsy Non-diagnostic

7 Assessment The additional diagnostics revealed chronic airway irritation and ruled out a bacterial pneumonia. Treatment plan was amended: Antibiotics were discontinued Filly was sent home on Banamine and dexamethasone

8 Second presentation to UF 3 weeks later New abnormalities: Severe hypoxemia PO2 of 46 mmhg (80-100) Elevated lactate of 2.9 mmol/l (1-2) Repeat thoracic ultrasound Diffuse areas of focal consolidation with comet tails Repeat thoracic radiographs Diffuse nodular soft tissue opacities Pentoxifylline was added to regiment with no effect

9 Gross findings Fibrous adhesion between the right costal and visceral pleura Tracheobronchial lymph nodes are markedly enlarged

10 Pulmonary parenchyma is incompletely collapsed 50-70% of the parenchyma over multiple sections is infiltrated by light tan and very firm tissue

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14 Trichrome

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17 Summary Chronic diffuse multinodular fibrosing interstitial pneumonia, severe, with intranuclear inclusions in macrophages. Lung tissue was confirmed positive for EHV-5 via PCR at the Michigan State University DCPAH. These findings are consistent with equine multinodular pulmonary fibrosis (EMPF).

18 EMPF 1 st described in 2007 in Vet Path by Williams et al. All reported cases have been associated with EHV-5, although the association is controversial due to the isolation of the virus in nonaffected horses. Vet Pathol 44: (2007)

19 What we know so far Thoroughbreds >4 years of age are the most commonly affected, although it has been reported in many breeds of all ages. EHV-5 can be detected within nasal swabs, transtracheal wash, and bronchoalveolar lavage in addition to lung and other organs tissue. The exact pathogenic role this virus plays in EMPF is still unknown.

20 Thanks Dr. Julia Conway UF Veterinary Diagnostic Laboratories Histology Staff Fellow Residents Marenzoni, et al. Quantification of Equid herpesvirus 5 DNA in clinical and necropsy specimens collected from a horse with equine multinodular pulmonary fibrosis. J Vet Diagn Invest Jul;23(4): PMID: Soare, et al. Equine multinodular pulmonary fibrosis in horses in the UK. Vet Rec Sep 17;169(12):313. PMID: Niedermaier, et al. Clinical aspects of multinodular pulmonary fibrosis in two warmblood horses. Vet Rec Apr 3;166(14): PMID: Wong, et al. Multinodular pulmonary fibrosis in five horses. J Am Vet Med Assoc Mar 15;232(6): PMID: Williams, et al. Equine multinodular pulmonary fibrosis: a newly recognized herpesvirusassociated fibrotic lung disease. Vet Pathol Nov;44(6): PMID:

21 Questions Photo by Alan Crowhurst/Getty Images Europe