Case reveal

Ultrasonographic findings

  • Within the pulmonary parenchyma, most severe caudodorsally and identified bilaterally within the 10-16th intercostal spaces, multiple small to medium-sized, well-defined and rounded hypoechoic nodules causes disruption of the normal peripheral gas interphase.
  • The pulmonary margins are mildly irregular with diffuse broad based comet tail artifacts noted bilaterally.

Thoracic radiographs

Radiographic findings:

  • Multifocally within the pulmonary parenchyma, most severe caudodorsally, numerous ill-defined, rounded and soft tissue opaque nodules are identified.
  • Throughout the pulmonary parenchyma, a mild to moderate increase in soft tissues opacity decreases the conspicuity of the pulmonary vasculature, cardiac silhouette and diaphragm.
  • Within the included cranial abdomen, mineral opaque material is identified in the plane of the colon.


  • Moderate to severe mixed nodular and unstructured interstitial pulmonary patterns. Equine multinodular pulmonary fibrosis is considered primarily. Metastatic neoplasia cannot be ruled out but it thought less likely.
  • Colonic sand accumulation

Case follow-up

  • Due to the patient’s poor prognosis, humane euthanasia was elected.


qPCR positive for Equine Herpesvirus 5 in lung sample. Viral load = 34,433 EHV-5(glycoprotein B gene) per million cells.

A little bit more…

Equine Multinodular Pulmonary Fibrosis (EMPF)

  • Causes a progressive fibrotic interstitial disease of the lungs (Schwarz et al., Wilkins et al.).
  • Most commonly affect middle-aged to older horses, but it has also been reported in young horses (Schwarz et al., Wilkins et al., Williams et al., Van Cleemput et al.).
  • Clinical signs include respiratory distress, lethargy, fever, and tachycardia (Schwarz et al., Wilkins et al., Williams et al., Van Cleemput et al.).
  • Blood work most often shows signs of inflammation (e.g. neutrophilia and hyperfibrinogenemia) (Williams et al.).
  • On radiographs, the lungs are found to have a structured and/or unstructured interstitial pulmonary pattern (Wilkins et al., Williams et al.).
  • On ultrasound, round hypoechoic masses are most often identified (Reef et al.).
  • EMPF has been associated with Equine Herpesvirus V, which may also lead to lymphoma, leukemia, or skin diseases (Van Cleemput et al.).


  • Schwarz, Bianca, et al. “Equine multinodular pulmonary fibrosis (EMPF): five case reports.” Acta Veterinaria Hungarica61.3 (2013): 319-332.
  • Wilkins, P. A. “Equine multinodular pulmonary fibrosis: diagnosis and treatment.” Equine Vet Educ 25.8 (2013): 393-397.
  • Van Cleemput, Jolien, et al. “Unravelling the first key steps in equine herpesvirus type 5 (EHV5) pathogenesis using ex vivo and in vitro equine models.” Veterinary research 50 (2019): 1-14.
  • Virginia B. Reef. (2012). Use of Thoracic Ultrasonography in the Ambulatory and Referral Setting.
  • Williams, Kurt J., et al. “Equine multinodular pulmonary fibrosis: a newly recognized herpesvirus-associated fibrotic lung disease.” Veterinary pathology 44.6 (2007): 849-862.