Equis ISSN 2398-2977

Lung: pneumonia - interstitial (foals)

Contributor(s): Rachael Conwell, Timothy Mair, Wendy E Vaala, Vetstream Ltd

Introduction

  • Interstitial pneumonia in foals is an uncommon condition that usually occurs secondary to a primary respiratory infection. It is also sometimes known as acute lung injury and can progress to acute respiratory distress syndrome (ADRS)
  • Cause: infectious most likely in foals, toxic, chemical and allergic causes also reported in adults.
  • Signs: respiratory distress.
  • Diagnosis: radiology and histology.
  • Treatment: oxygen therapy, DMSO, steroids, antimicrobials, NSAIDs.
  • Prognosis: guarded.

Pathogenesis

Etiology

Predisposing factors

General
  • Primary respiratory tract infection in foals.

Pathophysiology

  • Initiating insult, eg micro-organism   →    activation of leukocytes and pro-inflammatory transcription factors   →    amplification of inflammatory cycle   →    release of oxygen free radicals   →    interstitial edema and alveolar flooding with protein rich fluid   →    sudden onset respiratory distress.

Foals
Acute

  • Coagulative necrosis of alveolar septa, red blood cell diapedesis, fibrin microthrombi in alveolar capillaries and hyaline membrane formation.

Chronic

  • Adenomatoid epithelialization of the alveolar walls due to Type 2 pneumocyte proliferation.

Timecourse

  • Rapid (<48 h) onset of acute respiratory distress, although may have more prolonged (2-14 day) history of respiratory disease.

Epidemiology

  • Unclear - at present, only small number of case reports available.

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Dunkel B, Dolente B & Boston R (2005)Acute lung injury/acute respiratory distress syndrome in 15 foals.Equine Vet J37(5), 435-440 PubMed.
  • Peek S Fet al(2004)Acute respiratory distress syndrome and fatal interstitial pneumonia associated with equine influenza in a neonatal foal.J Vet Intern Med18(1), 132-134 PubMed.
  • Beurgelt C D (1995)Interstitial pneumonia in the horse - a fledgling morphologic entity with mysterious causes.Equine Vet J27(1), 4-5 (Excellent account of the pathogenesis and possible etiology of this condition) PubMed
  • Prescott J Fet al(1991)Sporadic, severe bronchointerstitial pneumonia of foals.Can Vet J32, 421 PubMed.
  • Winder Cet al(1988)Interstitial pneumonia in the horse - two unusual cases.Equine Vet J20(4), 298-301 PubMed.
  • Ainsworth D Met al(1985)Recognition ofPneumocystis cariniiin foals with respiratory distress.Equine Vet J25, 103-108 PubMed.

Other sources of information

  • McKenzie H C (2010)Foal Pneumonia.In:Proc NAVC, Orlando, Florida, USA. pp 219-223.


ADDED