Equis ISSN 2398-2977

Lung: EIPH (exercise-induced pulmonary hemorrhage)

Synonym(s): EIPH

Contributor(s): Christopher Brown, Timothy Mair, Nicola Menzies-Gow, Prof Jonathon Naylor, Colin Roberts

Introduction

  • Strenuous exercise results in hemorrhage in the dorsocaudal region of diaphragmatic lobes of the lungs.
  • Occurs in 55-95% of racing thoroughbreds.
  • Cause: structural failure of pulmonary capillaries due to high pressure pulmonary shearing forces; and possibly underlying airway disease.
  • Signs: vary - none, poor performance, epistaxis.
  • Diagnosis: history, signs, endoscopy, cytopathology, scintigraphy, radiography.
  • Treatment: rest, diuresis, clean air regime.
  • Prognosis: guarded with repeated episodes.
Print off the Owner factsheets Epistaxis - nosebleed and Respiratory problems - not a good wheeze to give to your clients.

Pathogenesis

Etiology

  • No specific causal agent has been identified; but there is an association in chronic EIPH with small airway disease.
  • Possible factors:
  • Bleeding in the small airways is followed by inflammation.

Predisposing factors

General

Pathophysiology

  • Stress failure of pulmonary capillaries during exercise.
  • High speed exercise   →   bleeding probably originates from vessels supplied by the high pressure bronchial artery rather than from capillaries supplied by the pulmonary artery. This may occur as the result of left to right shunts supplying the alveolar capillaries.
  • Dorsal distribution of lesions, hypotheses:
    • Pulmonary capillary walls may be weaker than in rest of lung.
    • Preferential volume distribution of blood flow to dorsal areas during exercise.
    • These lung segments are confined between ribs and diaphragm   →   large changes in alveolar pressure in connection with diaphragmatic movements.
    • Alveoli are larger due to downward pull of weight of lung   →   more susceptible to pressure changes.
  • Chronic small airway inflammation:
    • Always associated with chronic EIPH.
    • Definitely a secondary factor, may even be a primary trigger.
    • Uneven alveolar inflation, weakening within a lung segment   →   increased capillary stress.
    • EIPH may cause inflammation (demonstrated by experimental instillation of blood in airways or interstitium), so difficult to ascertain initiating pathology, ie what happened first - EIPH or inflammation?
  • Abnormal hemostasis:
    • Reports that platelet clumping and EIPH was responsive to acetyl salicylic acid therapy   Acetylsalicylic acid  .
    • Increased spontaneous contrast during post-race echocardiography   Heart: echocardiography  associated with increased platelet clumping and EIPH.

Timecourse

  • Instantaneous.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Derksen F J et al (2009) Regional distribution of collagen and haemosiderin in the lungs of horses with exercise-induced pulmonary haemorrhage. Equine Vet J 41 (6), 586-591 PubMed.
  • Archer D (2008) Differential diagnosis of epistaxis in the horse. In Pract 30 (1), 20-29 VetMedResource.
  • Poole D C, Epp T S & Erickson H H (2007) Exercise-induced pulmonary hemorrhage (EIPH): mechanistic bases and therapeutic interventions. Equine Vet J 39 (4), 292-293 PubMed.
  • Keen J (2007) Clinical forum - Exercise-induced pulmonary hemorrhage (EIPH). UK Vet 12 (2), 11-20 VetMedResource.
  • Barrelet A (2007) Laboratory investigation of poor performance in horses: Part 2 - Investigation of respiratory disease. UK Vet 12 (1), 15-21 VetMedResource.
  • Newton J R et al (2005) Risk factors for epistaxis on British racecourses: evidence for locomotory impact-induced trauma contributing to the aetiology of exercise-induced pulmonary haemorrhage. Equine Vet J 37 (5), 402-411 PubMed.
  • Kindig C A, Ramsel C et al (2003) Inclined running increases pulmonary haemorrhage in the Thoroughbred horse. Equine Vet J 35 (6), 581-585 PubMed.
  • Erickson H H, Kindig C A & Poole D C (2001) Role of the airways in exercise-induce pulmonary hemorrhage. Equine Vet J 33 (6), 537-539 PubMed.
  • Manohar M et al (2000) Clenbuterol administration does not attenuate the exercise-induced pulmonary arterial, capillary or venous hypertension in strenuously exercising Thoroughbred horses. Equine Vet J 31 (6), 546-550 PubMed.
  • Meyer T S, Fedde M R, Gaughan E M, Langsetmo I & Erickson H H (1998) Quantification of exercise-induced pulmonary hemorrhage with bronchoalveolar lavageEquine Vet J 30 (4), 284-288 PubMed.
  • Sweeney C R (1991) Exercise-induced pulmonary hemorrhage. Vet Clin North Am Equine Pract 7, 93-104 PubMed.
  • O'Callaghan et al (1987) EIPH in the horse. Equine Vet J 19, 384-423 (an extensive overview of EIPH in the horse) PubMed.

Other sources of information

  • Birks E K et al (1998) Exercise-induced pulmonary hemorrhage - capillary stress failure. In: Proc World Equine Airway Symposium.
  • West J B, Tyler W S, Birks, E K and Mathieu-Costello O (1997) EIPH. In: Proc Dubai International Equine Symposium - Diagnosis and Treatment of Respiratory Disease. Eds: Rantanen N W & Hauser M L. pp 353-368.
  • Pascoe J R (1997) EIPH - a unifying concept. In: Proc Dubai International Equine Symposium - Diagnosis and Treatment of Respiratory Disease. Eds: Rantanen N W & Hauser M L. pp 377-389.
  • Hinchliff K W (1997) Hemodynamic and performance effects of furosemide in horses. In: Proc Dubai International Equine Symposium - Diagnosis and Treatment of Respiratory Disease. Eds: Rantanen N W & Hauser M L. pp 379-384.
  • Roberts C, Hillidge C & Marlin D (1993) EIPH in racing thoroughbreds in Great Britain.  In: Proc Int EIPH Conference.


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