Equis ISSN 2398-2977

Respiratory: meconium aspiration

Contributor(s): Timothy Mair, Prof Derek Knottenbelt, Wendy E Vaala, Nicola Menzies-Gow

Introduction

  • Life-threatening condition which requires prompt treatment.
  • Cause: frequently related to a prolonged or difficult parturition Reproduction: dystocia or severe placental insufficiency prepartum.
  • Signs: fetal stress or asphyxia → voiding of meconium in utero → aspiration.
  • Chemical bronchopneumonia rapidly becomes secondarily infected → a neonatal bacterial pneumonia Lung: pneumonia - neonatal bacterial. Airway obstruction, regional atelectasis and surfactant dysfunction can also occur.
  • Diagnosis: history, signs, auscultation, radiography.
  • Treatment: postural drainage and/or suction of the upper airways and trachea may provide some relief; treatment of secondary bacterial pneumonia with antimicrobial therapy; supportive therapy, eg intranasal oxygen, parenteral nutrition.
  • Prognosis: guarded.

Pathogenesis

Predisposing factors

General

Specific

Pathophysiology

  • Fetal stress or asphyxia can → voiding of meconium. Inhalation of meconium during parturition → chemical bronchopneumonia which can rapidly → secondary infection, giving a bacterial pneumonia Lung: pneumonia - neonatal bacterial.
  • Meconium obstructs airways → regional atelectasis, meconium displaces surfactant → lung atelectasis.
  • Sequelae of meconium aspiration includes, chemical pneumonitis, bacterial pneumonia, surfactant displacement and secondary atelectasis, airway obstruction, pneumothorax.

Timecourse

  • Respiratory distress and coughing are usually observed within the first few hours.
  • Pneumonia Lung: pneumonia - interstitial (foals) can develop 1-3 days later.
  • Regional atelectasis associated with airway obstruction is observed within the first few hours.
  • Lung atelectasis associated with surfactant dysfunction can develop within 1-3 days.

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.
  • Lester G D (1999) Respiratory disease in the neonatal foal. Equine Vet Educ 11 (4), 208-217 WileyOnline.
  • Webb A I et al (1984) Developments in management of the newborn foal in respiratory distress 2: Treatment. Equine Vet J 16 (4), 319-323 PubMed.
  • Kosch P C et al (1984) Development in management of the newborn foal in respiratory distress 1; Evaluation. Equine Vet J 16 (4), 312-318 PubMed.


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