Equine Pulmonary Agenesis and Hypoplasia Associated With Diaphragmatic Herniation.
Authors: Loynachan Alan T
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Pulmonary malformations remain exceptionally uncommon in equine neonates, yet this case series documents a previously unreported congenital syndrome: three foals presented with left-sided pulmonary agenesis (complete absence of lung tissue) coupled with ipsilateral diaphragmatic herniation and concurrent right lung hypoplasia, identified across a three-year period in a perinatal population. The anatomical defect pattern—involving both pulmonary and diaphragmatic structures on the same side—suggests a shared developmental aetiology, possibly reflecting disrupted embryological patterning during early gestation. All three affected foals experienced acute perinatal asphyxia and died immediately after birth, correlating directly with the severe reduction in functional lung capacity created by the combined malformations. Whilst the rarity of this condition means it will rarely present in clinical practice, recognition of this syndrome matters for practitioners advising on dystocia management, neonatal respiratory distress aetiology, and breeding soundness—particularly when investigating recurrent perinatal losses or unexplained foal deaths with respiratory compromise. The authors' identification of this first equine case of pulmonary agenesis and its associated pattern may prompt retrospective recognition of similar presentations and warrant investigation into potential hereditary or environmental risk factors in affected lineages.
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Practical Takeaways
- •Pulmonary agenesis is a rare but lethal congenital condition in foals that should be considered in perinatal deaths with respiratory compromise
- •When diaphragmatic herniation is identified in a foal, concurrent pulmonary malformations should be investigated as they may be associated
- •These malformations result in immediate perinatal death; awareness supports appropriate client communication and post-mortem diagnostics
Key Findings
- •Three cases of left-sided pulmonary agenesis were diagnosed in perinatal foals over a 3-year period
- •All three cases presented with concurrent ipsilateral diaphragmatic herniation and right lung lobe hypoplasia
- •All three foals died immediately after parturition due to perinatal asphyxia
- •This is the first reported case of pulmonary agenesis in the equine species