latrogenic lipoid pneumonia in an adult horse

Mineral oil (liquid paraffin) is commonly used in equine practice as a lubricant in cases of gastrointestinal impaction and as a purgative in cases of potential toxicosis [5]. However, administration of mineral oil to horses via nasogastric intubation does carry a minor risk of causing mineral oil-induced pneumonitis (lipoid pneumonia). Lipoid pneumonia is a severe inflammatory reaction to the presence of oil in the lungs, which is usually fatal when it occurs in horses. The guarded prognosis is due in part to the fact that mineral oils appear to alter the viscoelastic properties of secretions as well as the mucociliary transport mechanism [8,11]. Human studies have shown that the clearance of aspirated oil from the respiratory tract is difficult with oily substances typically emulsified by lung lipase and engulfed by alveolar macrophages thus triggering local inflammation [6,12]. Lopez [9] reports that pro-inflammatory mediators open endothelial gaps, increasing the permeability of blood vessels and resulting in leakage of plasma and fibrinogen into the alveoli which progressively obliterates airspaces, causing consolidation of the lung. Due to the infrequency of the problem, there are few published reports describing the clinical findings associated with pulmonary aspiration of mineral oil in the horse.Scarratt et al. [11] and Davis et al. [5] reported the clinical presentation to be either acute or chronic in nature, depending upon the quantity of mineral oil aspirated. In acute cases, respiratory distress rapidly develops, whereas chronic cases may develop a cough, abnormal lung sounds and intermittent fever over several weeks, finally presenting at an advanced stage [5]. The following report describes a case of acute lipoid pneumonia in a horse that was being treated for gastrointestinal dysfunction with the risk factors, clinical presentations and diagnostic options discussed.A 20-year-old cob gelding presented to the University Veterinary Hospital (UVH) emerg