Congenital bilateral laryngeal paralysis in a neonatal foal

Laryngeal paralysis is rarely described in foals, despite being a known congenital condition in several dog breeds and the second most common laryngeal abnormality in human neonates. This report describes the case of a 3-h-old Warmblood colt referred for inspiratory stridor observed immediately after birth, which was diagnosed as bilateral laryngeal paralysis. The foal arrived in lateral recumbency, with an orotracheal tube in place, showing a weak suckle reflex and mild signs of dehydration. Blood analysis revealed an inverted neutrophil-to-lymphocyte ratio, increased creatine kinase activity, elevated haematocrit and higher blood lactate and creatinine concentrations. Airway endoscopy revealed bilateral laryngeal paralysis and intermittent dorsal displacement of the soft palate, without signs of inflammation. The foal was hospitalised in the neonatal intensive care unit; a nasotracheal tube was placed, and medical treatment was initiated (oxygen, intravenous fluid therapy with glucose and dimethyl sulfoxide, broad-spectrum antimicrobials, milk via nasogastric tube, and supplementation with B-complex vitamins, vitamin E and selenium). A diagnosis of neonatal encephalopathy was suspected, although nutritional myodegeneration could not be excluded. Laryngeal function progressively recovered, allowing removal of the nasotracheal tube 24 h after arrival and discharge from the clinic 10 days later, without the need for invasive surgical procedures. Follow-up 1 month after admission showed normal laryngeal function at rest. Bilateral laryngeal paralysis should be considered a differential diagnosis for neonatal stridor in foals. This case demonstrates that bilateral laryngeal paralysis can be fully reversible in foals and should not necessarily be associated with a poor prognosis.