Aspiration pneumonia in neonatal foals

Aspiration pneumonia in neonatal foals

Determining the cause, implementing effective treatment
Aug 01, 2010

Bacterial pneumonia is a common cause of disease in young foals. One source of infection frequently associated with neonates is the aspiration of foreign material. However, with early recognition and treatment, this condition does not have to progress to more serious disease or death.

"Pulmonary disease is more serious than upper respiratory disease in neonatal foals," says Jonathan Palmer, VMD, Dipl. ACVIM, chief of Neonatal Intensive Care Service at the University of Pennsylvania School of Veterinary Medicine's New Bolton Center. "We see upper airway problems in neonatal foals lead to lower lung problems such as aspiration pneumonia that are more serious, more life-threatening and perhaps cause more problems later in life."

Aspiration of foreign materials into the lung is a serious problem for young neonates, especially when the reasons for the aspiration are not addressed. "If you don't do something so that they stop aspirating, it can result in a fatal pneumonia," Palmer says.

Causes of aspiration pneumonia

Photos 1 & 2: A dysphagic foal with milky nasal discharge after nursing. (PHOTOS: COURTESY OF DR. MARY ROSE PARADIS)
"We see two types of aspiration pneumonia in neonatal foals," says Mary Rose Paradis, DVM, MS, Dipl. ACVIM, the section head of Large Animal Medicine & Surgery at Tufts University's Cummings School of Veterinary Medicine. The first is meconium aspiration, which is often seen after dystocia. "Those babies have a real tough time because there are chunks of fecal material in their lungs," Paradis states.

Photo 2
The other common situation is postpartum aspiration of milk. In these cases, as the foal nurses, milk may be seen discharged from its nose (Photos 1 & 2). "At that moment you have to decide, is the mare just producing a lot of milk and spraying the baby on the face, or is it actually dysphagia — improper swallowing?" says Paradis. After suckling, a small amount or several milliliters of milk may be expelled from the nostrils. "The important thing is not to take this clinical sign too lightly."

"It's important for practitioners to know that if they see milk come out of a young foal's nose, there may be aspiration," Palmer says.

A few things can result in milk aspiration. Although very rare in foals (about 1 percent of aspiration problems), it may be caused by a cleft palate. More common is pharyngeal dysfunction and/or dysphagia, especially in premature, weak foals or septic foals. When the foal attempts to swallow, it doesn't seal its larynx, so milk will go down the trachea, as well as out its nose. Pneumonia develops when milk is aspirated into the lungs. Milk is a nonsterile substance with a multitude of bacteria present and is a perfect bacterial growth media.

Another reason for milk regurgitation from the nose is a failure to clear the cervical esophagus of milk after drinking. The condition may be associated with neonatal encephalopathy or esophageal dysmotility. "Severely affected foals may have a large volume of milk flow from their noses, yet, because the problem is in the esophagus and not the pharynx or larynx, they will be able to guard their tracheae, and milk will not be aspirated," Palmer says. Therefore, it is important to determine the reason for the milk regurgitation.

If aspiration of milk is suspected "you need to do something to stop it," says Palmer. While these conditions may be transient, the foal should not be allowed to continue nursing if aspiration is confirmed (moist trachea, abnormal lung sounds).