DDSP is readily apparent on endoscopic examination if there are no other abnormalities. The normal triangular shaped epiglottis
is hidden under the soft palate (Figure 1). When DDSP is accompanied by other abnormalities, such as rostral displacement
of palatopharyngeal arch and collapse of the walls of the pharynx, it can be difficult to orient oneself to the larynx. In
small foals, such as miniatures, the presence of an endoscope in the nares actually can create enough rostral obstruction
to increase negative pressure in the pharynx and artificially displace the soft palate during scoping. In these cases, a lateral
radiograph of the throatlatch of the head often will be diagnostic of DDSP. In DDSP, the free edge of the soft palate can
be seen on the radiographs (Figure 2).
Figure 2: Lateral radiograph of the pharyngeal region of a foal with DDSP. Note the free edge of the soft palate is visible
over the tip of the epiglottis (Equine Neonatal Medicine: A Case Based Approach, Spring 2006, Elsevier).
In a complete cleft palate, involving the hard and soft palate, one can observe it on a simple oral examination. If the cleft
involves the caudal hard palate and soft palate then use of endoscopy or a long-bladed laryngoscope is necessary for the diagnosis.
Pharyngeal and subepiglottic cysts seen with the endoscope appear as fluid-filled masses and can also obscure the epiglottis
from view. Upper respiratory distress can prevent a safe endoscopic examination of these foals until a tracheotomy is performed.
Paralysis of the larynx and arytenoid chondritis can be seen endoscopically as lack of movement of the arytenoids. In arytenoid
chondritis, the arytenoids appear swollen and inflamed.
Radiography is the best diagnostic for determining the extent of the aspiration pneumonia. A heavy interstitial to alveolar
pattern in the caudal ventral lung field is found in milk aspiration.
A minimum database consisting of IgG levels, a CBC, a chemistry profile and an arterial blood gas analysis is important in
these foals. Decreased IgG levels and abnormalities in the CBC may indicate a concurrent sepsis as a cause of generalized
weakness. The chemistry profile abnormalities may be suggestive of muscle disease. An arterial blood gas analysis is helpful
in directing specific oxygen therapy.
Treatment of milk aspiration in foals focuses on the immediate cessation of aspiration, the provision of nutrition to the
foal, antibiotic therapy to eliminate any bacterial infection and eliminating the cause of the dysphagia.
It is essential to prevent the foal from nursing. This is done most easily by muzzling the foal. An alternative to muzzling
would be to separate the foal from the mare but because this condition is often temporary, orphaning the foal should be a
Nutrition can be provided to the foal through an indwelling nasogastric tube. Foals eat approximately 25-30 percent of their
body weight (BW kg). A 45-kg foal eating 30 percent of its BW would need 13.5 liters of milk, divided into two to four feedings
during a 24-hour period.
Occasionally a foal will not tolerate the presence of a nasogastric tube and will hypersalivate — continuing to aspirate saliva
into the lungs. Total parenteral nutrition may be an option. Placement of esophagotomy tube, bypassing the oropharynx, might
be a less-expensive alternative of providing nutrition.