It seems to me that mammals other than horses – cats, humans, annoying dogs, mostly seem to have a really rough time when they are choking.  But should you call Springhill to tell them your horse is choking, they will tell you to stay calm, and wait 30 minutes.  How and why is this?? Choke in a horse is a completely different syndrome that the typical “choking” episode you think of in a person.  The key difference is that choke in a horse results when there is a physical obstruction in the esophagus, not the trachea.

If you come upon a person who is choking, they will be doubled over, gasping for air. They are suffering from an obstruction of the trachea – the main tube connecting the larynx to the lungs. Horses are prone to obstructing at certain points along their esophagus, such as right behind the larynx (the junction of the mouth cavity, the trachea, and the esophagus).  A horse that is choking will appear variably distressed, with feed material coming out of his nose.  It usually occurs just after being fed grain, particularly if the horse is known to bolt (devour) his feed, or if feeding time is a bit later than usual. Dried beet pulp and pelleted grain have been implicated as well – water absorbs into these types feedstuffs and a bolus of food can expand mid-transport. Sometimes a mass is visible or palpable along the underside of the neck.

Call Springhill as soon as you notice your horse choking. Remove any feed, hay, and shavings if you think they will eat them, but leave the horse water. Often chokes resolve within 30 minutes of occurrence – the horse appears to get comfortable, the nasal flow stops, and he wants to go back to eating.  So Springhill will tell you to wait and watch your choking horse for this amount of time, and then Dr. Lacher or Dr. King will be on their way!

When they get there, they will get ready a long tube, a bucket of water, and a particular sedative, butorphanol, that has a specific side effect of making the horse drop his head. With the head below the blockage, the feed can passively drain back out of his nose. The horse also has a more pleasant and less memorable experience during the next part. The vet will pass the tube through the nose to the larynx, where they will encourage the sleepy horse to swallow the tube (against their own good instinct). Once in the esophagus, they will pass the tube forward to the blockage, and then begin to pump.  Slowly and steadily, they will have water pumped through the tube against the blockage, and they will move the tube forward and backward to break up the mass.  The water may bring material back out through the nose, or the water may pass through the blockage to the stomach, and slowly carry it along with it (like a large leaf in a shallow stream).

Most chokes resolve this way. Complicated, recurring, and difficult chokes require referral to an equine hospital, where a 3 meter camera is used to examine the entire length of the esophagus.  The gastroscope, as the camera is called, is passed to the entrance to the stomach (the cardiac sphincter), and the stomach and part of the small intestine is examined as thoroughly as possible (while we’re in there). This is the same exam used to diagnose gastric ulcers in horses, so don’t be surprised if you end up bringing some ulcer medication home from your visit. The esophagus is examined for abnormalities such as a stricture (narrowed section), diverticulum (pouch that develops off the main tube), or tumor. If a large object is obstructing the esophagus, such as a whole apple (just say no to feeding whole apples!), an instrument is passed through the gastroscope to attempt to retrieve the object.

After a choke, the horse will be uncomfortable and it’s best to give a small, warm soupy mash after a few hours. The vets will give re-feeding instructions when they are at your farm. A horse that bolts his feed can have some large, smooth river stones added to his bucket to make him slow down while he eats. If you are concerned, add some water to your feed and make it into a soup. Just don’t let your feed sit wet for too long – it could become rancid.

One of the most important things to be aware of with choke is the aspiration pneumonia that can result.  As the horse attempts to breathe through its nose as the feed is passing out, some of the feed (and all the bacteria living on it) end up in the lungs. It’s called aspiration pneumonia, and it can cause a nasty chain of events if left untreated. Thick pus fills the lungs, and eventually the infection passes into the space between the lungs and the ribcage (the pleural cavity – resultantly called pleuropneumonia), or abscesses may form and can rupture into this space. These infections can end up with the horse being hospitalized for IV antibiotics, and drainage of the pleural cavity with a chest tube. Pneumonia that has advanced to this stage can be extremely difficult and expensive to treat, and many horses eventually succumb to the infection.

It is therefore very important to have us out at some point to check your horse’s lungs, at the very least pay close attention to your horse’s breathing for 3-5 days after the choke episode.  This is especially important if the horse is a chronic choker. Look for increased rate and effort – normal respiration rate is 12 to 20 breaths per minute (watch the flank or put a hand a few inches from the nostril). You should be calling if you see significant nostril flaring, a large abdominal movement, or obvious rib excursions with breathing. Fever should also be reported (>102F). Horses with pleura-pneumonia will begin to act colicky – usually anxiously turning to look at their girth. Proper management of choke can be a smooth, simple experience or can be a fatal event.

On the lighter side, I am full-swing back into my Tony antics – cat-scanning trailers, running off the new neighborhood stray, and defending the clinic from other dangerous foes! I barely limp any more as I charge across the grassy yard toward the woods again. Keep me posted with ideas you want to see discussed on our blog! May your litter box be clean, and your food bowl full!

 

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