Tracheal collapse disease occurs mostly in older
small breeds of dogs, but occasionally in young dogs as an inherited
disease. This condition does occur in Bichons, but is not common.
The trachea (windpipe) is a tube of flexible tissue that connects
the larynx (voice box) in the throat to the lungs, which allows air
to enter and leave the lungs. Rings of cartilage maintain the
trachea in an open position, but with this disease those rings are
weakened and the trachea can collapse while breathing. At the bottom
of the trachea, where it divides into the right and left bronchi
(smaller airways) that lead to each lung, is an area called the
carina where the cough reflex exists. Coughing occurs if there is
stimulation to the carina by excess mucus, tubes, or tracheal
collapse. In addition to being a breathing tube, the trachea is
lined with cilia that move mucus and inhaled debris up and out of
the trachea, which can be impaired with this condition due to the
deformed trachea. The trachea, cilia, and cough reflex serve as a
filter to prevent mucus and debris from reaching the lungs, so
malfunction of this mechanism can lead to respiratory infections.
The major clinical sign of this disease is a chronic honk-type of
cough that is worse with stress, exertion, inhaled irritants
(cigarette smoke or dust), hot and humid weather, and drinking
water. Also the dog may exhibit a rapid respiratory rate, excessive
panting, reverse sneezing, exercise intolerance, and frequent
respiratory infections. Clinical signs worsen as the disease
progresses.
Tracheal collapse needs to be differentiated from another disease
that may cause similar symptoms, laryngeal paralysis (LP), which
researchers suggest may affect 25% of dogs, mostly larger breeds. LP
is a condition in which the muscles surrounding the voice box
(larynx) do not function properly causing coughing while drinking,
excessive panting, exercise intolerance, voice changes, and loud
breathing.
Treatment for mild cases of tracheal collapse is aimed at early
antibiotics for respiratory infections, weight loss if obese,
low-stress routines, avoiding situations that trigger episodes of
coughing, moderate exercise, using a harness instead of collar which
can press on the trachea, and avoiding cigarette smoke in the house.
During more severe episodes some drugs that may be helpful are
steroids, bronchodilators (they dilate the airways), cough syrup,
and low-dose sedatives. If your dog seems to be in extreme
respiratory distress, seek emergency veterinary care immediately.
Surgical splinting of the trachea can be done for more advanced
cases, but this is a major surgery that may have complications. Some
universities are inserting a stent to keep the trachea open, which
is a smaller surgery.
Research for this article includes:
The Merck Veterinary Manual
The 5 Minute Veterinary Consult by Larry Tilley& Francis Smith
Textbook of Medical Physiology by Arthur Guyton & John E. Hall
The Dog Owner’s Home Veterinary Handbook by James Griffin & Liisa
Carlson
Jeff Grognet, “Laryngeal Paralysis More Frequent Than Commonly
Thought”, AKC Gazette, December, 2006.