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Stertor is noisy breathing that occurs during inhalation. It is a low-pitched, snoring type of sound that usually arises from the vibration of fluid, or the vibration of tissue that is relaxed or flabby. It usually arises from airway blockage in the throat (pharynx).
Stridor is high-pitched, noisy breathing. The higher-pitched sounds result when relatively rigid tissues vibrate with the passage of air. It often occurs as the result of partial or complete blockage of the nasal passages or voice box (larynx), or collapse of the upper part of the windpipe (known as cervical tracheal collapse).
Unusually loud breathing sounds are often the result of air passing through abnormally narrowed passageways, meeting resistance to airflow because of partial blockage of these regions. The origin may be the back of the throat (nasopharynx), the throat (pharynx), the voice box (larynx), or the windpipe (trachea). Abnormal breathing sounds of this type can be heard without using a stethoscope.
The upper respiratory tract or upper airways includes the nose, nasal passages, throat (pharynx), and windpipe (trachea).
Noisy breathing is common in short-nosed, flat-faced (brachycephalic) cat breeds, such as Persians and Himalayans. Affected short-nosed, flat-faced (brachycephalic) cats with inherited paralysis of the voice box (laryngeal paralysis) typically are younger than one year of age when breathing problems are detected. The acquired paralysis of the voice box (laryngeal paralysis) typically occurs in older cats. Cats are diagnosed less commonly than are dogs, with no obvious age pattern.
You will need to provide a thorough history of your cat's health leading up to the onset of symptoms. Your veterinarian will use a stethoscope to listen to the entire area from the pharynx to the trachea. If the sound persists when your cat opens its mouth, a nasal cause can virtually be ruled out. If the sound occurs only during expiration, it is likely that airway narrowing is the cause. If the abnormal sounds are loudest during inspiration, they are from disease other than in the chest. If you have noticed a change in your cat's voice, the larynx is the likely abnormal site. Your veterinarian will systematically listen with the stethoscope over the nose, pharynx, larynx, and trachea to identify the point of maximal intensity of any abnormal sound and to identify the phase of respiration when it is most obvious. It is important to identify the location from which the abnormal sound arises and to seek the aggravating causes.
Internal imaging techniques, such as radiography and fluoroscopy, are important for assessing the cardiorespiratory system and to rule out other or additional causes of respiratory difficulty. Such conditions may add to an underlying upper airway obstruction, causing a subclinical condition to become clinical. X-rays of the head and neck may help to identify abnormal soft tissues of the airway. A computed tomography (CT) scan may also be used to provide additional anatomic detail.
In some cases, your cat's physiological inheritance can make the diagnosis more apparent, such as with cats that are brachycephalic. In these situations, your veterinarian will determine the location that is being most affected by your cat's conformation and decide where to go from there.
Keep your cat cool, quiet, and calm. Anxiety, exertion, and pain can lead to increased movement of air into and out of the lungs, potentially worsening the airflow. Low levels of oxygen in the blood and tissues, and decreased movement of air into and out of the lungs occur with prolonged, severe blockage to airflow; supplemental oxygen is not always critical for sustaining patients with partial airway collapse. In addition closely monitor the effects of sedatives that have been prescribed, as sedatives are known for relaxing the upper airway muscles and worsening the blockage to airflow. Be prepared for emergency treatment if complete obstruction occurs.
Extreme airway blockage or obstruction may require an emergency intubation (that is, passage of an endotracheal tube through the mouth and into the windpipe [trachea] to allow oxygen to reach the lungs). If obstruction prevents intubation, an emergency tracheotomy (a surgical opening into the windpipe [trachea]) or passage of a tracheal catheter to administer oxygen) may be the only available means for sustaining life. However, a tracheal catheter can sustain oxygenation only briefly while a more permanent solution is sought. Surgery may be required if a biopsy has indicated a mass in the airways.
Avoid strenuous exercise, high ambient temperatures, and extreme excitement. Your veterinarian will advise you on the correct level of exercise to encourage in your dog.
Your cat's breathing rate and effort will need to be monitored closely. Complete blockage or obstruction could occur after an apparently stable patient is taken home or if continual observation is not feasible. Even with surgical treatment, some degree of obstruction may remain for 7 to 10 days due to postoperative swelling. Care will need to be taken during this time to protect your cat from complications due to labored breathing.
After surgery, your cat may feel sore and will need proper rest in a quiet place, away from other pets and active children. You might consider cage rest for a short time, until your cat can safely move about again without overexertion. Your veterinarian will also prescribe a short course of pain killers until your cat has fully recovered, along with a mild course of antibiotics, to prevent any opportunistic bacteria from attacking your cat. Medications will need to be given precisely as directed, at the proper dosage and frequency. Keep in mind that over dosage of pain medications is one of the most preventable causes for death in household pets.
The return of food into the oral cavity after it has been swallowed
A medical condition; the contamination of a living thing by a harmful type of bacteria
A procedure of imaging internal body structures by exposing film
A product made of fluid, cell waste, and cells
A cavity in the mouth where the respiratory systems and gastrointestinal systems come together
The act of making an opening narrower.
Nostrils that are narrow or have been narrowed
The section of the respiratory system that contains the mouth, nose, pharynx, larynx, trachea, and epiglottis.
An incision into the trachea
The windpipe; it carries air from the bronchi to the mouth
Does not show any signs of a disease
The ability to create a disease where a disease might not normally be found, usually due to an ill timed or unlikely weakness
A type of slime that is made up of certain salts, cells, or leukocytes
Turned inside out
The hormones that stimulate growth of the body
The collection of fluid in the tissue
An animal with a wide head, short in stature.
The process of removing tissue to examine it, usually for medical reasons.
Transmitting genes from parent to child
Inflammation of the larynx
Not being able to cause harm; the opposite of malignant.
Something that becomes worse or life threatening as it spreads
Any opening in an organ
The voice box; this is one part of the respiratory system
The part of the throat above the soft palate