Wheezing is the abnormal whistling sound which accompanies breathing that is caused by a narrowing of the airways due to a partial blockage, constriction or inflammation. The most common causes of wheezing in cats are:
Asthma - Feline asthma is usually the result of inhaled allergies which trigger an immune response, leading to constriction of the airways. Common allergens include dust, pollen, and moulds, but any airborne particle can potentially result in asthma. Cold weather often makes the condition worse due to the dryness in the air. Common symptoms of asthma are coughing, wheezing and difficulty breathing.
Asthma attacks can be fatal. One of our forum members lost her beloved cat very suddenly to an attack. So avoiding the triggers, if known, should be the first line of defence. Of course, this isn't always possible. If you do suspect your cat is having an asthma attack, take him to a veterinarian immediately.
Treatment of asthma includes oral or inhaled steroids to reduce inflammation and bronchodilators to open up the airways. Increasing humidity, especially in the cooler months can also help.
Upper respiratory infection - "Cat flu" is caused primarily by the feline herpes virus, calicivirus, reovirus. It is similar to colds and flu in humans with typical symptoms being a runny nose, sneezing, fever, eye discharge. The airways can become inflamed leading to wheezing.
Treatment of cat flu is generally supportive such as fluids, encouraging your cat to eat. If a bacterial infection is suspected (either primary or secondary), antibiotics will be prescribed.
Heartworm - Parasitic worms which live in the heart, pulmonary arteries and lungs of cats. They are spread by mosquitoes. Symptoms of heartworm infection include coughing, wheezing, shortness of breath, lethargy, anorexia and in some cases, death.
There are no approved medications for heartworm at this time and treatment can be risky. In mild cases, your vet may decide to wait for the parasite to be cleared, more severe cases will require supportive care such as bronchodilators, oxygen, and prednisone to reduce inflammation. In cats who are unresponsive to treatment, an adulticide may be recommended. This comes with the risk of the dead worms dislodging and causing a pulmonary embolism. Confinement is necessary while this treatment is underway.
Lungworm infection - Slim, hair like worms which are acquired by consuming hosts (such as snails) infected with the worm or contaminated food and water. They reside in the lungs of cats, laying their eggs which hatch into larvae (L1), that are coughed up, swallowed and passed out of the body via the feces. Lungworm larvae in the airways can cause irritation, inflammation, and mucus resulting in coughing and wheezing.
Treatment of lungworms is anti-parasitic medication such as Fenbendazole, Ivermectin, Levamisole, and Praziquantel.
Hairballs - As the cat grooms, he ingests small amounts of hair. This usually passes through the body and out, via the feces without incident. However, in some cats hair can build up inside your cat resulting in him eventually either coughing up the hairball or becoming blocked.
Treatment is usually aimed at adding fibre or giving lubricants (such as butter or petroleum jelly) in his diet to help with the passage of the hairball. Regular grooming to reduce the amount of fur your cat ingests and in some cases, your cat may need to go on a "hairball" diet.
Anaphylaxis - A life-threatening allergic reaction which results in a narrowing of the airways, it can be triggered by almost anything, common causes include insect bites, medications, and food allergies. Symptoms of anaphylaxis include wheezing, difficulty breathing, rash, swelling, pale gums, collapse. Urgent veterinary care is absolutely vital.
Treatment of anaphylaxis is the administration of adrenaline to counteract the effects of the body's immune response, oxygen, and IV fluids may also be given to your cat.
Airway obstruction - Aside from many of the conditions listed above which can cause obstruction to the airways (such as asthma, hairballs, worms etc.) swallowed objects can also lead to an obstruction, common items may include bone, food, toys etc., leading to difficulty breathing, wheezing, gagging, loss of consciousness.
Treatment of an airway obstruction caused by a foreign body is the Heimlich maneuver, in which force is applied to the cat's abdomen order to dislodge the object.
How is the cause of wheezing diagnosed?
Your veterinarian will perform a complete physical examination of your cat and obtain a history from you including other symptoms you may have noticed. Your veterinarian will be able to narrow down the cause depending on presenting symptoms. A cat with an upper respiratory tract infection will usually have nasal discharge, coughing, sneezing and fever. A cat suffering from allergies will have an itchy face and neck. He may want to run some tests to determine the exact cause.
These may include:
- Ultrasound and/or chest x-ray to look for the presence of worms in the heart or lungs or for asthma, signs of inflammation, flattened diaphragm and doughnuts.
- Fecal flotation to look for the presence of eggs in the feces.
- Tracheal wash to look for eggs or larvae or signs of inflammation.
- Antigen, antibody or microfilariae tests to look for heartworm larvae or antibodies.
- Skin patch tests if an allergy is suspected. This involves introducing common allergens to the cat's skin via small needles. The area is then checked for signs of allergic reaction.
- Complete blood count may reveal higher numbers of eosinophils (a type of white blood cell), which can suggest asthma or allergies.