Infectious tracheobronchitis

ITB (Infectious Tracheobronchitis)

  • You might think your dog has something stuck in his throat.
  • The cough associated with acute infectious tracheobronchitis, (ITB) or kennel cough, is a high-pitched, honk-like cough, sometimes followed by retching.
  • Kennel cough is a highly contagious inflammation of the trachea (windpipe) and bronchial tree caused by a contagious virus (adenovirus, parainfluenza virus, canine distemper virus) or bacterium (Bordetella bronchiseptica).
  • The disease is associated most often with dogs housed in a high-density population or boarding kennel.
  • The infectious agents can be transmitted through the air or by contact with contaminated surfaces.
  • Puppies and younger dogs are at greatest risk, but even old dogs can acquire kennel cough.
  • The incubation period from the time the dog first contracts the infection to the time that symptoms develop is typically between 3 to 10 days, and the symptoms can last for days to weeks.
  • A mild to moderate cough without other symptoms is usually self-limiting; however, occasional cases become lingering and cause chronic bronchitis.

Diagnosis

  • Complete medical history will usually reveal recent exposure to a kennel or other dogs. Windpipe sensitivity is present in most cases.
  • Diagnostic tests are needed to recognize kennel cough and exclude other diseases.
  • These tests may include:
    • A chest X-ray may be recommended to determine if pneumonia is present.
    • Routine laboratory blood tests-a complete blood count (CBC) or blood chemistry panel is not necessary unless your pet is showing signs of generalized illness, fever or loss of appetite.
    • A fecal flotation should be done to exclude intestinal parasites.
    • If signs of eye involvement are observed, the cornea of the eye should be examined carefully.

Treatment

  • Therapy is controversial because the disease is usually self-limiting (like a human cold) and, if a viral infection is suspected, antibiotics can't kill the virus.
  • This is especially true in mild, uncomplicated cases where treatment is supportive-not unlike that given to a person with a bad cold.
  • Treatments for kennel cough may include one or more of the following:
    • Cough suppressants are appropriate for some pets with kennel cough.
    • Your veterinarian can discuss the pros and cons of this treatment. Injections or pills (butorphanol) are often used, but occasionally, a stronger medicine is needed (codeine-related) to break the cough cycle.
    • Don't use over-the-counter human medicine without first speaking to your veterinarian.
  • Antibiotics are used in some patients, especially if Bordetella infection or secondary bacterial infection is likely.
  • If the symptoms do not improve or should they become chronic, a careful re-evaluation including blood tests and a chest X-ray is indicated.

Veterinary Care In-depth

  • Veterinary care should include diagnostic tests and subsequent treatment recommendations.

Diagnosis In-depth

  • Diagnostic tests are needed to recognize ITB, and exclude other diseases.
  • Often the diagnosis is made from the history of exposure and the typical clinical signs.
  • If, however, the condition does not improve within 3 to 7 days, additional tests will be needed.
  • If the patient shows "constitutional signs"-such as lethargy, fever, productive cough, cloudy nasal discharge-it is often recommended to obtain basic diagnostic tests to ensure that pneumonia has not developed. Tests may include:
    • A complete medical history and physical history.
    • A chest X-ray may be requested to screen for infections or anemia.
    • Routine laboratory blood tests should be done. A blood chemistry panel is only important if your pet is older, has previously identified diseases or is showing signs of generalized illness, fever or loss of appetite.
    • A fecal flotation should be done to exclude intestinal parasites in all puppies unless they have been previously subjected to a regular deworming program.
  • Additional diagnostic tests may be recommended on an individual pet basis, including:
  • If signs of eye involvement are observed, the cornea of the eye should be examined carefully.
  • This should also include tests that can detect a corneal ulcer (especially if the eye seems painful).
  • Thoracic X-rays (or repeated films) may be needed to follow the progress of disease.
  • A tracheoscopy and bronchoscopy should be done if a foreign body is suspected from history and review of radiographs (x-rays) or if there is a poor response to treatment.
  • A culture and cytology of bronchial fluid should be taken. This is especially important if there is a suspicion of a resistant bacteria or a severe pneumonia is present.
  • The procedure is called a "tracheal wash" and can be done under a local anesthetic (placing a needle through the windpipe and flushing in fluid) or by briefly anesthetizing the dog to obtain fluid from the lung. This is then examined under a microscope and cultured for bacteria.
  • Fungal tests may be indicated based on results of radiographs in areas endemic for fungal infections such as histoplasmosis and blastomycosis.

Therapy In-depth

  • Treatments for ITB may include one or more of the following:
    • Because antibiotics can't kill the viruses that are usually responsible for kennel cough, don't expect your veterinarian to automatically prescribe them. Antibiotics are more likely to be used if Bordetella bacterial infection or secondary bacterial infection is suspected; however, there is no "quick test" for this infection.
    • The mild, uncomplicated patient may be given no medication or only a mild cough suppressant.
    • Cough suppressants are appropriate when the cough is frequent and debilitating and there is no evidence of pneumonia.
    • An initial injection of butorphanol may help break the cough cycle. Oral administered pills are also available.
    • Stronger medicine codeine-related such as hydrocodone sold as Hycodan or Tussinex) may be needed to break the cough cycle in severe cases. Over-the-counter medicines such as Robitussin should only be used after speaking to your veterinarian.
    • In cases of lingering kennel cough, a tracheal washing should be done to culture any offending bacteria.
    • If Bordetella bronchiseptica is found, a powerful antibiotic may be needed (as many routine drugs such as amoxicillin won't usually kill this bacterium).
    • Some of these can only be given by injection. Some powerful and commonly used oral antibiotics (enrofloxacin (Baytril®) or other fluoroquinolone antibiotics) should not be used in rapidly growing puppies.
    •  Occasionally, an antibiotic such as gentamicin may be nebulized ("vaporized") in the veterinary hospital.
    • Very rarely, a brief course of an anti-inflammatory medicine may be needed to quiet a severe cough due to tracheobronchitis; however, these drugs can decrease resistance to secondary bacteria thereby promoting pneumonia.

Follow-up

  • Optimal treatment for your pet requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your dog does not rapidly improve.
  • Administer prescribed veterinary medication as directed and be certain to alert your veterinarian if you are experiencing problems treating your dog.
  • Follow up chest X-rays may be required.
  • Remember, vaccination can be performed routinely against canine parainfluenza virus, canine adenovirus type 2 and canine distemper virus.
  • Such vaccinations help to prevent infectious tracheobronchitis. A vaccine against Bordetella bronchiseptica may also be administered.
  • This is especially helpful in pets frequently exposed to other dogs.
Last modified: Thursday, 7 June 2012, 11:17 AM