nasal disease

• Shelters are stressful environments that often have high close contact and hence are perfect environments for infectious disease
• what clinical signs are consistent with URT?

  • ocular discharge
  • Nasal Discharge
  • conjunctivitis
  • cough (also LRT)
• which is more severe, URT or LRT?

  LRT
• what clinical signs are consistent with LRT?

  Dyspnoea and Tachypnoea
• Inspiratory dyspnoea is associated with upper airway obstruction (stridor and stertor). It is therefore typically associated with nasal, pharyngeal, laryngeal and tracheal disease.

  • Inspiratory cackles are found with restrictive lung diseases such as pulmonary oedema and pulmonary fibrosis (but may also be present with chronic bronchitis)
• Expiratory dyspnoea can be recognised as a discrete end-expiratory effort or grunt (and may only be heard on auscultation) and may have apparent abdominal effort. It is typically associated with intra-thoracic tracheal collapse, neoplasia and feline asthma (lung hyperinflation)

  • Expiratory and dyspnoea and wheezing = fixed airway obstruction e.g. bronchoconstriction with feline asthma
• Dyspnoea indicates a significant degree of respiratory impairment and is best described as laboured or difficult breathing. It is best recognised as slow and purposeful breathing.
• label the anatomical area associated with the causes of dyspnoea

  A) URT

  B) LRT

  C) lung

  
• which inspiratory noise is high-pitched?

  stridor
• which inspiratory noise is low-pitched?

  stertor
• which inspiratory noise is tracheal or laryngeal?

  stridor
• which inspiratory noise is common with BOAS?

  stertor
• Hyperthermia = an elevated body temperature due to failed thermoregulation

  • This occurs when the body produces and/or absorbs more heat than it can dissipate. The set-point of the body's internal temperature is not altered
• Pyrexia = a fever or febrile response

  • Endogenous or exogenous pyrogens cause an elevation in the body's thermoregulatory set-point
• will an animal feel hot or cold with hyperthermia?

  hot
• will an animal feel hot or cold with pyrexia?

  cold
• History can help identify the cause e.g. neoplasia and degenerative causes will worsen over time and for a longer time than a traumatic cause. Label the diagram via the cause

  A) trauma

  B) neoplasia

  C) infection

  
• Kennel cough is often mild/moderate but occasionally severe/ fatal. The common clinical presentation includes…

  • Hacking cough which may or may not be productive
  • Some clients see a productive cough as V+
  • Submandibular lymphadenopathy
  • Ocular/ nasal discharge
  • Possible lethargy
  • Possible pyrexia
• Dogs that are more likely to catch KC includes agility dogs, puppies, those that mix in a park or daycare, vets' dogs, working, breeding and showing dogs.
• The usual suspects of KC have an initial low pathogenicity virus (CPiV, CRCoV, CAV-2) which disrupts the mucociliary escalator. This allows for the invasion of “bystander”/ secondary bacteria.
• What is the significance of the viral envelope?

  Those with a viral envelope have better protection from the host's immune system, enzymes and certain chemicals. Hence, enveloped viruses are more hardy so are better at surviving in the body and environment
• What is the significance of the difference between DNA and RNA viruses?

  DNA viruses can encode up to a hundred viral proteins while RNA viruses have smaller genomes and usually encode only a few proteins. Hence, RNA viruses are less stable and more prone to mutation so they generally change and evolve faster, this can make them harder to treat and can also jump from species to species
• list the common causes of KC

  Canine parainfluenza virus, Canine adenovirus-2, Canine respiratory coronavirus, Bordetella bronchiseptica
• Canine parainfluenza virus is an enveloped RNA virus which only affects the upper respiratory tract only
• Canine adenovirus-2 is a non-enveloped DNA virus which is closely related to CAV-1 (infectious canine hepatitis)

  • The vaccine for this agent is based on CAV-2 and protects against both pathogens. This vaccine is part of the “core” vaccine schedule
• Canine respiratory coronavirus is an enveloped RNA virus and is NOT the same as canine enteric coronavirus
• Bordetella bronchiseptica is a gram-negative aerobic, coccobacillus bacterium which can be a primary or secondary problem

  • This disease it causes can vary from mild to severe and spreads between dogs, humans and cats. (zoonotic potential). This bacterium can be carried by rats, guinea pigs and rabbits with no clinical signs.
  • Shedding post-infection occurs up to 12 weeks
• the uncommon causes of KC include canine distemper virus, canine influenza and strep equi
• Strep equi has a high morbidity (90%) and a high mortality (50%). It causes pyrexia, bloody nasal discharge and haematemesis (severe broncho-pneumonias)
• Canine Distemper Virus is an enveloped RNA virus that is shed in all body fluids

  • It causes severe disease including bronchopneumonia, purulent ocular and nasal discharge, haemorrhagic vomiting and diarrhoea, neurological signs and hyperkeratosis “hard pad”
• Transmission of KC is mainly by aerosols (the smaller the particle the longer they can stay in the air and the easier it is for them to enter the lungs) but some direct transmission is possible

  • CAV and Bordetella are environmentally labile
• do animals with deep pneumonia cough?

  no
• do animals with bronchopneumonia cough?

  yes
• why do animals with deep pneumonia not cough?

  there are no cough receptors in the alveoli
• why would you want to diagnose the specific cause of kennel cough?

  if it will change management e.g. prescribing antibiotics, if the pattern of disease changes or refractory disease
• Diagnostic options for KC include…

  • Paired serology (looking at antibody titres)
  • Nasal or oropharyngeal swab for most pathogens (PCR)
  • Conjunctival swab for distemper (contact the lab if suspicious of distemper)
• Symptomatic treatment for KC include: avoiding choke chains/pulling on the collar, cleaning the eyes and nose, NSAIDS to reduce pyrexia (but not ideal treatment choice), paracetamol (better anti-pyrectic agent), butorphanol, codeine and glycerine. Antibiotics are not always necessary to treat KC as most cases are viral in origin.
• If the cause of KC is believed to be Bordetella then the antibiotic must have gram-negative cover.

  • Secondary pathogens are usually gram-negative – Pseudomonas, Klebsiella but may be gram-positive
  • Tetracyclines (doxycycline), potentiated sulphonamides and potentiated amoxicillin is best
• Pneumonia can develop following initial URT disease

  • Cough (depending on location, broncho pneumonias cough)
  • Dyspnoea/tachypnoea
  • May have marked pyrexia (not always)

  This may become life-threatening very quickly
• To prevent KC: maintain environmental hygiene, reduce dog-to-dog contact, reduce fomite transmission, improve ventilation and implement vaccination strategies.