Coughing in small animals

• Acute coughing

  • Tracheobronchitis - Kennel cough
  • Irritation by smoke/dust/chemicals/medicines
  • Airway FB - may have been in there some time.
  • Pulmonary haemorrhage - often + dyspnoea
  • Acute pneumonia e.g. inhalation - often + dyspnoea
  • Acute oedema - often + dyspnoea (Cardiogenic/non-cardiogenic)
  • Airway trauma - choke chains/ bites ect…
• Infectious tracheo-bronchitis

  Infectious disease of canine URT. Any contact - not just kennels.

  Causes include; canine parainfluenzavirus, canine adenovirus, bordetella bronchiseptica.
• Bordetella bronchiseptica

  Occurs in puppies, especially groups. URT/nasal infection - bronchopneumonia. Can be fatal - treat with calvulanate + potentiated amoxicillin.
• Anti-tussives

  Drugs that suppress coughing. Should not use these drugs unless absolutely necessary, coughing is protective in most cases. Use Butorphanol/codeine instead.
• differentials for chronic coughing

  Chronic bronchitis/ bronchiectasis.

  Left heart failure

  Oslerus/ Aelurostrongylus infestation.

  Tracheal collapse

  Airway F.B

  Bronchopneumonia

  Pulmonary neoplasia - primary or secondary

  Extra-luminal mass lesions - thyroid, abscess, lymphoma.

  Eosinophillic disease

  Pulmonary fibrosis.
• Characterisation of canine chronic bronchitis

  The combination of these events leads to thickening of bronchial tissue, overproduction of airway mucus and narrowing of the airways (particularly terminal bronchi).
• Aetiology of canine chronic bronchitis

  Maybe seen to secondary to underlying conditions - tracheal collapse, chronic barking, FB, previous infections or inhalant toxins, environmental factors, chronic smoke inhalation/ noxious gas.
• Presentation of canine chronic bronchitis

  Typically seen in small/ toy breeds. Worse on excitement, harsh cough with attempts at production, (usually clear/frothy, yellow suggests infection. Usually externally well, often obese - occasionally pant excessively, tracheal pinch positive.
• Diagnosis of CCB

  Typical history, physical findings - often exaggerated sinus arrhythmias. Thoracic radiographs - increased bronchial lung pattern. Bronchoscopy and BAL.

  
• Typical BAL results for CCB

  Increased mucus. Non-degenerate neutrophils, eosinophils and macrophages. Cushmann’s spirals (airway mucus casts). Presence of bacteria/ particulate matter are less common and if present would suggest underlying cause present.
• Management of CCB

  General management; weight control, harness rather than collar/ lead. Avoid irritants/ smoking environment.

  Mucous is easier to shift if hydrated; avoid very dry environments, steam in bathroom.

  Any damage done is permanent, owner needs to be aware that cough may not go away.
• Medical management of CCB

  Glucocorticoids - oral and inhaled approaches.

  Bronchodilator therapy - Theophylline, beta agonists (terbutaline, salbutamol, salmeterol).

  Inhaled medications - long term goal to reduce side effects.

  Coupage

  Antimicrobials based on evidence of need.
• Bacterial cultures

  URT and large airways are not sterile - have commensal bacteria, numbers are increased in dogs with reduced clearance.

  Quantitative culture - rarely performed, can be requested.

  Evidence of infection - intracellular bacteria, growth from BAL fluid, Neutrophilia inflammation on cytology.
• Problems with diagnosis bacterial infection

  BAL often not performed until after antibiotic therapy has not resolved clinical signs, antibiotics persist in lung in sufficient quantities for at least 7 days or longer.

  Also risk of contamination from the URT.
• Treatments for lower airway disease

  Inhaled medications

  Corticosteroids

  Bronchodilators

  Nebulisers

  Oral therapy

  Anti-inflammatories - corticosteroids, NSAIDs, anti-leukotrienes.

  Bronchodilators - terbutaline, theophylline.

  Antibiotics, anthelmintics

  Mucolytics - N-acetyl cysteine (NAC)
• Value of inhaled medications

  Management of chronic airway disease.

  Minimal absorption into systemic circulation - less systemic side effects (particularly steroids).

  Faster onset of action.
• Drugs that can be delivered by inhalation

  Beta 2 agonist - salbutamol, salmeterol (longer lasting medication)

  Corticosteroids - Fluticasone, Beclomethasone

  Inhibition of mast cell degranulation - unclear efficacy in dogs and cats with airway disease.
• bacterial Bronchopneumonia

  Primary infections in healthy dogs (and cats). Common pathogens are E.coli, Klebsiella, Pasteurella, staphs, streps, mycoplasma and B bronchiseptica. Primary infections most common with primary pathogens. Often mixed infections, obligate anaerobes may account for up to 25% of pathogens.
• Factors predisposing to bronchopneumonia

  Debilitation

  Prolonged recumbency

  Systemic immunosuppressant (HAC, chemo, pred’s)

  Immunodefiency states

  Defective respiratory defenses

  Damaged respiratory epithelium

  Aspiration

  Airway obstruction

  Systemic sepsis

  Bronchiectasis.
• Clinical signs of bronchopneumonia

  Occasionally only minor clinical signs, signs often relate to extent of pneumonia, cough, respiratory distress, exercise intolerance, more severe infections may produce hyperthermia, anorexia and lethargy are common signs, increased or decreased lung sounds may be present, may include crackles, respiratory distress and cyanosis may develop in severe cases.
• Treatment for bacterial bronchopneumonia

  Antibiotics - broad spectrum. Supplemental humidifield oxygen, IVFT, anti-inflammatories, bronchodilators, mucolytics, physiotherapist, nebulisation, surgery.
• Bronchial foreign bodies

  Sudden onset of coughing and gagging. High frequency in working dogs or those living in rural environments. Often see good initial response to antibiotics. Halitosis may be present and progressive. More substantial respiratory signs may suggest progression to pleural disease.
• Primary lung cancer

  Median age 11 years, generally carcinomas, classified by location, often hard to tell exact origin. More than half are solitary. Present with non-productive cough or exercise intolerance.
• Primary cardiorespiratory parasites

  Oslerus osleri (Filaroides osleri) - Dog

  Filaroides spp - Dog

  Crenosoma vulpis - Dog

  Aelustrongylus abstrusus - Cat

  Angiostrongylus vasorum - Dog
• Clinical signs of O. osleri

  Pre-patent period varies between 10-18 weeks. Nodules in which worms live appear around 2 months from infection - immune response to adults in trachea and bronchus causes the worm to encapsulate. Signs include chronic cough, often dry rasping cough, particularly after exercise.

  
• How to treat Oslerus osleri?

  Can be hard to treat, nodules remain, may even calcify and cough persists.

  Fenbendazole - (Panacur, Granofen), 50mg/kg daily for 10 days, often need to repeat 4 weeks later.