nasal discharge

• The first part of the diagnostic approach is localising the lesion as the approach and differentials are different for lower and upper airway disease. We can also identify the most likely location depending on whether the discharge is unilateral or bilateral.
• The nasal septum divides the nasal passages into left and right sides up to the level of the pharynx so…

  A) unilateral

  B) bilateral

  C) unilateral

  
• The onset and progression of clinical signs can help differentiate trauma and infection.
• The most commonly used upper airway diagnostic techniques are…

  • Oral/dental examination
  • Head radiography
  • Endoscopy (resting and exercising, sinoscopy)
  • Computed tomography
  • Haematology and Biochemistry
  • Specific tests for infectious diseases such as Strangles and equine influenza. (culture, PCR, ELISA)
• Lower airway diagnostic techniques are…

  • Endoscopy
  • Tracheal wash (culture and cytology)
  • This is one of the main tests to sample the LRT
  • Bronchioalveolar lavage (culture and cytology)
  • This is one of the main tests to sample the LRT
  • Ultrasonography
  • Radiography (less useful)
  • Haematology and Biochemistry
  • Specific tests for infectious diseases (Serology, ELISA)
• Typical signs of upper respiratory tract conditions include…

  • Unilateral nasal discharge
  • Swellings around the head and lymph node enlargement
  • Respiratory noise
  • Dysphagia and cranial nerve involvement.
• Lower respiratory conditions typically have a cough and increased respiratory rate and noise on auscultation (bilateral discharge).
• Some diseases may affect other body systems, such as Herpes (abortion and neurological disease), Equine Viral Arteritis (peripheral oedema) and guttural pouch disease (cranial nerve neuropathies), so note should be taken of all signs reported, even if they not initially appear to be linked to the respiratory system.
• if the signs are mild or intermittent, then use of a rebreathing bag or examination after exercise can be helpful
• Strangles cases may have draining tracts from abscesses or lymph nodes, and palpable abnormalities associated with dental disease include bony swellings, pain or gaps in dental arcade on palpation, and discharging tracts.
• fill in the blanks

  A) trauma

  B) vascular

  C) mycosis

  D) asthma

  E) anaerobes

  F) dental

  G) choke

  
• Don’t forget the odour, nasal discharge associated with a rotting tooth or foreign body is pretty pungent.
• Radiography is useful for bony lesions and soft tissue masses and fluid lines in air filled structures, but it won’t show you details of some soft tissue and any mucosal lesions. It also has limited use for thoracic lesions due to the large size of the horse.

  • Hence this is best for dental, sinus and guttural pouch conditions
• Endoscopy allows to see inside the upper and lower respiratory tract, including the guttural pouch, and even the sinuses (through a trephine hole), and many conditions can be diagnosed on endoscopic appearance.

  • Its limitations are that the lesions have to be in an accessible space, and large amounts of discharge or haemorrhage will just cover the end of the scope limiting or preventing visibility.
• there are a range of tests to help identify specific diagnostic tests, including nasal swabs, guttural pouch lavage and serology, with ELISA and PCR the main analysis methods.

  A) strangles

  B) influenza

  C) herpes

  D) arteritis

  
• Tracheal wash and bronchioalveolar lavage are key diagnostic tests for most lower airway disease

  A) focal or diffuse

  B) diffuse

  C) poor

  D) good

  
• • Ultrasonography and radiography can be useful for lower airway disease, but only for specific disease conditions e.g., pneumonia.
  • Ultrasonography…
  • Good for: pleural disease, diseases affecting periphery/surface of lung
  • Not so good for: diseases deeper within lung tissue due to acoustic shadowing for air
  • Radiography
  • Good for: Large masses, fluid lines, foals / small equids
  • Not so good for: Most diseases, larger horses
• Aspiration and analysis of pleural fluid are for cases with pleural fluid lines / neoplasia