unilateral nasal discharge

• label the image

  A) sinuses

  B) pharynx

  C) guttural pouches

  D) trauma

  E) equi

  F) zooepidemicus

  G) dental

  H) mycosis

  I) bilateral

  
• Unilateral discharge usually originates in front of the nasal septum, so there are more rostral structures in the head (nasal passages, sinuses, and guttural pouches), but this is not an exact rule. You can get bilateral discharge from rostral structures if there is large amounts of fluid that pass back into the pharynx and then down either the nasal meatus, or in some cases, discharge from more caudal structures can be predominantly from one nostril.

  • Occasionally can see unilateral discharge with other respiratory conditions but may swap sides
• Younger horses are at higher risk of infectious diseases (primary infections), and developmental problems such as cleft palate, guttural pouch tympany and sinus cysts.
• Older horses are at higher risk of neoplasia (such as squamous cell carcinomas in the sinuses or melanomas in the guttural pouch), ethmoid haematoma and dental disease with secondary sinusitis.
• Your physical exam of the upper respiratory tract should include observing the nature of the discharge (type and smell), palpating the lymph nodes (especially submandibular), checking temperature for infectious diseases, feeling for lumps, bumps (trauma or dental disease), heat, pain, and percussing the sinuses.
• Radiography

  A) fractures

  B) fluid

  C) air

  D) soft

  E) mycosis

  
• Endoscopy is often the most useful technique for identifying where discharge is coming from and visualising lesions. Don’t forget that you will need to endoscope the guttural pouches in most cases.

  A) differentiating

  B) mycosis

  C) ethmoid

  D) epistaxis

  E) guttural pouches

  
• you can perform sinoscopy through a trephine hole, and take biopsy, lavage and culture samples through the endoscope.
• • A dental exam is an essential part of investigating purulent nasal discharge in older horses, as sinusitis secondary to dental abnormalities causing communication from the oral cavity to the sinuses is possible.
  • The last three to four cheek teeth are in contact with the sinus
• Strep equi diagnostics = Nasal swab and culture, blood ELISA, PCR of guttural pouch lavage
• Radiography and endoscopy are our main diagnostic tests, and in many cases we may require both technique. The other tests (those that are not common) are used for specific more challenging cases, and are more expensive and referral hospital only procedures.

  • Dental disease is one of the times we may consider using CT if budget allows, as early disease or complex conditions can be difficult to identify and visualise.
• In summary, the common diagnostic approach goes as follows…

  • Watch horse eating for signs of pain or quidding
  • Palpate dental arcades externally for pain or abnormalities
  • Oral examination (dentistry sessions)
  • Radiography (does not always identify disease)
  • Computed tomography (gold standard diagnostics but cost and availability limits use)