Rhinoscopy

• Evaluation of the nasal passages, particularly for investigation of nasal discharge Nasal discharge or deformity.
• Evaluation of chronic or acute rhinitis Rhinitis.
• Evaluation of the nasopharynx Rhinoscopy: retrograde - normal .
• Removal of foreign objects Airway foreign body.
• Identification and subsequent biopsy of masses Nasal cavity: neoplasia.
• Collection of washings or brushings for cytology Nasal flushing.

Advantages

• Well-tolerated.
• May be curative if foreign object present.
• Biopsy sample may be readily obtained.

Disadvantages

• Tendency for hemorrhage.
• Deep planes of anesthesia required for evaluation of nasopharynx.
• Further therapy indicated if mass or fungal infection identified:
  • Surgery.
  • Radiation therapy.
  • Infusion of anti-fungals.
• Relatively expensive equipment.

• Radiography.
• CT imaging.
• Blind flushing or biopsy.

Preparation

• 10-15 minutes for induction of anesthesia.
  To avert aspiration of blood use cuffed endotracheal tube for general anesthesia .

Procedure

• 10-15 minutes for procedure
  Perform radiographs or CT prior to rhinoscopy.

Criteria for choosing test

• Based on clinician preference.
• Helpful for animals with suspected foreign bodies Airway foreign body or chronic rhinitis Rhinitis.

Risk assessment

• Low risk for the patient from the procedure.
• Some risk of hemorrhage, which at times may be dramatic.
• Older patients may have systemic disease.

Veterinarian expertise

• Medium.

Anesthetist expertise

• Medium.
• Dog needs to be deep enough to tolerate the procedure but high risk of hemorrhage.

Nursing expertise

• Medium
• Relatively straight-forward procedure.
• Equipment cleaning may be complex.

Minimum equipment

• May be performed with a an otoscopic cone and light source in some cases.
• Additionally, the caudal nasal cavity may be viewed with a spay hook to retract the palate, dental mirror and light source.

Ideal equipment

• Rigid or flexible endoscope of small diameter is optimum.
• Flexible endoscope may be retroflexed behind the soft palate to permit inspection of the caudal nasopharynx.

Ideal consumables

• Standard equipment for care and cleaning of endoscopy.

• None required

• Nothing per os for 8-12 hours prior to anesthesia.

• General anesthesia with endotracheal intubation Endotracheal intubation.
• Nasopharynx, very sensitive to stimulation; potential for aspiration of blood and other fluids exists.

Step 1 -

• Induce general anesthesia using standard techniques General anesthesia: overview.
• Perform complete oral examination, including laryngeal examination if indicated.

Step 2 -

• Perform diagnostic imaging as clinically indicated/available.
  Skull radiographs, and/or CT or MRI scanning are very beneficial.

Step 1 -

• Place patient in sternal recumbency with nose positioned over the table.

Step 2 -

• Place a receptacle on the floor underneath nose to collect hemorrhage.

Step 3 -

• Inspect external nasal passages and feel for asymmetry.
• Palpate regional lymph nodes.

Step 4 -

• Examine posterior nasal cavity using either a dental mirror and spay hook or by retroflexing the endoscope.
  Anesthesia should be very deep to prevent patient struggling or reflexes.
• Document and biopsy any masses visualized.
• Nasal washing Nasal flushing may be less sensitive than biopsy Biopsy: nasal.
• Endoscopic brushing specimen may be taken from focal lesions for cytologic evaluation.

Step 5 -

• Examine both nasal passages from an anterior approach.
• Evaluate:
  • Mucosa.
  • Secretions (if present).
  • Presence of fungal plaques  or foreign bodies.
  • Turbinates and ability to enter sinuses.
  • Presence of masses.
• Biopsy abnormal regions Biopsy: nasal.

Step 1 -

• Remove endoscope carefully.
• Request assistant to clean endoscope.

Step 2 -

• Control hemorrhage as needed.
• Can infuse dilute phenylephrine Phenylephrine into nasal cavity to help trigger vasoconstriction.
• Can place ice packs on nasal passage.
• In rare cases with severe hemorrhage, ligation of the ipsilateral carotid artery may be necessary to stop bleeding.

Monitoring

• Monitor for hemorrhage or difficulty in breathing during recovery from anesthesia.

Fluid requirements

• Geriatric pets or animals with significant hemorrhage may require supplemental intravenous fluids Fluid therapy: for hemorrhage.

Analgesia

• Usually not required.

Antimicrobial therapy

• Rarely required.
• Secondary bacterial infections may occur.

Other medication

• Other therapy as directed by rhinoscopy and biopsy results.

Potential complications

• Hemorrhage is the most common; generally responds to standard methods of control.
  In very rare cases, an overzealous endoscopist could enter into the brain in a dog with a nasal tumor entering the brain.

Medication

• As directed by underlying disease.

Follow up

• As directed by underlying disease.

• Hemorrhage.
• Failure to get diagnostic sample.

• Dependant upon underlying disease.

• Operator difficulty.
• Dog size or bleeding causing inadequate viewing of nasal passages.

Refereed papers

• Recent references from PubMed and VetMedResource.
• Harcourt-Brown N (2006) Rhinoscopy in the dog 1. Anatomy and techniques. In Practice 28 (4), 170-175 VetMedResource.
• Harcourt-Brown N (2006) Rhinoscopy in the dog 2. Conditions associated with chronic nasal discharge. In Practice 28 (5), 238-246 VetMedResource.
• Noone K E (2001) Rhinoscopy, pharyngoscopy, and laryngoscopy. Vet Clin North Am Small Anim Pract 31 (4), 671-689 PubMed.
• Lent S E & Hawkins E C (1992) Evaluation of rhinoscopy and rhinoscopy-assisted mucosal biopsy in the diagnosis of nasal disease in dogs: 119 cases (1985-1989). J Am Vet Med Assoc 201 (9) 1425-1429 PubMed.