Ch. 47: Guttural pouch

Question 1

Which are the anatomical landmarks that delineate the pouches?

Answer 1

Midline: Rectus capitis ventralis, longus capitis muscles, median septum
Rostrally: Basisphenoid bone
Ventrally: retropharyngeal LNs, pharynx, oesophagus
Caudally: atlantooccipital joint
Laterally: digastricus muscle, parotid, mandibular salivary glands
Dorsally: petrous part of the temporal bone, tympanic bulla, auditory meatus

Question 2

Which cranial nerves can be affected by guttural pouch disease?

Answer 2

LATERAL COMPARTEMENT
Facial n. (VII) from stylomastoid foramen

MEDIAL COMPARTMENT
Glossopharyngeal n. (IX) + pharyngeal branch, vagus n. (X) + pharyngeal branch, accessory n. (XI)  from jugular foramen
Hypoglossal n. (XII)  from hypoglossal nerve canal
! pharyngeal branch of X and cranial laryngeal nerve on floor

Question 3

What is the typical signalment and clinical signs for gp tympany?

Answer 3

Arabian, Paint horse fillies (sex specific quantitative trait locus identified), shorlty after birth up to 1yo
Nonpainful elastic swelling at parotid region, usually unilateral, that if severe can cause dysphagia, dyspnoea, inhalation pneumonia, secondary empyema

Question 4

Treatment options for gp tympany?

Answer 4

• Indwelling Foley catheter in pharyngeal orifice (2 if bilateral)
• Median septum fenestration (Viborg/modified Whitehouse) for unilateral cases
• Fenestration + removal of plica salpyngopharingea (+/- removal of small segment of medial lamina of Eustachian tube) for bilateral cases
• Removal of plica salpyngopharingea alone (bilateral cases)
• Creation of salpyngopharyngeal fistula in dorsal nasopharyngeal recess or on floor of medial compartment (just caudo-dorsal to nasopharyngeal ostium) +/- laser fenestration

Question 5

Non-infectious causes of gp empyema?

Answer 5

• Infusion of irritant drugs
• Deep penetration of periocular fb
• Fx of stylohyoid bone
• Congenital/acquired stenosis of pharyngeal orifice
• Gp tympany
• Pharyngeal perforation by NGT

Question 6

Clinical signs of gp mycosis?

Answer 6

• Unilateral/bilateral nasal discharge with or without epistaxis (usually bilateral)
• Dysphagia (damage to pharyngeal branch of X and IX)
• Aspiration pneumonia
• Abnormal respiratory noise (pharyngeal paresis/ laryngeal hemiplegia)
• Ipsilateral Horner syndrome (damage to cranial cervical ganglion and postganglionic fibres): ptosis, miosis (+/-), enophtalmos +/- slight protruding of third eyelid, patchy cervical sweating, congestion of nasal mucosa
• Parotid pain
• Abnormal head posture
• Head shyness
• Sweating and shivering
• Corneal ulcers
• Colic
• Blindness
• Locomotion disturbances
• VII paralysis
• Tongue paralysis
• Septic arthritis of atlantooccipital joint