Page 693 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

668 CHAPTER 3

VetBooks.ir 3.124 3.125

Fig. 3.124 Guttural pouch mycosis of the lateral Fig. 3.125 A life-threatening epistaxis caused by
compartment, showing the normal unaffected sigmoid guttural pouch mycosis.
flexure of the internal carotid artery (arrow), and the
mycotic plaque lateral to the stylohyoid bone (obscured).
Differential diagnosis
The principal other cause of severe epistaxis is nasal
laryngeal nerve are also involved in some cases. Less trauma. This can be external – a severe blow to the
commonly the plaque is more lateral, resulting in head can cause marked haemorrhage. The trauma
damage to a branch of the external carotid artery, can be internal (either iatrogenic such as a stomach
the external maxillary artery (Fig. 3.124). tube or accidental such as the horse getting a twig
or fence splinter up the nose). Exercise-induced pul-
Clinical presentation monary haemorrhage can be severe, but obviously
The most common presentation is severe epistaxis always has a history of strenuous exercise immedi-
(Fig. 3.125). Usually horses are discovered after a ately before-hand.
haemorrhage, with the stable heavily contaminated Dysphagia has multiple causes; however, pharyn-
with blood, giving the traditional ‘slaughterhouse’ geal phase dysphagia is generally neurogenic in origin.
image. The next most common presentation is acute- Various poisonings, such as lead, can cause neuro-
onset, often severe, pharyngeal phase dysphagia. genic damage. Masses below the epiglottis can cause
This includes coughing when eating and discharge permanent DDSP and dysphagia, and if the mass is
of food, mucus and saliva from both nostrils. The caused by a foreign body the onset can be acute.
discharge is often stained with dark blood. Other
cranial neuropathies can include laryngeal hemiple- Diagnosis
gia, facial paralysis and Horner syndrome. Right- Endoscopy is the principal diagnostic aid, but care
sided RLN should always raise suspicion of guttural must be exercised during examination. Examination
pouch mycosis. Pain in the caudal head/cranial neck of the nasopharynx will usually reveal a large blood
region can also occur, leading to head carriage and clot distending the ostia of the guttural pouch
position changes. (Fig. 3.126). Horses with blood in the pharynx from
Following the initial bleed horses will usually other causes will often aspirate some into the gut-
continue to discharge dark blood from principally tural pouch ostia during swallowing. Therefore, a
one nostril. If untreated, a second severe bleed usu- small trickle of blood from the ostia is not necessarily
ally occurs a few hours or days later. It is seldom that significant. A large blood clot is not usually mistaken
the first bout of epistaxis is fatal. Usually horses will and is quite obvious during examination. Following
bleed three times before dying, but this is highly this examination, the operator needs to decide
variable and should not be relied upon. whether to examine the pouch itself. This decision