Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT
(No. )
Obstruction of the upper airway in horses or laryngeal hemiplegia
(ROARERS'):
Obstruction of the upper airway is a common cause of exercise
intolerance in horses and is characterized in most cases by unusual
respiratory noise during heavy exercise.
Etiology:
Degeneration of the recurrent laryngeal nerve with subsequent
neurogenic atrophy of the cricoarytenoid dorsalis and other intrinsic
muscles of the larynx.
Epidemiology:
Prevalence :The disease affects large horses more commonly than
ponies, and it is commonly recognized in draft horses, Thoroughbreds,
Standardbreds, Warmbloods and other breeds of large horse.
Pathogenesis:
- Axonal degeneration causes preferential atrophy of the adductor
muscles of the larynx, although both adductor (dorsal
cricoarytenoid muscle) and adductor (lateral cricoarytenoid
muscle) are involved.
- Laryngeal obstruction increases the work of breathing, decreases
the maximal rate of oxygen consumption and exacerbates the
hypoxemia and hypercarbia normally associated with strenuous
exercise by horses.
Clinical findings
include exercise intolerance and production of a whistling or roaring
noise during strenuous exercise. The disease can be detected by analysis
of respiratory noise.
Necropsy finding:
Lesions are confined to an axonopathy of the recurrent laryngeal nerves
and neurogenic muscle atrophy of the intrinsic muscles of the larynx.
Treatment:
Treatment requires a prosthetic laryngoplasty with or without
ventriculectomy.
1
Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT
(No. )
Disease of the guttural pouches (Auditory tube diverticulum,
Eustachian tube diverticulum).
The guttural pouches are diverticula of the auditory (or eustachian) tubes
found in equids and a limited number of other species, and is divided by
the stylohyoid bone into lateral and medial compartments. The function of
the guttural pouch is unclear, although it may have a role in regulation of
cerebral blood pressure, swallowing, and hearing.
 Guttural Pouch Empyema
Etiology:
Empyema is the accumulation of purulent material in one or both guttural
pouches, Initially, the purulent material is liquid, although it is usually
viscid, but over time becomes inspissated and is kneaded into ovoid
masses called chondroids.
Epidemiology:
The disease occurs in all ages of horses, including foals, and all equids,
including asses and donkeys. The case fatality rate is approximately 10%,
with one-third of horses having complete resolution of the disease,
Guttural pouch empyema occurs in approximately 7% of horses with
strangles.
Pathogenesis
 The rupture of abscessed retropharyngeal lymph nodes into the
medial compartment. Continued drainage of the abscesses
presumably overwhelms the normal drainage and protective
mechanisms of the guttural pouch,
 Allowing bacterial colonization, influx of neutrophils and
accumulation of purulent material.
 Swelling of the mucosa, especially around the opening to the
pharynx, impairs drainage and facilitates fluid accumulation in the
pouch.
 The accumulation of material in the pouch causes distension and
mechanical interference with swallowing and breathing.
 Inflammation of the guttural pouch mucosa may involve the nerves
that lie beneath it and result in neuritis with subsequent pharyngeal
and laryngeal dysfunction and dysphagia.
2
Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT
(No. )
Clinical finding : These include:
 The nasal discharge unilateral, as is the disease, intermittent and
white to yellow 0r Purulent nasal discharge
 Guttural pouch empyema is not usually associated with
hemorrhage, although the discharge may be blood tinged. Bilateral
disease, and the resultant neuritis and mechanical interference with
swallowing and breathing, may cause discharge of feed material
from the nostrils.
 Swelling of the area caudal to the ramus of the mandible and
ventral to the ear
 Lymphadenopathy
 Carriage of the head with the nose elevated above its usual position
 Dysphagia and other cranial nerve dysfunction and Respiratory
stertor.
Clinical pathology
- Hematological examination : may reveal evidence of chronic
infection, including a mild leukocytosis, hyperproteinemia, and
hyperfibrinogenemia.
- Fluid from the affected guttural pouch contains large numbers of
degenerate neutrophils and occasional intracellular and
extracellular bacteria.
Necropsy finding:
Lesions of guttural pouch empyema include the presence of purulent
material in the guttural pouch and inflammation of the mucosa of the
affected guttural pouch.
Diagnostic confirmation
Diagnostic confirmation in a horse with clinical signs of guttural pouch
disease is achieved by demonstration of purulent material in the guttural
pouch by endoscopic or radiographic examination and examination of the
fluid.
Differential diagnosis of guttural pouch empyema includes:
• Abscessation of retropharyngeal lymph nodes
• Guttural pouch tympany
• Guttural pouch mycosis.
3
Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT
(No. )
Guttural pouch empyema should also be differentiated from other causes
of nasal discharge in horses including:
• Sinusitis
• Recurrent airway obstruction (heaves)
• Pneumonia
• Esophageal obstruction
• Dysphagia of other cause.
Treatment
 The principles of treatment are removal of the purulent material,
eradication of infection, reduction of inflammation, relief of
respiratory distress and provision of nutritional support in severely
affected horses.
 The guttural pouch can be flushed through a catheter (10-20
French,3.3-7 mm male dog urinary catheter) inserted as needed via
the nares, or a catheter (polyethylene 240 tubing) with a coiled end
inserted via the nares and retained in the pouch for several days.
The pouch can also be flushed through the biopsy port of an
endoscope inserted into the guttural pouch. The choice of fluid
with which to flush the guttural pouch is arbitrary but frequently
used fluids include normal (isotonic) saline, lactated Ringer's
solution or 1% (v/v) povidone-iodine solution.
 It is important that the fluid infused into the guttural pouch be
nonirritating as introduction of fluids such as hydrogen peroxide or
strong solutions of iodine (e.g. 10% v/v povidone iodine) will
exacerbate the inflammation of the mucosa and underlying nerves
and can actually prolong the course of the diseases The frequency
of flushing is initially daily, with reduced frequency as the
empyema resolve.
 Systemic antimicrobial administration is recommended for all
cases of guttural pouch empyema because of the frequent
association of the disease with bacterial infection and especially S.
equi and S. zooepidemicus infection of the retropharyngeal lymph
nodes.
 The antibiotic of choice is penicillin G (procaine penicillin G, 20
000 IU/kgintramuscularly every 12 h for 5-7 d), although a
combination of sulfonamide and trimethoprim (15-30 mg/kg orally
every 12 h for 5-7 d) is often used. Topical application of
4
Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT
(No. )
antimicrobials into the guttural pouch is probably ineffective
because they do not penetrate the infected soft tissues of the pouch
and retropharyngeal area.
 NSAIDs such as flunixin meglumine (1 mg/kg intravenously or
orally every 12 h) or phenylbutazone (2.2 mg/kg intravenously or
orally every 12 h) are used toreduce inflammation and pain.
Severely affected horses may require relief of respiratory distress
by tracheotomy. Dysphagic horses may need nutritional support,
including administration of fluids. Chronic cases refractory to
treatment might require fistulation of the guttural pouch into the
pharynx.
Guttural pouch mycosis
Etiology
Mycosis of the guttural pouch is caused by infection of the dorsal wall of
the medial compartment of the pouch, caudal and medial to the
articulation of the stylohyoid bone and the petrous temporal bone.
Epidemiology
The disease occurs in horses of both genders and all breeds. Horses are
affected at all ages, with the youngest recorded case being a 6-month-old
foal.The overall prevalence is low, although precise figures are lacking.
The case fatality rate is approximately 33%.
Pathogenesis
The pathogenesis of the disease is unclear,

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The fungal spores gain access to the guttural pouch through
the pharyngeal opening.
The spores then generate and proliferate in the mucosa of the
dorsal, medial aspect of the medial compartment of the
guttural pouch. The location of the lesion is consistent but
the reason for the disease occurring in this particular position
is unclear.
Invasion of guttural pouch mucosa is followed by invasion
of the nerves, arteries, and soft tissues adjacent to it.
Invasion of the nerves causes glossopharyngeal, hypoglossal,
facial, sympathetic or vagal dysfunction.
Invasion of the internal carotid artery, and occasionally the
maxillary or external carotid, causes weakening of the
5
Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT

(No. )
arterial wall and aneurysmal dilatation of the artery, with
subsequent rupture and hemorrhage.
Death is caused by hemorrhagic shock or, in horses with
dysphagia, aspiration pneumonia or starvation.
Clinical finding
 Epistaxis is usually severe and frequently life-threatening.
 There is profuse bleecling of bright red blood from both nostrils
during an episode, and between episodes there may be a slight,
serosanguineous nasal discharge.
 There are usually several episodes of epistaxis over a period of
weeks before the horse dies. Most horses that die of guttural pouch
mycosis do so because of hemorrhagic shock.
 Signs of cranial nerve dysfunction are common in horses with
guttural pouch mycosis and may precede or accompany epistaxis.
 Dysphagia is the most common sign of cranial nerve disease and is
attributable to lesions of the glossopharyngeal and cranial laryngeal
(vagus) nerves.
 Dysphagic horses may attempt to eat or drink but are unable
to move the food bolus from the oral cavity to the esophagus.
 Affected horses frequently have nasal discharge that contains
feed material and often develop aspiration pneumonia. Lesions
of the recurrent laryngeal nerve cause laryngeal hemiplegia .
 Horner's syndrome (ptosis of the upper eyelid, miosis,
enophthalmos and prolapse of the nictitating membrane) is seen
when the lesion involves the cranial cervical ganglion or
sympathetic nerve.
 Facial nerve dysfunction, evident as drooping of the ear on the
affected side, lack of facial expression, inability to close the
eyelids, corneal ulceration and deviation of the muzzle away
from the affected side.
Guttural pouch tympany
Etiology and Epidemiology
Guttural pouch tympany refers to the gaseous distension of one, rarely
both, guttural pouches of young horses. Tympany develops in foals up to
1 year of age but is usually apparent within the first several months of
life.
6
Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT
(No. )
Clinical finding
 Marked swelling of the parotid region of the affected side with
lesser swelling of the contralateral side.
 The swelling of the affected side is not painful on palpation and is
elastic and compressible.
 There are stertorous breath sounds in most affected foals due to
impingement of the distended pouch on the nasopharynx.
Respiratory distress may develop.
 Severely affected foals may be dysphagic and develop aspiration
pneumonia.
Clinical pathology
 Endoscopic examination of the pharynx reveals narrowing of the
nasopharynx by the distended guttural pouch. The guttural pouch
openings are usually normal. There are usually no detectable
abnormalities of the guttural pouches apart from distension.
 Radiographic examination demonstrates air-filled pouches, and
dorsoventral images permit documentation of which side is
affected.
 There are no characteristic changes in the hemogram or serum
biochemical profile.There are no characteristic lesions and
necropsy examination usually does not demonstrate a cause for the
disease.
TREATMENT
Treatment consists of surgical fenestration of the medial septum allowing
drainage of air from the affected pouch into the unaffected side. The
prognosis for long term resolution of the problem after surgery is
approximately 60 % .
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