1. science
2. medicine
3. surgery

RESPIRATORY SYSTEM ‫ المرحلة الخامسة‬/ ‫ سروة‬.‫ تكملة محاضرات د‬/ ‫نسخة الموقع االلكتروني‬
Guttural pouch: also known as Auditory Tube Diverticulum
G. P.: are paired of ventral diverticlae of the Eustachian (auditory) tubes. Formed by escape of
mucosal lining of the tube through relatively long ventral slit in the supporting cartilages.
Pouches are normally filled with air located dorsal to the pharynx. G.P. has close association
with many major structures, including several cranial nerves (glossopharyngeal,vagus,
accessory hypoglossal ), sympathetic trunk and internal and external carotid arteries.
Function:
Largely unknown ,however hypothesis for its function are :
1- Its may influence carotid artery blood pressure (regulate B.p.).
2- Cerebral blood cooling mechanism.(horses can easily overheat their brains when exercise ,so
blood that goes through carotid As. cool when pass through the pouch.
Diseases of G.p.:
1- Guttural pouch tympany / birth defect.
2- Guttural pouch empyema ( pus collection in the pouches.
3- Guttural pouch mycosis ( fungal infection, Aspergillosis most common fungi.
* Guttural pouch tympany :
Observed only in young foals up to 1.5 year age , this is a congenital deformity & it occurs
unilaterally , air enters the pouch during expiration or when animal swallow the cough. Since
air is intrapted in G.P there is usually mild infection with tympanitis.
Diagnosis.
1- Distention of affected side (not painful).
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2- Resonant sound on percussion .
3- Harsh snoring or gasping sound on pharyngeal area.
4- Difficulty in swallowing when the animal eat, may be accompanied by cough or projection of
food particles through nostril.
5- In severe cases aspiration pneumonia may develop.
Diagnosis is confirmed by endoscopic examination , radiography also can be helpful .
Treatment: Surgery could be done in standing position or under general anesthesia after
surgical preparation of area. G.P entered then determine whether is opening in Eustachian
tube if not , one should be made , if the opening is covered by flap. Valve on the outlet of
Eustachian tube, this mucous membrane flap can be dissected free and cut away, then G.P.is
closed with PGA, subcutaneous then skin closed ventral incision through viborg’s triangle is
then made. Penrose drain fixed to the area to flush wound daily with nitrofurazone till
swelling resolved post operation ; tetanus prophylaxis, systemic antibiotic for 5 days.
Boundaries of viborg’s triangle are:
Ventrally
external maxillary v.
dorsally
sternocephalicus m.
anteriorly
vertical ramus of mandible.
*Guttural pouch empyema:
Pus filled pouches, caused by bacterial growth, is more common than tympany. Empyema
usually occurs following an infection in the pharynx . often significant infection can be
present before external swelling of the pouch is noted . Most common organism involved is
streptococcus equi , the causative agent strangles. Horses with strangles often have
abscesses in the pharynx that rupture and drain ,which allows bacteria to gain entry to the
pouches this bacteria can live in G.P for weeks to months causing large amount of mucus that
contains W.B.Cs from immune system ,bacteria and necrotic tissue from the G.P. a thick pasty
material develop that is not easily drained away, the top part of the pouch might contain
more fluid, but the bottom holds thicker material almost cheesy consistency with occasional
solid masses of debris called chondroids [ inspissated mucopurulent exudate ]as G.P. becomes
distended with purulentexodate.
Diagnosis; is based on the following sings :
1- Persistent creamy discharge usually from one nostril, when the horse lowers its head to
graze.
2- There may be distention on the affected side of the neck horse shows tenderness over the
area.
3- Difficulty in swallowing (when nerves damaged ).
4- On deep palpation of G.P. ,mucopurulent discharge may come from the affected side .
5- Progressive weight loss, debilitation .
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6- Difficulty in breathing some times when nerves damaged.
7- When facial n. is affected , the horse might show dropping lip or ear.
Treatment :
Some cases of empyema resolve themselves without treatment as the pus drains from the
pouch but majority of horses require aggressive flushing of the pouch and antibiotic therapy.
Specialized catheter is placed in the affected pouch and large volumes of fluid are repeatedly
flushed in and out with significant pressure, if the condition is chondroids, chronic and sever
enough, surgery is sometimes needed to drain the pouch and ventral drainage is necessary to
effect a cure.
*Guttural pouch mycosis;
Is the most dangerous of three affections and is caused by fungi in the pouch , most
commonly Aspergillus is the cause. Fungal infection usually began over one of the main
arteries that transvers the pouch walls if mycosis is not resolved fungal infection slowly will
erode walls of blood vessels and the horse will began to bleed.
Signs :
1- First sign of the G.P. mycosis is intermittent bleeding from one nostril.
2- Sometimes epistaxis, if bleeding or the case not treated at this point the horse will bleed to
death.
3- If the nerves are damaged (that are within the walls of the pouch)even if treated could remain
unable to eat and swallow, continuously lose weight and eventually die.
Treatment :
Complicated surgery involved
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Ligation of the blood vessels that travels through affected pouch.
Balloon catheters.
Surgical lasers are now used in these procedures , but prognosis remain guarded.
Antifungal medications is administrated along with surgery.
Recurrent Laryngeal Neuropathy (Roaring), (laryngeal hemiplegia)
A common disease of the horses that had been recognized for centuries this disorder usually
affects the left side of larynx (voice box ) and occurs most commonly in larger horses.
Causes: cause of PLN is unknown. The proposed causes include:
1- Stretching of the recurrent laryngeal n.( that supplies nerves to the larynx ) as it has very long
tortuous pathway to larynx .
2- Injury to recurrent laryngeal n.
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3- Inherited condition, studies have shown that offspring of PLN affected stallions are more likely
to be affected with RLN than offspring of unaffected stallions.
Cause of roaring:
When there is RLN, there is progressive destruction and weakening of nerve supply to larynx
muscles as a result these muscles are unable to fully open the larynx and so air is breathed in
through a smaller than normal airway hole which results in roaring or whistling noise, specially
at fast work.
Clinical signs :
1- abnormal noises are heard when the horse breathes in during faster levels of exercise
(Roaring)
2- Reduced exercise tolerance,(poor performance).
3- Loss of larynx musculature.
Diagnosis:
1- Case history.
2- Clinical signs.
3- Endoscopic examination (viewing horse’s larynx using flexible video camera). Both asymmetry
of the aryteniods and synchrony of their movement must be assessed during endoscopy. (best
endoscopic photo taken during high speed treadmill exercise),Photo will reveal collapse of left
artenoid cartilage and vocal fold collapse during breathing in.
Treatment:
1- Ventriculectomy (Hobday)and ventriculocodectomy. Surgical removal of a pocket of mucosal
T.(lateral ventricle) of larynx. The resulted scart will stabilize the vocal cord.
Now surgeons remove both of the affected vocal cord and ventricle (ventriculocordectomy)
this procedure is perfomed through incision in the throat into the larynx under general
anesthesia, or alternatively using endoscopic laser with horse sedated. This surgery has been
shown to be useful in non-performance horses and also with low grade laryngeal disease.
2- Prosthetic larynggoplasty (tie back).
Involves placing a suture (prosthesis) to fix diseased artenoid in an open position.
Laryngoplasty reduces respiratory noise production but not completely and therefore
ventriculocardectomy is usually performed at the same time . Postoperative complications
associated with laryngoplasty include coughing (due to aspiration of food caused by
permenantly open larynx) occasionally aspiration pneumonia
3- Nerve muscle pedicle graft technique. Grafting of a piece of nerve and muscle onto the larynx.
This procedure is technically difficult.infrequently performed.
4- Partial arytenoidectomy:
Performed in horses in which laryngoplasty surgery has failed.
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Epistaxis :
Also known as nose bleed.
When a horse begins bleeding from the nostrils. One should ask about:
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Age of the horse.
Exercise tolerance of the horse.
Volume and frequency of blood loss.
Character of epistaxis.
Blood may come out from one or both nostrils due to:
1- Damage of blood vessels that richly supply nasal passages and throat.
2- Lower airways.
3- Lungs
Symptoms:
Bleeding from one or both nostrils.
Causes of epistaxic:
1- Trauma. ( fractures in skull bone, sinuses).
2- Complication of pneumonia.
3- Pulmonary abscesses.
4- Pulmonary infarction.
5- Exercise-induced pulmonary hemorrhage.
6- Foreign bodies in the nostrils.
7- Neoplasia
8- Sinusitis.
9- Nasal polyps.
10- Systemic diseases.
11- Ethmoid hematoma.
12- Guttural pouch mycosis.
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*bleeding that occurs shortly after racing is strongly suggestive of exercise induced pulmonary
hemorrhage.
* muco-purulent nasal discharge with blood staining is associated with ethmoid hematoma.
*in guttural pouch mycosis there is bright red blood drain through nostrils.
Diagnosis: 1- Through endoscopic examination of the airways and lungs.
2- Collection of blood sample for hematology and biochemical profiles.
3- Skull radiography.
Horse with epistaxis should be kept calm, nose should never be packed since horses breath
through their noses, ice packs may be held just below horses eyes, while cases of polyes,
hematomas need surgery.
Treatment: Treatment is related directly to the cause of the bleeding
Sinusitis in equine. (Horse)
Term sinusitis refers to inflammation of one or more of the paranasal sinuses in horse’s head.
These are air cavities in the bones of the skull that communicate with nasal cavity itself.
Horse’s head is designed to be suitable for the large no. of teeth and their long roots and to
give an eye position allowing all vision, two vital requirements for survival . without these
sinuses,head would be too heavy to be raised and lowered easily .
The horse has six pairs of paranasal sinuses ;frontal, sphenopalatine & maxillary and dorsal ,
middle and ventral conchal sinuses , all lined with mucoperiosteum mucus produced in
cleared from sinuses by dynamic flow method as the drainage points do not lie in the lowest
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points in the sinus. Any disruption to this drainage results in stagnation of mucus in sinus
cavities. Usually sinusitis is unilateral, discharge present at one nostril on the same affected
site.
Causes of sinusitis :
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Trauma .
Infection of the upper respiratory tract.
Tumor.
Cyst.
Dental diseases can result in sinusitis( secondary s.).
Deformity in facial area.
Diagnosis:
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clinical signs (unilateral nasal discharge)
percussion of sinuses (dullness)
radiography to sinuses and cheek roots.
Foul- smelling nasal discharge specially when sinusitis is secondary to tooth infection.
Endoscopic examination (using flexible light source) through trephining.
(combination of radiography and endoscopy give definitive diagnosis )
Treatment:
Aim of treatment is to restore the horse’s sinus drainage mechanism.
Atrephine site allows the sinus to be irrigated with topical antibiotic solution.
Trephination is performed with the horse in standing position under sedation and local
anesthesia.
Caudal maxillary sinus is the preferred site as this communicate with all of the sinuses except
the rostral maxillary s.
Operation is done by removing a circle of bone and overlying T. of approximately 1cm., just
below the inner angle of the eye on the affected site, catheter is passed and allow for regular
irrigation ,flushing large volumes of fluid through the sinus a generous flow of fluid out
through the horse’s nostrils is an encouraging sign as it indicates normal route patency. once
nasal discharge c is eases and the sinus is clean on endoscopic examination the catheter is
removed and the hole is left to heal.
(light exercise while the catheter in place is helpful in draining .
If the case persists (chronic sinusitis), radical facial flap surgery will be required. The Aim of
this surgery is to break down the barriers between sinuses and convert them into a single
common air place with anew large drainage hole into the horse’s nasal passage. It,s a very
bloody operation and exact approach depends on which of the sinuses is affected.
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In case of secondary sinusitis which is usually due to dental infection (one of the cheek tooth
roots)that site in the maxillary s. tooth removal is usually required which can be done in
standing position under sedation and in some cases general anesthesia is required.
Disorders of the paranasal sinuses in cattle.
Cattle do not have a fully developed system until age of 7,
Sinuses are:
1- frontal sinus.
2- palatomaxillary sinus (because maxillary sinus is continuous with the
palative sinus.
3- sphenoidal sinuses.
4- conchal sinuses.
Frontal sinus in cattle has a diverticle for the corneal process (horn)
Within the medial orbit there is lacrimal sinus.
Causes of sinus affections.
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Infections.
Congenital anomalies.
Neoplasms.
As secondary affection of disease process extension.
Most common cause of infections sinusitis is extension of septic complication
after dehorning.
6- Trauma.
7- Sinus cysts.
8- Parasites.
(inflammation of the sinuses due to any of previous causes is termed sinusitis)
Clinical signs of sinusitis:
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Unilateral or bilateral nasal discharge.
Facial distortion.
Abnormal head posturing which includes pain
There might be foul breath.
Dullness upon sinus percussion.
Fever.
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7- Anorexia.
8- Depression.
9- Weight loss or decreased production.
On physical examination; bulging of the sinus and purulent exudates at the site of
dehorning or nasal discharge are typical of sinusitis.
Diagnosis.
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Clinical signs.
Physical examination
Radiography (lateral and dorsoventral views).
Endoscopic examination.
Final etiologic diagnosis depends on microbial culture, cytology , and/ or
histology of abnormal tissues within the affected sinus.
6- Sinus centesis and aspiration after small trephine hole which is produce with
Steinman pin.
*Actinomyces pyogenes is commonly isolated after dehorning.
* pasturella mucocida is often associated with sinusitis un related to dehorning.
Treatment:
Chronic sinusitis is best treated by open drainage and lavage of the affected sinus.
Under physical restraint and local anesthesia, localization of the site of trephining of
the affected sinus, trephination is done (making a hole in the affected sinus),then
large volume lavage with sterile fluid is necessary to remove exudate and debris .
saline 0.9%, lactated Ringer’s ,or tap water with povidone iodine solution can work
well, this is a accompanied by local and systemic antibiotics.
In cattle with dental disease as primary cause of sinus involvement dental extraction
is required.
Frontal sinus is most commonly affected sinus.
*Drainage site is 4cm. caudal to the edge of the orbit just above temporal fossa.
* Rostral site of frontal sinus can be drained by trephining 2.5cm from the midline
on a line passing through the orbit Center.
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*Turbinate part of frontal sinus drained by trephining just caudal to the nasal bone
divergence point again 2.5cm from mid line.
Some times 2 trephining holes are needed for the affected sinus depending on the
individual’s needs.
*maxillary sinus can be opened with a trephine hole immediately dorsal and caudal
to facial tubercle and more dorsally in younger cows (cattle) to avoid the maxillary
teeth.
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Thoracic Injuries:
Relatively uncommon in horses ,
Causes:
1- Blunt trauma
2- Penetrating trauma
Sequelae of thoracic injuries include: [penetrating wounds sq.]
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Subcutaneous emphysema.
Pneumothorax.
Pneumomediastinum.
Hemothorax.
Pleuritis.
Diaphragmatic Hernia.
Damage to the lung, heart, and blood vessels.
Abdominal and spinal injury may also occur in association with thoracic trauma
Clinical signs:
Are attributed to damage of internal or external thoracic structures:
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Muscle damage (soft t. damage, skin and muscles )
Blood vessel lacerations.
Rib fracture.
Systemically ,pain ,shock.
If internal thoracic trauma, pneumothorax or hemothorax reflected by presence
of respiratory distress.
6- Nostril flaring (spreading outward)
7- Dyspnea.
8- Tachypnea.
9- Cyanotic m.m.
10- If abdomen issociated in trauma colic may develop due to damage or rupture of
abdominal vescera.
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Diagnosis:
1- Case history.
2- Auscultation and percussion of chest wall in equine patient help to identify
pneumothorax or hemothorax,in pneumothorax lung sounds are absent, but
increased resonance is percussed dorsally.
*in hemothorax: diminished lung sounds ventrally and percussion of fluid line.
3- Diagnostic thoracocentesis to confirm pneumo or hemothorax.
4-Palpation of chest wall may help to identify rib fractures.
5- Blood gas analysis.
6-Radiograpy.
7-Ultrasonography.( help in diagnosing chest affection also useful for determining
amount of blood or fluid or air in thorax also for guiding pleurocentesis and insert chest
tubes.
Pneumothorax:
There are 3 types of pneumothorax:
a- Open pneumothorax: occur with penetrating, open chest, wounds, when air
moves freely during inspiration and expiration.
b- Closed pneumothorax: due to damage to the lung parenchyma by displaced rib
fractures or a ruptured lung bulla permits air to enter the pleural space.
c- Tension pneumothorax: due to or occurs when intrapleural pressure exceed
atmospheric pressure this life threatening condition usually follows formation of
pleurocutaneous fistula in which air enters pleural sac during inspiration but
blocked from getting out during expiration ,thoracic pressure fluids on the
affected side, forcing air across the mediastinal cavity and/or decreasing
compliance of the opposite lung.
Treatment:
1- Chest wounds should be sealed with sterile, air tight dressing to prevent further
movement of the air into thorax.
2- Temporary wound closure or packing.
3- Stent bandages or standard bandage material should be placed fully around
thorax .
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4- Nasal or tracheal insufflation of O2 is indicated in hypoxemic or cyanotic adult
equine patient.
5- Emergency evacuation of pleural air should be performed after wound closure,
when tension pneumothorax is suspected immediate opening of thorax or
placement of cannula allows supra- atmospheric pressure to return to
atmospheric p.
In case of hemothorax sterile teat cannula or 14 gauge catheter or thoracostomy tube is
inserted into dorsal thorax at the 11th to 15th intercostal space.
Thoracostomy tube is inserted ventrally in thorax to provide complete drainage of large
volumes of fluid or blood are present. Cannula should be placed directly infront of rib
avoids the intercostal blood vessels located caudal to the ribs.
Hemothorax and hemorrhagic shock:
Hemorrhagic shock results from loss of blood from.
1- Trauma which cause bleeding leads to hypovolemia.
2- Thoracic trauma which leads to damage to heart, great vessels and intercostal
and pulmonary vasculature that cause loss of large blood volumes.
Signs (symptoms) of hemorrhagic shock.
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Tachycardia
Tachypnea.
Pale mucous membranes
Trembling (shivering)
Sweating.
Distress (painful situation)
Systolic heart murmur.
Previous sings vary with the severity of blood loss and acute or chronic H.and the
underlying lesion.
Treatment of thoracic hemorrhage:
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Fluid therapy I/V immediately Ringer lactate 20-80 ml /kg .over several hours.
Stopping hemorrhage if possible.
Whole blood transfusion when indicated.
Draining of the collected blood in the thorax via aseptic technique to avoid
bacterial contamination.
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Most horses with massive hemothorax from thoracic injury do not survive.
Rib fractures:
Most rib fractures in equine patient occur in foals during parturition, also common in
adult horses following blunt or penetrating thoracic injuries. Although some fractured
ribs can be diagnosed by physical or radiographical examination, many fractures may
not palpable or visible and may be missed.
Most rib fractures in adult horses may heal without fixation of fractured ribs is indicated
in displaced rib fractures because they may lacerate the lungs, heart, B.Vs., diaphragmor
other deep structures so surgical fixation is indicated to minimize continued thoracic
injury, also among complications of rib fracture is closed pneumothorax if cranial ribs
are fractured (not usual because they are protected by shoulder girdle)
Brachial nerve injury can be expected. except for swelling and chest soreness simple
fractures may not show prominent clinical features.
Techniques used to stabilize rib fractures:
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Use of Quill sutures.
External splints.
Pins.
Wires.
Plates.
When realignment is not possible, the remaining bone and fragments should be
removed.
Lung lacerations:
Rare in harses, although there are reports of intrathoracic surgery in large animals, in
this case partial or complete lunglobectomy is recommended for severe lacerations.
Horses with simple rib fractures or small chest wounds or modest degree of
pneumothorax or hemothorax, and without severe lung lacerations or deep penetration
or contamination are candidates for conservative management.
Medical therapy includes:
1- Antimicrobials and NSAIDS.
2- Thoracocentesis or thoracostomy tube placement.
3- Bandaging.
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4- Supportive care measures.
Emergency management.
Emergency triage treatment of equine patients should follow the ABC protocol.
Airway, Breathing and Circulation
Restore alveolar ventilation and oxygenation as well as managing shock.
Anesthesia and surgical approach:
Selecting the appropriate type of anesthesia and surgical approach for treating
thoracic injuries require careful considerations of several factors.
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Patient stability.
Location, type and extension of injury.
Clinician experience.
Response to initial treatment.
General anesthesia should be used with caution in thoracic injuries’ treatment until the
patient condition is stabilized.
Clinician should select standing wound exploration and treatment when possible.
Intercostal perineural is recommended for standing procedures.
Through wound exploration, debridement and lavage are necessary to remove bacteria,
foreign bodies, rib fragments and other debris. Many of these treatment my be used in
standing position.
While general anesthesia is indicated in horses with:
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Sever chest wall distruption.
Deep penetrating wound.
Foreign bodies.
Abdominal cavity involvement.
Complicated rib fractures.
Extensive lung lacerations.
Severe contamination that require aggressive thoracic lavage.
In these cases use of controlled positive-pressure ventilation is essential in equine
patients with open pneumothorax or hemothorax or hypoxemia persists despite
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conservative treatment or wound closure techniques that necessitate mechanical
ventilation and general anesthesia.
Most thoracic approaches in equine patients simply involve enlarging the existing
traumatic wound, however several other techniques are performed including: *lateral
thoracotomy via *intercostal technique or* rib resection and thoracoscopy.
In small animals, *median sternotomy has been describedfor gaining entrance to both
sides of the thorax this approach is also useful in calves and foals.
In most cases thoracic wound should be enlarged, thoracotomy incision is centered over
the initial wound to expose ribs, heart, lungs, diaphragm and pleura, using retractors
will also help in exploration.
Thoracoscopy is more beneficial than thoracotomy for evaluating and treating thoracic
injuries in equine, it allows detailed exploration of the thoracic cavity in patients with
minimal morbidity while thoracotomy is more invasive and is limited by difficult
exposure.
Standing thoracoscopy provides excellent excess to the dorsal and lateral aspects of the
thorax while cranial and ventral portions are best viewed with lateral or dorsal on
oblique recumbency.
Accessible foreign bodies are diagnosed by thoracoscopy could be removed.
Postoperative complications of thoracic injuries:
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Pleuritis.
Pericarditis.
Abscesses
Pleural adhesions
diaphragmatic hernia.
Wound closure:
1- primary wound closure is recommended when possible after thoracic injury in
horses, in small uncomplicated wounds, thoracic mms. and soft tissues are
opposed over the defect.
2- For large chest wounds closure.
a- Primary muscle flap.
b- Prosthetic mesh repair.
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a- Rotating muscle pedicle flaps of longissimus dorsi and external abdominal
oblique m. transported via a Z- plasty technique is used to close caudal
and lateral thoracic wounds in horse
b- Polypropylene mesh although useful for closing large defect, care should
be taken to avoid complications related to infection.
3- Second intention healing may be selected for specially in large and highly
contaminated wounds. Closed suction drain placed in wound can help in
preventing seroma formation and secondary incisional infection.
Close postoperative monitoring is essential when infection persist, aggressive
retreatment via debridement and drainage, lavage and appropriate antimicrobial
selection based on culture and sensitivity test to prevent secondary pleuritis.
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