◊ Respiratory System Affections ◊

AFFECTIONS OF THE RESPIRATORY SYSTEM

The incidences of respiratory disorders are less common in ruminants and small animals as compared to equines.

I-EPISTAXIS

Definition: -

It is a state of bleeding from the nose which is a sign of respiratory diseases.

1-UNILATERAL

It resulted from trauma, dehorning, nasal granuloma, tumors or entrance of leeches into the nasal cavity.

2-BILATERAL

It results from septicemic conditions, diseases of blood coagulation, some infectious diseases as bovine rhinotracheitis or malignant catarrhal fever, deficiencies of vitamin K or calcium or during extreme exertion due to increased blood pressure.

Signs: -

Epistaxis may be continues or recurrent and may be profuse or scanty. If the epistaxis is due to an obstruction, inspiratory dyspnea will be present, while if it is due to pulmonary tissue involvement, the blood is frothy fresh and increase whenever the animal lower its head. When it caused by sinus affection the blood may be mixed with purulent exudates. Epistaxis associated with systemic disease has a characteristic necrotic odor. In case of heamoptysis, cough is usually noticed and in case of sinusitis, percussion of the infected sinuses produces dull sound.

Diagnosis: -

1-History                            2-Signs

3-X-ray                              4-Endoscopy

Treatment: -

1-Treatment of the cause is essential

2-Application of ice or cold water over the nostrils and flushing the nasal cavity with epinephrine solution or packing it with a gauze tape immersed with epinephrine (in case of unilateral epistaxis).

3-In case of bilateral epistaxisis, tracheostomy should be performed and packing of both nostrils as described above

4-Administration of coagulants as vitamins K and Calcium are helpful.

II-NASAL CAVITY OBSTRUCTION

Obstruction of nasal passage ensues as a result of space occupying lesion that may be neoplastic or non-neoplastic

1-NON-NEOPLASTIC (polyps)

Polyps may be formed either due to continuous irritation of mucous membrane with foreign body or infectious diseases as nasal schistosomiasis, rhinopordiasis, T.B, actinomycosis or actinobacillosis. The newly formed tissue (polyps) is usually attached to the lateral wall of nasal cavity and rarely to the nasal septum.

2-NEOPLASTIC CAUSE (epithelial & non-epithelial neoplasms)

Signs: -

A-Unilateral obstruction

1-The animal shows restlessness and may rub the nostrils against the ground

2-Nasal discharge, inspiratory dyspnea, stertor and frequent sneezing

B-Bilateral obstruction

1-The animal exhibits mouth breathing

2-In long standing cases, facial deformity may be observed

Diagnosis: -

1-History                2-Signs

3-X-ray                  4-Endoscopy                 5-Histopathology

Treatment: -

1-Pedunculated growths at the external nares are removed by excision at the base of attachment.

2-Rhinotomy is indicated when the growth is excessive and inaccessible through external nares.

a-An incision is made through the skin and cartilage on the dorsolateral aspect of the nostril

b-The base of the growth is debrided and cauterized

c-Hemorrhage is controlled by packing the nasal cavity with a gauze immersed with antiseptics

3-Trephining of the nasal bone is indicated for removal of growths that extends up to the nasal septum.

4-Tracheostomy facilitates the surgical intervention.

III-ATHEROMA

Definition: -

Sebaceous cyst located in the false nostril of the horse, it may reach the size of the hen egg

Causes: -

It is a retention cyst formed by obstruction of the duct of the sebaceous gland

Signs: -

1-Presence of non-painful swelling caudal and dorsal to the nares

2-Atheroma may cause respiratory sound during breathing due to narrowing of the nasal passage, but it rarely causes blockage

Treatment: -

The case is treated by surgical excision and suturing the resulted wound

IV-SINUS EMPYEMA

Anatomy of sinus: -

1-In domestic animals, there are four pairs of paranasal sinuses; frontal, maxillary, ethemoidal and spheno-palatine. The frontal sinuses are mostly affected, followed by the maxillary.

2-In equines; the frontal sinus communicates with the maxillary one by opening in the floor.

3-In cattle; the frontal sinus has a post-orbital diverticulum, in addition to presence of transverse septum making difficulty in its drainage.

Definition: -

It is a suppurative inflammation of the nasal sinus associated with accumulation of pus within the paranasal sinus

Causes: -

It usually ensues as a sequel to

1-Dehorning or fracture of horn in cattle; because the frontal sinus communicates with the horn core

2-Oestrus ovis larvae infestation in sheep (frontal and maxillary)

3-Depressed fractures of the frontal or maxillary bone

4-Dental diseases especially in equines and canines (maxillary)

5-Actinomyces and actinobacillous infection in bovines (maxillary)

6-Infection from the nasal cavity (frontal and maxillary)

Signs: -

1-Unilateral or bilateral purulent discharge may be seen unless the nasal openings of the sinuses are occluded; these discharges increase with exercise and it is of bad odor when the cause is infected tooth.

2-These discharges may accumulate causing bulging of the frontal bone at the affected side

3-The affected animal appears depressed and may shows convulsions due to pressure on the brain

4-In cattle; accumulation of pus in the postorbital diverticulum may cause bulging eye, walk in circles, holding the neck to one side, closing the eyes and carrying the nose higher than usual.

5-In case of camel, it will refuse to lower its head to drink

6-In long standing cases, the pus may extends through bones forming fistulae discharging pus.

Diagnosis: -

1-History of dehorning, dental problem, trauma, …..etc

2-Signs            3-Examination                4-X-ray

Treatment: -

A-Sinusitis secondary to dehorning

1-Irrigation of the sinus with antiseptic antibiotic solution through the dehorning wound

2-Parentral antibiotics

B-Chronic cases

1-Remove and treat the cause (actinomycosis or actinobacillosis or dental problem)

2-Surgical exposure of the affected sinus (trephining)

3-Flushing the sinus with antiseptic solution

4-In case of cellulites, warm application is indicated

BONE FLAP TECHNIQUES &TREPHINATION

Surgical access to the paranasal sinuses can be obtained by either bone flap techniques or trephination. The bone flap techniques are superior to trephination because they provide better exposure, visualization, and access for surgical manipulation within the sinuses, and they eliminate the need for multiple trephine openings. Trephination is the traditional approach for surgical access to the paranasal sinuses. It is useful for diagnostic and therapeutic access to the sinuses.

Indications: -

1-Chronic empyema          2-Fractured facial bones

3-Repulsion of tooth           4-Removal of foreign bodies from the sinus

Site of the operation: -

A-Frontal sinus

1-Cattle

There are five sites;

1-To drain post-orbital diverticulum; 4 cm above the upper border of the orbital cavity at the level of the supraorbital foramen

2-To drain the caudal compartment; halfway between the midline and horn base over the nuchal diverticulum

3-To drain the medial compartment and base of the horn; below the base of the horn (care should be taken to avoid puncturing the cranium in this area)

4-To drain the rostral compartment; caudal to a line passing through the center of the orbit, about 2.5 cm from the midline

5-To drain the turbinate portion of the frontal sinus; at the point of diversion of the nasal bone (identified by the thumb and index)

2-Camel

Opening is done near the orbit and over a line connects the two canthi

3-Equines

For the fronto-nasal bone flap, the caudal margin is a  perpendicular line from the dorsal midline to a point midway between the supraorbital foramen and the medial canthus of the eye; the lateral margin begins at the caudal margin 2 to 2.5 cm medial to the medial canthus of the eye and extends to a point approximately two-thirds the distance from the medial canthus of the eye to the infraorbital foramen; and the rostral margin is a perpendicular line from the dorsal midline to the rostral extension of the lateral margin. The estimated course of the nasolacrimal duct is a line from the medial canthus of the eye to the naso-incisive notch.

For trephination, an opening is made midway between medial canthus and midline.

B-Maxillary sinus

1-Cattle

Just above the facial tuberosity

2-Equines

Maxillary sinus is divided into two compartments; the superior and inferior maxillary sinuses. The superior maxillary sinus communicates dorsally with the frontal sinus. For the maxillary bone flap, the rostral margin is a line drawn from the rostral end of the facial crest to the infra-orbital foramen; the dorsal margin is a line from the infra-orbital foramen to the medial canthus of the eye; the caudal margin is a line (parallel to the rostral margin) from the medial canthus of the eye to the caudal aspect of the facial crest; and the ventral margin is the facial crest. These boundaries provide maximal exposure of the maxillary sinus while protecting the vulnerable infra-orbital canal and nasolacrimal duct.

For the maxillary Trephination, opening of the superior (posterior) maxillary sinus is made in an area just dorsal to the facial crest and 5-7 cm posterior to the end of the facial crest. The inferior (anterior) one is opened in an area just dorsal to the facial crest and 2-3 cm posterior to the end of the facial crest.

Anesthesia and control: -

1-The animal either in standing or lateral recumbency

2-The operation is done under sedation with local analgesia, basal narcosis or general anesthesia

Technique: -

1-Surgical preparation of the area of operation

2-Incision is made through skin, subcutaneous tissue and periosteum

3-The trephining is then done by pierce the bone with the central pin of the trephine machine and rotate till complete incision of the bone

4-After removal of a circular disc of the bone, the sinus is irrigated thoroughly with antiseptic solution like 1:1000 potassium permanganate

5-The sinus opening should be packed with gauze plugs to prevent its premature closure and keep maggots away from the sinus

Postoperative care: -

1-Daily flushing with antiseptic solution till healing (indicated by absence of pus discharges)

2-After irrigation, the animal exercised to encourage drainage.

3-The trephine hole should be plugged with gauze till complete healing.

V-LARYNGEAL HEMIPLEGIA

Definition: -

It is Permanent paresis or paralysis of the left arytenoids cartilage and vocal fold manifested clinically by exercise intolerance and respiratory noise (roaring or whistling). Right sided or bilateral involvement (laryngeal paraplegia) is uncommon. It is also known as roaring or recurrent laryngeal neuropathy.

Causes: -

1-Hereditary; more common in long necked and larger breeds

2-The left recurrent nerve is more commonly involved because of its longer length and subjected to more stretching as it pass around the aortic arch.

3-It may be resulted from peri-vascular injection of irritating substances or intoxication from chemicals or plants.

Clinical findings diagnosis: -

1-Abnormal respiratory noise during Exercise and exercise intolerance

2-Laryngeal palpation and observation of the arytenoid movement is helpful aid for diagnosis

3-Endoscopic examination show the focal fold is located in the median position and immobile

Treatment: -

1-The case is incurable and the line of treatment is directed towards stabilization of affected side of the larynx during inspiration

2-Laryngeal ventriculectomy; by removing the mucous membrane lining the laryngeal saccules to permit adhesion between the arytenoid and vocal cord, and this usually improves inspiratory noise.

3-Prosthetic laryngoplasty may be used in racing horses

4-Subtotal arytenoidectomy

VI-LARYNGEAL OBSTRUCTION IN RUMINANTS

Laryngeal obstruction in cattle is either

A-Acute

It resulted from laryngeal necrosis due to balling gun and drenching injuries or laryngeal edema due to smoke inhalation

B-Chronic

It resulted from retropharyngeal swelling as abscess or tumor, calf diphtheria in calves 3-18 months, or laryngitis caused by fusobacterium necrophorum in sheep and goats

Signs: -

1-Excessive salivation and dysphagia, inspiratory dyspnea and stertor due to laryngitis

2-Anorexia and depression

3-In calve diphtheria; fever and characteristic foul odor can be observed

Diagnosis: -

1-History and signs

2-Oral examination with a speculum or endoscope via the nares

3-X-ray; may show presence of gas, foreign bodies or laryngeal abnormalities.

Treatment: -

1-Parentral Antibiotics

2-In severe dyspnea; tracheostomy is needed

3-Fluid therapy

4-Severe affected cases are directed to slaughter

TRACHEOSTOMY

Temporary or permanent opening of the trachea to keep the air way patent

Indications: -

A-Temporary tracheostomy

1-Obstruction of the upper respiratory tract as in bilateral epistaxis, tracheal ring fracture or collapse, swelling as a result of snake or insect bites

2-Before operations in the nose or larynx

 B-Permanent tracheostomy

1-Irreversible obstruction of the upper respiratory tract as neoplasm

Anesthesia and control: -

1-Either in standing or lateral recumbency

2-Either Sedation with a local infiltration analgesia or general anesthesia is needed

Site of operation: -

The ventral midline at the junction between the upper and middle one third of  the neck region (fourth to sixth tracheal ring) is preferred because this area is usually free from harness and also operation in this area give a roomy place for repeating the operation if needed.

Technique: -

1-After surgical preparation to the site, the head and neck are extended fully by an assistant to make the trachea prominent.

2-A longitudinal midline skin incision is made through the skin between the bellies of the sternoihyodieus muscles.

3-The tracheal rings are exposed

4-In dogs, the incision is extends 3-4 cm just caudal to the cricoids cartilage of the larynx while the animal in dorsal recumbency.

5-For temporary tracheotomy, a stab incision is made through the annular ligament connecting the two adjacent rings and a plastic, rubber or metal tracheotomy tube is introduced in the created place.

6-For permanent tracheostomy, or when the tracheostomy tube is expected to remain prolonged time, an elliptical piece of cartilage is removed from the cranial and caudal tracheal rings.

7-The piece of cartilage removed should not exceed than half the ring.

8-Selfretaining metallic tracheostomy tube is introduced through the window in the trachea.

VII-THORASIC WOUNDS

Most of thoracic wound are a result of trauma, special attention must be taken to prevent pnemothorax and collapse of the lung. Wounds of the thoracic wall may cause rib fracture and the resulted splinters may penetrate the lung causing pnemothorax.

Treatment: -

The wounds treated on the same principals of open wound treatment.