Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNA
(No. )
Diseases of the pleura and diaphragm
Hydrothorax and Hemothorax
The accumulation of edematous transudate or whole blood in the
pleural cavities is manifested by respiratory embarrassment caused by
collapse of the ventral parts of the lungs.
Etiology :
Hydrothorax and hemothorax occur as part of a number of diseases.
Hydrothorax
- As part of a general edema due to congestive heart failure or
hypoproteinemia- As part of African horse sickness or bovine viral leukosis- Secondary to thoracic neoplasia
Hemothorax
- Traumatic injury to thoracic wall, a particular case of which is rib
fractures in newborn foals
- Hemangiosarcoma of pleura
- Lung biopsy
- Strenuous exercise by horses
Pathogenesis:
 Accumulation of fluid in the pleural cavities causes compression
atelectasis of the ventral portions of the lungs and the degree of
atelectasis governs the severity of the resulting dyspnea.
 Compression of the atria by fluid may cause an increase in venous
pressure in the great veins, decreased cardiac return and reduced
cardiac output.
 Extensive hemorrhage into the pleural space can cause
hemorrhagic shock.
Clinical finding :
 In both diseases there is an absence of systemic signs, although
acute hemorrhagic anemia may be present when extensive bleeding
occurs in the pleural cavity.
 There is dyspnea, which usually develops gradually, and an
absence of breath sounds, accompanied by dullness on percussion
1
Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNA
(No. )
over the lower parts of the chest. In thin animals the intercostals
spaces may be observed to bulge.
 Present of sufficient fluid may cause compression of the atria and
engorgement of the jugular veins and Increased of a jugular pulse
amplitude .
Clinical pathology:
Thoracocentesis :
 present of clear serous fluid in hydrothorax.
 Blood in recent cases of hemothorax.
Radiographic or ultrasonographic examination:
 The accumulation of pleural fluid or blood is evident on of the
thorax.
 Large quantities of blood in the pleural cavity have a characteristic
Swirling, turbulent appearance.
Necropsy finding:
In animals that die of acute hemorrhagic anemia resulting from
hemothorax
The pleural cavity is filled with blood, not clotted, the clot having been
broken down by the constant respiratory movement. Hydrothorax is not
usually fatal but is a common accompaniment of other diseases.
Differential diagnosis :
Hydrothorax and hemothorax can be d differentiated from pleurisy by
the absence of pain, toxemia and fever and by the sterility of an aspirated
fluid sample.
Treatment:
In severe dyspnea aspiration of fluid from the pleural sac causes a
temporary improvement but the fluid usually reaccumulates rapidly.
In severe hemothorax Parenteral coagulants and blood transfusion .
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Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNA
(No. )
PNEUMOTHORAX
Pneumothorax refers to the presence of air (or other gas) in the pleural
cavity. Entry of air into the pleural cavity in sufficient quantity causes
collapse of the lung and impaired respiratory gasexchange with
consequent respiratory distress.
Etiology:
- The common cause is rupture of the lung or secondary to thoracic
trauma,
- Penetrating wound that injures the lung, or lung disease.
- Trauma to thoracic wall when a wound penetrates the thoracic wall,
including the parietal pleura.
- Thoracotomy, thoracoscopy or drainage of pleural or pericardial
fluid.
- Injury or surgery to the upper respiratory tract, presumably
because of migration of air around the trachea into the
mediastinum and subsequent leakage into the pleural space.
- Perforating lung injury in newborns as rib fractured during birth
and the lung lacerated by the sharp edges of the fractured rib.
Type of Pneumothorax:
- Spontaneous pneumothorax
occur without any identifiable inciting event.
- Open pneumothorax
describes the situation in which gas enters the pleural space other
than from a ruptured or lacerated lung, such as through an open
wound in the chest wall.
- Closed pneumothorax
refers to gas accumulation in the pleural space in the absence of an
open chest wound.
- Tension pneumothorax
occurs when a wound acts as a one-way valve, with air entering the
pleural space during inspiration but being prevented from exiting
during expiration by a valve-like action of the wound margins.
3
Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNA
(No. )
Pathogenesis:
- Entry of air into the pleural cavity
collapse of the lung.
partial or complete
- Collapse of the lung results in alveolar hypoventilation,
hypoxemia, hypercapnia, cyanosis, dyspnea, anxiety.
- Tension pneumothorax lead to a direct decrease in venous return to
the heart by compression and collapse of the vena cava.
-
The degree of lung collapse varies with the amount of air that
enters the cavity;,small amounts are absorbed very quickly . but
large amounts may cause fatal anoxia.
Clinical signs:
1- There is an acute onset of inspiratory dyspnea, which may
terminate fatally within a few minutes if the pneumothorax is
bilateral and severe.
2- The rib cage on the affected side collapses and shows decreased
movement when one pleural sac is collapse.
3- On auscultation of the thorax, the breath sounds are markedly
decreased in intensity and commonly absent. The mediastinum
may bulge toward the unaffected side and may cause moderate
displacement of the heart and the apex beat, with accentuation of
the heart sounds and the apex beat.
4- The heart sounds on the affected side have a metallic note and the
apex beat may be absent.
5- On percussion of the thorax on the affected side, a hyperresonance
is detectable over the dorsal aspects of the thorax.
6- There are usually signs of the inciting disease, including fever,
toxemia, purulent nasal discharge and cough due to secondary lung
disease particularly infectious lung disease.
Clinical pathology:
Definitive diagnosis is based on demonstration of pneumothorax by
radiographic or ultrasonographic examination.
4
Stage : 4th Stage
Diyala University
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNA
(No. )
A- Radiography permits the detection of bilateral and unilateral
pneumothorax and permits identification of other air leakage
syndromes including pneumomediastinum, pneumoperitoneum,
and pneumopericardium.
B- Ultrasonography is also useful in determining the extent of
pneumothorax and the presence of consolidated lung and pleural
fluid.
C- No specific changes in hematological and serum biochemical
Values.
D- Arterial blood gas analysis reveals hypoxemia and hypercapnia.
Necropsy finding
The lung in the affected sac is collapsed. In cases where spontaneous
rupture occurs there is discontinuity of the pleura, usually over an
emphysematous bulla. Hemothorax may also be evident.
Differential diagnosis :
The clinical findings are usually diagnostic. Diaphragmatic hernia may
cause similar clinical signs but is relatively rare in farm animals.
In cattle, Diaphragmatic hernia is usually associated with traumatic
reticulitis and is not usually manifested by respiratory distress. Large
hernias with entry of liver, stomach, and intestines cause respiratory
embarrassment, a tympanitic note on percussion and audible peristaltic
sounds on auscultation.
Treatment:
The treatment depends on the cause of the pneumothorax and the severity
of the respiratory distress and hypoxemia.
- Animals with closed pneumothorax not require specific treatment
should be confined and prevented from exercising until the signs of
pneumothorax have resolved.
- An open pneumothorax, due to a thoracic wound, should be
surgically closed.
- Prophylactic antimicrobial treatment is advisable to avoid the
development of pleurisy.
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