56 - Respiratory System: Thoracic Cavity & Lung Conditions that are not Pneumonia

What is a transudate found in the thorax called?

Hydrothorax

What is a modified transudate found in the thorax called?

Fibrinous hydrothorax

What is an exudate found in the thorax called?

Pyothorax

What is blood found in the thorax called?

Hemothorax

What is lymph found in the thorax called?

Chylothorax

What is the gross appearance of hydrothorax?

Serous, clear-slightly yellow, thin, watery fluid in thoracic cavity

What are the 2 causes of hydrothorax?

Increased hydrostatic pressure

Decreased oncotic pressure

What can hydrothorax lead to?

compressive atelectasis & respiratory distress

What is the gross appearance of hemothorax?

Red-tinged, watery-coagulated blood in the thoracic cavity

What are causes of hemothorax?

Rupture of major blood vessel from trauma

Erosion of vascular wall via inflammation or malignant cells

Ruptured aortic aneuysms

Coagulopathies

Thrombocytopenia

What causes chylothorax, generally?

Impaired thoracic duct outflow

What causes chylothorax, specifically?

Impaired/obstructed drainage from chyle from the major lymphatic vessels

What gross lesions are seen with Chylothorax?

White fluid with fat droples in thorax

Pleural fibrosis (chronic)

Compressive atelectasis (if severe)

What causes pylothorax in dogs?

Bacterial infections

What allows bacteria to enter the thorax in dogs?

Inhaled/impaled plant material

Esophageal perforation

Extension of discospondylitis/vertebral osteomyelitis

Idiopathic

What is seen grossly with pyothorax?

Yellow fluid +/- suppurative depris

What is seen grossly with pyothorax caused by Nocardia, Actinomyces & Bacteriodes?

Pyogranulomatous pleuritis

Blood-tained pus in thoracic cavity

Sulfur granules (yellowish aggregates)

What causes pyothorax in felids?

Bite wounds

Parapneumonic spread of pneumonia

What is pneumothroax?

Air in the pleural space

What causes spontaneous pneumothrax?

Unknown - no known underlying disease of trauma

What causes secondary pneumothroax?

Penetrating wounds

Perforated esophagous

Iatrogenic

Tracheal rupture from intubation

Rupture of emphysematous bullae

What gross lesions are seen with pneumothroax?

Collapses, atelectatic lung

How is pneumothroax diagnosed?

Radiographs

What is seen with acute pneumonia?

Hyperemic lungs

Engorged alveolar capillaries & blood vessels

Pulmonary congestion is most frequently caused by ________ _______

Heart failure

How does chronic heart failure manifest as lung lesions?

Patchy red appearance with tan/brown foci

What causes the tan/brown foci in chronic lung congestion caused by chronic heart failure?

Hemosiderin accumulation

T/F - Pulmonary hemorrhage is a nonspecific lesion

True - only indicates vascular compromise

What gross appearance is seen with pulmonary hemorrhage?

Random circular red lesions

Pulmonary effusion occurs when the rate of fluid movement from _______ _______ into the interstium/alveoli exceeds that of _________ and _________ removal

Pulmonary vessels; Lymphatic & Alveolar

What gross lesions are seen with pulmonary edema?

Wet, shiny, heavy lungs

Expansion of interlobular septum by clear fluid (species specific)

+/- stable white foam in trachea

T/F - Acute respiratory distress syndrome (ARDS) is only a gross diagnosis

False - only a clinical diagnosis

What is the pathogenesis of ARDS

Diffuse alveolar damage = severe and diffuse endothelial & alveolar damage = fulminating pulmonary edema

ARDS results in the generation of _________ membranes

Hyaline

What do hyaline membranes do?

Line septa & thicken them

What are the 4 most common pulmonary emboli in domestic animals?

Thromboemboli

Septic emboli

Fat emboli

Neoplastic emboli

What is a pulmonary thromboembolism (PTE)

Local thrombus formation (in lung) that gets translocated elsewhere in circulation

PTE is a result of conditions that predispose to _____________ states

hypercoagulaable

What are examples of things that cause PTE?

Parasites

Endocrinopathies

Glomerulopathies

Long-term IVC where thrombi build up and break off

What are septic pulmonary emboli?

Pieces of thrombi contaminted with bacteria/fungi that have broken free and trapped in lung

What are sources of septic pulmonary emboli?

Right sided Bacterial endocarditis

Jugular thrombophlebitis

Hepatic abscesses

Septic arthritis & omphalitis

Embolic pneumonia can progress to pulmonary __________ and/or pumonary ________

Necrosis

Abscesses

T/F - Congenital pulmonary defects are rare and are of little significance if they occur

True

Pulmonary calcification occurs during hypercalcemic/hypocalcemic states

Hypercalcemic

What gross lesions are seen with pulmonary calcification?

Pale pink-tan

Lungs fail to collapse when throacic cavity is opened

Gritty texture when cut

What is atelectasis (lungs)?

Incomplete distention of alveoli

What gross lesions are seen with atelectasis?

Depressed lung

Darker apperance

Mosaic pattern of inflated and non inflated tissue (acquired)

What is unique about atelectic lungs?

They will sink in water/formalin

What are the 2 causes of atelectasis?

Congenital/neonatal

Acquired

What is congenital/neonatal atelectasis?

Lungs fail to expand with air at the time of birth

What are causes of congenital/neontal atelectasis?

Airway obstruction

Issues with pulmonary surfactant

What is acquired atelectasis?

Lungs collapse after inflation has taken place

What are the 2 types of acquired atelectasis?

Obstructive

Compressive

What causes compressive atelectasis?

Space-occupying masses in pleural cavity

Transferred pressure

Loss of negative pressure

Acute fibrinous pleuritisis can progress to pleural __________ with time

fibrobsis

What are causes of pleuritis?

Bacterial infections

Hardware disease

Trauma

Rupture of pulmonary abscesses

What causes pleuropneumonia in equids, generally?

Bacteria

Which bacteria causes pleuropnemonia in equids most frequently?

Streptococcus zooepidemicus

What are risk factors for pleuropneumonia?

Long distance transport

Confinement with head elevated/Prolonged head elevation

Viral infections

Why does head elevation cause pleuropneumonia?

Prevents normal drainage of nasopharngeal secretions

What gross lesions are seen with pleuropneumonia?

Pneumonia that extends to pleura

Unilateral or bilateral

+/- extensive fibrin deposition on pleura

Pleuritis in cattle is most often the result of direct extension from __________

pneumonia

What bacteria commonly cause pleuritis in cattle?

Mannheimia haemolytica

Histophilus somni

E. coli (calves)

What gross lesions are seen with pleuritis in cattle?

Unilateral, abundant fibrin depositions on pleural surface

Why is pleuritis typcially unilateral in cattle, but pleuropneumomia can be bilateral in horses?

Cattle have a complete mediastinum while horses have fenestrated

What are the 2 forms of feline infectious peritonitis?

Noneffusive

Effusive

What is seen with noneffusive FIP?

Pyogranulomatous pleuritis

What is seen with effusive FIP?

Pleural effusion (straw colored)

White plaques on pleural surface

Noneffusive/Effusive FIP has a weak cell mediated response

Noneffusive

T/F - Effusive FIP has a severe cell mediated response

False - ineffective to no cell-mediated response