Disease of the Pleura and Mediastinum

Question 1

what are the pleural membranes and what is within them?

Answer 1

single layer mesothelial cells
fat, elastin, lymphatics, vessels

Question 2

what is in the mediastinum?

Answer 2

thymus
lymph nodes
esophagus
large thoracic vessels
heart

Question 3

what species has a complete mediastinum and what is it?

Answer 3

humans, ruminants, swine
thick fascia completely separates the two pleural cavities

Question 4

what species has a fenestrated or incomplete mediastinum and what is it?

Answer 4

horses
very thin fascia that can be easily ruptured by changes in intra-thoracic pressure

Question 5

what are some causes of pleural effusion?

Answer 5

increased hydrostatic pressure in the microvascular circulation
decreased oncotic pressure
changes in microvascular permeability
impaired lymphatic drainage

Question 6

what caused pleural transudate?

Answer 6

imbalance in hydrostatic and oncotic pressures

Question 7

what causes pleural exudation?

Answer 7

pleural inflammation and impaired lymphatic drainage of protein and fluid

Question 8

what are the non-inflammatory pleural effusions?

Answer 8

hydrothorax
hemothorax
chylothorax

Question 9

what are the inflammatory pleural effusions?

Answer 9

serous or serofibrinous pleuritis
pyothorax or empyema
hemorrhagic pleuritis

Question 10

when is a hemothorax usually seen?

Answer 10

thoracic trauma or surgery
can occur with coagulation defect
erosion vascular wall due to neoplasia or aneurysm

Question 11

when is chylothorax seen?

Answer 11

traumatic or surgical duct rupture
less commonly neoplasia with thoracic duct obstruction, dilation, rupture
idiopathic in some, especially afgans and borzois

Question 12

what do serous or serofibrinous pleuritis describe?

Answer 12

progressively more inflammatory exudates with accumulation of protein, inflammatory cells, and finally fibrin within pleural fluid

Question 13

when does a pyothorax most commonly occur in companion animals?

Answer 13

penetrating foreign bodies or bite wounds

Question 14

when does a pyothorax occur in a horse?

Answer 14

complication primary pneumonia or pulmonary abscess

Question 15

what bacteria most commonly causes pleuropneumonia in horses?

Answer 15

Streptococcus equi subspecies zooepidemicus

Question 16

what is pleuropneumonia from?

Answer 16

devastating complication of pneumonia or pulmonary abscesses

Question 17

what are some risk factors of pleuropneumonia in horses?

Answer 17

long distance transportation
prior viral respiratory infection
exercise

Question 18

what are the clinical signs of a pneumothorax?

Answer 18

pain
dyspnea

Question 19

what is a flail chest?

Answer 19

2 rib fractures causing unstable segment of thoracic wall
moves in when breathe in and out when breathe out

Question 20

what are primary pleural tumors?

Answer 20

mesotheliomas arising for either visceral or parietal pleura
mesenchymal or epithelial

Question 21

what does pleural effusion cause?

Answer 21

restrictive disease pattern
V/Q inequality
reduced lung volumes
atelectatic lobes

Question 22

how do you tap a chest so that you do not cause a pneumothorax?

Answer 22

offset skin stab incision and site of parietal pleura

Question 23

is mediastinal disease usually primary?

Answer 23

no
usually sequela of systemic, thoracic, or cervical disorders

Question 24

what are some common entities of mediastinal space-occupying masses?

Answer 24

lipoma
abscesses
lymphoma
granuloma

Question 25

why can a pneumomediastinum lead to subcutaneous emphysema?

Answer 25

mediastinal space potentially communicates with the subcutaneous space via fascial planes

Question 26

what is commonly associated with a hydrothorax?

Answer 26

cardiac disease decreased oncotic pressure

Question 27

what is commonly associated with a hemothorax?

Answer 27

trauma rupture of large vessels

Question 28

what is commonly associated with hemorrhagic pleuritis?

Answer 28

penetrating foreign body neoplasia

Question 29

what might non-fatal leakage of a smaller volume of blood in a hemothorax lead to?

Answer 29

development of pleural adhesions

Question 30

what clinical signs are associated with pyothorax?

Answer 30

pain dyspnea respiratory distress fever signs of systemic infection

Question 31

what is fibrinous pleuritis?

Answer 31

inflammation and thickening of the pleural membranes without effusion

Question 32

what should be performed when pleural fluid volume increases?

Answer 32

culture and cytologic examination for neoplastic cells

Question 33

when can a pneumomediastinum occur?

Answer 33

gas migration from deep neck wounds esophageal or tracheal rupture sequela of transtracheal aspirate bronchial rupture

Question 34

what are sequelae of pneumomediastinum?

Answer 34

generalized subcutaneous emphysema accumulation of air along aorta or in retroperitoneal space

Question 35

can a pneumothorax progress to a pneumomediastinum?

Answer 35

unlikely