Ch 105 - Thoracic Cavity Flashcards

1
Q

What is normal plural fluid volume in dogs and cats?

A
  • Dog - 0.1ml/kg
  • Cats: 0.3ml/kg
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What cells make up normal plueral fluid?

A
  • mesothelial cells 9-30%
  • Monocytes/macrophages 61-77%
  • Lymphocytes 7-11%
  • Neutrophils under 2%

1500-2500 cells/mcL
Protein less than 2.5g/dL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What % of dogs have a dorsal thoracic lymph centre?

A

25%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which parts of the body are NOT drained by the thoracic duct?

A
  • Right thoracic limb
  • Right shoulder
  • Cervical regions

Drained by the right lymphatic duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the cisterna chyli and where is it located?

A
  • Bipartite, dilated, retroperitoneal lymph channel, ventral to L1-L4 along cranial abdominal aorta
  • Most commonly sits ventral to L3, caudal to coeliac and cranial mesenteric arteries
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the major difference in the thoracic duct anatomy in dogs and cats?

A
  • Dogs - travel on right sife through caudal thorax, dorsolateral to aorta. Crosses to left at T5/6
  • Cats: On the left!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where does the thoracic duct drain?

A

Left external jugular vein or jugulosubclavian vein
(Significant anatomical variation - some branches may terminate in azygous)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What embryonic structure forms the thymus?
At what age does it stop growing and starts to involute?

A
  • Arises from the 3rd pharyngeal pouch
  • Grows until 4-5mo
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the normal functional residual capacity (volume of air remaining in lung at end of expiration)

A

45ml/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What fluid dynamics favour pleural fluid production and absorption?

A
  • Increased hydrostatic pressure of systemic and pulmonary capillaries compared to pleural fluid favours pleural fluid production
  • Increased osmotic pressure of systemic and pulmonary vascular beds are greater than pleural fluid, favouring absorption

Tends to enter pleural space from parietal pleura and be absorbed by visceral pleura

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the functions of the thymus?

A

Cell mediated immunity
- maturation and selection of T-cells
- Termination of defective or autoreactive thymocytes

Endocrine
- Secretion of thymosin, thymic humoral factor, thymopoietin, thymostimulin, thymulin
- Involved in T-cell enhancement and maturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do you classify pleural transudate, modified transudate and exudate?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

List causes of a pleural transudate

A
  • Hypoproteinaemia
  • Increased hydrostatic pressure as with CHF (NT-proBNP significantly higher in cats with effusion from heart disease)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

List DDx for a serosanguinous (modified transudate) effusion

A
  • Lung lobe torsion
  • D-hernia with liver entrapment
  • Pericardial effusion
  • Right sided heart failure
  • Neoplasia (diffuse mesothelioma or carcinomatosis)
  • Idiopathic pleuritis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

List DDx for a sanguinous effusion

A
  • Trauma
  • Coagulopathy
  • Acute lung lobe torsion
  • Iatrogenic
  • Tumours (chemodectoma, right atrial HSA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

List DDx for chylous effusion

A
  • Any condition that increases hydrostatic pressure in the cranial vena cava
  • Trauma
  • Idiopathic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do you confirm chylothorax?

A
  • Triglycerides higher and cholesterol lower than serum
  • Chylomicrons in the fluid can be stained with Sudan black
  • Positive ether clearance test
  • Modified transudate (protein 2.5-4g/dL, cell count less than 7000/mcL, specific grav leass than 1.032

Pseudochylus has higher cholesterol and lower triglycerides, and absent chylomicrons.

18
Q

List DDx for inflammatory effusion

A
  • D-hernia
  • Neoplasia
  • Chronic chylothorax
  • Lung lobe torsion
  • Infectious disease
  • Pancreatitis
  • Penetrating FB
  • Oesophageal trauma
  • Repeat thoracocentesis
  • Surgery

Oropharyngeal flora are most commonly isolated from cats

19
Q

What is the reported rate of pneumothorax and haemorrhage after a CT-guided lung FNA?

A
  • Pneumothorax 0-27%
  • Haemorrhage up to 30%

Usually minimal and require no treatment

20
Q

What is the most realiable way to differentiate transudates and exudates in cats?

A
  • Pleural fluid lactate dehydrogenase
  • Ratio of pleural fluid to serum TP.

Senstivity, specificity and accuracy 100% with a cut off for lactate at 226IU/L
Accuracy of TP ratio 95% with a cutoff greater than 0.56

21
Q

What is a reliable measurement to differentiate transudate and exudate in dogs?

A

C-Reactive Protein
- Greater than 4mcg/ml 100% sensitive and 94% specific
- 11mcg/ml 88% sensitive and 100% specific for differentiating modified transudate and exudate

22
Q

What intercostal space is used for thoracocentesis?

A

7th-9th

23
Q

What effect does mechanical ventilation have on the lungs and heart?

A
  • In closed chest, increases intrapulmonary pressures to 3-5cmH2O
  • This decreases coronary circulation, pulmonary circulation and venous return to the heart
  • Inspiratory:expiratory phases should be kept between 1:2 to 1:3
24
Q

In which intercostal space is a thoracostomy tube placed?

A

7th or 8th

25
Q

What is the recommended amount of crossing of a finger-trap

A

Spaced apart approx equal to width of tube with atleast 6 crosses on each side

26
Q

What has been shown to be more effective at preventing leakage around the chest tube?

A
  • Trocar tipper tube for tunneling rather than Carmalt forceps
  • Polyvinyl tubes more effecting than red rubber
27
Q

What is the recommended ICS for surgical approach to the following structures
- Heart and pericardium
- PDA, PRAA
- Pulmonic valve
- Cranial lung lobe
- Middle lung lobe
- Caudal lung lobe
- Cranial oesophagus
- Caudal oesophagus
- Cranial vena cava
- Caudal vena cava
- Thoracic duct in dog and cat

A
28
Q

What pressure is continuous suction usually maintained at for a thoracostomy tube?

A

5-10cmH2O

29
Q

What is the motality rate of thoracotomies?
What factors are associated with nonsurvival?

A

Mortality rate 13-22% (5.9% in another study)
Factors assoc with nonsurvival:
- Preanaesthetic O2 requirement
- Use of neuromuscular blocking agents during anaesthesia
- Surgical duration over 180min
- Blood products

30
Q

What is the mortality rate of thoracic trauma?

A
  • 11-15.5% with extensive bite wound trauma
  • 63% survival in cats
31
Q

List DDx for spontaneous pneumonthorax

A
  • Bullae/blebs
  • Emphysema
  • Neoplasia
  • Pleuritis
  • Migrating plant material
  • Pulm abscess
  • Feline asthsma or inflammatory airway disease (most common cause in cats)
  • Chronic pneumonia
  • Heartworm, lungworm

Siberian Huskies overrepresented

32
Q

What is the outcome of autologous blood patching for spontaneous pneumothorax?

A
  • Resolved pneumothorax in 7/8 dogs after 1-3 treatments (5-10ml/kg blood)
33
Q

What is the recurrence rate and mortality rate of spontaneous pneumo in dogs treated conservatively vs surgically

A
  • Conservatively 50% recurrence, 53% mortality
  • Surgically 3% recurrence, 12% mortality
34
Q

What do desquamated mesothelial cells make with chronic chylothorax?

A
  • Type III collagen promoting fibrosis and leading to Fibrosing Pleuritis
35
Q

What are the surgical options for chylothorax?

A
  • Thoracic duct occlusion/embolisation
  • Pericardiectomy
  • Cisterna chyli ablation
  • Omentalisation
36
Q

WHat is the prognosis for idiopathic chylothorax?

A
  • Thoracic duct attenuation alone: 50-59% dogs, 14-53% cats successful
  • Thoracic duct and subphrenic pericardiectomy: 55-100% dogs, 80% cats
  • Thoracoscopic duct ligation and pericardial window 83-86%
  • Thoracic duct and cisterna chyli 63-88%
  • Thoracic duct, percardiectomy and omentalisation 57-77%
37
Q

What are the options for managing recurrent chylous effusion?

A
  • Percutaneous drainage systems (Pleuraport)
  • Pleuroperitoneal shunts
38
Q

What breed is predisposed to pyothorax?

A

Labs and English Pointers

39
Q

What is the prognosis of pyothorax?

What factors are associated with increased survival in cats?

A

Successful Tx in 47.8 - 86%
85% disease free at 6m and 78% at 1yr post-op
Factors assoc with increased survival in cats:
- Lower resp rate
- Higer heart rate
- Higher WBC counts

40
Q

What breeds are overrepresented with thymoma?
What paraneoplastic syndromes are common?
How many have concurrent nonthymic neoplasia?

A
  • Labs and Goldens
  • Myaesthenis gravis (up to 47%), hypercalcaemia, feline exfoliative dermatitis (generalized severe desquamation)
  • 27% concurrent nonthymic neoplasia
41
Q

How can you differentiate thymoma and lymphoma on cytology?

A
  • Both contain large numbers of lymphocytes
  • Thymoma will more consistently have epithelial cells which may also exfoliate mast cells, eosinophils and erythrocytes
  • Flow cytometry