Week 1 - Pleural Space and Mediastinum Disease Flashcards

1
Q

What is the pleural space?

A

Two membranes that surround the lungs that contain fluid.

A space between the two pleura which helps the lungs move and expand to fill with air.

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2
Q

How much fluid and what sort of pressure should there be in the pleural space?

A

0.1 ml/kg of fluid.

Negative pressure - acts as a suction to keep the lungs from collapsing.

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3
Q

What is the mediastinum and what does it contain?

A

The space between the pleural sac.

Contains blood vessels, nerves, oesophagus, trachea, heart, lymphatic vessels, thymus.

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4
Q

Why can’t patients breathe with pleural disease?

A

There is a loss of thoracic capacity = less room in the chest for the lungs to expand.

Severity depends on quantity of fluids, air or size of mass.

Known as restrictive disease

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5
Q

How to patients present with pleural space disease?

A

Restrictive breathing: short, shallow breathes
Tachypnea
Open mouth breathing
Dyspnoea
Orthopnoea
Cyanosis
Muffled heart sounds

Acute or chronic

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6
Q

How do you investigate pleural space disease?

A

Clinical exam
Percussion
Imagine (FAST, TFAST or radiography)

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7
Q

What can cause the loss of thoracic capacity?

A

Pleural effusion
Pneumothorax
Neoplasia
Ruptured diaphragm
Abdominal abnormality
Gross cardiomegaly

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8
Q

What is pleural effusion and what causes it?

A

Fluid in the pleural space (more than normal)

Causes:
- Decreased absorption (from parietal lymphatic vessels)
- Increased production (from parietal pleural vessels)

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9
Q

What are the three types of fluid that causes pleural effusion?

A
  1. Transudate
  2. Modified transudate
  3. Exudate (with cells)
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10
Q

If a suspected pleural effusion presented, what steps would you take?

A
  1. Oxygen supplementation
  2. Thoracic ultrasound (often too severely dyspneic to radiograph)
  3. Thoraconcetesis (sample fluid, diagnostic (cytology, cell count, protein, bacterial culture), relief from clinical signs, stabilise)
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11
Q

How is a thoracoentesis performed?

A
  1. Aspetic
  2. Local anaesthesia rarely needed
  3. Clip area
  4. Surgically prep skin
  5. +/- ultrasound guided
  6. Butterfly needle or catheter into ICS 6-8
  7. Insert chest drain fro effusions that quickly reappear or that need lavaging (pus present)
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12
Q

What is a transudate and what are the characteristics?

A

Low protein fluid -> caused by hypoalbuminaemia (low oncotic pressure) -> lead to a leakage of fluid out from the vascular compartment.

  1. Clear
  2. Protein <2g/l
  3. SG <1.018 (low)
  4. Few cells (if any)
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13
Q

What conditions can cause transudate?

A

Low protein

  • Liver failure (failure of synthesis)
  • Protein loosing enteropahty
  • Protein loosing nephropahty
  • Haemorrhage
  • Starvation
  • Hyperglobulinaemia (high globulin = low albumin)
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14
Q

What is a modified transudate and what are the characteristics?

A

High protein fluid -> caused by increased hydrostatic pressure

  1. Clear
  2. Protein 2-5 g/dL
  3. Few cells (if any)
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15
Q

What conditions can cause a modified transudate?

A

Common - secondary to right sided heart failure

Diaphragmatic hernia (no negative pressure)

Damage to pleural vessels which leak fluid
- Lung lobe torsion
- Neoplasia

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16
Q

What is a exudate and what are the characteristics?

A

Filled with cells, higher protein and tends to be coloured.

  1. Coloured
  2. Protein >2.5 g/dL
  3. Lots of cells
17
Q

What 4 conditions can cause an exudate?

A
  1. Blood (haemothorax)
  2. Chyle (chylothorax)
  3. Septic exudate (pyothorax)
  4. Non septic exudate
18
Q

What characterises and causes a haemothorax?

A

Contains RBCs
Red colour

Trauma
Coagulopathy
Neoplasia
Lung lobe torsion

19
Q

What characterises and causes a chylothorax?

A

Small lymphocytes
Lipid looking

Disruption to the thoracic chyle duct -> lung lobe torsion, trauma, tumour pressing on duct.

20
Q

What characterises and causes a pyothorax?

A

Bacterial and inflammatory leukocytes

Infection
Foreign body
Ruptured pulmonary abscess or mass

21
Q

What characterises and causes a non-septic exudate?

A

Inflammatory cells without bacterial cells visualised.

Feline infectious peritonitis (FIP_
Neoplasia
Chronic chylothorax/torsion -> develop inflammatory cells over time.
Fungal infection (rare)

22
Q

What is a pneumothorax?

A

Air around the lung -> compressed the lung.

There is a loss of negative pressure in the pleural space -> lung collapses and struggles to inflate.

23
Q

How do you treat the following that cause pleural effusion:

  1. Heart failure
  2. Pericardial effusion
  3. Pyothorax
  4. Chylothorax
A
  1. Heart failure -> treat the failure
  2. Pericardial effusion -> drain effusion or PTS
  3. Pyothorax -> Antibiotics (culture but start on broad while wait for results), lavage, long term treatment with hospitalisation.
  4. Chylothorax -> diet/surgery and treat heart failure
24
Q

What can cause a pneumothorax?

A

Rupture of airway/lung tissue (tension pneumothorax) -> neoplasia or trauma

Perforation of oesophagus
Thoracic trauma
Iatrogenic
Gas producing bacterial infection in the pleural space

25
Q

How do you diagnose a pneumothorax?

A

Auscultation
- Dorsally = dull sounds
- Ventrally = increased sounds

Percussion = sounds like a drum

T-FAST = loss of glide sign

Blood gas and pulse oximetry

26
Q

How do you treat a pneumothorax?

A

Oxygenate
Drain (chest drain or one way valve)
Locate the cause (could be spontaneous)
Cage rest

27
Q

What is this pleural space neoplasia and how is it diagnosed and treated?

A

Mesothelioma

Affects lining of pleural sacs and pericardial sac

CT for best diagnosis

Cytology

Chemotherapy possible but poor prognosis

28
Q

What neoplasia can be found in pleural space?

A

Mesothelioma

Rib tumours that can invade the pleural space:
- Osteosarcoma
- Chondrosarcoma

29
Q

What types of disease can affect the mediastinum and what do they do?

A

Trauma
Infection/inflammation
Neoplasia

Generally causes pressure on the structures in the mediastinum.

30
Q

If the following where affected in the mediastina, what signs would there be?

  1. Lungs
  2. Oepshagus
  3. Vena cava
  4. Heart
  5. Sympathetic pathway to orbit
A
  1. Lungs = respiratory signs
  2. Oepshagus = regurgitation
  3. Vena cava = oedema in head and forelimbs
  4. Heart = Right sided heart failure
  5. Sympathetic pathway to orbit = Horner’s syndrome
31
Q

What diagnostics can be done for mediastinum investigations?

A

Radiography
- Check tracheal position
- Check lung lobe boarders

Ultrasound - less useful as structures need to be big enough to visualise

CT = most useful!

Sampling = not 1st opinion

32
Q

What are three mediastinum neoplasia’s?

A
  1. Lymphoma (common in young cats)
  2. Thymoma (young or older dogs)
  3. Thyroid carcinoma (rare)
33
Q

What are the signs, diagnosis and treatment for lymphoma?

A

Young cats or dogs with multi centric lymphoma

Signs
- none
- non-compressible anterior mediastinum
- Respiratory signs

Diagnosis:
- Radiograph, CT
- Cytology
- FeLV status (predisposes)

Treatment
- Chemotherapy (can go into remission)

34
Q

What are the signs, diagnosis and treatment for thymoma?

A

Rare = young and older dogs

Benign (but can keep growing)
Malignant (metastases rare)

Signs
- Similar to lymphoma
- None
- Mild respiratory signs
- Megaoesphagus
- Paraneoplastic syndrome (parathyroid hormone related peptide -> hypercalcemia)

Diagnosis:
- Radiograph, CT
- Cytology

Treatment
- Chemotherapy
- Surgical removal
- Megaoesphagus = prognosis poor

35
Q

What are the signs, diagnosis and treatment for thyroid carcinoma?

A

Cats that are unresponsive to hyperthyroid treatment

Dogs = mass signs

Treat with radioactive iodine.