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Flashcards in Pleural disorders Deck (19):
1

Pleural effusion and pneumothorax

Signalment?

Respiratory signs?

  • Cats and dogs of any age
  • Resp signs
    • Rapid shallow breathing (restrictive breathing pattern); tachypnea
    • Dyspnea
    • Poss. open-mouthed breathing
    • Cyanosis
    • Exercise intolerance
  • Non-respiratory signs: anorexia and lethargy

2

Pleural effusion and pneumothorax

Physical examination

  • +/- pyrexia (depends on underlying disease)
  • Barrel-shaped chest, esp. pneumothorax
  • Muffled heart sounds and diminished/muffled lung sounds ventrally
    • Dorsal--inc. lung sounds = pleural effusion (fluid at bottom--> lungs float to top)
    • Dorsal--dec. lung sounds = pneumothorax

3

What does this indicate?

Pleural effusion

4

What is pleural effusion? What are the different types of fluid?

  • Accumulation of excessive amounts of fluid w/in pleural space
    • Exudate (pyothorax) = >3.0 protein + >7000 cell
    • Transudate (CHF) = <2.5 protein + <1500 cell
    • Modified transudate = 2.5-7.5 protein + 1000-7000 cell
    • Hemorrhage (trauma)

5

What are the various exudative pleural effusion types?

  • Hemorrhage
  • Bile
  • Chyle
  • Septic
    • Bacterial (pyothorax)
  • Aseptic
    • Neoplasia 
    • Feline infectious peritonitis

6

Pleural effusion

Mechanisms of fluid accumulation?

  • Decreased oncotic pressure (hypoalbuminemia)
  • Increased hydrostatic pressure (CHF)
  • Increased capillary membrane permeability (inflammation due to FIP, neoplasia, pyothorax)
  • Lymphatic malfunction (obstruction or lymphagiectasia) 

7

Pleural effusion

What is done once pleural effusion is suspected after auscultation (2 things)?

  • Stabilize first
    • Thoracocentesis
  • Thoracic radiographs

8

Pyothorax

Etiology

  • Dogs--secondary to inhaled foreign bodies or penetrating injury, pneumonia
  • Cats--secondary to bite wounds, oropharyngeal aspiration or URTI

9

Pyothorax

Diagnosis

  • Relatively straight-forward
  • Thoracocentesis
    • Cytology--degenerative neuts; bacteria
    • Culture (aerobic and anaerobic), gram stain helpful
  • Imaging--radiographs, CT

10

Pyothorax

Treatment: drain/lavage?

  • Drainage and lavage through thoracotomy tube (chest drain)
    • Unilateral or bilateral
      • Unilateral--dogs, or unilateral effusions
      • Bilateral--cats, or effusions with multiple pockets/abscesses
  • Lavage
    • Warm saline 10-20ml/kg into chest over 3-5 min in lat recumbency, rotate, then aspirate out
    • Repeat 2-4x daily for 2-5 days
    • Record amount of fluid into/out of pleural space

11

Pyothorax

Treatment: antibiotics?

  • Long-term antibiotics based on culture
  • Dogs--start w/ amoxyclav and metronidazole
  • Cats--start w/ amoxyclav, enrofloxacin, and metronidazole
  • If no culture, base on cytology
    • Nocardia spp--TMS
    • Actinomyces spp and Pasteurella spp--penicillins
    • Anaerobes--metronidazole, penicillins, clindamycin

12

If there's no improvement w/in 3-4 days after antibiotics for a pyothorax, what should be done?

Surgical exploration--FB/abscess--thorough lavage

13

What can cause a chylothorax?

Any disease that increases systemic venous pressure

14

What are 7 possible causes of accumulation of chyle in the pleural space?

  1. Trauma--rupture of thoracic lymphatic duct
  2. Neoplasia--cranial mediastinal mass, heart-based tumor, R atrial hemangiosarcoma
  3. Cardiac disease--cardiomyopathy, RCHF, pericardial disease, HW
  4. Thoracic duct lymphangiectasia
  5. Inflammation--fungal
  6. Lung lobe torsion
  7. Idiopathic, 60-70% cases have no underlying cause

15

How do you diagnose a chylothorax?

Thoracocentesis

Triglycerides in fluid > triglycerides in serum

16

What should you always look for when treating a chylothorax?

Underlying cardiomyopathy

17

How do you treat an idiopathic chylothorax?

  • Thoracic drainage--intermittent thoracocentesis vs. chest tube drain
  • Low fat diet
  • Rutin--for 2 months (may reduce effusion or resolve signs in 50% dogs); stimulates macrophages to carry away fat
  • Ligation of thoracic ducts works 60% of the time

18

What is a possible sequela to a chylothorax?

Restrictive pleuritis

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