Pleural Effusion and Pneumothorax Flashcards
Is pleural disease common in horses?
NO
Is pleural disease common in SA?
YEs
FIndings associated with plerual disease?
- dyspnoea
- pyrexia with septic effusion
- cause of hypoproteinaemia eg. chronic D+
- trauma with pneumothorax, haemothorax, diaphragmatic hernia
- history of coagulopathy
- neoplasia and paraneoplastic disease
- concurrent abdo abnormlaities (empty cranial abdo with diaphragmatic hernia, concurrent ascites (bicavity effusion indicates more systemic disease) )
- RCHF (jugular distension, peropheral oedema, murmur) esp. seen in cats
PE findings with pleural disease?
- ^ RR and effort
- rapid and shallow
- orthopnoea - reluctance to assume position other than standing and sternal
- dullness on percussion of ventral thorax (v lung sounds)
- resonance on percussion of dorsal thorax (v lung sounds)
- displacement of apex beat may suggest mass lesion
Where should the apex beat be?
Left
Why are resp sounds not heard ventrally with plerual effusion?
Lung floats on fluid
WHat is indicated as further investigation of pleural disease?
- radiographs
- ultrasound
- do not stress!
- thoracocentesis most important tx, may go straight to this if patient severely dyspnoeic
WHat are the 2 aims of thoracocentesis?
- therapeutic to relive discofort
- sample taken
What is the most important part of the thoracocentesis technique?
- maintain a closed system to prevent air leakage into the pleural space
- maintain sterility
- cranial/caudal to heart
Why is ultrasound useful for thoracocentesis?
- confirm presence of fluid
- choose optimum rib space to catheterise (Avoid heart!)
How does thoracocentesis technique differ in horses cf sa?
- use gravity and large bore catheter with valves to drain
Which samples will be taken for analysis of pleural fluid?
- EDTA for cytology
- Plain tube for culture/biochem
> cytology, total cell count, differential count
> TP
> bacterial culture and sense
> Gram stain
> TG and cholesterol levels (Chylous effusion) - Measure NT-proBNP in cats for cardiogenic v non-cardiogenic
Types of pleural fluid?
Transudate and modified transudate (hydrothorax) LOOK UP SLIDE
Causes of hypoproteinaemic?
transudatess
causes of exudates?
septic/non-septic (eg. coronovirus FIP)
causes of modified transudates
venous obstruction
- RCHF
- neoplasia
- lung lobe torsion
- diaphragmatic hernia
causes of chylothorax? appearance?
- damage of thoracic duct - intestinal lymph drains into thoracic cavity
- gross milky appearance
- high in TG (fluid TG> plasma TG indicates chylous effusion)
- cell count and SG similar to modified transudate but cells predominantly lymphocytes
causes and appearance of haemothorax?
- grossly haemorrhagic
- indicates coagulopathy, trauma and neoplasia
- usually defribrinated and SHOULD NOT CLOT! (does NOT indicate coagulopathy)
> if it clots, you may have stabbed heart - protein and cell content similar to whole blood
Is dyspnoea often caused by pure frank blood?
NO! Will present with hypovolaemia before dyspnoea (eg. 4kg cat 200ml fluid in thorax needed for dyspnoea - only has 300ml sirculating blood volulme!)
Pheumothorax caused by air leaking from where?
- lung
- mediastinum
- through thoracic wall
> small amount common after RTA
Further diagnostic testss for pleural disease?
BLOODS > hypoproteinaemia - hepatic, renal, GIT > Hyperglobulilnaemia - FIP in cats > Neutrophilia - INflammaotry disease > Cytopeania - Bone marrow disease eg. lymphoma > serology - FIP, FelV, FIV - Coronavirus poor - FeLV and mediastinal lymphosarcoma link > clotting times - APTT and OSPT - platelet abnormalities less likely to cause cavity bleed
What should be performed before and after thoracocentesis?
> Radiographs for comparison - may reveal changes obscured by fluid - pneumothorax also seen - pneumomediastinum also seen > CT?
Is US useful for pleural disease?
Not normally as air usually present
- presence of fluid will enhance US utility and sometiems allows abnormalities to be seen eg. masses
- US guidance useful for aspirating lesions or draining pocketed pleural fluid
Are invasive techniques ever indicated for pleural disease?
> exploratory thoracostomy - pleural biopsy - detection of abnormlaities not detectable by other means > Thoracoscopy - minimally invasive surgical technique
Tx pleural disease?
- manage underlying disease > lung lobe torsion Sx > RCHF > Neoplasia > Hypoproteinaemia > FIP > DIaphragmatic hernia
How does pleuropneumonia in horses differ from normal bacterial pneumonia?
Not pure respiratory pathogens - usually oropharyngeal contaminates
Pathogens involved in pleuropneumonia in equines?
- mixed bacterial infection of pharynx flora (ie. NOT pure resp pathogens)
- B haemolytic streptococcus
- E coli
- Klebsiella spp.
- Pasteurella
- Bordatella
- Bacteroides spp. NB: Anaerobes
Most common predisposing factor of pleuropneumonia?
- travel (head tied up, mucociliary escalator imparied)
- surgery - anaesthesia
- intense excercise
- respiratory viral infection1*
- stress eg. foaling
Where is equine pleuropnumonia commonly seen?
Cranioventral lung (organisms inhaled, this is the first place they go)
Clinical signs of acute, longterm and chronic pleuropneumonia?
- pyrexia, lethargy, slight nasal discahrge, shallow breathing, guarded cough, painful stilted gait, pleurodynia
- nostril flare, tachycardia, ^ jugulr pulse height (>1/3), toxic mm, guarded, soft, moist cough, foetid nasal discharge
- chronic: intermittent fever, weight loss, ventral and limb oedema (will have abcesses walled off in chest)
DIagnosis of pleuropneumonia in equines
- history
- clinical signs
- PE
- haem/US
- thoracocentesis
- radiography
- transtracheal aspirate
PE findings of equine pleuropneumonia?
> auscultation - ventral dullness (But may not be heard noramlly anyway!) - fluid in trachea - pleural friction rubs? - cardiac sounds radiate? > percussion - ventral dullness
What is the best diagnostic test for pleural disease in horses?
Ultrasound
- chalaracterise fluid (volume , location, how high the fluid comes up, gas bubbles indicate anaerobic bacteria)
- lungs consolidation, abscessation
WHat should be performed as well as thoracocentesis when diagnosing pleural effusion in horses? What are you looking for on thoracocentesis?
- Transtracheal aspirate (important to not have contamination from upper airway)
- Thoracocentesis: physical characteristics, cytology, bacteriology
Aims of Tx in equine pleuropneumonia?
- remove pleural fluid
- ABx
- nti-inflammatory and analgesic tx
- supportive care
Why is drainage useful for tx fo pleural fluid in horses? How is this performed differently to SA?
- removes debris, inflam mediators, toxins
- improves pulmonary clearance
- removes restrictive forces
> Drain both sides as fenestrated mediastinum often blocked with inflam mediators
> indwelling cannula, repeated intermittent drainage
What can pleurscopy be used for? Is this common?
NOt common
- excellent drainage
- visualisation
- break down adhesions
Medical and supportive care for equine pleuropneumonia?
> Anti-inflams and analgesics - NSAIDS, opiates > Abx - broad spec - anaerobes - culture and sensitivity > Supportive care - oxygen - bronchodilators - fluids - nutrition
Tx of chronic pleuropneumonia in the horse?
- pleural and pulmonary abscesses may be drained via resection of intercostal mm. and rib (providing they are walled off from the rest of the pleural cavity)
Prognosis of equine pleuropnemonia?
- mild cases diagnosed early 50% - 100% success (can return to original career)
- later severe cases: salvage attempts for breeding, $$$$
Complications of pleuropneumonia in horses?
- pulmonary abscess (cranial mediastinal masses)
- pleural adhesions
- bronchopleural fistula
- constrictive pericarditis
- thrombophlebitis
- laminitis
- diarrhoea
Principles of Tx of pyothorax in SA?
- remove infected material
- remove causative agent
- risk of less aggressive Tx is that a nidus of infection will remain and problem will recur
Why may single thoracocentesis followed by systemic ABx not be effective?
- remove insufficient infection material
- systemic ABx unlikely to penetrate inspissated purulent material in pleural space
- high likelyhood of recrudescence
What is a better Tx plan than single thoracocentesis with ABx?
- implant indwelling drain, pleural lavage
- leave in situ for 5-7d
- systemic ABx (lavage facilitates ABx penetration)
- NB. will still recur if FB present to act as nidus, PLUS risk of infection via indwelling drain and potential for pneumothorax if dog chews out drain
What is the more aggressive form of pyothorx tx?
> exploratory thoracotomy
- debridement and lavage of thoracic cavity
- placement of indwelling drains
+ greatest likelihood of success at resolving pyothorax
- perioperative morbidity and mortality
Is Tx of chylothorx often successfully treated? What tx are available?
Not really
- surgical
> ID and ligate thoracic duct
> redistribute pleural fluid
> enhance absorption of pleural fluid
> SALVAGE: Pleurodesis to get pleura to adhere and eradicate space where fluid forms)
- medical
> detect underlying cause (lymphoma, RCHF) though usually idiopathic
> reduce formation of intestinal lymph (low fat diet, MCTO, diuresis)
> enhance resorption of fluid from pleura (Rutin = Benzopyrone)
Most common cause of chylothorax?
Idiopathic
Tx of small, moderate and large volume pneumothorax?
Small
- rest and check for resolution
Medium
- Drain air, rest patient, manage conservatively
Large
- place indwelling drain, drain repeatedly, exploratory thoracotomy likely indicated to ID and correct underlying cause
