18. Pleural Diseases Flashcards
Label A-C of the pleural space.
A) parietal pleura
B) pleural cavity
C) visceral pleura
pic - SC = systemic circulation, PC = pulmonary circulation. Most fluid in pleural space from systemic circultion. Some contribution from pulmonary circulation. Leaves pleural space via lymphatic channels. If disrupted, or too much fluid produced = fluid accumulates.
A pleural effusion = fluid in pleural space. Effusions can be divided by their protein concentration into transudates (<30g/L) and exudates (>30g/L)
Suggest diagnoses for the following pleural effusion mechanisms:
Local Factors (exudates)
a) increased capillary permeability
b) increased pleural permeability
c) decreased lymphatic drainage
d) increased -ve pleural pressure
Systemic factors (transudates)
e) increased capillary hydrostatic pressure
f) increased pulmonary interstitial fluid
g) decreased intravascular oncotic pressure
h) increased flow of fluid from other cavities
NB: Atelectasis - collapse or closure of a lung/part of, resulting in reduced/absent gas exchange.
What are symptoms of pleural effusion?
What are the clinical signs of pleural effusion noticeable upon respiratory examination (inspection, palpaption, percussion, auscultation)?
When classifying if the pleural effusion is exudate or transudate, what can you do in those with borderline pleural protein (25-30g/L) or with abnormal serum protein?
Asymptomatic, dry cough, breathlessness, pleuritic chest pain, “shoulder pain”/”heaviness”.
Inspection: decreased chest expansion
Palpation: decreased chest expansion, decreased tactile vocal fremitus, tracheal deviation
Percussion: stony, dull
Auscultation: decreased/absent breath sounds, bronchial breathing?
Use Light’s Criteria:
Pleural fluid is an exudate if ONE of the following are met:
- Pleural fluid protein ÷ serum protein > 0.5
- Pleural fluid LDH ÷ serum LDH > 0.6
- Pleural fluid LDH > 2/3 of upper limit of serum LDH
(LDH = lactate dehydrogenase)
What are some common and less common causes of exudate effusions?
What are some common and less common causes of transudate effusions?
Common: parapneumonic effusion (result of pneumonia, lung abscess, or bronchiectasis), malignancy, pulmonary embolism, rheumatoid arthritis, mesothelioma.
Less common: drugs, empyema, TB, pancreatitis, oesophageal rupture, post cardiac injury (Dressler’s syndrome), post-CABG, benign asbestos-related effusions.
Common: L ventricular failure, cirrhotic liver disease, peritoneal dialysis, nephrotic syndrome
Less common: constrictive pericarditis, hypothyroidism, Meig’s syndrome (triad of ascites, pleural effusion, and benign ovarian tumor - resolves after tumour resection).
-> SUMMARY: Exudates are mostly due to increased leakiness of pleural capillaries secondary to infection, inflammation or malignancy. Transudates mostly due to increased venous pressure (cardiac failure, constrictive pericarditis etc.) or hypoproteinaemia (cirrhosis, nephrotic syndrome, malabsorption etc.).
What investigations would you do for a potential pleural effusion?
(top R pic: trachea slightly pushed -> b/c larger effusion)
Where is pleural aspiration done?
CXR, pleural fluid analysis (exudate or transudate?), US, CT, pleural biopsy (image-guided or medical thorascopy), video-assisted thoracic surgery (VATS).
Triangle of safety: anterior border = lateral pec major, posterior border = lateral edge of latissimus dorsi, bottom = 5th ICS. (pic)
What can you see on this ultrasound (top) and CT (bottom)?
Describe how pleural effusions are investigated.
What is VATS?
Pleural effusions. Top L: simple effusion. Top R: more complicated effusion - empyema, harder to manage. Bottom: see large pleural effusion on L.
(pic)
Video-assisted thoracoscopic surgery: performed using a small video camera introduced into the patient’s chest via small incisions. The surgeon can view instruments being used + anatomy. Camera and instruments are inserted through separate holes in the chest wall = “ports”, advantageous b/c chance for infection and wound dehiscence are drastically reduced.
List 4 symptoms of pleural infection (parapneimonic effusion/empyema).
What conditions would make you consider this diagnosis?
What investigations would you do?
Fever, sputum, chest pain, breathlessness.
Slow to respond pneumonia. Pleural effusion with fever. Malaise/wt loss. High risk groups: DM, excess ETOH intake, GORD, IVDU, aspiration and poor dental hyginene.
Diagnositc pleural tap (exudate/transudate?culture), blood culture, US, CT chest.
Describe the 3 stages of progression of pleural infection.
What are the main causes of:
a) community acquired pleural infection?
b) hospital acquired pleural infection?
1) Simple parapneumonic effusion: clear sterile fluid, normal pH, glucose and LDH, resolves with abx. Chest drain usually not required.
2) Complicated parapneumonic effusion: fibrinopurulent stage, fluid infected but not purulent. pH <7.2, gluc <2.2mmol/L, LDH >1000IU/L, fluid gram stain may be +ve. Chest drain indicated.
3) Empyema: pus in pleural space, free flowing, or multi loculated, fluid gram stain may be +ve. Drainage required. Fibroblasts may cause thick pleura -> long term problem b/c lung won’t expand properly.
a) Streptococcus spp (52%): S. milleri, S. pneumoniae, S. intermedius.
Staphylococcus aureus (11%)
Gram -ve aerobes (9%): Enterobacteriaceae e.g. E. coli
Anarobes (20%): Fusobacterium spp., Bacteroids spp., Peptostreptococcus spp., Mixed
b) Staphylocci: MRSA (25%), S. aureus (10%)
Gram -ve aerobes (17%): E. coli, Pseudomonas aeruginosa, Klebsiella spp.
Anaerobes (8%)
Up to 40% = culture -ve
How is a pleural infection managed?
What is pleural malignancy (mesothelioma)?
List some occupations/industries at risk.
Abx. Chest tube drainage (purulent or turbid fluid, pH <7.2, organisms in pleural fluid gram stain or culture). Intrapleural fibrinolytics (not routinely used). Nutritional support. Surgery (VATS, thoracotomy and decortication, open thoracic drainage).
Malignant tumour of serosal surfaces (usually pleura). Asbestos exposure hx identified in 90% cases. 3 main types of asbestos fibres (pic). Latent period (>40 yrs after exposure). Poor prognosis (median survival: 9-12m).
Plumbers, pipe/steamfitters, electricians, insulation workers, carpenters, laborers, boilermakers, welders/cutters, janitors. Construction, shipbuilding/repairing, chemicals, railways, trucking, fabric mills, plastic/rubber making.
List 4 signs/symptoms of mesothelioma.
What investigations would you do?
What are the 3 histological types of mesothelioma?
Chest pain (dull ache), symptoms of pleural effusion, wt loss and fatigue (uncommon), chest wall invasion.
- Radiology** (CXR and CT thorax) (pic - L = effusion on L and thickening of L pleura. R = lung much smaller, diffuse pleural thickening all around*)
- *Pleural fluid analysis** (bloody/straw-coloured, cytology (30-80% yield).
- *Biopsy** (US/CT guided pleural biopsy, medical thorascopy or VATS)
Epitheloid (50% cases, better prognosis). Mixed (biphasic). Sarcomatoid.
How would you manage mesothelioma?
- Pleural effusions** -> drainage and pleurodesis (obliterate pleural space*) (medical/surgical).
- *Radiotherapy** -> reduces chest wall invasion risk and pain relief.
- *Chemo** -> Cisplatin with Pemetrexed/Gemcitibine.
- *Surgery** -> selected cases only (high mortality)
- *Pain relief, palliative care, compensation**.
Case Study
52 yr old man, background of HTN, schizophrenia, previous bowel surgery for intestinal obstruction. Non smoker. Admitted with 1 wk hx of coughs, fevers, breathlessness. CRP 350, WBC 15.
What is the likely diagnosis?
a) Lung cancer
b) Pulmonary embolism
c) Pneumonia/parapneumonic effusion
d) Heart failure
Which test should be done next?
a) CT chest
b) Sputum microscopy
c) Pleural tap
d) Echocardiogram
US guided pleural aspiration showed staw-coloured fluid with a protein count 38g/L, LDH 3500, pH 6.9.
What is the next management step?
a) Chest drain insertion
b) IV abx
c) Blood cultures
d) All of the above
C (b/c infection - high CRP and WBC). See white opacification in CXR - may be pleural effusion?
C (exudate or transudate? send sample to microbiology)
D (to prevent progression to empyema, protein count = exudate, pH below 7.2 = indication for chest drain).
