Pulmonary And Pleural Lung Disease. Flashcards
What is the pulmonary oedema? What pattern of disease does it cause?
Accumulation of fluid in the lung interstitium and alveolar spaces. Causes a restrictive pattern of disease.
What are some of the causes of pulmonary oedema?
Haemodynamic from increased hydrostatic pressure.
Cellular injury e.g. Alveolar lining cells or alveolar endothelium.
Can be localised e.g. Pneumonia.
Or general e.g. ARDS.
What are the two types of ARDS?
Alveolar damage syndrome (DADS)
Or
Shock lung.
What can cause shock lung?
Sepsis, diffuse infection, severe trauma and O2 damage.
What is the pathogenesis of ARDS?
Injury e.g. From a bacterial endotoxin leading to:
Infiltration of inflammatory cells
Cytokines
Oxygen free radicals and injury to cell membranes.
What pathological findings do we have in ARDS?
Fibrous exudate lining the alveolar walls.
Cellular regeneration and inflammation.
What are the possible outcomes of ARDS?
Death, resolution or fibrosis e.g. Chronic restrictive lung disease.
What two arterial supplies does the pulmonary circulation get?
Bronchial and pulmonary arteries.
What two types of hypertension are there?
Primary and secondary.
What type of pulmonary hypertension is more common?
Secondary
What can cause pulmonary hypertension?
What are the mechanisms behind them?
Hypoxia (vascular constriction).
Congenital heart disease (increased flow).
Blockage (PE) or loss of vascular bed (emphysema)
Back pressure from LVH.
Morphology change of vessels e.g. Intima thickening by fibrosis and medial hypertrophy of arteries.
RVH.
Cardiac left to right shunt.
Drugs e.g. Appetite suppressants.
What are some cardiac causes of pulmonary hypertension?
LVF, mistral regurg or stenosis and cardiomyopathy e.g. From alcohol or a virus.
What are the signs of pulmonary hypertension?
Central cyanosis if hypoxic, dependent oedema, raised JVP with V waves (due to tricuspid regurg) right ventricular heave at left para sternal edge, tricuspid regurg murmur and enlarged pulsatile liver.
What investigations do we do for pulmonary hypertension?
ECG, CXR, sats and ABGs, pulmonary function tests, echo, D dimers, VQ scan if PE suspected, CT pulmonary angiogram, cardiac MRI and auto-antibodies if vasculitis supspected.
How do we diagnose primary pulmonary hypertension?
Diagnosis by exclusion of other causes. Progressive shortness of breath and signs of right sided heart failure.
What is the pharmacological treatment of primary pulmonary hypertension?
Prophylactic anticoagulation - warfarin.
PO vasodilators e.g. Calcium channel blockers - oral nifedipine, diltiazem.
Endothelin antagonists - oral bosentan
PDE5 inhibitor - oral sildenafil.
Prostanoids - IV epoprostenol or inhiloprost.
Guanylate cyclase stimulator - oral riociguat.
What is cor pulmonale?
Pulmonary hypertension complicating lung disease causing right ventricular hypertrophy.
What is the pathogenesis of cor pulmonale?
Hypoxaemic pulmonary vasoconstriction causing increased ventricular afterload. This causes right ventricular hypertrophy which leads to dilation and failure.
How do we treat cor pulmonale?
Optimise small degree of reversibility with high dose B2 agonists and anticholinergics.
Remove hypoxic stimulus with home 02.
Thiazides or loop diuretic to remove oedema.
What type of cells make the pleura and what do they do to fluid?
How does disease affect this?
Mesothelial cells that are designed to absorb fluid.
Hallmark of pleural disease is effusion.
How much pleural fluid of we normally have and what type of fluid is it?
Serous fluid, usually around 4mls.
What happens to the pleura at the root of the lung?
The two layers combine, meaning the root of the lung has no pleural coverage. The layers combine to form the pulmonary ligament which runs inferiorly and attaches the root of the lung to the diaphragm.
What can the parietal pleura sense and what is its innervation?
Senses pain. Is supplied by the intercostal and the phrenic nerves.
What does the visceral pleura sense and what is its nerve supply?
Sensitive to stretch. It contains vasomotor fibres and sensory endings of the cranial nerve X for respiratory reflexes.
What is a pleural effusion and what does it look like on X-ray?
It is common in numerous diseases and is an abnormal collection of fluid in the pleural space.
Looks almost completely white on X-ray and we can see the line of the lung edge.
What effusions should we be particularly worried about?
Unilateral effusions in a smoker or patient with significant asbestos exposure.
What two categories of effusion do we have and what is the difference?
Transudates - protein under 30g/L
Exudates - protein over 30g/L
What condition gives a pleural effusion that we dont have to drain or aspirate?
Heart failure.
What tests do we do to find the cause of pleural effusions?
History and examination.
PA CXR and lateral.
Pleural aspirate if it’s not convincingly caused by heart failure.
CT
Repeat cytology
Pleural biopsy and bronchoscopy if concern of malignancy.
If the pleural fluid is bloody what does this mean?
Trauma, malignancy, infection and infarction.
If the pleural fluid is straw coloured what does this mean?
Cardiac failure and hypoalbuminaemia.
If the pleural fluid is turbid/milky what does this mean?
Empyema or chylothorax.