The respiratory system - Pleural and pulmonary vascular disease Flashcards
Differential diagnosis of chest pain
Cardiac – myocardial ischaemia/infarction, pericarditis, aortic dissection
Respiratory – pulmonary embolism, pneumothorax, pneumonia, pleural inflammation
Gastrointestinal – oesophageal spasm, dysmotility/reflux, oesophageal rupture (Boerhaave’s)
Musculoskeletal – rib fracture/metastasis, muscle spasm/strain, costochondritis
Consider other systems – breasts, skin (herpes zoster), upper abdomen (biliary tree, pancreas
Describe the investigations undertaken for chest pain
Bloods - FBC, U&Es, LFTs, CRP ,ESR, troponin
ECG
CXR
Echocardiogram
What is a pneumothorax
A pneumothorax is a collapsed lung causing a collection of air/fluid within the pleural space
Name the two major types of pneumothoraces
Spontaneous (non-traumatic)
Traumatic
Describe the two types of spontaneous pneumothoraces
Primary spontaneous pneumothorax - occurs spontaneous in previously non-pathalogical lung
Secondary spontaneous pneumothorax - occur in previously diseased lungs
Give 4 types patients at risk primary spontaneous pneumothorax
- Thing young men
- Cannabis smokers
- Marfans
- Apical pleural blebs
Why are tall individuals at increased risk of primary spontaneous pneumothorax?
The gradient of negative pleural pressure increases from the lung base to the apex, so that alveoli at the lung apex in tall individuals are subject to significant greater distending pressure than those at the lung base
Clinical features of a pneumothorax
a) Symptoms
b) Signs
a)
- Dyspnoea
- Pleuritic chest pain (usually unilateral)
b)
- Tracheal deviation: pushed away from side of the pneumothorax
- Reduced/absent breath sounds with no added sounds on affected side
- Hyperresonance on percussion of affected side
- Absent tactile fremitus/vocal resonance on affected side
a) What concerning features of a patient with suspected pneumothorax must you look out for?
b) Why must you look out for this?
a) Respiratory distress and/or haemodynamic instability (e.g., hypotension, marked tachycardia)
b) Indicates tension pneumothorax
What does imaging of a suspected pneumothorax depend on?
Describe how this affects imaging
Imaging depends on whether the patient is haemodynamically stable or unstable
Unstable: in a hameodynamically unstable patient, this likely represent s a tension pneumothorax, and the priority is clinical assessment and urgent decompression
Stable: in a haemodynamiical
What does imaging of a suspected pneumothorax depend on?
Describe how this affects imaging
Imaging depends on whether the patient is haemodynamically stable or unstable
Unstable: in a hameodynamically unstable patient, this likely represent s a tension pneumothorax, and the priority is clinical assessment and urgent decompression
Stable: in a haemodynamically stable patient, there is time to request appropriate modality
What is the 1st line imagine for a spontaneous pneumothorax?
CXR
Supine radiographs are less sensitive that erect CXR in diagnosing pneumothoraces.
What should be considered in patients unable to have an erect film?
CT or ultrasound
Describe the management of a primary spontaneous pneumothorax
Large (>2cm or breathless)
- 1st line: Needle aspiration (14-16G needle). Stop after 2.5L has been aspirated
- 2nd line: Small bore (<14 F) seldinger chest drain
Small (<2cm) and asymptomatic
- Observation with outpatient follow-up
- Patients should e advised to return if they develop breathlessness
Describe the management of a secondary spontaneous pneumothorax
Large (>2cm) or breathless: Small bore (<14 F) seldinger chest drain
Size 1-2cm: needle aspiration (14-16G needle). Stop after 2.5L has been aspirated. If unsuccessful then small bore Seldinger chest drain
Size < 2cm: Admit and observe for 24h, consider supplemental oxygen
What are the indications of referral to thoracic surgery
- Patients with persistent air leak
- Ipsilateral recurrence
- Bilateral pneumothoraces
- Contralateral non-synchronous pneumothoraces
- Pregnancy
- At risk occupations (e.g., pilots)
Why does tension in a pneumothorax occur?
Tension occurs when a ‘one way valve’ system allow air into the inter-pleural space but does not let it escape. This results on increasing pressure, which impairs venous return to the heart, compromising cardiac output
Clinical features of tension pneumothorax
- Features of respiratory distress e.g., tachycardia, hypotension
- SOB
- Tracheal deviation
- Hyperresonance
- Chest pain
- Hypoxaemia
- Hypotension
- Tachycardia
Describe the management of a tension pneumothorax
- Imaging should not be awaiting
- Carry out urgent needle decompression – using a large-bore cannula in the 2nd intercostal space mid-clavicular line on the side of the pneumothorax (above 3rd intercostal space to avoid neurovascular bundle).
- Cannula should be left in place until a formal chest drain is correctly placed
- High flow oxygen (15 L/min) via a non-rebreather mask should be administered.
What further advice would you give patients who have had tension pneumothorax on discharged?
- At discharge, clear advice to return if they develop breathlessness or chest pain
- Patients should be booked respiratory follow-up discharge
- Smoking cessation support offered
- Flight must be avoided until complete resolution. Recommended to wait at leats 2 weeks after successful treatment and re-expansion
- Advice to germanely avoid diving (however may be possible after successful surgical intervention)
Name 3 complications of a tension pneumothorax
- Infection
- Pain
- Drain dislodgement
- Drain blockage
- Visceral injury
- Death
What is a pleural effusion?
A pleural effusion refers to an abnormal collection of fluid within the pleural space
Describe the three key layers of the pluera
Parietal pleurs: outer layer, Produces pleural fluid
Pleural space: Potential space that contains approx. 10-20ml of fluid that is constantly turned over each day
Visceral pleura: inner layer. Covers the lungs, blood vessels and bronchi
What are the two major functions of the pleural fluid
- Lubricates the pleural surfaces to make it easier for the layers to slide over one another during respiration
- Generates surface tension by pulling the parietal and visceral layers adjacent to one another
What produces pleural fluid?
The parietal layer
Name the 3 factors that contribute to the balance of fluid entry and exit with the pleural space
- Hydrostatic pressure (pressure exerted by a fluid against a membrane)
- Osmotic pressure (pressure exerted by a fluid against a membrane)
- Lymphatic drainage
a) What is transudate?
b) Why does it occur
a) An extravascular fluid with low protein and cellar content (< 30 g/L)
b) It occurs due to alterations in hydrostatic and oncotic pressure leading to the fluid being ‘squeezed’ into the pleural space (ultrafiltration)
Provide 5 causes of transudates
Vey common causes
- Left ventricular failure
- Liver cirrhosis
Less common causes
- Hypoalbuminaemia
- Peritoneal dialysis
- Hypothryoidism
- Nephrotic syndorne
- Mitral stenosis
Rare causes
- Constrictive pericarditis
- Unithorax
- Meig’s syndrome: eponymous syndrome classified by a triad of benign ovarian tumour, pleural effusion (classically associated with a right-sided pleural effusion), and ascites
a) What is an exudate?
b) why doe it occur
a) an extravascular fluid with a high protein and cellular content (> 30 g/L)
b) Occurs due to a variety of inflammatory conditions that affect vessel permeability and/or lymphatic drainage
What are exudates commonly due to?
Infection or malignancy
Provide 6 causes of exudates
Common causes
- Malignancy
- Parapneumonic effusions
- Tuberculosis
Less common causes
- Pulmonary embolism
- RhA and other autoimmune pleuritis
- Benign asbestos effusion
- Pancreatitis
- Post MI
- Post CABG
Rare causes
- Yellow nail syndrome (and the lymphatic disorders e.g., lymphangioleimyomatosis)
- Drugs
- Fungal infections
How do effusions due RhA effusions relate to glucose levels
Almost 100% of effusions due to rheumatoid arthritis have low glucose levels.
Clinical features
a) Symptoms
b) Signs
a)
- Breathlessness
- Non-productive cough
- Pleuritic pain
- Extra-pulmonary symptoms depending on the underlying cause (e.g., weight loss in malignancy or fever in infection)
b)
- Reduced chest expansion
- Reduced/absent breath sounds
- Stony dull percussion
- Reduced vocal resonance/tactile fremitus
- Tracheal deviation pushed away from side of effusion
- Extra-pulmonary signs: depends on the underlying cause (e.g., finger clubbing in lung cancer)
Describe the investigations for a pleural effusion and the indications
Bloods
- WBC: assess for infection
- U&Es: assess for raised creatinine suggestive of renal impairement
- LFTs: assess for a low albumin
- ALT/AST: raised may be suggestive of cirrhosis
Imagine
- CXR: 1st line imaging
- Ultrasound: to dent pleural effusion with high sensitivity
Pleural paracentesis: if exudate
What is the 1st line imaging for a pleural effusion?
CXR
How much pleural fluid is needed to be detected on PA CXR?
Approximately 200mL
Describe the CXR changes of a pleural effusion
- White out of a one hemifield/Hazy opacity of one hemithorax
- Blunting of the costophrenic angle
- Tracheal deviation to opposite side
Describe the diagnostic algorithm of managing a pleural effusion
- If high suspicion of transudate(usually a bilateral pleural effusion) then treat the underlying cause
- If high suspicion of exudate (usually a unilateral pleural effusion) or treatment of underlying cause of transudate not resolved the pleural paracentesis required
- If diagnosis is given the treat appropriately
- if diagnosis unclear then request contract enhanced CT thorax
- If cause still not found the re-considertreatable conditions such as PE, TB, chronic hF and lymphoma. Watchful waiting often appropriated
What is the principal investigation for assessment of. pleural effusion?
Pleural paracentesis and analysis
a) What is pleural paracentesis
b) Describe the 2 ways this can be completed
a) Involves inserting a small needle into the pleural cavity under ultrasound guidance to remove a sample of fluid for further analysis
b) It can be completed as a simple diagnostic test by removing a small amount of fluid (e.g., 20 mL) or completed as part of a therapeutic pleural aspiration removing several 1-1.5l of fluid for symptomatic relief