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
Give the basic tests that should be completed on all pleural samples
- pH
- Protein count
- Lactate dehyrogenase (LDH)
- Microscopy, culture, and sensitivity (MC&S)
- Cytology
- Gram stain
- TB investigations (e.g., MC&S, PCR, acid-fast bacilli)
- Lipid testing
- Glucose
- Amylase
- Haematocrit
- Nucleated cell count
In which patients is pleural paracentesis not be performed in?
Pleural paracentèses is not performed in patient with bilateral pleural fusion where the cause is strongly suspected to be a transudate
What is the role of the lights criteria in interpreting pleural fluid
Pleural effusions can be categorised into transudates or exudates based on their protein content. The broad cut off is 30 g/L
However, when the level of protein is close to 30 g/L (25-30 g/L), lights criteria can be applied to narrow the differential diagnosis and guide further investigations
What is needed to apply the Lights criteria?
The Toal protein and LDH levels should be measure in both the pleural fluid and serum
Describe the parameters of the Lights criteria that would determine if a pleural fluid is an exudate
Pleural fluid is an exudate if one or more of the following criteria are met:
- Pleural fluid protein divided by serum protein is > 0.5
- Pleural fluid LDH divided by serum LDH is > 0.6
- Pleural fluid LDH >2/3 the upper limits of laboratory normal value of serum LDH
Describe the management of a pleural effusion
- Address underlying cause
- Pleural paracentesis and/or chest drains
- Patients with small or asymptomatic pleural effusions do not need drainage
- Large or symptomatic can undergo therapeutic paracentesis/chest drain insertion - Pleurodesis
- A procedure to obliterate the pleural space and prevent re-accumulation of fluid or air for those with recurrent pleural effusions/malignant pleural effusions - Surgical intervention
- To aid diagnosis or treat underlying effusion
- Video-assisted thoracoscopic surgery (VATS) can enable a number of surgical procedures (e.g., pleural biopsy, pleural wash-out and decortication, pleurectomy)
Name 4 complications of pleural paracentesis and/or chest drains
- Re-expansion pulmonary oedema
- Pneumothorax
- Infection
- Bleeding
- Damage to thoracic viscera
- Subcutaneous emphysema
a) Describe pleurodesis
b) Indications
a) Pleurodesis is a procedure to obliterate the pleural space and prevent re-accumulation of fluid or air.
It involved inducing pleural inflammation and fibrosis with a chemical sclerosant (e.g., tetracycline, bleomycin) or manual abrasion
b)
- Recurrent pleural effusions
- Patients with malignant pleural effusion that is likely to re-accumulate after drainage
Paraneumonic effusion
a) What is it?
b) It can be categorised into 3, according to the severity of the effusion and whether the pleural fluid has become infected. Describe the 3 categories
c) Management
a) A pleural effusion secondary to pneumonia
b)
1. Uncomplicated (simple effusion): reactive effusion. Fluid is sterile
- Complicated effusion: fluid has become infected with a microorganism
- Empyema: a collect of pus within the pleural space. Patients are very unwell
c) Prompt antibiotics and / or drainage if complicated effusion or empyema
Describe the management of an empyema
Urgent drainage and antibiotics
What is pulmonary hypertension (PH) defined as?
Pulmonary hypertension (PH) is defined as a mean pulmonary artery pressure > 25 mmHg at rest
Name the 5 groups of pulmonary hypertension
- Pulmonary arterial hypertension (PAH)
- PH due to left heart disease
- PH due to lung disease
- Mechanical pulmonary artery obstruction
- PH with unclear or multifactorial mechanisms
a) What is the most mechanisms of pulmonary hypertension?
b What is the second most common cause?
a) Group 1 - PH due to left heart disease
b) Group 3 - PH due to lung disease
Examples of diseases causing PAH
- Idiopathic PAH
- Heritable PAH
- PAH secondary to drugs
- PAH secondary to systemic disease e.g., connective tissue disorders or HIV
Examples of diseases cause PH that is due to left heart disease
- Left ventricular systolic dysfunction
- Left ventricular diastolic dysfunction
- Valvular disease
Examples of diseases causing PH that is due to lung disease
- COPD
- ILD
Examples of diseases causing PH that is due to mechanical pulmonary artery obstruction
Chronic thromboembolic pulmonary hypertension (CTEPH)
Examples of diseases causing PH with unclear or multifactorial mechanisms
- Haematological disorders
- Systemic disorders e.g., sarcoid
- Metabolic disorders
Clinical features of pulmonary hypertension
a) Symptoms
b) Signs
a) Progressive exertional dyspnoea
b) Usually owing to HF secondary to pulmonary pressure
- Raised JVP
- Accentuated P2 of the second heart sound
- Third heart sound
- Right ventricular parasternal heave
- Tricuspid regurgitation
- Pedal oedema
- Ascites
investigations for pulmonary hypertensions and the indications
ECG - look for signs of right ventricular hypertrophy
CXR - look for evidence of cardiac failure and any underlying respiratory pathology
Full pulmonary function test
CTPA - to look for Chronic thromboembolic pulmonary hypertension (CTEPH)
Echocardiogram - to estimate systolic pulmonary
Right heart catheterisation - for confirmation of
Describe the general management for pulmonary hypertension
- Avoid pregnancy: maternal mortality remains high in women with PH during pregnancy, and therefore women should be counselled and offered contraceptive therapy
- Influenza, COVID19 and pneumococcal vaccination
- Psychosocial support
- Pulmonary/cardiac rehabilitation
- Diuretics to treat symptoms of heart failure
- LTOT if PaO2 consistently less than 8kPa
- Correct anaemia
- Lung transplant may be considered in severe end-stage disease
Describe the management of group 1 PH - PAH
- Depends on function class
- Assess severity
- Vasodilator drugs: Prostanoids endothelia receptors antagonists9e.g.,s prostacyclin, Iloprost), Endothelin report antagonists (Bosnian, Ambrisentan), Phosphodiesterase 5 inhibitors (e.g., Sildenafil)
Describe the management of group 2 PH - PH due to left heart disease
- Treat underlying cause
- Targeted therapy not currently recommended
Describe the management of group 3 PH - PH due to lung disease
- Treat underlying disease
- Consider inhaled Treporostinil in ILD
Describe the management of group 4 PH - Mechanical pulmonary artery obstruction
Anticoagulation and pulmonary endarterectomy are considered as specific treatment for CTPEH
Describe the management of group 5 PH - PH with unclear or multifactorial mechanisms
Very difficult to manage
Describe the prognosis of pulmonary hypertension
- Poor prognosis as disease is often detected ;ate, can be rapidly progressive and response to treatment is variable
- Mean survival is 2-3 years after diagnosis
- Death is usually secondary to right heart failure
a) CTEPH disease develops in 0.5-4% of patients following acute PE. Why is this?
b) Describe the management if suspected and after diagnosis
a) There is fibrotic transformation of a pulmonary arterial thrombus, causing fixed mechanical obstruction of pulmonary arteries
b)
If suspected
- Patients should undergo echocardiogram to look for evidence of PH and a repeat CTPA to assess for chronic clot formation
After diagnosis
- Lifelong anticoagulation.
- If a surgical candidate, patients can undergo pulmonary endarterectomy to remove the chronic thrombus with the aim of improving symptoms
Describe the pathophysiology of obstructive sleep apnoea (OSA)
OSA occurs due to a loss of tone in the pharyngeal dilator muscles
During deep sleep, these muscles relax causing narrowing of the upper airways. However, if the airways is already narrowed, the airway collapses and OSA results
Describe the cycle that is generated during sleep in OSA
- The upper airway dilating muscles lose tone (usually accompanied by snoring)
- The airway is occluded
- The patient wakes (often not completely)
- The airway opens
Risk factors OSA
- Obesity
- Male
- Down syndrome
- Adenotonsillar hypertrophy
- Soft tissue deposition seen n hypothyroidism or amyloidosis
- Macroglossia (enlarged tongue - can be seen in acromegaly)
- Nasal obstruction
- Alcohol
- Micrognathia (undersized lower jaw/mandible)
- Retrognathia (the lower jaw/mandible is set back further than the upper jaw/maxilla)
Describe the investigations for OSA
- Epworth sleepiness scale (ESS): gives ideas if patients are excessively sleeping
Other sleep questionnaires
- Pittsburgh sleep quality index (PSQI)
- STOP BANG (Pre-op screening)
- 4 variable screening tools
- The mallampati score: assesses the size and shape of a patient’s tongue and oesophageal airway
- Polysomnography: gold standard diagnostic test
- Desaturation index
a) Describe the role of the Hepworth sleepiness scale (ESS) in diagnosing OSA
b) What is a pathological ESS score?
a) Gives idea if patients are excessively sleeping
b) ESS > 11/14 is pathological
Aside from the Epworth sleepiness scale, name at least 2 other sleep questionnaires
- Pittsburgh sleep quality index (PSQI)
- STOP BANG (Pre-op screening)
- 4 variable screening tools
a) Describe the role of the mallampati score in diagnosing OSA?
b) Describe the 4 classes
a) Assesses the size and shape of a patient’s tongue and oesophageal airway
b)
Class I - complete visualisation of the soft palate
Class II - complete visualisation of the uvula
Class II - Visualisation of only the base of the uvula
Class IV - Soft palate is not visible at all
a) What is the gold standard diagnostic test for OSA?
b) What is the diagnostic result?
a) Polysomnography
b) 15 or more episodes per hour is diagnostic
What results would be diagnostic on polysomnography for the following:
a) Mild OSA
b) Moderate OSA
c) Severe OSA
a) 5-15 episodes per hour
b) 15-30 episodes per hour
c) > 30 episodes per hour
a) The apnoeic episodes are usually associated with a desaturation index of what?
b) What parameters are measured for the desaturation index
a) 4% criteria
b)
- Brain activity (assess stage of sleep with electrocenephalography - EEG)
- Eye movements
- Oxygen and carbon dioxide levels
- Blood pressure and pulse
- Inspiratory and expiratory flow
What is apnoea?
Cessation of breathing for 10 seconds or more. Usually scored with > 4% desaturation
What is hypopnea?
Reduction in the airflow (nasal flow) by 50% or more. May not cause O2 desaturations
What is the normal apnoea hypnoea index?
<5 episodes per hour
Compare the difference between obstructive sleep apnoea vs obstructive sleep apnoea syndrome
OSA = Abnormal sleep study and no excessive day time sleepiness
OSAS = Abnormal sleep study and excessive day time sleepiness
Describe the management of OSA(S)
- Lifestyle modifications
- Weight reduction
- Sleep hygiene
- Positional training
- Devices and equipment
- Mandibular advancement devices
- Continuous positive airway pressure (CPAP) = definitive management and to use at least 4 hrs a night
a) Describe how mandibular advancement devices work
b) What type of OSA(S) is it for?
a) This is a dental device in mouth whilst asleep - it moves the mandible forward and increases the area of the oropharynx (back of throat)
a) Describe how continuous positive airway pressure (CPAP) works?
b) How long is CPAP recommended to be used for every night?
a) CPAP is a mask that blows air to the back of the throat. It can be in the form a whole airway mask (cover nose and mouth) or nasal mask
b) Recommended to use at least 4hrs a night
What advice would you give patients with OSA(S) ?
- Patients must declare OSA(S) diagnosis to DVLA
- Patients must declare to DVLA if CPAP compliance > 4 hrs/night
What is Obesity hypoventilation syndrome or Pickwickian syndrome?
Obesity hypoventilation syndrome, or Pickwickian syndrome, is a disorder of breathing commonly associated with OSA, characterised by chronic hypoxia and daytime hypercapnia, in the absence of parenchymal lung disease
Describe the 4 diagnostic criteria of Obesity hypoventilation syndrome/Pickwickian syndrome
- BMI > 30kg/m2
- Daytime paCO2 > 4.5 mmHg
- Associated sleep apnoea syndrome
- Absence of other causes of hypoventilation
Describe the management of Obesity hypoventilation syndrome/Pickwickian syndrome
Conservative measures
- Weight loss
Secondary measures
- Non-invasive ventilation e.g.m bilevel positive airway pressure (BiPAP) - to blow off the excess CO2
Name 5 consequences of sleep disordered breathing
- Systemic hypertension
- Pulmonary arterial hypertension
- Cor pulmonale
- Ischaemic heart disease
- AF
- Stroke
What is pleural malignancy?
The build-up of fluid and cancer cells that collects between the chest wall and the lung (pleura0])
What are the causes of pleural malignancy
Primary pleural malignancy: mesothelioma
Secondary pleural malignancies
- Lung
- Breast
- Lymphoma
- almost any cancer can metastasise to the pleura
Describe the epidemiology of pleural malignancies
- Common
- Sex ratio depends on degree of asbestos exposure/smoking
- Increasing incidence with age
Give 4 differential diagnoses of pleural effusion
- Transudative pleural effusion - cardiac, renal, or hepatic failure
- Pleural infection
- Pulmonary embolism
- Connective tissue disease
- Benign asbestos pleural disease
Pleural malignancy
Symptoms
- Constitutional symptoms: weight loss, loss of appetite, fatigue
- Symptoms specific to effusion : breathlessness, cough, dull chest pain
- Symptoms of other malignancy: dysphagia, change in bowel habit, lumps
Signs
- Increased respiratory rate
- Decreased lung expansion
- Dull percussion note
- Decreased vocal resonance/tactile fremitus
- Other signs of malignancy e.g., breast lumps, testicular lumps, lymphadenopathy
Describe the investigations for pleural malignancy
Bloods: U&Es, FBC, CRP, Clotting, PSA (specific test for prostate cancer)
CXR
Thoracic ultrasound
CT sacan
Pleural aspiration
- Biochemistry
- MC&S
- Cytology : Positive in about 60% malignant pleural effusion and only 20% in mesothelioma
Thoracoscopy
- Fluid drainage
- Pleural biopsy
- Pleurodesis
- IPC (implantable catheter) insertion
Describe the management of pleural malignancy
- Treat underlying malignancy
- Therapeutic aspiration
- Chest drain and pleurodesis OR Indwelling pleural catheter insertion
- Pleurectomy
Compare the difference between chest drain/pleurodesis vs. Indwelling pleural catheter (IPC) insertion
Chest drain/pleurodesis
- Effective treatment of breathlessness
- Inpatient 2-5 days
- 75% success rate
- May require IPC if fails
IPC
- Effect treatment of breathlessness
- Outpatient
- 50% spontaneous pleurodesis
- Ongoing drainage
- Definite treatment
a) indications of an indwelling pleural catheter (IPC)
b) Complications
a)
- Trapped lung
- Failed pleurodesis
b)
- Blockage
- Infection
What can be used to describe a cancer patient’s level of functioning and disease progress
ECOG performance status
Thoracic ultrasound changes of pleural malignancy
- Pleural effusion
- Pleural thickening
- Pleural nodularity
