Respiratory Flashcards
Define pleural effusion
Accumulation of an abnormal volume of fluid in the pleural space
Describe the fluid that is normally found in the pleural space
<15ml in volume
Clear, serous fluid with few cells
What sign is suggestive of a pleural effusion on a CXR?
Blunting of the costaphrenic angles
What symptoms can be associated with a pleural effusion?
Asymptomatic
SOB
Cough
Pleuritic chest pain
What clinical signs are associated with a pleural effusion? I.e 1. chest expansion 2. tacile vocal fremitis 3. percussion 4. breath sounds 5. any other...
- Chest expansion is reduced
- Reduced tactile vocal fremitis
- Stony dull percussion
- Quiet breath sounds
+ Bronchial breathing above fluid level
+ Rub with pleural inflammation
Describe the mechanism of a pleural effusion
Disturbed balance between pleural fluid production and absorption
If there is a bilateral pleural effusion, what type of effusion is it generally?
Transudate (protein <30g/l)
What type of pleural effusion can be caused by cardiac failure?
Unilateral effusion on the right
How should pleural effusion be sampled?
USS guidance
Need >100ml to cytology + paired serum samples
Biochemistry - Light’s criteria
Microbiology
How much pleural effusion can be drained at a time?
1 litres
What are causes of transudative pleural effusion?
Cardiac failure
Hepatic cirrhosis
Nephrotic syndrome
Hypoalbuminaemia
What are causes of exudative pleural effusion?
Bacterial pneumonia
Malignancy
Mesothelioma
TB
At what site should a thoracentesis be performed?
Above the rib (below rib is the neurovascular bundle)
Describe Light’s criteria for establishing whether a pleural effusion is a transudate or exudate
- Pleural/serum protein ratio >0.5
- Pleural LDH/serum LDH >0.6
- LDH >2/3 the upper limit of normal value for serum LDH
When is a medical thoracoscopy indicated?
Undiagnosed cytology negative pleural effusions
What are the four management options for malignant pleural effusion?
- Drain to dryness and discharge
- , Medical pleurodesis
- Thoracoscopic pleurodesis
- Indwelling pleural catheter (IPC) - high output pleural effusion
What percentage of pneumonias will have an associated effusion?
50% (parapneumonic)
Describe a complex parapneumonic effusion
pH <7.2
LDH >1000
Glucose <2.2
Loculated on ultrasound
What mortality is associated with an empyema?
15%
On CXR, what shaped effusion is suggestive of empyema?
D-shaped
When should an empyema be considered?
Effusion + sepsis
Pneumonia and not improving
How should an empyema be managed?
Small bore chest drain
Frequent sterile saline flushes
IV antibiotics and DVT prophylaxis
Fibrinolytics - streptokinase or DNAase and tPA (alteplase)
Describe sarcoidosis
Multisystem inflammatory disease of unknown aetiology that predominantly affects the lungs and the intrathroacic lymph nodes
What skin lesion is associated with sarcoidosis?
Erythema nodosum
What eye condition is associated with sarcoidosis?
Uveitis
In what population is sarcoidosis most commonly seen?
African American women
What type of granulomas are associated with sarcoidosis?
Non-caseating granulomas (T cell surrounding macrophages)
What histology is commonly present in sarcoidosis?
Langhans Giant Cells
Contain Schaumann bodies and astroid bodies
What are the general symptoms of sarcoidosis?
In what percentage of patients are these present?
Weight loss Anorexia Fever Malaise Night sweats
45%
What electrolyte disturbance is associated with sarcoidosis?
Hypercalcaemia (increased Vitamin D produced by macrophages)
What happens to ACE levels in sarcoidosis?
Increased (from T cells)
What is stage 1 CXR classification for sarcoidosis?
Bilateral hilar lymphadenopathy without infiltration
What is stage 2 CXR classification for sarcoidosis?
Bilateral hilar lymphadenopathy with infiltration
What is stage 3 CXR classification for sarcoidosis?
Peripheral infiltration alone
What is stage 4 CXR classification for sarcoidosis?
Bullae Fibrotic bands Bronchiectasis Diaphragmatic tenting Hilar retraction
How can severe symptoms of sarcoidosis be managed?
Steroids
Describe the epidemiology of Usual Interstitial Pneumonia (UIP)
Age >50y
M:F = 2:1
What signs and symptoms are associated with UIP?
Progressive breathlessness (worse with exercise), hacking cough
Bibasilar crackles
Clubbing
Appetite and weight loss
What pathological findings are associated with UIP?
Peripheral interstitial pattern Subpleural honeycombing (radiological sign)
What are some of the non-idiopathic causes of UIP?
Occupational and environmental
Drug induced - amiodarone, cocaine, nitrofurantoin, methotrexate
Connective tissue disease - SLE, RA, scleroderma
Primary disease - sarcoidosis, LAM
What percentage of cases of UIP are idiopathic?
25%
How can UIP be diagnosed?
High resolution CT
VATS (3 samples)
What are the four features of UIP that need to be detected following VATS?
- Spatial heterogeneity
- Temporal heterogeneity
- Smooth muscle hyperplasia
- Fibroblastic focus
What is extrinsic allergic alveolitis also called?
Hypersensitivity pneumonitis
Define EAA/HSP:
Immunologically mediated (T-cells) inflammatory reaction in the alveoli and respiratory bronchioles following exposure to organic dust, moulds, foreign proteins (animal dander), and some chemicals
How long after the exposure to the allergen do symptoms develop?
4-8 hours
What symptoms are associated with EAA/HSP?
Flu-like symptoms: high fever, chills, malaise and myalgia
Chest symptoms: cough, dyspnoea, chest tightness
Describe some of the radiological findings associated with acute HSP:
Numerous poorly defined small opacities throughout both lungs May have sparing of the apices/bases Ground glass opacities Fine reticulation may occur Zonal distribution
What are the symptoms of chronic HSP?
Dyspnoea on strain Sputum production Fatigue Anorexia Weight loss
Describe the pathology of chronic HSP:
Non-necrotising granulomatous inflammation (Giant cells)
Overproduction of surfactant –> lipid is phagocytksed by macrophages –> foamy macrophages in alveolar space
What is the difference, in terms of pathology, of sarcoidosis and EAA/HSP?
Sarcoidosis = non-necrotising granulomatous inflammation in the interstitium
EAA/HSP = non-necrotising granulomatous inflammation in the alveolar air space
Define COPD
Progressive, irreversible airway obstruction which does not change markedly over several months
Define Emphysema
Permanently dilated airways distal to the terminal bronchioles with alveolar destruction and bullae formation
Define chronic bronchitis
Cough with sputum production for at least three months in two consecutive years
What percentage of lung cancers are due to lifestyle factors, the most important being smoking?
90%
What types of lung cancer does smoking predispose the most to?
Squamous carcinoma
Small cell carcinoma
Give 4 risk factors (other than smoking) for developing lung cancer
Environmental tobacco smoke Irradiation - radon, uranium Air pollution Asbestos Other - HPV, fibrosing conditions of the lung, hereditary
What are some of the common signs and symptoms of a lung cancer?
Cough Haemoptysis SOB Chest pain Weight loss/anaemia General malaise
What symptoms are more commonly seen in central lung cancers?
Haemoptysis
Bronchial obstruction - SOB, retention pneumonia
Cough
What symptoms are more commonly seen in peripheral lung cancers?
Largely asymptomatic
Pain if pleura/chest wall involvement
Give some signs and symptoms that may occur if there is local spread of a lung cancer?
Pancoast tumour - brachial plexus involvement, Horner’s syndrome
Mediastinum involvement:
Paralysis of diaphragm - involvement of phrenic nerve
Hoarseness - involvement of recurrent pharyngeal nerve
Super vena caval obstruction
Describe haematogenous spread of lung cancer
Spread through pulmonary veins
Mets in liver, bone, brain, adrenals
Which lymph nodes are involved in lung mets?
Cervical lymph nodes
Describe the hormonal effects of lung cancer
ACTH released by tumour –> adrenal hyperplasia –> raised blood cortisol –> Cushing’s syndrome
ADH secretion –> water retention –> dilute hypernatraemia
Parathyroid Hormone Related Peptide released –> increased osteoclast activity –> increased bone resorption —> hypercalcaemia
What are non-hormonal non-metastatic effects of lung cancers?
Encephalopathy
Cerebellar degeneration
Neuropathy
Myopathy
Describe small cell lung carcinoma
Most aggressive form of lung cancer
Metastasises early and widely
Treat with chemo - usually good response but most patients relapse
Describe the histology associated with small cell lung carcinoma
Oval to spindle shaped cells Scant cytoplasm Inconspicious nucleoli Nuclear moulding Lots of apoptosis and mitosis
What are the types of non-small cell lung carcinoma?
Squamous cell carcinoma
Adenocarcinoma
Large cell carcinoma
Describe squamous cell carcinoma
Tends to arise centrally from the major bronchi - may block the bronchi –> retention pneumonia/collapse
Slow growing and metastases late –> ? surgery
Describe the histological appearance of squamous cell carcinoma
Malignant epithelial tumour with keritanisation and/or intracellular bridges (desmosomes)
In situ squamous cell carcinoma may be seen in adjacent airway
Describe adenocarcinoma lung cancer
Common in females
Can be seen in non-smokers
2/3 in periphery
Can spread from lobe to lobe
Describe the histological appearance of adenocarcinoma lung cancer
Glandular
Solid
Papillary
(Grows along alveolar walls –> produce mucin)
Define large cell carcinoma
An undifferentiated malignant epithelial tumour that lacks the cytological features of SCLC and glandular/squamous differentiation
What are carcinoid tumours?
Neuroendocrine cells
Can metastases but much better prognosis
What lung cancers are arise centrally?
Squamous
Small cell carcinoma
(arise in and around the Hilar)
What lung tumour generally arises in the periphery?
Adenocarcinoma
Describe the role of EGFR in NSCLC
Ligand binds –> activation of tyrosine kinase –> pathway activation –> production of GF, proliferation etc
If tyrosine kinase is continually activated –> continuous cell division
What two drugs target EGFR in NSCLC?
Cetruximab
Erlotinib
Describe the MoA of Cetruximab
Targets the ligand binding site with a blocker
Describe the MoA of Erlotinib
Tyrosine kinase inhibitor
What can be used to assess for mutation in EGFR gene?
PCR
What is associated with a good response to EGFR inhibitors?
Deletion in exon 19
What fusion gene is implicated in some NSCLC?
ALK-EML4
What occurs following the chromosomal translocation that results in ALK-EML4 fusion gene being produced?
Activation of tyrosine kinase –> cell proliferation
What drug can inhibit ALK-EML4?
Crizotinib
How can ALK-EML4 gene be assessed?
FISH
Describe how PD-L1 inhibitors can be used to treat NSCLC
PD-L1 (tumour cell) binds to PD-1 on T lymphocytes to prevent the T cells from killing the tumour cell
inhibiting PD-L1 will prevent the tumour cell from evading the immune system
Describe mesothelioma
Primary pleural tumour
Almost always due to asbestos exposure
Very long lag period before disease develops
What is the most common cause of Community Acquired Pneumonia?
S.pneumoniae
Give bacteria which cause typical CAP
S.pneumoniae
H.influenzae
Moraxella catharralis
Give bacteria which cause atypical CAP
Mycoplasma pneumoniae
Legionella pneumoniae
Chlamydophilia pneumoniae
What is the appearance of S.pneumoniae?
Chains of gram positive cocci
What are risk factors of developing CAP caused by S.pneumoniae?
Alcohol Smoking Influenza Airway disease Immunosuppression
What signs and symptoms are associated with CAP caused by S.pneumoniae?
Abrupt onset Cough Fever Pleuritic chest pain Dull percussion Coarse crepitations Increased vocal resonance
What Abx should be prescribed for a patient who has CAP due to S.pneumoniae?
Amoxicillin
Clarithromycin or doxycycline if allergy to penicillin
What is the appearance of Haemophilius influnzae?
Gram negative
Who is at risk of developing CAP due to Haemophilius influenzas infection?
Older people
People with underlying lung disease
What other infections can be caused by H.influenzae?
Otitis media
Conjunctivitis
Headache/sinusitis
Meningitis (type B)
What are the signs and symptoms of H.influenzae CAP?
Abrupt onset Fever Pleuritic chest pain Dull percussion Coarse creps Increased vocal resonance
Describe the management of H.influenzae CAP
Co-amoxiclav
if allergy to penicillin: clarithromycin, doxycycline
Describe the presentation of Mycoplasma pneumoniae
Non-specific (headache, lethargy, cough, myalgia)
Signs of consolidation on auscultation
Higher rates in autumn and winter
Spreads from person to person
Affects younger people
What are the other effects of Mycoplasma pneumoniae?
Haemolysis (cold agglutinins) Guillain-Barre syndrome Erythema multiform Arrhythmias Arthritis
How is Mycoplasma pneumoniae CAP diagnosed?
Serology - rising Ab against M.pneumoniae
PCR from sputum, gargle, throat swab
Describe the treatment of Mycoplasma pneumoniae CAP
Macrolides - clarithromycin
Tetracyclines - doxycycline
Quinolones - ciprofloxacin
Describe legionella pneumophilia
Exists within the soil and water
Hx is key
Causes atypical presentation
How is Legionella pneumophilia diagnosed?
Ab raised against legionella
Urinary antigen test
How is legionella pneumophilia CAP treated?
Macrolides - clarithromycin
Tetracycline - doxycycline
Quinolones - ciprofloxacin
What is the CURB65 score?
Assess severity of pneumonia
C = confusion U = urea >7 R = RR >/= 30 B = DBP <60 or SBP <90 65 = >65y
> 2 = severe pneumonia
What is Sepsis qSOFA score?
SBP <100mmHg
Altered mental state
Respiratory rate >22 breaths/min
Other than the CURB65 score, what is the other definition of a severe pneumonia?
Multilobular consolidation on CXR and/or hypoxic on RA
Define obstructive sleep apnoea
Recurrent episodes of partial or complete upper (pharyngeal) airway obstruction during sleep resulting in intermittent hypoxia and sleep fragmentation
(If manifests with excessive daytime sleepiness –> obstructive sleep apnoea syndrome)
Describe of mechanism of OSAS
Airway collapses and closes during sleep
Hypoxia –> arousal
Sleep disruption –> sleepiness, reduced QoL, increase risk of RTA
Blood BP surge –> increased free radical production –> CVA (MI, stroke)
What are the symptoms of OSAS?
Snorer Witnessed apnoea Disrupted sleep - nocturia, choking, dry mouth, sweating Unrefreshed sleep Daytime somnolence Fatigue, low mood, poor concentration
What scoring system quantifies daytime sleepiness?
Epworth Sleepiness Sore
What are the components of a physical examination in OSAS?
Weight/BMI BP Neck circumference (>40%) Craniofacial appearance: retrognathia (abnormal posterior position of maxilla/mandible) or micrognathia (small jaw) Tonsils Nasal patency
What are the two methods in which OSAS can be investigated?
Limited Sleep Study - at home
Full polysomnography
Define apnoea
The cessation, or near cessation, of airflow
4% oxygen desaturations, lasting >/= 10 seconds
Define hypopnoea
Reduction in airflow to a degree insufficient to meet the criteria for an apnoea
What is the Apnoea-Hypoapnoea Index?
Calculated by adding the total number of apnoeas and hypopnoeas and dividing by the total sleep time (in hours)
How is the Apnoea-Hypoapnoea Index used to diagnose OSAS?
AHI >/= 15 = diagnostic
AHI 5-14 + symptoms = diagnostic
Define Oxygen Desaturation Index
The number of times per hour of sleep that the SpO2 falls >/= 4% from baseline
