Respiratory Flashcards
Comment on this CXR
Consolidation in the right middle lobe consistent with pneumonia
Comment on this CXR
Right lower lobe collapse
Comment on this CXR
A well defined thick walled cavitatory lesion is noted in the right para-hilar area in the midzone of right lung
aka Pulmonary TB
Define COPD
‘a chronic disease characterised by progressive airflow limitation that is not fully reversible and characterised by chronic bronchitis and emphysema’
Define Obstructive Sleep Apnoea Syndrome
Recurrent episodes of partial or complete upper airway (pharyngeal) obstruction during sleep, intermittent hypoxia and sleep fragmentation manifesting as excessive daytime sleepiness
Describe an approach to the analysis of blood gases in clinical practice
Always look at pO2 first to assess if the patient is in respiratory failure or requires additional oxygen
Next look at the pCO2 to determine Type 1 vs Type 2 Resp. Failure
Then look at the acid-base balance to determine if:
Acute Resp. Acidosis (Elevated pCO2, Normal Bicarb, Acidosis)
Comp. Resp. Acidosis (Elevated pCO2, Elevated Bicarb, Not Acidotic)
Acute on Chronic Resp. Acidosis (Elevated pCO2, Elevated Bicarb. Acidosis)
Describe clinical features of pulmonary embolism
Tachypnoea
Crackles
Tachycardia
Fever
Signs of Peripheral DVT
Pleuritic Chest Pain
Dyspnoea
Cough
Haemoptysis
Syncope
Describe investigations for pulmonary embolism
Modified Geneve Score (Risk Assessment)
D-Dimer (Raised, >230mg/L)
ABGs (Resp. Alkalosis with Reduced PaCO2)
Troponin
ECG
Echocardiogram
Radiology (CXR, CT-Pulmonary Angiogram, V/Q Scan)
Describe pathological features in the lung which lead to pneumothorax
Sub-Pleural Blebs (blister-like air pockets) at the apex of the lung
Diffuse, microscopic emphysema below the surface of the visceral pleura
Spontaneous rupture can lead to a tear in the visceral pleura
Describe the clinical diagnosis of Pulmonary Fibrosis
Clinical manifestation of UIP
Fibrotic lung disease, usually with no definitive cause
Progressive Breathlessness, Bibasilar Crackling, Hacking Dry Cough, Fatigue, Weakness, Finger Clubbing, Appetite and Weight Loss
Describe the clinical presentation of Sarcoidosis
May present with pulmonary, neurological, cardiac, dermatological or ocular findings
Systemic symptoms: Fever, Anorexia, Fatigue, Night Sweats, Weight Loss
Pulmonary symptoms: Cough, Haemoptysis, Dyspnoea on Exertion, Chest Pain
May be asymptomatic
Describe the clinical application of the Alveolar Air Equation
Arterial pO2 can be directly measured by ABG analysis, whereas Alveolar pO2 must be calculated
The difference between Alveolar pO2 and Arterial pO2 is known as the Alveolar-Arterial Oxygen Gradient
Normally, this should be less than 2-4kPa
Higher than this suggests a V/Q mismatch
Describe the distant spread of lung cancer
Haematogenous - Liver, Bone, Brain, Adrenal
Lymphatic - Cervical Lymph Nodes
Describe the effects of cigarette smoke on the airways and how this leads to pathology
Mucus Gland and Goblet Cell Hypertrophy –> Increased Mucus Production –> Cough and Sputum
Reduced Cilial Motility –> Decreased Mucus Clearance –> Increased Infection Risk
Anti-Protease Inhibition –> Increased Protease Activity –> Inflammation
Describe the features of Usual Interstitial Pneumonia
Heterogenous appearance with areas of normal lung punctuated by marked fibrosis and honeycombing (mainly in subpleural areas) and fibroblastic foci (dense proliferations of fibroblasts and myofibroblasts)
Describe the immediate management of pulmonary embolism
Massive:
(PE associated with SBP <90mmHg or a drop in SBP of >40mmHg in <15 Minutes)
Give Unfractionated Heparin IV
Fluid Resuscitation
Thrombolysis with Alteplase if Fails to Improve
Sub-Massive:
Initially LMWH
Then Oral Anti-Coagulant for 3 Months (Factor Xa Inhibitors or Warfarin)
Describe the investigations used in the diagnosis of Obstructive Sleep Apnoea Syndrome
History (from Pt and Family)
Clinical Exam
Daytime Sleepiness Assessment (Epworth Score)
Limited Polysomnography (Home, 5 Channel; O2 Sats, HR, Flow, Thoracic and Abdominal Effort and Position)
Full Polysomnography (In-Hospital, Multi-Channel; EEG, Video, Audio, Thoracic/Abdominal Bands, Position, Flow, O2 Sats, Limb Leads, Snore)
Transcutaneous Oxygen Saturation and Carbon Dioxide Assessment
Describe the mechanism of action of anti-fungal drugs
- Azoles
- e.g. Miconazole, Imidazole, Triazole, Thiazole
- Inhibitors of 14-methylsterol alpha-demethylase which produces ergosterol
- Ergosterol is an essential component of the fungal plasma membrane
- Does not occur in animal or plants cells
- Amphotericin B
- Also exploits the ergosterol/cholesterol difference
- It is not an enzyme inhibitor
- Binds to ergosterol to form a pore in fungal membranes, leading to cell death
Describe the methods of management of Obstructive Sleep Apnoea Syndrome
Weight Loss
Avoidance of Triggers (e.g. Alcohol)
Treatment of Underlying Factors
Continuous Positive Airway Pressure (Splints airway open to stop snoring and sleep fragmentation to reduce daytime sleepiness and improve quality of life)
Mandibular Advancement Device
Sleep Position Training
State the pathological classification of Lung Cancer
Small Cell
Non-Small Cell (Large Cell, Adenocarcinoma or Squamous Cell)
Describe the pathological consequences of local spread of lung cancer
Bronchial Obstruction
Lung Collapse or Consolidation (Retention Pneumonia)
Pleura - Haemorrhagic Effusion
Blood Vessels - Haemoptysis
Pericardium - Pericardial Effusion
Mediastinum - SVC Obstruction
Pancoast Tumour - Horner’s Syndrome, Brachial Plexus Compression
Describe the pathology and presentation of Extrinsic Allergic Alveolitis
T-Cell mediated (immunological) inflammatory reaction in the alveoli and respiratory bronchioles
(N.B. EAA is NOT atopy)
May present with flu-like illness, cough, fever, chills, myalgia, malaise, dyspnoea
Describe the pathology of Adenocarcinoma Non-Small Cell Lung Cancer
Common tumour in females
Also seen in non-smokers
Two-thirds arise in the periphery
Appearance: Glandular, Solid, Papillary or Lepidic with Mucin Production
Describe the pathology of COPD
Increased number of mucus-secreting cells
CD8 lymphocyte driven inflammation of the airways, leading to scarring and thickening
Neutrophil infiltration
Loss of defined alveolar air spaces leading to loss of elasticity and air trapping
Causes airway collapse, and blockage of airways
Describe the pathology of Large Cell (Non-Small Cell) Lung Cancer
Usually arises centrally
Undifferentiated malignant epithelial tumour that lacks the cytological features of SCLC and glandular or squamous differentiation
Describe the pathology of Small Cell Lung Cancers
Most aggressive form, often metastasising early and widely
Often a good initial response to chemotherapy, but most patients relapse
Appearance: Oval to Spindle Shaped Cells, Inconspicuous Nucleoli, Scant Cytoplasm, Nuclear Moulding
Describe the pathology of Squamous Non-Small Cell Lung Cancer
Tends to arise centrally from major bronchi
Slow growing and late to metastasise
Often within dysplastic epithelium following squamous metaplasia
Appearance: Malignant Epithelial Tumour showing Keratinisation and/or Intracellular Bridges
Describe the serum biochemical adaptations to acute and chronic respiratory failure
In acute resp. failure, there is insufficient time for full renal compensation so the pH is low with a high/normal bicarbonate
In chronic resp. failure the kidneys are able to compensate with a raised bicarbonate and normal pH
Describe the spirometric pattern that would be expected in obstructive versus restrictive respiratory disease
Obstructive (e.g. COPD/Asthma) - Reduced FEV1:FVC (<70%), Reversibility (>15% AND 400ml in Post-BD FEV1) in Asthma but NOT in COPD
Restrictive - Preserved FEV1:FVC (>70%) with Reduced % Predicted FVC
Describe the typical features of a ‘Blue Bloater’
Usually in chronic bronchitis
Due to CO2 retention (becomes insensitive to it)
Low Resp. Drive and Type 2 Resp. Failure
(Low PaO2 and High PaCO2)
Cyanosis, Obesity, Crackles and Wheeze, Peripheral Oedema
Chronic Productive Cough, Purulent Sputum
Describe the typical features of a ‘Pink Puffer’
Due to Emphysema
CO2 responsive with compensatory hyperventilation
Desaturates on Exercise, Pursed Lip Breathing, Use of Accessory Muscles, Wheeze, Indrawing of Intercostals, Tachypnoea, Cachectic Appearance
High Resp. Drive, Type 2 Resp. Failure
Low PaO2 and PaCO2
Describe the pathological processes in Sarcoidosis
Chronic granulomatous disorder characterised by accumulation of lymphocytes and macrophages in organs (typically the lungs and intrathoracic lymph nodes)
Non-necrotising granulomas with multi-nucleated giant cells in the centre
Outline the diagnostic features of spontaneous pneumothorax
Pleuritic Chest Pain
Dyspnoea
Respiratory Distress
Reduced Air Entry on Affected Side
Hyper-Resonance to Percussion
Reduced Vocal Resonance
Tracheal Deviation (If Tension)
Outline the initial management of spontaneous pneumothorax
Observation if small or not very symptomatic
Aspiration (urgently if tension) with syringe in 2nd intercostal space, midclavicular line
Intercostal drain with underwater seal
State cancers which most commonly metastasise to the lungs
Bowel, Breast, Prostate, Bladder, Kidney
State indications for the use of non-invasive ventilation in COPD
Acute Exacerbations of COPD with Persistent Hypercapnic Respiratory Failure
(should be considered in the presence of respiratory acidosis with pH <7.35 or if acidosis persists despite maximal medical management)
State pathological and clinical features that predispose to pulmonary embolism
Surgery <12 Weeks Previously
Immobilisation >3 Days in Previous 4 Weeks
Previous DVT/PTE
FHx of PTE/DVT
Lower Limb Fracture
Pregnancy or Post-Partum
Long Distance Travel
Oestrogen-Containing OCP Use
Antithrombin Deficiency
Protein S or C Deficiency
Factor V Leiden
State potential drug interactions and pitfalls when using theophylline
Side effects include GI upset, palpitations, tachycardia/arrhythmias, headache, insomnia and hypokalaemia
Caution in liver disease and with concomitant use of enzyme inducers (rifampicin) and inhibitors (clarithromycin, ciprofloxacin)
Smoking increases theophylline clearance – dose may need to be adjusted following smoking cessation
State risk factors which predispose to development of Obstructive Sleep Apnoea Syndrome
Obesity
Male Sex
Post-Menopause (Women)
Large Neck Circumference (>40cm)
Maxillomandibular Anomalies (Narrowing, Retrognathia)
Increased Tonsil/Adenoid/Tongue Size
FHx
State some clinically differentiating features of Asthma and COPD
Episodic SOB in Asthma
Nocturnal Symptoms and Diurnal Variation in Asthma
Productive Cough in COPD
Asthma is Not Progressive, Has Exacerbations and Variable Symptoms
COPD is Progressive, Has Exacerbations and Persistent Symptoms
State the Alveolar Air Equation
PaO2 = FiO2 - (1.25 x PaCO2)
PaO2 - Alveolar Oxygen Partial Pressure, kPa
FiO2 - Inspired Oxygen Concentration, kPa
Using the Alveolar Air Equation comment on the following patient:
Man with COPD, on 28% Oxygen
pO2 - 7.6
pCO2 - 6.6
Alveolar pO2 = 28 - (1.25 x 6.6) = 19.75
Therefore, A-a = 19.75 - 7.6 = 12.15
Alveolar-Arterial Gradient is increased, suggesting V/Q mismatch
