Respiratory Flashcards
The majority of carbon dioxide in blood is carried in the form of:
A. Carbamino compounds bound to Hb B. Bicarbonate ions C. Carbon monoxide D. Carbonic acid E. Dissolved in plasma
Answer: B - Bicarbonate ions
The majority of CO2 in blood is carried as bicarbonate ions (70-80%). The solubility in blood is about 20x greater than oxygen. Upon diffusing into the RBC, it is rapidly hydrated to H2CO3 by intracellular carbonic anhydrase - then it dissociates into H and HCO3.
Which one of the following statements concerning the diaphragm is correct?
A. It is innervated by the phrenic nerves that arise from C1-3
B. In diaphragmatic paralysis, the abdomen may be seen to move outwards on inspiration
C. A common cause of paralysis is cardiothoracic surgery
D. In bilateral paralysis the vital capacity is unaffected
E. Sleep disordered breathing is rare among patients with diaphragmatic dysfunction
Answer: C - A common cause of paralysis is cardiothoracic surgery
The diaphragm is innervated by C3-C5.
Normal contraction leads to an outward movement of the abdomen but in paralysis there is paradoxical inward motion during inspiration.
Phrenic nerve injury may occur in 2% of patients undergoing cardiothoracic surgery.
There will usually be moderate-severe restriction in total lung capacity in bilateral paralysis.
The oxygen dissociation curve is characterised by:
A. Shift to right by carbon monoxide
B. Shift to right by CO2, leading to enhanced O2 release
C. Shift to left by acidosis, leading to enhanced O2 release
D. Shift to left by 2,3 -BPG
E. Percentage saturation of Hb (y-axis) at various partial pressures of CO2 (x-axis)
Answer: B - Shift to right by CO2, leading to enhanced O2 release
Hot, high (2-3BPG) and acidic = right shift
CO & HBF = left shift
Which of the following acute physiological cardiovascular effects occurs in OSA?
A. Decreased LV afterload B. Decreased venous return to the right ventricle C. Increased left ventricular preload D. Increased stroke volume during apnoea E. Increased sympathetic activity
Answer: E - Increased sympathetic activity
The role of O2 in cellular respiration is:
A. Metabolism of glucose to acetyl CoA B. Cofactor in citric acid cycle C. Terminal electron acceptor in the electron transport chain D. Production of ATP by glycolysis E. Conversion of pyruvate to lactate
Answer: C - Terminal electron acceptor in the electron transport chain
Cellular respiration requires oxygen as the terminal electron acceptor to allow proton gradients and mitochondrial ATP generation.
Rapid eye movement (REM) behaviour sleep disorder is associated with:
A. No therapeutic response to Clonazepam B. Obstructive sleep apnoea C. Increased female incidence D. Epileptiform EEG trace E. An increased subsequent risk of Parkinsonism
Answer: E - An increased subsequent risk of Parkinsonism
REM sleep behaviour disorder is a parasomnia with vivid and often frightening dreams are acted upon.
Marked male predominance and can be an early feature of alpha-synucleinopathies e.g. PD, LBD or MSA.
Which of the following structures is devoid of cartilage?
A. Primary bronchus B. Larynx C. Respiratory bronchiole D. Trachea E. Segmental bronchus
Answer: C - Respiratory bronchiole
Respiratory bronchioles are devoid of cartilage
Vital capacity is the sum of:
A. Tidal volume and expiratory reserve volume
B. Tidal volume and inspiratory reserve volume
C. Tidal volume, inspiratory and expiratory reserve volume
D. Tidal volume and reserve volume
E. Inspiratory volume and expiratory reserve volume
Answer: C - Tidal volume, inspiratory and expiratory reserve volume
Vital capacity is the large volume of air that can be expired after maximal inspiratory effort.
The amount of air that moves into the lungs with each normal breath is the tidal volume.
Air left after the maximal expiration is the residual volume.
Air expelled by active expiration after normal passive expiration is the expiratory reserve volume.
Vital capacity is the total sum of TV, IRV and ERV.
Which one of the following changes in sleep pattern occurs in the elderly?
A, Longer duration of sleep at night B. Increased duration of non REM sleep C. Increased duration of slow wave sleep D. Increased sleep onset latency E. Decreased frequency of nocturnal awakenings
Answer: D - Increased sleep onset latency
Elderly persons achieve less total sleep compared to younger people. There are more awakenings/arousals/fragmentation.
Deep non-REM sleep tends to be reduced but REM is usually preserved.
In familial pulmonary arterial hypertension, which gene is commonly mutated?
A. Bone morphogenic protein receptor 2 B. Endothelin receptor type A C. Endothelin receptor type B D. Matrix protein fibrillin E. Polycystin
Answer: A - Bone morphogenic protein receptor 2 (BMPR2)
The majority of familial PAH are associated with mutations in the BMPR2 or ALK1 genes.
Note the matrix protein fibrillin is encoded by the FBN1 gene (Marfan syndrome)
A 40 year old man has experienced increased breathlessness on exertion over the last few weeks. His arterial blood gases whilst breathing room air are given below. What is the alveolar-arterial O2 gradient?
pH 7.47 PaCO2 49 PaO2 56 HCO3 33 Base excess 8.8 O2 saturation 89%
A. 33 B. 12 C. 56 D. 89 E. 8
Answer: A - 33
A-a gradient = [150 - (pCO2 / 0.8)] - PaO2
= 150 - (49 / 0.8) - 56
= 150 - 61.25 - 56
= 32.75
Which one of the following is associated with narcolepsy?
A. Increased daytime sleep latency B. Reduced levels of CSF hypocretin C. Improvement in symptoms with clonazepam D. Temporal lobe abnormalities E. HLA-B29
Answer: B - Reduced levels of CSF hypocretin
Narcolepsy is characterised by severe daytime somnolence and often cataplexy (involuntary sudden loss of muscle tone e.g. with emotional response).
Sleep monitoring shows rapid sleep onset (significantly reduced sleep latency) and rapid onset of REM. Onset is usually during teenage years/young adulthood.
There is an associated with loss of hypothalamic neurons secreting hypocretin, a wakefulness neurotransmitter.
A 72 year old man with CKD presents with 1 week of intermittent fevers, mild chest pain and dyspnoea. CXR shows a unilateral left sided effusion.
Which of the following is the least useful prognostic factor for his illness?
A. Serum urea B. Age C. Pleural fluid appearance D. Serum albumin E. Serum CRP
Answer: E - serum CRP
Serum CRP may provide some prognostic information but not established for this purpose
Outcome score in pleural infection: Renal (urea) Age Purulence of fluid Infection source (CAP vs HAP) Dietary factors (Albumin)
A 65 year old woman with severe kyphoscoliosis undergoes a preoperative PFT. Which one of the following components of the lung function test is likely to be impacted by the above disorder?
A. Increased total lung capacity (TLC)
B. Increased functional residual capacity
C. Increased maximal inspiratory pressure (MIP)
D. Decreased vital capacity
E. Reduced forced expiratory volume in 1s (FEV1) - to forced vital capacity (FVC) ratio
Answer: D - Decreased vital capacity
Kyphoscoliosis causes a restriction of lung function. There is a decrease in FVC and TLC in proportion to the deformity.
Omalizumab is the first monoclonal antibody used in the treatment of asthma. The mechanism of action of Omalizumab is best explained by:
A. Binding to IgE with reductions in serum IgE and reduced IgE binding to the IgE receptor on basophils and mast cells
B. Blockage of binding of leukotrienes to type 1 cysteinyl leukotriene receptor
C. Binding to tumour necrosis factor
D. Inhibition of IgE synthesis
E. Inhibition of degranulation of mast cells
Answer: A - Binding to IgE with reductions in serum IgE and reduced IgE binding to the IgE receptor on basophils and mast cells
Omalizumab is a humanised IgG monoclonal antibody that binds IgE. It is indicated for moderate-severe persistent asthma despite ICS/LABA +/- LTRA treatment. It requires elevation of serum IgE.
EMQ ABGs
A. pH 7.50 pO2 55 pCO2 33 HCO3 25 B. pH 7.50 pO2 100 pCO2 33 HCO3 25 C. pH 7.45 pO2 100 pCO2 24 HCO3 18 D. pH 7.40 pO2 100 pCO2 40 HCO3 25 E. pH 7.33 pO2 61 pCO2 75 HCO3 38 F. pH 7.20 pO2 54 pCO2 55 HCO3 16 G. pH 7.26 pO2 128 pCO2 16 HCO3 7 H. pH 7.15 pO2 96 pCO2 33 HCO3 11
Select the most appropriate ABG for each patient
- A 20 year old woman was brought in after ingesting a hundred 300mg aspirin tablets. She is semi-conscious but responding to painful stimuli. Her blood pressure is 125/80, HR 100bpm and RR 36/min.
- A 63 year old man has long-term COPD (reformed smoker) and is on domicilliary oxygen. He has previously been admitted to hospital with acute exacerbation of respiratory symptoms requiring NIV.
- A 19year old pregnant women with T1 diabetes presents with 2 days of polyuria, dysuria and general unwellness. There is a history of poor compliance with medical therapy. Examination is normal and her BP is 110/60.
Bloods show Na 135, K 4.8, Cl 101, HCO3 10, Urea 8.1, Creatinine 90, Glucose 24
- Answer: C - Salicylate intoxication causes a primary respiratory alkalosis from salicylate induced hyperventilation and a metabolic acidosis from overproduction of organic acids.
- Answer: E - chronic compensated respiratory acidosis
- Answer: G - DKA
Which one of the following features excludes a diagnosis of COPD?
A. FEV1/FVC <0.70 post bronchodilator B. FEV1/FVC >0.70 post bronchodilator C. Non-smoker D. Weight loss E. Improvement with pulmonary rehabilitation program
Answer: B - FEV1/FVC >0.70 post bronchodilator
Which one of the following treatment modalities for cystic fibrosis is described correctly?
A. Bronchodilator therapy is helpful in the majority of patients
B. Nebulised dornase alpha can improve the viscosity of mucus
C. Oral Azithromycin is used to eradicate staph. aureus
D. Regular use of oral corticosteroids reduces the frequency of infective exacerbations
E. A course of single IV antibiotic is adequate treatment for a severe exacerbation
Answer: B - Nebulised dornase alpha can improve the viscosity of mucus
CF exacerbations generally require multiple agents e.g. ciprofloxacin 2 weeks with nebulised aminoglycosides such as tobramycin.
Bronchodilators are often unhelpful though some 30% may derive benefit. Many exhibit a paradoxical worsening of air flow.
A 58 year old woman develops a moderate pleural effusion following a right lower lobe pneumonia. Thoracocentesis reveals straw coloured fluid with gram positive diplococci on gram stain, pH 6.9, glucose 2.2 mmoL and LDH 1400 U/L. Which one of the following is the next best step?
A. Continue current antibiotics for penumonia
B. IV Ceftriaxone for 5 days
C. Tube thoracostomy to drain the effusion
D. Administer streptokinase intrapleurally
E. Repeat CXR in 2 weeks to re-evaluate the size of effusion
Answer: C - Tube thoracostomy to drain the effusion
Parapneumonic effusions are common and occur in 20-40% of hospitalised patients with pneumonia.
Features that indicate an empyema including low pH <7.20, glucose <3.33 or LDH >3x normal ULN serum).
Effusions more than minimal should have thoracocentesis and consideration given to intrapleural fibrinolytics and DNAse.
Previous studies suggested no benefit but a more recent study using DNAse and tPA intrapleurally showed improved outcomes.
If a loculated effusion persists then a VATS may be needed to re-expand the lung and if this fails then full thoracotomy with decortication could be considered.
Which one of the following does not preclude an attempt at curative lobectomy for non-small cell lung carcinoma?
A. Pulmonary osteoarthropathy B. Hoarseness of voice C. Superior vena cava obstruction D. Blood stained pleural effusion E. Preoperative FEV1 of 1.0L
Answer: A - Pulmonary osteoarthropathy
HPOA is a paraneoplastic phenomenon.
The other options suggest invasion of locally advanced disease.
Preoperative cut-offs for FEV1 are 1.5L generally in order to tolerate a lobectomy.
Which one of the following is correct in patients with malignant mesothelioma?
A. A median survival from diagnosis of 30 months
B. PET scanning is not helpful
C. Mesothelioma does not affect the peritoneum
D. It is associated with prior exposure to amphibole asbestos fibres
E. Imatinib therapy significantly improves survival.
Answer: D - It is associated with prior exposure to amphibole asbestos fibres
There are 2 forms of asbestos: long thin fibres known as amphiboles (blue asbestos) and feathery fibres known as chrysotile (white asbestos. Amphibole fibres/blue asbestos are the major cause of mesothelioma.
Median survival from diagnosis is 12 months. There is no curative treatment. In rare localised cases, surgical treatments can be trialled. Subcutaneous masses almost always are associated with seeding from medical procedures.
Targeted radiotherapy can assist with pain but chemotherapy has no benefit.
Which one of the following findings indicates a high risk of adverse outcomes in a patient with newly diagnosed acute pulmonary embolism?
A. Normal troponin B. Hypertension C. Normal CRP D. Westermark's sign on CXR E. RV dysfunction on echocardiogram
Answer: E - RV dysfunction on echocardiogram
RV dysfunction is associated with increased mortality. The death rate is nearly 58% among those who are in shock and haemodynamically unstable.
A 58 year old man has worked as a miner for 20 years. He presents with a 3 month history of cough and breathlessness. CXR shows diffuse interstitial shadowing. A sputum sample is positive for acid-fast bacilli. Which one of the following dusts is most likely o have predisposed the patient to tuberculosis?
A. Beryllium B. Cadmium C. Coal dust D. Copper dust E. Silica
Answer: E - Silica
Silica dust is associated with mycobacterial, fungal and bacterial lung infections. It impairs macrophage function and in particular predisposes to TB.
Exposure even without silicosis increases risk.
Which one of the following antibiotics has been found to have potential immunomodulatory benefits in the treatment of non cystic fibrosis bronchiectasis?
A. Azithromycin B. Tobramycin C. Amoxicillin/clavulanate D. Vancomycin E. Metronidazole
Answer: A - Azithromycin
Long term low dose oral Azithromycin improves frequency of exacerbations and sputum microbiology/volume, improves FEV1. It has an inhibitory effect on biofilm formation and an immunomodulatory effect.
Patients should be screened for non-tuberculous mycobacteria to avoid the emergence of resistant NTM.
Which one of the following is commonly associated with secondary pneumothorax?
A. Bronchiectasis B. Cystic fibrosis C. Wegener granulomatosis D. Osteogenesis imperfecta E. Pneumocystic jiroveci pneumonia in patients with HIV infection
Answer: E - Pneumocystic jiroveci pneumonia in patients with HIV infection
COPD as well as HIV-related PJP infection are the most common causes of secondary pneumothoraces. The rate of spontaneous pneumothorax in HIV infected patients is between 2 and 6% - 80% of these are PJP related.
A 56 year old woman with a history of depression and chronic back pain is admitted to an acute medical unit after her daughter found her unresponsive on the floor with shallow breathing. She was well 2 hours before her daughter left to go shopping. Her arterial blood gas on room air is shown below. What is the most likely explanation for her presentation?
pH 7.23 pCO2 68 pO2 60 HCO3 26 Anion gap 12
A. Lactic acidosis B. Opioid overdose C. Distal renal tubular acidosis D. Proximal renal tubular acidosis E. Ethylene glycol poisoning
Answer: B - Opioid overdose
Clinical presentation suggestive of opioid overdose and respiratory depression of the medullary respiratory centre with hypoventilation and hypercapnia.
A 38 year old Aboriginal man presents with a 4 week history of low grade fever, weight loss and cough. As the treating medical practitioner, you are considering the possibility of active pulmonary tuberculosis. Which one of the following is the most sensitive test to confirm the diagnosis?
A. Tuberculin skin test B. Sputum smear C. Rapid PCR D. Sputum mycobacterial culture E. Interferon gamma release assay
Answer: D - Sputum mycobacterial culture
TB sputum culture is the most sensitive test. AFB smears are rapid and positive samples are highly sensitive with PCR but if smear negative then sensitivity drops to 50%.
A 72 year old woman with a known history of sarcoidosis presents with hypercalcaemia (total 3.10) and renal impairment (creatinine 219), Which one of the following best explains the mechanism of hypercalcaemia in sarcoidosis?
A. Chronic renal failure with secondary hyperparathyroidism
B. Increased formation of 1,25-OH-vitamin D
C. Milk alkali syndrome
D. Immobility
E. Ectopic calcitonin formation
Answer: B - Increased formation of 1,25-OH-vitamin D
Enhanced 1-alpha hydroxylation of 25-OH-vitamin D by macrophages in granulomatous tissue generates increased 1,25-OH-vitamin D.
A 65 year old Caucasian man with a 60 pack year smoking history and previous asbestos exposure presents with dsypnoea. He has a past medical history of congestive cardiac failure with a recent echocardiogram showing impairment of LV function with ejection fraction 28%. CXR shows a large right sided pleural effusion. A pleural tap reveals fluid with an LDH of 150U/L (serum LDH 300) and a pleural fluid protein of 12g/L (serum 40g/L). These results are most consistent with which one of the following as the cause?
A. Congestive heart failure B. Mesothelioma C. Pulmonary embolism D. Bronchial carcinoma E. Tuberculosis
Answer: A - Congestive heart failure
The most widely used criteria for pleural effusions is Light’s criteria:
- Pleural fluid protein : Serum >0.50
- Pleural fluid LDH : serum LDH >0.60
- Pleural fluid LDH >2/3 ULN serum LDH
Any 1 criteria = exudate.
Which one of the following best reduces lung function decline and mortality in patients with COPD?
A. Budesonide B. Salbutamol C. Smoking cessation D. Long term antibiotics E. Ipratropium
Answer: C - smoking cessation
A 25 year old pregnant woman was found to have a pulmonary embolism on investigation for dyspnoea during her 3rd trimester (week 39). Which one of the following treatments is most appropriate in this setting?
A. Warfarin B. LMWH C. Aspirin D. IV unfractionated heparin E. Graduated compression stockings
Answer: D - IV unfractionated heparin
Warfarin is contraindicated in pregnancy and crosses the placenta. It causes midface hypoplasia, stippled chondral calcification, scoliosis, short limbs and phalanges + risk of foetal intracranial bleeding. Warfarin can be used while breastfeeding.
LMWH could be used during pregnancy and for prophylaxis however she is now close to delivery which may be unpredictably timed. Heparin is the agent of choice due to reversibility to allow planning for labour.
NOACs are not appropriate if pregnant or breastfeeding
A 70 year old man presents with a history of progressive dyspnoea for the past few years. He has COPD resulting from 45 pack years of smoking but quit 4 years ago. He is currently on Budesonide 160ug and Formoterol 4.5ug BD and salbutmol 2 puff 4-6 hourly PRN. The results of his investigations are shown below. Which one of the following treatments is most likely to improve his long-term survival?
ABG on room air: pH 7.40 pCO2 40 pO2 53 FEV1/FVC 43% FEV1 30% predicted
A. Pulmonary rehabilitation B. Ambulatory O2 18h/day C. Lung volume reduction surgery D. Lung transplantation E. Theophylline SR 200mg daily
Answer: B - Ambulatory O2 18h/day
Trials have found reduced mortality in COPD with persistent hypoxaemia who meet the criteria:
- PO2 <55 or arterial saturation <88%
- PO2 55-60 if right heart failure or polycythaemia
Which one of the following is a major risk factor for chronic allograft dysfunction due to bronchiolitis obliterans after lung transplantation?
A. Silent aspiration B. Acute cellular rejection C. Use of Azithromycin D. Cyclosporine E. Nissen fundoplication
Answer: B - Acute cellular rejection
In lung transplantation, chronic allograft dysfunction due to bronchiolitis obliterans (BOS) is a major impediment to long-term graft function and patient survival.
BOS narrows and ultimately obliterates the lumens of the small airways resulting in progressive largely irreversible airflow obstruction.
50% of lung transplant recipients develop by 5 years and 75% by 10 years.
Acute cellular rejection is a consistent risk factor for BOS. GORD and silent aspiration are non-immunological factors that may contribute.
A 55 year old woman has had 6 admissions in the last 12 months for infective bronchiectasis exacerbations. A trial of long-term oral macrolides is considered. Which one of the following must be done prior?
A. Sputum specimen to exclude non-tuberculous mycobacterial infection
B. CXR to exclude pleural effusion
C. High resolution CT chest to evaluate extent of disease
D. Spirometry to assess FEV1
E. Transthoracic echocardiogram to estimate pulmonary artery pressure
Answer: A - Sputum specimen to exclude non-tuberculous mycobacterial infection
EMQ
A. Bronchiolitis obliterans organising pneumonia (BOOP)
B. Desquamative interstitial pneumonitis
C. Idiopathic pulmonary fibrosis
D. Acute interstitial fibrosis (Hamman-Rich syndrome)
E. Allergic bronchopulmonary aspergillosis
F. Alveolar proteinosis
G. Loffler syndrome
H. Lymphangioleiomyomatosis
- A 43 year woman who has had asthma for 15 year presents with progressive dyspnoea, chills and productive cough. Physical examination reveals a thin woman in moderate respiratory distress. She is afebrile but has mild tachypnoea and tachycardia. Chest examination reveals moderate air movement, diffuse wheezes and egophony in the left upper zones without change in tactile fremitus. The CXR shows segmental atelectasis in the upper lobes. Which diagnosis best explains her presentation?
- A 64 year old Caucasian man presents with 1 year of worsening exertional dyspnoea with mild non-productive cough. He reports previous asbestos exposure when working in a shipyard. He has never smoked. He has been treated with several inhaled beta-agonists without improvement. Examination shows dry inspiratory crackles and digital clubbing. CXR shows a diffuse infiltrative process without lymphadenopathy or effusions. He undergoes a lung biopsy which shows minimal inflammatory round cell infiltrate, widening of alveolar septa and fibrosis without fibroelastic foci. What is the most likely diagnosis?
- A 34 year old man presents with abrupt onset fever and chest pain without prior medical history. He is admitted to ICU where his respiratory distress worsens to the point of requiring intubation. CXR shows diffuse patchy ground glass opacities and intralobular septal thickening. Bronchoscopy with lavage shows copious amounts of grossly turbid exudates with material positive for periodic acid-Schiff (PAS) reagent. What is the most likely diagnosis?
- A 32 year old woman presents with dyspnoea, non-productive cough and a previous history of left sided pneumothorax. Bronchoscopic biopsy revealed proliferation of atypical pulmonary interstitial smooth muscle cells. What is the diagnosis?
- Answer: E - ABPA
Sensitivity to aspergillus fumigatus occurring in virtually always longstanding asthma or CF. - Answer: C - IPF
Classic for IPF with biopsy findings of UIP. - Answer: F - Pulmonary Alveolar Proteinosis
Presentations vary considerably. Diagnosis is made with BAL showing grossly turbid exudates with PAS material.
PAP is a rare accumulation of surfactant. It may be from toxic inhalation, haematologic disorders or autoimmune. - Answer: H - Lymphangioleiomyomatosis (LAM)
Uncommon disease occurs in women, more frequently (30%) with tuberous sclerosis.
- Loffler syndrome is characterised by transient and migratory lung infiltrates and predominance of eosinophils. May be result of parasitic infection (e.g. ascaris lumbricoides or stronglyoides)
2016
Question 46: A 25yo man is admitted with carbon monoxide poisoning. He is treated with 100% oxygen and discharged the next day as he remained well. A delayed toxicity from CO affects which of the following systems? A. Respiratory B. Cardiovascular C. Neuropsychiatric D. Renal E. Haematological
Answer: C - Neuropsychiatric
Delayed neuropsychiatric syndrome in up to 40% of patients with CO poisoning
2016
Question 26 : In patients with scleroderma, which of the following confers the greatest risk of interstitial lung disease? A. Anti-Sm B. Anti-Topoisomerase C. Anti-centromere D. Anti-U1 RNP E. Anti-RNA polymerase III
Answer: B - anti-topoisomerase
Anti-centromere antibodies are more commonly seen in limited sclerosis. Associated with pulmonary arterial hypertension, not ILD
Anti-Topoisomerase / Anti-Scl-70 are seen in systemic (diffuse) sclerosis and have the highest association with ILD.
Anti-RNA polymerase III is a specific marker for systemic sclerosis, associated with severe disease with renal crisis and diffuse cutaneous involvement.
Anti-U1 RNP is a marker of mixed connective tissue disease.
Anti-Smith (Sm) is a highly specific antibody for SLE.
2016
Question 22:
Testing for gene mutations is becoming common place in cancer diagnosis and treatment. ALK is commonly looked for in patients with lung cancer. Why type of genetic abnormality does ALK represent?
A. Chromosomal translocation
B. Splice site mutation
C. Clonal expansion
D. Mutation in the methylated region of the gene
E. Point mutation
Answer: A - Chromosomal translocation
Lung cancer driver mutations
- EGFR (Epidermal growth factor receptor) mutation
- Treatment with erlotinib TKI, Gefitinib
- Highest incidence in female, non-smokers and Asian populations - ALK (Anaplastic Lymphoma kinase) rearrangement
- 5-7% NSCLC
- Gene fusion by translocation –> constitutional activation
- Predominantly non-smokers and exclusively in adenocarcinoma
- Crizotinib treatment - ROS1
- Similar to ALK population but less frequent (1-2%)
- Also a translocation
- Responds to ALK therapy with Crizotinib
2016 Question 60: Which of the following leads to falsely normal pulse oximetry measurements? A. Carbon monoxide poisoning B. Hyperbilirubinaemia C. Methylene blue treatment D. Peripheral vasoconstriction E. Polycythaemia
Answer: A - Carbon monoxide poisoning
Falsely low SpO2 can be caused by severe anaemia, severe hyperbilirubinaemia, peripheral vasoconstriction.
Falsely normal or high SpO2 can be caused by carbon monoxide poisoning, pr sickle cell anaemia vasoocclusive crisis.
2016 Question 39: Which of the following common causes of dyspnoea may manifest an arterial paradox >10mmh? A. Acute heart failure B. Pulmonary embolism C. Anaphylaxis D. Myocardial infarction E. Acute asthma
Answer: E - Acute asthma
Pulsus paradoxus is an abnormally large decrease in systolic blood pressure during inspiration (> 10mmHg).
Seen in obstructive airway disease and cardiac tamponade.
During inspiration, the negative intra-thoracic pressure results in increased right venous return, increased right atrial filling, and decreasing the compliance of the left atrium, leading to reduced left atrial and ventricular filling, leading to reduced systolic blood pressure.
In obstructive airway disease, intrathroacic pressure swings are exaggerated, or the right ventricle is distended, leading to amplified effect and pulses paradoxus.
2013 Question 49 At which lung volumes is pulmonary vascular resistance lowest? A. TLC B. FRC+TV C. FRC+ TV/2 D. FRC E. RV
Answer: D - FRC
2013
Question 22
Sleep-disordered breathing is rare in premenopausal women. This is due to the respiratory stimulating effect of certain hormones. Which of the following hormones provides the greatest stimulation of respiration?
a) progesterone
b) Oestradiol
c) FSH
d) LH
e) prolactin
Answer: A - Progesterone
Describe the flow-volume curves for the following:
- Normal
- Fixed obstruction
- Variable extra-thoracic obstruction
- Causes? - Variable intra-thoracic obstruction
- Causes? - Restrictive disease
- Normal = upside down ice-cream cone
- Fixed obstruction = flat top and bottom (pancake)
- causes: goitre, tracheal stenosis, masses - Variable extra-thoracic obstruction = flat inspiration (stingy upside down ice cream cone)
- causes: laryngomalacia, vocal cord palsy
- Inspiration sucks in the upper airways - Variable intra-thoracic obstruction = flat expiration
( stingy upright ice cream cone)
- causes: tracheal masses, tracheomalacia
- Expiration increases pleural pressure worsening obstruction - Restrictive = small, low volume but normal shape
What respiratory diseases cause an increase in CD4 : CD8 ratio?
• CD4/8 ratio can be altered in several disease processes o Increased CD4:8 seen in: Sarcoidosis Crohn’s disease Some vasculitis (GPA) o Decreased CD4: 8 seen in: HIV (reduced CD4 count) Extrinsic allergic alveolitis
