Respiratory Flashcards
(44 cards)
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.
