Respiratory System/Lungs/Chest Wall Flashcards
A 77-year-old man presents with shortness of breath and right-sided chest discomfort. A chest X- ray shows a right-sided pleural effusion. A thoracocentesis is performed and the pleural fluid sent to laboratory for evaluation. The results are as follows:
Pleural fluid protein to serum protein ratio: 0.7
Pleural fluid LDH to serum LDH:0.8
Glucose of 45mg/dl
Which one of the following is the most likely underlying cause of for this pleural effusion?
A. Congestive heart failure.
B. Hepatic cirrhosis.
C. Autoimmune hemolytic anemia.
D. Malignancy.
E. Nephrosis.
D. Malignancy.
Pleural effusion is accumulation of fluid in the pleural cavity. It can be transudative, exudative, or hemorrhagic.
Transudate
Transudate effusionsare caused by either increased hydrostatic pressure e.g. congestive heart failure, or decreased oncotic pressure, usually due to decreased serum albumin level, such as in chronic liver disease and cirrhosis or nephrosis in which protein is lost through the urine. Because of systemic involvement, transudate pleural effusion is often bilateral and equal in both lungs.
Exudate
Exudate effusions are caused by a local pathology such as pneumonia, tuberculosis, or
malignancies. This type of effusion is usually unilateral and needs more investigation.
Hemorrhagic
Hemorrhagic pleural effusion is seen in malignancies, trauma or pulmonary effusion.
The following table summarizes the most common causes of each type:
See table below.
Pulmonary embolism (PE) can cause both transudative and exudative types. Always consider PE if the transudate effusion cannot be attributed to any other underlying cause.
Exudateversus transudate pleural effusion:
After thoracocentesis, the effusion fluid albumin and lactated dehydrogenase (LDH) should be
measured, as well as those of the serum at the same time. The effusion is exudative if there is any of the following:
- Effusion fluid albumin to serum albumin ration>0.5
- Effusion fluid LDH to serum LDH ration>0.6
- Effusion fluid LDH>200 IU/ml
If none of the above criteria are met, the effusion is transudative.
A low pleural glucose concentration (1.6-2.8 mmol/L or 30-50 mg/dL) is seen in the following
conditions:
- Malignant effusion
- Empyema
- Tuberculosis pleuritis
- Esophageal rupture
- Lupus pleuritis
A very low glucose concentration (<1.6 mmol/L) narrows down the possibilities to rheumatoid
pleurisy or empyema.
A normal pleural fluid has a pH of 7.6 – 7.64.
Pleural fluid pH highly correlated with pleural fluid glucose levels. A pleural fluid pH of less than 7.30 with a normal arterial blood pH level is caused by the same diagnoses for low pleural fluid glucose. However, for parapneumonic effusiona low pleural fluid pH level is more predictive of complicated effusion (that requires drainage) than is a low pleural fluid glucose level.
This patient has exudative pleural effusion and of the given options only malignancies (lung, breast, lymphoma) can be the underlying cause.
References
* http://emedicine.medscape.com/article/299959-worku
* http://emedicine.medscape.com/article/299959-worku
A 57-year-old man, who has been a smoker for most of his adult life, presents to your clinic complaining of coughing up blood after he wakes up in the morning. Which one of the following is the most important condition to exclude?
A. Bronchiectasis.
B. Leukemia.
C. Laryngeal cancer.
D. Bronchogenic carcinoma.
E. Pulmonary embolus.
D. Bronchogenic carcinoma.
Coughing up blood indicates a pulmonary pathology, requiring a thorough investigation. Pulmonary tuberculosis and bronchogenic carcinoma should always be considered. Although bronchiectasis, COPD, bronchitis, etc can all cause cough as the most common cause of hemoptysis, since bronchogenic carcinoma has a significant aggressive course than other mentioned conditions and should be considered and excluded first.
Which one of the following could trigger an asthma attack?
A. Sulphites.
B. Benzyl benzoate.
C. Lecithin.
D. Terbutaline.
E. Ephedrine.
A. Sulphites.
The most common adverse reaction with exposure to sulfites is asthma like symptoms, estimated to occur in 5 to 10% of patients with asthma. These symptoms are more likely to occur in patients with severe asthma, or those in whom asthma is poorly controlled. Reactions can vary from mild to life-threatening.
Sulfites are used to preserve many foods and beverages. The addition of sulfites to some foods like beer and wine is permitted in most countries. However, it is illegal to add these to foods like fresh salads or fruit salads, or to meats like mincemeat. Unfortunately, these can be added from time to time illegally.
The following is a list of the most common sources of accidental exposure to sulfites.
- Drinks: cordials and some fruit juices as well as beer and wine, occasionally soft drinks and
instant tea.
- Other liquids: commercial preparations of lemon and lime juice, vinegar, grape juice.
- Commercial foods: dry potatoes, gravy and sauces and fruit toppings, maraschino cherries,
pickled onions, Maple syrup, jams, jellies, some biscuits and bread, or pie or pizza dough.
- Fruit: dried apricots, and sometimes grapes will be transported with sachets of the sulfite
containing preservative.
- Salads and fruit salads: sometimes restaurant salads and fruit salads will have sulfites added
to preserve their color.
- Crustaceans: sulphur powder is sometimes added over the top of crustaceans to stop them
discoloring.
- Meat: sulfites are sometimes illegally added to mincemeat or sausage meat.
- Other foods: gelatin, coconut.
References
* http://www.ncbi.nlm.nih.gov/pmc/articles/PMC401744
* http://www.asthmaaustralia.org.au/onAIR/Food_addit
* http://www.allergy.org.au/patients/product-allergy
A mother brings her 3-year-old boy to your practice with episodic asthma and persistent interval symptoms of nocturnal cough and exercise-induced wheezing. You plan to start him on fluticasone.
Which one of the following delivery methods is most appropriate for this age group?
A. Oral suspension.
B. Metered dose inhaler (MDI).
C. MDI and spacer device with mask.
D. Nebulizer and pump.
E. Breath-actuated inhaler (Accuhaler®).
C. MDI and spacer device with mask.
(Option A) Fluticasone is not available in form oral suspension or solution. Moreover, systemic use of corticosteroids unnecessarily poses the child at adverse effects assoiciated with systemic corticosteroids.
(Option B) Metered dose inhalers are not an effective delivery mode in this age group, as it needs breath-holding.
(Option C) MDI and spacer device with mask is the preferred mode of delivery for inhalers in young children unable to efficiently hold their breath.
(Option D) Nebulizers are also effectivebut are more expensive and difficult to use compared with spacers with face mask. They should be considered if the patient cannot cope with spacer and face mask. They are the second best option.
(Option E) Breath-actuated inhalers are inhalers that automatically release a spray of medication when the person begins to inhale. Like MDIs this mode of delivery is difficult to use in young children.
http://www.asthmawa.org.au/PageFiles/181/AA-Medica
Which one of the following is never indicated in acute management of an asthma attack in
children?
A. Steroids.
B. Salbutamol.
C. Ipratropium bromide.
D. Sodium cromoglycate.
E. Adrenaline.
D. Sodium cromoglycate.
Sodium cromoglycate is indicated in the prophylactic treatment of asthma, including prevention of exercise-induced bronchospasm. It is not useful in management of an acute asthma attack.
The management of acute asthma depends on the severity of the symptoms:
- Salbutamol (short-acting β2 agonist) is the best initial treatment in all cases of acute asthma.
- Systemic steroids are useful in moderate to severe attacks adn should be continued for 3 days and stopped without tapering.
- Ipratropium bromide (an anticholinergic agent) can also be helpful in management of moderate to severe asthma attack if maximum dose of short-acting β2 agonists fail to break the attack.
- Adrenaline can be used in severe asthma attack where there is imminent cardiorespiratory arrest or when there is anaphylactic reaction.
- Therapeutic Guidelines – Respiratory; available from http://tg.org.au
A 5-year-old child is brought to your clinic with complaint of cough. His mother explains that the coughs started 2 months ago, and sometimes wakes him up at night. He also has them when he plays with other children or runs and sometimes is associated with small amount of clear phlegm. On history, you realize that he had flexural eczema when he was 2years old. There child is afebrile. On chest examination, no wheeze is heard. The rest of the physical exam is inconclusive. Which one of the following is the most likely diagnosis?
A. Epiglottitis.
B. Chronic sinusitis.
C. Asthma.
D. Gastro-esophageal reflux disease.
E. Whooping cough.
C. Asthma.
The age of the child, history of atopy (eczema) and chronic intermittent cough favor the diagnosis of asthma. Asthma is common inthis age group and is usually underdiagnosed. In atopic asthma, the child usually has the history of other atopies such as allergic rhinitis, eczema, etc.
(Option A) Epiglotitis has more pronounced and acute presentation with fever and cough, respiratory distress and drooling. The child is usually very ill.
(Option B) Chronic sinusitis may present with nocturnal cough caused by post nasal drip, but exertional cough is not usually a feature. Besides, the discharges tend to be more thick and purulent. There is also history of facial tenderness or fullness and recurrent upper respiratory infections.
(Option D) Gastro-esophageal reflux is rare in this age group. If present, it may causechronic calf and mimic cough-variant asthma especially at night, but not exertional cough. Moreover, absence of other features such as heart burn makes this diagnosis far less unlikely.
(Option E) Whooping cough (pertussis) has a different presentation with paroxysms of cough and the terminal inspiratory whoop.
- http://emedicine.medscape.com/article/296301-clini
A 4-year-old boy, with background history of asthma, presents with a severe attack of asthma following an upper respiratory infection. On physical examination, he appears distressed with a pulse rate of 130 bpm, respiratory rate of 48 breaths per minute and temperature37.1°C. Bedside pulseoxymetry shows an oxygen saturation of 85% while on room air. Which one of the following is the most appropriate initial step in management?
A. Give salbutamol inhalation and recommend salbutamol inhaler4-hourlyat homeand review in 24 hours.
B. Start 4-hourly salbutamol and ipratropium bromide inhalersand oral prednisolone, and review in 24 hours.
C. Start inhaled salbutamol and oral amoxicillin 4-hourly, and review in 24 hours.
D. Give oxygen and continuous salbutamol inhalations and transfer to the hospital by ambulance.
E. Refer for admission to the hospital for salbutamol and ipratropium inhalations.
D. Give oxygen and continuous salbutamol inhalations and transfer to the hospital by ambulance.
Initial assessment of the severity of an asthma attack in children is according to the following table:
See table below.
With an oxygen saturation of less than 90%, this child has a severe asthma attack and should be transferred to the hospital for close monitoring and treatment; however, initial treatment with oxygen and short-acting β2 agonists (e.g. salbutamol) should be started without delay and maintained on the way to the hospital.
Options suggesting outpatient management are incorrect. Transferring to the hospital without oxygen supplementation and bronchodilators is inappropriate, because this boy is hypoxic and at increased risk of respiratory failure.
- Therapeutic Guidelines – Respiratory; available from http://tg.org.au
- http://www.asthmahandbook.org.au/uploads/Australia
A 25-year-old woman presents to the emergency department with exacerbation of asthma. Which one of the following is the most accurate tool to assess the severity of the attack?
A. Oxygen pressure of arterial blood (PaO2).
B. Loudness of the wheeze.
C. Severity of the dyspnoea.
D. Forced expiratory volume in one second (FEV1).
E. Pulse rate.
D. Forced expiratory volume in one second (FEV1).
Option A: Oxygen pressure of arterial blood (PaO2) is reduced in severe asthma as a result of ventilation/perfusion mismatch, but it must be interpreted in relation to the concentration of inhaled oxygen to in order to determine the arterial-alveolar (a-A) oxygen gradient.
Option B: Wheezing and its loudness is not a reliable indicator. In severe disease, the wheezing may decrease significantly, resulting in ‘silent-chest’ that is an ominous sign. The wheezing is minimal both with mild attack and just prior to respiratory arrest in very severe attacks.
Option C: In an asthma attack, the severity of the dyspnea is usually a marker of the disease severity, but not the best one because it may be affected by physiologic conditions such as anxiety.
Option D: Forced expiratory volume in one second (FEV1), or peak expiratory flow rate (PEFR) is the best guide to assess the severity, as well as the response to treatment. Of these two, FEV1 is the best single indicator.
Option E: Pulse rate is usually increased in an asthma attack but it might be a consequence of anxiety or the effect of beta 2 agonist or atropine –like drugs such as ipratropium bromide.
- http://www.ncbi.nlm.nih.gov/pmc/articles/PMC211718
Which of the following statements is correct regarding asthma in children?
A. Inhaled bronchodilators are very effective under the age of 12 months.
B. Oral bronchodilators are very effective under the age of 12 months.
C. A spacer with face mask should be used for children aged between 1 to 2 years.
D. Most of the children do not grow out of asthma when they become adults.
E. Giving more than 6 inhaled doses of beta-2 agonist can be life-threatening in severe asthma.
C. A spacer with face mask should be used for children aged between 1 to 2 years.
For children aged 1-2 years (or even older)a spacer with face mask provides adequate delivery of the inhaled drug and is a the preferred mode to deliver asthma medicine.
(Options A and B) Bronchodilators, inhaled or oral, are not very effective in children younger than 12 months.
(Option D) Most of the children grow out of asthma in adulthood and very few continue to be asthmatic adults.
(Option E) Giving 6 to 12 inhaled doses of beta-2 agonist isvery safe and appropriate if used in
severe asthma.
- Therapeutic Guidelines – Respiratory; available from http://tg.au.org
A 12-year-old boy is brought tothe hospital by his mother with acute shortness of breath and wheezing. He has background history of asthma and uses inhalers on an as-required basis. Which one of the following is the best bedside measure to assess the severity of asthma?
A. Severity of the wheeze.
B. Response to inhalers.
C. The degree of dyspnea.
D. Peak expiratory flow rate.
E. Formal pulmonary function tests
D. Peak expiratory flow rate.
The peak expiratory flow rate (PEF, also known as a peak flow) is the maximum rate that a person can exhale during a short maximal expiratory effort after a full inspiration.
In patients with asthma, the PEF correlates reasonably well with the the forced expiratory volume in one second (FEV1). FEV1 (not an option) is the most useful tool for bedside assessment of asthma response to treatment. In the absence of FEV1, PEF is the best option for this objective.
Peak flow meters have a limited role in establishing the diagnosis of asthma. However, they are very useful in measuring the severity of asthma exacerbation, or response to treatment.Peak flow meter readings become higher while patients are recovering and lower when the airways are constricted.
(Option A) Severity of wheeze is not reliable sign of severity of asthma. Severe asthma usually presents with silent chest and low grade wheeze.
(Option B) Response to inhalers and degree of dyspnea are also very unreliable signs to assess theseverity of asthma.
(Option C) Dyspnea is not a reliable predictor of asthma severity because apatient with mild asthma and one with severe asthma may be equally breathless.
(Option E) Formal pulmonary function testing is performed at specialized centers and is used to diagnose asthma. In contrast, peak flow measurement is quick and useful in emergency situation to assess the severity of an asthma attack.
References
* http://www.ncbi.nlm.nih.gov/pmc/articles/PMC211718
A 6-month-old child, with confirmed diagnosis of asthma, is given 6 puffs of salbutamol during an acute asthma attack without adequate response.Which one of the following would be the next best step in management?
A. Repeat another 6 puffs of salbutamol.
B. Give 4 puffs of ipratropium bromide.
C. Give oral steroids.
D. Give intravenous steroids.
E. Give inhaled steroids.
A. Repeat another 6 puffs of salbutamol.
Asthma is less common in children younger than 12 months of age. However, if contracted at this age, it is poorly responsive to bronchodilators.
Oxygen and short-acting beta-2 agonists such as salbutamol are used routinely despite poor response to β2 agonists, because a mild asthma attack can still be managed by salbutamol.
Initially up to 6 puffs for children ages 0-5 years and up to 12 puffs for those 6 years or older are given. 20 minutes is waited and the respond assessed. If the attack does not subside, upto 6 puffs can be given every 20 minutes for one hour. If these measures failed ipratropium bromide would be added (4 puffs by mask and spacer or 250 mcg by nebuliser for children 0-5 years, or8 puffs by mask and spacer or 500 mcg by nebuliser for children older than 6 years.
The role of ipratropium in management of an acute asthma attack is controversial. It should be considered if the asthma is severe and unresponsive to maximum dose of short-acting beta agonists.
Oral prednisolone 1 mg/kg should also be given for the first 3 days after the asthma attack.
Corticosteroids have minimal role in acute management of asthma, but should be considered to prevent relapses. Oral forms of steroids (suspension) are available in Australia.
Once the acute attack subsides, the child should be reviewed daily for revision of management plan.
A 37-year-old woman presents to the emergency department with shortness of breath. She is a known case of asthma and smokes heavily. On pulseoxymetry, she is found to have an O2 saturation of 85% on room air. Which one of the following would be the next best step in management of this patient?
A. 100% oxygen by Hudson mask.
B. Intubation and mechanical ventilation.
C. 100% oxygen by nasal prongs at 3 litres/minute.
D. Oxygen 28% by Venturi mask.
E. Continuous positive airway pressure.
D. Oxygen 28% by Venturi mask.
With an O2 saturation of 85% on room hair, this woman is definitely hypoxemic and requires oxygen supplementation. There is no comment about the patient CO2 status to differentiate whether this patient has type I or type II respiratory failure, but patients with the following conditions, if hypoxemic, are at increased risk of hypercapnia if they are given oxygen with FiO2 between 35-60% (either by nasal cannula or face mask) as the respiratory drive relies on hypoxemia and not hypercarbia:
- Known chronic obstructive pulmonary disease or bronchiectasis
- Severe kyphoscoliosis or ankylosing spondylitis
- A known history of heavy smoking
- Severe obstructive sleep apnea
- Morbid obesity (BMI more than 40 kg/m2)
- Musculoskeletal disorders with respiratory muscle weakness, especially if on home ventilation
- Overdose of opioids, benzodiazepines or other respiratory depressant drugs.
Under above-mentioned condition, the first-line oxygen therapy would be oxygen 24-28% through Venturi mask. If Venturi mask is not available, oxygen through nasal prongs at a rate of 1- 2 litres/minute could be an acceptable option.
This woman is asthmatic (obstructive) and smokes heavily. High-flow oxygen is very likely to pose her at the risk of hypercapnia; hence she should be started on low-flow oxygen either through Venturi mask or 1-2 liter/min oxygen through nasal prongs.
Which one of the following lung cancers is most common in non-smokers?
A. Squamous cell carcinoma.
B. Small cell carcinoma.
C. Adenocarcinoma.
D. Mesothelioma.
E. Large cell carcinoma.
C. Adenocarcinoma.
95% of all of bronchogenic carcinomas are directly related to cigarette smoking. If non-smokers develop lung cancer, it is more likely to be of adenocarcinoma type.
A 57-year-old man presents with progressive shortness of breath and cough for the past 4 months. He has smoked 40 cigarettes a day for the past 30 years and worked in a coal mine for the past 20 years. On chest auscultation, expiratory wheezes are heard over the left lung. The only abnormal finding on chest X-ray is a 3x4 opacity in the lower lobe of the left lung. Which one of the following is the most likely diagnosis?
A. Bronchogenic carcinoma.
B. Coal workers’ pneumoconiosis.
C. Mesothelioma.
D. Chronic obstructive lung disease (COPD).
E. Extrinsic allergic alveolitis.
A. Bronchogenic carcinoma.
In this patient, with wheezing over the left lung, indicating local obstruction of the small airways and a single opacity in the left lower lobe, as well as long-standing history of heavy smoking, bronchogenic carcinoma would be the most likely diagnosis.
(Option B) Coal workers’ pneumoconiosis is an occupational interstitial lung disease seen in coal miners. It can present with progressive shortness of breath and respiratory crackles. Chest X-ray shows small round densities in the parenchyma, usually involving the upper half of the lungs.
(Option C) Mesothelioma is a rare malignancy, which is associated with asbestosis and presents with pleural thickening on chest X-ray.
(Option D) With the chest X-ray findings, COPD is it less likely. Chest X-ray findings in COPD are hyper-inflated lungs, flattened hemi-diaphragms if emphysema is dominant and increased pulmonary markings if the chronic bronchitis is a feature.
(Option E) Although there are no typical findings on chest X-ray characteristic of extrinsic allergic pneumonitis, just a single opacity on X-ray makes this diagnosis less likely.
A 70-year-old man presents with recurrent right-sided pleural effusions and 10kg weight loss in the past 6 months. He has the history of smoking 40cigarettes a day for the past 40 years. Chest X-ray shows pleural thickening with no consolidation in the lung fields. Pleural fluid cytology does not show any malignant cells. Which one of the following is the next best step in management?
A. Thoracoscopy.
B. Repeat the chest X-ray.
C. Permanent intercostal catheter.
D. Diuretics.
E. Fluid restriction.
A. Thoracoscopy.
The pleural thickening on chest X-ray, the pleural effusion and significant weight loss, in the absence of any abnormalities in lung fields, are suggestive mesothelioma as the most likely diagnosis.
More than 90% of patients with pleural mesothelioma present with pleural effusion. Cytologic examination of the pleural fluid is diagnostic in only 32% of patient, and suggestive in 56%. If a diagnosis cannot be made based on cytologic exam of the pleural fluid, thoracoscopy-guided pleural biopsy should be performed as the next best step in management. The results are 98% diagnostic.
A 55-year-old man presents with complains of dry cough and hemoptysis. He had worked in a gold mine for 15 years and in a petrol station for another 9 years. Physical examination is inconclusive. A chest X-ray is obtained that is remarkable for a 2 x 3 cm opacity in the right lung field. Which one of the following would be the next best step in management?
A. Bronchoscopy.
B. Computed tomogram (CT) of the chest.
C. Fine needle aspiration.
D. Ultrasonography.
E. Chemotherapy.
B. Computed tomogram (CT) of the chest.
Considering the age and the history of working in gold mine and petrol station, this man has bronchogenic cancer until proven otherwise. For every patient with suspected pulmonary pathology, chest X-ray is always the best initial diagnostic tool. With an opacity in the right lung field, two more steps would be ahead: (1) spiral CT scan of the chest to further visualize the lesion and its extend, and (probably) (2) sputum cytology. Once the lesion is confirmed on the spiral CT, referral specialist for bronchoscopy or open lung biopsy is the most appropriate step.
Which one of the following is unlikely to cause central cyanosis?
A. Polycythemia.
B. Right-to-left cardiac shunt.
C. Left-to-right cardiac shunt.
D. Acute pulmonary edema.
E. Respiratory depression.
C. Left-to-right cardiac shunt.
All the given options are associated with central cyanosis except left-to-right shunts. With left-to- right shunts oxygenated blood goes from the left heart to the right heart and no unsaturated blood enters the systemic circulation to cause cyanosis.
Examples of left-to-right shunt include patent foramen ovale, atrial septal defects, ventricle septal defects and patent ductus arteriosus.
Right-to-left shunting is seen in transposition of the great vessels, persistent truncus arteriosus and tetralogy of Fallot.
Polycythemia, decreased respiration and acute pulmonary edema can cause central cyanosis.
A 27-year-old asthmatic man presents to the Emergency Department with sudden onset of right- sided pleuretic chest pain. On physical examination, he has a blood pressure of 120/75 mmHg, pulse rate of 94 bpm and respiratory rate of 18 breaths per minute. Chest auscultation reveals diminished breath and hyper-resonance in the right lung. No respiratory distress is noted. A chest X-ray is obtained that is significant for a 20% right-sided pneumothorax. Which one of the following will be the most appropriate next step in management?
A. Admit the patient for observation.
B. Perform thoracotomy.
C. Needle aspiration.
D. Water-sealed catheter thoracostomy.
E. Discharge the patient and review in 24 hours.
D. Water-sealed catheter thoracostomy.
Pneumothorax is defined as presence of air in the pleural space. Based on the etiology, pneumothorax can be defined as traumatic or spontaneous.
Traumatic pneumothorax is caused by blunt or penetrating chest traumas or invasive procedures (iatrogenic) such as central vein catheterization, pleural biopsy, etc.
Spontaneous pneumothorax is the term used when the condition occurs in the absence of an apparent trauma or procedure. Spontaneous pneumothorax is classified as primary or secondary based on absence or presence of an underlying lung pathology or chest X-ray abnormalities.
Primary spontaneous pneumothorax (PSP) - spontaneous pneumothorax is primary if all of following criteria are met:
* There is no respiratory finding on exam except those related to the pneumothorax
* There is no history of lung disease
* There is no chest X-ray finding other than those related to the pneumothorax
* The patient is young (≤50 years)
* There is no significant history of smoking
Secondary spontaneous pneumothorax (SSP) - spontaneous pneumothorax is considered secondary if either of the following is present:
* Respiratory findings other than those related to pneumothorax
* History of lung disease such as COPD (the most common cause of SSP), asthma, cystic fibrosis sarcoidosis, TB, lung cancer, chronic bronchitis, bronchiectasis, extra- or intrathoracic restrictive lung disease, etc
* Any chest X-ray abnormality other than those related to pneumothorax
* Age >50 years
* Significant history of smoking
NOTE - the typical patient with PSP is a thin tall man of 20- to 40-years old. PSP is rarely seen after 40 year and almost never after the age of 50; therefore, spontaneous pneumothorax in those older than 50 is considered secondary and treated accordingly until proven otherwise.
Size of pneumothorax - Accurate estimation of the size of a pneumothorax is difficult. There different methods for estimation:
Average interpleural distance (AID) method - approximates the size of a pneumothorax from a PA CXR in standing position by taking the sum of the distances (measured in millimeters) between the ribs and the visceral pleura at the apical level (A), midthoracic (B), and basal level (C), then dividing the sum by 3.
Light index - An upright PA chest X-ray is obtained. The width of the lung and the hemithorax are measured (in centimeters). The percentage of pneumothorax is calculated from the following formula:
Pneumothorax percentage = (1 - (width of the lung)^3 / (width of the hemithorax)^3) x 100
*For example if the width of the lung and the hemithorax are 5cm and 10cm respectively, the percentage of pneumothorax will be:
1 - (5)^3 / (10)^3 = 1 - 0.125 = 0.875 or 87.5% (87.5% of the affected hemithorax is occupied with the pneumothorax)
These methods are difficult to apply in practice and often underestimate the size of the pneumothorax. As a result, some clinicians tend to describe a pneumothorax as large or small, rather than using the percentage.
Chest wall - pleural line distance at the hilum level - British Thoracic Society guidelines define a pneumothorax as small if the distance from chest wall to the visceral pleural line (at the
level of the hilum) is less than 2 cm or large if the distance from the chest wall to the visceral pleural line is 2 cm or greater. Some clinicians prefer 3 cm laterally and 4 cm apically as the threshold to distinguish small and large pneumothoraces.
Symptoms:
* Small pneumothoraces are often asymptomatic.
* Larger pneumothoraces can present with:
-Pleuretic chest pain (pain may be referred to shoulder tip)
-Shortness of breath
Clinical findings associated with pneumothoraces include:
* Decreased breath sounds over the affected area due to decreased air entry
* Hyperresonance over the affected area
* Decreased tactile fremitus
* Tracheal deviation to the affected side
Management:
Primary spontaneous hemothorax (PSP) – management of PSP depends on the presence of the symptoms and/or the size of the pneumothorax:
Consider discharging the patient and review in 24 hours, and every 1-2 weeks until the pneumothorax is resolved if:
* The patient is asymptomatic (or minimal symptoms) AND
* The size of the pneumothorax is less than 15% of the affected lung, or the distance between the chest wall and the visceral plural line is ≤2cm
Consider needle aspiration and REVIEW if:
* The patient is symptomatic (pleuretic chest pain or dyspnoea), OR
* The size of the pneumothorax is ≥15%of the affected lung, or the distance between the chest wall and the visceral plural line >2cm
After needle aspiration, admission and catheter drainage (chest tube) would be indicated as the next best step in management if:
* The aspirated air is ≥3 litres
* The distance between the chest wall and visceral pleural line is still >2cm on a chest x- ray taken 4 hours after needle aspiration
* There is significant shortness of breath
NOTE - the rationale behind less invasive initial management of PSP is based upon the fact that the patients with PSP are young and otherwise healthy, and there is no underlying pathology to perpetuate the pneumothorax or prevent it from spontaneous healing.
Secondary spontaneous pneumothorax (SSP) – in SSP, the underlying lung problem prevents the pneumothorax from spontaneous healing. All patients with SPS need to be admitted to the hospital and undergo:
- Needle aspiration and REVIEW if there are no significant symptoms AND the size of the pneumothorax is less than 15% of the affected lung (or the distance between the chest wall and the visceral plural line is ≤2cm)
- Catheter drainage (chest tube) if the patient is symptomatic (pleuretic chest pain or dyspnoea) OR the size of the pneumothorax is ≥15%of the affected lung (or the distance between the chest wall and the visceral plural line >2cm)
Traumatic pneumothorax
Unless the patient is asymptomatic and the size of pneumothorax is <15% (or the distance between the chest wall and the visceral plural line is ≤2cm), he patient should undergo catheter drainage (chest tubes). Asymptomatic patients whose pneumothorax is 15% (or the distance between the chest wall and the visceral plural line is ≤2cm) cab be closely observed for spontaneous resolution of the pneumothorax.
NOTE - pneumothorax of any kind and size should be treated with chest catheter (chest tube) insertions if:
* The patient is undergoing general anaesthesia for any reason
* The patient is planned to be intubated and mechanically ventilated
* The patient is planned to be transported by air (air transport)
With the history of asthma, this patient has SSP until proven otherwise. Furthermore, not only is he is symptomatic (pleuretic chest pain), but the size of the pneumothorax is also large. The best management option for him will be water-sealed chest catheter thoracostomy (chest tube insertion).
A 68-year-old woman, with history of stage IV chronic kidney disease (CKD) presents to the Emergency Department with sudden-onset acute chest pain and shortness of breath. The chest pain is pleuretic in nature. On examination, she has a blood pressure of 130/90 mmHg, pulse rate of 120 bpm and respiratory rate of 24 cycles per minute. ECG shows no abnormalities. A chest X- ray is obtained that is completely clear. Ventilation/perfusion scan is performed showing decreased perfusion in the lower lobe of the left lung. Which one of the following is the most appropriate next step in management?
A. Low-molecular weight heparin (LMWH).
B. Thrombolysis.
C. CTPA.
D. Unfractionated heparin.
E. Warfarin.
D. Unfractionated heparin.
Clinical findings suggest pulmonary embolism (PE) as the most likely diagnosis. Decreased perfusion confirms the diagnosis. V/Q scan can be reliable if there is no pre-existing underlying lung pathology leading to misinterpretation of the result. The validity of the V/Q scan in this scenario can be trusted as there is no abnormal finding on chest X-ray.
Although both unfractionated heparin and low-molecular weight heparin (LMWH) have about the same efficacy for treatment of PE, unfractionated heparin is the preferred option in patients with renal disease because LMWH is excreted renally.
(Option A) LMWH is better avoided in patients with renal disease. If LMWH is considered for treatment, the dose should be adjusted according to glomerular filtration rate (GFR).
(Option B) Thrombolysis is reserved for selected patients with hemodynamic instability, in whom there is no contraindication to thrombolysis.
(Option C) Since V/Q scan has already established the diagnosis, CTPA would not be required. Furthermore, CTPA needs intravenous injection of contrast material that is contraindicated in patients with renal impairment. This is the reason why V/Q scan has been used for the diagnosis of PE in the first place.
(Option E) Warfarin is a part of management after INR reaches the therapeutic dose of 2-3. Warfarin has delayed action, and has initial pro-thrombotic effects. Anticoagulation never starts with warfarin alone.
A 47-year-old man has developed cough and dyspnea over the past few months. There is no history of smoking or occupational exposure. Marked findings on examination are clubbing of the fingers and inspiratory crepitations. Which one of the following is the most likely diagnosis?
A. Mesothelioma.
B. Sarcoidosis.
C. Pulmonary fibrosis.
D. Lung cancer.
E. Mycoplasma infection.
C. Pulmonary fibrosis.
The history and physical findings are characteristic of interstitial lung disease (IDL).
Interstitial lung diseases are a group of heterogenous lung diseases with different clinical, physiologic, radiographic, and pathologic presentations. However, a number of common features justify their inclusion in a single disease category.
IDL is characterized by chronic inflammation and fibrosis of the interstitium and lung parenchyma.
The interstitium of the lung (supporting structure) is the area in and around the small blood vessels and alveoli where the exchange of oxygen and carbon dioxide takes place. Inflammation and scarring of the interstitium, and eventually extension into the alveoli, will disrupt normal gas exchange. Although the progression of IDL may be variable from one disease to another, they have common clinical, radiographic, and spirometric findings:
- Dyspnea - all patients with IDL develop exertional dyspnea that is the most common complaint bringing them to medical attention
- Nonproductive cough
- Bibasal inspiratory crackles
- Evidence of pulmonary hypertension (in advanced disease) such as increased pulmonic sound, right heart failure, etc.
- Clubbing (not always) especially in idiopathic pulmonary fibrosis and asbestosis
- Reticular or reticulonodular pattern (‘ground-glass appearance) on chest X-ray
- Intrapulmonary restrictive pattern and decreased DLCO on pulmonary function testing
Of the given options, only pulmonary fibrosis as an ILD fits the scenario.
(Option A) Mesothelioma is a rare malignancy of the pleural and peritoneum, highly associated with asbestos exposure. It presents with weight loss, recurrent pleural effusions, and pleural thickening and calcification on imaging. Neither the history, nor the clinical findings is consistent with mesothelioma.
(Option B) Sarcoidosis is a multisystem disease characterized by non-caseating granuloma formation in different organ systems. Pulmonary system is the most common affected system. Although pulmonary sarcoidosis is classified as ILD, most patients with pulmonary involvement (90%) are asymptomatic. Symptoms, if present, resemble those of pulmonary TB including productive cough, hemoptysis, and constitutional symptoms such as weight loss, fever, night sweats and malaise.
(Option D) Absence of smoking in the history makes lung cancer less likely. Moreover, lung cancer is associated with more systemic manifestation such as weight loss.
(Option E) Mycoplasma infection such as TB or atypical pneumonia caused by mycoplasma pneumoniae presents with a completely different picture. Pulmonary TB presents with signs and symptoms such as cough, weight loss, night sweats and malaise. Mycoplasma pneumoniae presents with a prodromal syndrome followed by dry cough, sore throat, and low-grade fever. None of these infections are associated with clubbing.
A 28-year-old woman presents to the Emergency Department with sudden onset dyspnea and pleuretic chest pain. She is 18 weeks pregnant and has a previous history of deep venous thrombosis (DVT). Which one of the following would be the most appropriate initial investigation in this patient leading to a definite diagnosis?
A. D-dimer assay.
B. Ventilation/perfusion scan.
C. ECG.
D. CTPA.
E. Doppler ultrasound scan.
B. Ventilation/perfusion scan.
Investigation for pulmonary embolus (PE) in pregnancy is a complicated issue. PE is the leading cause of death in pregnancy in the developed world. Pregnant women have all the 3 components of the Virchow’s triad that are (1) venous stasis, (2) vessel damage and, (3) hypercoagulable state.
Difficulty and confusion in assessment of PE in a pregnant woman is due to the following:
- Normal physiological changes in pregnancy such as dyspnea, tachycardia, and leg swelling are also symptoms that PE can present with.
- Pre-test probability tests such as Wells score, simplified Wells score (SWS) or revised Geneva score, cannot be applied for a pregnant woman because pregnant women were excluded from the analysis group for criteria validation.
- The d-dimer will start to rise in the second trimester and remain elevated for 4-6 weeks post- partum; therefore, it is not a reliable test to use as a screening tool.
If PE is suspected, it is important to make a definitive diagnosis, as management of a PE during pregnancy needs to include choice of anticoagulation, mode of delivery, and consideration of prophylaxis in future pregnancies. There are debates as to optimal methods of diagnostic work-up for pregnant women with suspected PE. For PE, we use latest guidelines by The Royal Australian and New Zealand College of Radiologists as the most accurate and reliable reference for the exam.
The sudden-onset chest pain and shortness of breath and previous history of DVT make PE a very likely diagnosis. If PE is suspected in a pregnant woman, a chest radiograph (not an option) should be performed as the most appropriate initial step to exclude other causes of the symptoms such as pneumonia, and to determine if V/Q scan or CTPA should be performed as the diagnostic test for suspected PE. If the chest radiograph is clear, VQ scan using a lower dose technique is recommended because it is associated with a lower breast dose than CTPA and a comparably small dose to the fetus.
(Option A) D-dimer levels become elevated in most patients after the first trimester. Normal values for each trimester have yet to be validated in a large patient population to enable them to be used to screen for the possibility of pulmonary embolism during pregnancy in routine clinical practice. Therefore, D dimer is generally not used to screen pregnant women for suspected PE, particularly during the second and third trimester when it is physiologically elevated.
(Option C) Ischemia is among differential diagnoses of chest pain. ECG may be considered to exclude cardiac causes of the chest pain, and also to look for ECG changes favoring PE as a diagnosis. Given the sudden-onset of chest pain and shortness of breath in an otherwise healthy young woman who has risk factors for PE, ECG is not likely to be of significant benefit. The pleuretic nature of the pain, on the other hand, makes cardiac ischemia almost unlikely; however, it may be considered in the initial work-up along with chest radiograph. It is not a priority in this woman though.
(Option D) CTPA is associated with increased risk of breast cancer in women of reproductive age and should be replaced with V/Q scan in this patient group if possible. The most common indication for CTPA instead of V/Q scan is an abnormal chest radiograph.
(Option E) Lower limb venous ultrasound is negative in more than 90% of pregnant women with PE. Lower limb venous ultrasound is not recommended as a first line investigation unless there are clinical symptoms of DVT (e.g., unilateral leg swelling, calf tenderness). This is due to the very low rate of lower limb deep venous thrombosis in pregnant women with PE. Almost no V/Q scans or CTPAs would be avoided in pregnant women with possible PE by performing ultrasound first, because ultrasound is almost invariably negative in the absence of specific leg symptoms in favor of DVT. Therefore, the reduction in radiation exposure to the population of women with possible PE and their fetuses that would result from an “ultrasound first” strategy is negligible. However, with leg symptoms, Doppler ultrasound is the most appropriate initial investigation.
Which one of the following is the most appropriate initial investigation in a patient with suspected pulmonary embolism?
A. Chest X-ray.
B. CTPA.
C. V/Q scan.
D. D-dimer assay.
E. Doppler ultrasound scan.
A. Chest X-ray.
When pulmonary embolism is suspected based on history and clinical findings, chest X-ray is the most appropriate investigation to consider first. There are two objectives; the first one is to exclude other lung pathologies that might have similar presentation. The second is to determine whether a V/Q scan or is CTPA is the most appropriate next investigation, because patients with an abnormal chest X-rays are more likely to have a non-diagnostic V/Q scan than those with a normal chest X- rays.
An ECG would be indicated if there is chest pain which cannot be solely attributed to PE as the cause.
After other possible conditions are excluded by chest X-ray and ECG, a clinical pretest probability (PTP) assessment using Well score system, simplified Wells score, or revised Geneva scoring system should be performed. D-dimer assay is then used, as a screening test, to exclude PE
in patients with low to moderate likelihood of having PE.
(Options B and C) CTPA is considered the imaging modality of choice for definite diagosis of PE, provided that it is available and there is no condition on the patient’s side to make its use undesirable (e.g. pregnancy, women of reproductive age, allergic reaction to contrast media, renal impairment, etc), in which case V/Q should be considered the first-line diagnostic modality.
(Option D) D-dimer assay is indicated in patients with low and moderate pretest probability. A negative D-dimer excludes PE, but positive results will require further assessment with CTPA or V/Q scan. Even if D-dimer is considered, an initial chest X-ray is required to estimate the pretest probability.
(Option E)
Doppler ultrasound is used if there are leg symptoms suggesting a DVT as the source of PE. However, CXR remains the most important initial investigation.
A 45-year-old man presents to your office concerned about asbestosis. He is a construction worker and gets involved in demolitions of old houses for renovation. He has read smewhere that old houses are a source of asbestos and that asbestosis is a serious condition associated with cancer. He says that he and his coworkers do not use protective measures during the work. Which one of the following would be the most appropriate action to take in this situation?
A. Refer him to respiratory specialist.
B. Chest X-ray now and in 5 years’ time.
C. Inform the authorities about the breach of workplace safety. D. Do nothing.
E. Inform him that asbestos carries a very low risk of cancer.
B. Chest X-ray now and in 5 years’ time.
Asbestos has been linked to an increased risk of bronchogenic carcinoma, mesothelioma, gastrointestinal cancers, and asbestosis among occupationally-exposed workers. Adequate screening for asbestos-related diseases does not exist at present. However, some tests, particularly chest X-rays and pulmonary function tests, may indicate that an individual has been overexposed to asbestos. It is important for physicians to become familiar with the operating conditions that are associated with potential asbestos exposure. This is particularly important in evaluating medical and work histories and in performing physical examinations.
The current recommendations include taking a complete history, performing physical exam with close attention to respiratory system and the following diagnostic measures:
- Chest X-ray – A chest X-ray should be taken for all patients with exposure to asbestos; however, initially, the chest X-rays are often inconclusive because it takes approximately 3- 5 years for radiographic signs of asbestos exposure to be evident on X-rays. It is recommended that chest X-rays be repeated at 3-5 years intervals.
- Pulmonary function tests (PFTs) – simple PFTs available at general practice level should be applied to recognize the possible restrictive patterns caused by asbestosis.
If the condition is work-related, involvement of a respiratory or occupational physician is needed to consider factors such as the effect of the exposure on other workers, how to control the exposure at the workplace and appropriate use of personal protective equipment.
When a current worker has been identified to have been overexposed to asbestos, measures taken by the employer to eliminate or mitigate further exposure should also lower the risk of serious long- term consequences. The employer is required to institute a medical surveillance program for all employees who are or will be exposed to asbestos at or above the permissible exposure limit (0.1 fiber per cubic centimeter of air).
NOTE - Although most patients with asbestos-related lung disease have a strong exposure history, significant disease can occur with even minimal exposure; therefore, even minor or accidental exposures mandates evaluation.
Referring the patient to respiratory specialist (option A) is not necessary at this stage because he is asymptomatic and does not seem to have any issues right now. The surveillance program can be carried out by the general practitioner.
Informing the case to authorities for the breach of workplace safety (option C) may be considered if there is a significant risk that other employees are at risk of harm inflicted on their health. At this stage, however, the most important step is to perform an initial evaluation and setting a surveillance plan for thes patient.
(Option D) While this patient is in need of assessment and being monitored, doing nothing is the most inappropriate action to take.
(Option E) Asbestos exposure and asbestosis are significant risk factor for bronchogenic cancer and mesothelioma, and telling the patient that such correlation is not strong and there is only a slightly increased risk of cancer is incorrect.
A 26-year-old woman presents to the Emergency Department with dyspnea and sudden-onset chest pain that worsens with respiration. On examination, she has a blood pressure of 130/95 mmHg, pulse rate of 110 bpm and respiratory rate of 24 breaths per minute. Her family history is significant for protein C deficiency in her mother and older sister. Which one of the following is the most diagnostic investigation in this patient?
A. Doppler ultrasound scan.
B. Chest X-ray.
C. V/Q scan.
D. CTPA.
E. D-dimer assay.
C. V/Q scan.
Family history of thrombophilia is associated with increased risk of venous thromboembolism (moderate risk factor). With this risk factor present in the history, acute-onset pleuretic chest pain (worsened by respiration) and shortness of breath, pulmonary embolism (PE) would be the most likely possibility.
Not all patients presenting with possible symptoms of PE need to undergo imaging tests such as computer tomography pulmonary angiography (CTPA), V/Q scan, Doppler ultrasound, etc. Decision as to whether this tests are performed depends on pretest probability of PE. A reasonable way to stratify patient risk is to use one of the validated clinical decision rules (CDR). Simplified Wells Score (SWS) is one of recently validated ones.
SWS takes into account different variables to generate a score. In SWS, each element in the CDR is scored 1 point. The cut-off value distinguishing between “PE likely” and “PE unlikely” is 2, so patients with a score of 1 or 0 are classified as “PE unlikely” (chance of having PE ≤10%), while those with scores 2 or above are classified as PE likely.
Elements for calculation of SWS and an algorithmic approach based on SWS score are shown in the following table and diagram respectively:
See table below.
See flow chart on Simplified Well’s Score on Page 1820.
The question however asks about the most diagnostic test and not the approach sequence. CTPA and V/Q scan are used to confirm the diagnosis of PE. Diagnostic accuracy of CTPA and V/Q scan is similar. However, CTPA detects clots in smaller vessels. CTPA may have the advantage of widespread availability where V/Q scanning may not be available outside working hours. Radiation dose of V/Q is significantly less than CTPA, making V/Q scan the preferred option for women of reproductive age (< 55 years) to avoid the risk of breast cancer associated with higher radiation exposure in CTPA.
(Option A) Doppler ultrasound, when leg symptoms associated with deep vein thrombosis (DVT) are absent, is not very helpful to establish a diagnosis.
(Option B) Chest X-ray is the initial imaging in all patients with suspected PE to exclude other pathologies and guide further assessment. However, the chest X-ray findings are often non-specific and non-diagnostic.
(Option D)
CTPA is a very useful diagnostic test for PE, but not preferred over V/Q scan in this young woman because it is associated with more radiation exposure and increased risk of breast cancer.
(Option E) D-dimer assay is used to exclude PE in patients, who are unlikely to have PE, based on pretest probability. It is sensitive enough to be used as a screening test, but not specific to establish a diagnosis.
A 45-year-old man, who had a hip replacement surgery 2 weeks ago, presents with sudden-onset chest pain and shortness of breath. Pulse oxymetry reveals an oxygen saturation of 89% on room air. On physical examination, his blood pressure is 100/75mmHg, heart rate 113 bpm, respiratory rate 23 breaths per minute and temperature 37.3°C. Which one of the following is the most appropriate next step in management of this patient?
A. CTPA.
B. V/Q scan.
C. ECG.
D. Chest X-ray.
E. D-dimer assay.
C. ECG.
Both major surgery and possible immobilization of longer than 3 days are strong risk factors for thromboembolism; therefore, with sudden-onset chest pain, shortness of breath and hypoxia, PE tops the list of differentials. CTPA and V/Q scan are used to confirm the diagnoses; however, not every patient with clinical manifestations of PE and a suggestive history should undergo imaging studies, unless other potential causes of the presentation have been excluded.
Although the acute onset of the chest pain is not in favor of ischemic heart problems such as acute coronary syndrome, an ECG should be considered the very first step to exclude cardiac problems as a cause.
Moreover, some ECG findings such as Q1S3T3 (Q wave in lead I, prominent S wave and inverted T-wave on lead III) or T –wave inversion in leads V1 through V4, although non-specific, might support PE as diagnosis (but not diagnostic).
A 27-year-old woman presents to your clinic with fever and cough since yesterday. On examination, she looks ill and unwell. Her blood pressure is 110/70 mmHg, pulse rate 110 bpm, respiratory rate 22 breaths per minute and temperature 38.7°C. Pulse oxymetry shows oxygen saturation of 89% while on room air. Which one of the following is the next best step in management?
A. Continuous positive airway pressure (CPAP).
B. 60% Oxygen through nasal prongs.
C. 100 % Oxygen through Hudson’s mask.
D. Oxygen through Venturi mask – 28%.
E. Intubation and ventilation.
C. 100 % Oxygen through Hudson’s mask.
This patient has clinical features of pneumonia. With an oxygen saturation of 89% (less than 90%), she should be considered hypoxemic until ABG results are available.
Patients with serious acute respiratory illnesses such as acute asthma, pneumonia, lung cancer, pulmonary embolism, pleural effusion, and pneumothorax require moderate levels of supplemental oxygen. If the patient is hypoxemic on pulse oxymetry (oxygen saturation less than 90%). This may be 100% oxygen by nasal cannulae at 2 to 6 L/minute or a simple face mask at 5 to 10 L/min initially, but if the oxygen saturation is less than 85% and the patient is not at risk of hypercapnic respiratory failure, treatment should be commenced with 100% oxygen through reservoir mask at 10 to 15 L/min.Mechanical ventilation such as CPAP and intubation and ventilation are considered if the patient fails to maintain the target O2 saturationdespite adequate supplementation of oxygen with other delivery systems such as nasal cannulae, simple face mask, reservoir masks or no-rebreather masks
Oxygen through Venturi mask is first-line option for patients at risk developing hypercapnic respiratory failure (type II). These patients include the following:
1. Known cases of chronic obstructive pulmonary disease or bronchiectasis
2. Severe kyphoscoliosis or ankylosing spondylitis
3. A known history of heavy smoking
4. Severe obstructive sleep apnoea
5. Morbid obesity (BMI more than 40 kg/m2)
6. Musculoskeletal disorders with respiratory muscle weakness, especially if on home
ventilation
7. Overdose of opioids, benzodiazepines or other respiratory depressant drugs.
NOTE - ‘Hudson mask’ is a confusing name. ‘Hudson RCI’ is the manufacturer and produces a variety of oxygen delivery devices including nasal prongs, simple face masks, reservoir face masks and non-rebreather masks, but historically the Hudson mask is the inappropriate equivalent of simple face masks.
References
* https://www.brit-thoracic.org.uk/document-library/
* http://www.ncbi.nlm.nih.gov/pmc/articles/PMC111390
* http://www.respiratoryupdate.com/members/Levels_of
* Therapeutic Guidelines – Respiratory; available on http://www.tg.org.auOxford Handbook of
Clinical Medicine – 8th Edition – pages 180-181
A 12-year-old boy is brought to the emergency department with a progressively worsening asthma attack. He has past medical history of previous asthma attacks and recurrent chest infections.
Which one of the following, if present, would indicate life-threatening asthma?
A. Wheeze.
B. Cyanosis.
C. Speaking in sentences.
D. Peak expiratory flow more than 75%.
E. Oxygen saturation 95%.
B. Cyanosis.
If present, cyanosis indicates a life-threatening asthma episode. Other indicators of severity are FEV1< 50%, peak expiratory flow < 50%, the patient speaking in words, physical exhaustion, pulse rate> 120bpm, oxygen saturation< 92%, and significant accessory muscles use.
(Option A) Wheeze is not a reliable indicator of the severity of an asthma attack. In a severe attack, the wheeze disappears and results in the ‘silent chest’ just prior to respiratory collpase. A loud wheeze may not be heard in the noisy environmet of the emergency department.
(Option C) A patient can speak in sentences in mild attack, in phrases in moderate and in words in severe attacks.
(Option D) Peak expiratory flow meter is usually more than 75% in mild asthma, 50-75% in moderated and < 50% is severe asthma attacks.
(Option E) Oxygen saturation of more than 94% is seen in mild, between 92-94% in moderate and < 92% in a severe attacks.
A 68-year-old nursing home resident man, with long standing chronic obstructive pulmonary
disease (COPD), has been brought by ambulance to the emergency department because of an exacerbation of his condition. En route to the emergency department, he was severely short of breath and was given oxygen 10 L/min via nasal canula. On examination, he is drowsy and disoriented. Which one of the following could be the most likely result of his arterial blood gas
(ABG)?
A. Ph=7.29, PaCO2=65mmHg, PaO2=85mmHg.
B. Ph=7.15, PaCO2=50mmHg, PaO2=68mmHg.
C. Ph=7.25, PaCO2=25mmHg,PaO2=100mmHg.
D. Ph=7.35, PaCO2=40mmHg, PaO2=40mmHg.
E. Ph=7.45, PaCO2=85mmHg, PaO2=40mmHg.
A. Ph=7.29, PaCO2=65mmHg, PaO2=85mmHg.
The clinical picture is consistent with carbon dioxide (Co2) narcosis. Agitation, confusion, tremors, convulsions, and possible coma may occur if blood levels of carbon dioxide rise to 70 mmHg or higher. Individuals with chronic obstructive pulmonary disease (COPD) can have CO2 narcosis with no symptoms other than confusion and/or drowsiness, because they have already developed tolerance to elevated amounts of CO2. When ventilation is sufficient to maintain a normal PaO2 in the arteries, the carbon dioxide partial pressure is generally expected to be near 40 mmHg.
This patient has been on high-flow oxygen so his blood oxygen content is expected to be normal or even high. On the other hand, this patient is dependent on hypoxia rather than hypercapnia as the main stimulant of respirtory drive. With excessive oxygenation respiration will be suppressed and he is likely to have CO2 retention and increased blood CO2. CO2 retention also results in repiratroy
acidosis. Of the options, option A is consistent with these findings.
TOPIC REVIEW
If apatient with acute exacerbation of COPD is hypoxemic, oxygen should be used as the most
appropriate next step in management to maintain the arterial oxygen saturation at about 90% (88%-92%). Oxygen therapy startswith 2L/minute through nasal cannula (prongs) or 24- 28% oxygen viaVenturi mask.
Serial ABGs are used to monitor for hypercapnia or acidosis and accurate measurement of blood oxygen content.
With high flow or high concentration of oxygen some patients may develop hypercapnia, probably because supplemental oxygen contributes to the following:
1. Increasing the perfusion/ventilation mismatch
2. Suppression of respiratory drive
Ventilatory support may be needed if hypercapnia develops or worsens despite:
- Optimal drug therapy
- Treatment of other complications
- Attempt to minimize inspired oxygen while maintaining adequate O2sat≥88% to 90%
Non-invasive ventilatory support (NIVS) with CPAP or BiPAP may avoid the need for intubation.
Supplemental oxygen should be maintained at minimum levels required for adequate oxygen
saturation, peripheral oxygen delivery, and stable pressure of PaCO2 and pH. Adjust the oxygen or decide for ventilation according to the following table:
- Therapeutic Guidelines – Respiratory; available from http://tg.org.au
- http://www.uptodate.com/contents/management-of-exa
A 72-year-old man, who is a known case of chronic obstructive pulmonary disease (COPD),
presents to the emergency department with severe shortness of breath and cough. Based on the diagnosis of a COPD exacerbation, he is started on oxygen 28% by Venturi mask. After one hour, an ABG is obtained that shows a PaO2 of 42mmHg and a PaCO2 of 68mmHg. Which one of the following is the next best step in management?
A. Increase the oxygen flow and use face mask.
B. Assisted ventilation.
C. Decrease the oxygen flow.
D. Continue with the same amount of oxygen and repeat the ABG after one hour.
E. Add inhaled short-acting β2 agonists.
B. Assisted ventilation.
Thispatient has been started on standard oxygen therapy with 28% oxygen viaVenturi mask, but has not responded to the treatment, and now has a PaO2 of less than 60 mmHg. The next step for this patient would be assisted ventilation either by CPAP or BiPAP (preferred), or intubation and mechanical ventilation.
Recommendations for oxygen adjustment for patients with an episode of COPD exacerbation is summarized in the following table: - See table below.
(Option A)Patients with COPD are dependent on hypoxia rather than hypercapnia to increase their respiratory drive. Increasing the oxygen flow in this patient may initially result in increased levels of blood oxygen, which results in decreased respiration and deterioration of their hypercapnia.
(Option C) Decreasing the oxygen flow will lead to more hypoxia and deterioration of the condition.
(Option D) Current oxygen flow has failed to provide adequate oxygenation for this patient and has also resulted in further hypercapnia. Continuation of treatment with the same amount of oxygen will not benefit the patient.
(Option E) Adding β2 agonists and anticholinergic agents are an essential part of the management plan, but should be administered with nebulisers. Inhaled drugs are of trivial benefit in COPD exacerbations.
- Therapeutic Guidelines – Respiratory; available from http://tg.org.au
- http://www.uptodate.com/contents/management-of-exa
A 37-year-old man presents to the Emergency Department with fever, malaise, and cough for the past 10 hours. He mentions that he has had foursimilar episodes before, but he is quite well in between the episodes. On examination, he has a blood pressure of 130/90 mmHg, pulse rate of 110 bpm, respiratory rate of 24 breaths per minute and temperature of 38.2°C. On chest examination, bilateral crackles are heard. Which one of the following is the most likely diagnosis?
A. Asthma.
B. Asbestosis.
C. Allergic bronchitis.
D. Extrinsic allergic alveolitis.
E. Left ventricular failure.
D. Extrinsic allergic alveolitis.
Recurrent episodes of flu like symptoms (fever, malaise, cough) associated with acute shortness of breath are characteristic of extrinsic alveolitis, also known ashypersensitivity pneumonitis. This disease is caused by a hypersensitivity reaction to specific antigens. The subtypes and specific antigens are listed in the following table: See photo below.
Chronic exposure leads to gradual fibrosis of the lungs and bilateral crackles (crepitations).
Removing the offending antigen is the management of choice. Corticosteroids are used to prevent fibrosis, but ineffective if the source of exposure is not removed.
In early stages of the disease, the patient usually does not have interval symptoms. With
progressive fibrosis, exertional dyspnea, pulmonary hypertension, and other characteristic findings of interstitial lung disease develops. In chronic cases, the pulmonary function tests will show intrapulmonary restrictive pattern.
(Option A)Asthma has an intermittent presentation, but the patient does not have fever or malaise.
(Option B) Asbestosis is an occupational lung disease presentingwith progressive shortness of breath, exercise intolerance, and lung fibrosis. There is no intermittent acute exacerbation. Moreover, fever and malaise are not seen in asbestosis.
(Option C) Allergic bronchitis is a variant of asthma in which involvement of bronchi rather than smaller airways are prominent. The main presenting symptom is cough or, less commonly, wheezing. Patients allergic bronchitis are not febrile and do not have malaise during attacks.
(Option E) Although left ventricular failure can result in cough, shortness of breath, and bibasal crepitations, fever and malaise are not expected features. Moreover, the patient is less likely to be asymptomatic in between exacerbations.
- Medscape - Hypersensitivity pneumonitis
- Therapeutic Guidelines – Respiratory
A 45-year-old non-smoker man comes to your practice with complaint of progressive dyspnea. He has worked in an insulating factory for the last 15 years. Significant physical findings on physical examinationare clubbing, peripheral cyanosis, and inspiratory crackles. A chest X-ray
showsbilateral calcified opacities in both lung fields. For further visualization of the lesions ,you order a high resolution CT scan of the chest. The CT is remarkable for calcified pleural plaques and small opacities in middle lung fields. There is no history of weight loss. Which one of the following is the most likely diagnosis?
A. Pleural effusion.
B. Mesothelioma.
C. Asbestosis.
D. Small cell lung cancer.
E. Squamous cell lung cancer.
C. Asbestosis.
The history, clinical findings, and radiological characteristics are consistent with nodular
asbestosis which is a common finding in people withthe history of exposure to asbestos. The
absence of weight loss in history makes the bronchogenic carcinomas a less likely possibility.
Asbestosis is highly associated with both non-malignant and malignant lung disease.
Chest X-ray and spiral CT scan in patients with asbestosis show calcified pleural plaques
suggestive of asbestos exposure.
See photos of Asbestosis on X-Ray & CT scan below.
Pleural mesothelioma (option B) is associated with pleural thickening and calcification, pleuritic chest pain and weight loss, as well as recurrent pleural effusions. There is a connection between asbestos exposure and mesothelioma, but the most common malignancyassociated with asbestosis isbronchogenic carcinoma, not mesothelioma.
Bronchogenic lung cancers are usually seen after 20 years of exposure to asbestosis. However, in the absence of weight loss and lack of supporting findings of a tumor on imaging studies, cancers such as small cell lung cancer (option D) or squamous cell lung cancer (option E) are less likely to be the diagnosis.
Pleural effusion (option A) can cause shortness of breath. With pleural effusion, thelungs will be dullto percussion over the affected areas. It is unlikely for pleural effusion to be missed on both CXR and CT scan.
- Therapeutic Guidelines - Respiratory
- Medscape - Asbestosis
A 40-year-old woman comes to your clinic with complaint of acute onset shortness of breath. She had one round of chemotherapy 3 weeks ago with both chest exam and X-ray being normal at that time. You assess her and found that her clinical Well score is 4. Which one of the following would be the diagnostic investigation of choice in this patient?
A. D-dimer assay.
B. CTPA.
C. Chest X-ray.
D. Doppler ultrasound scan.
E. V/Q scan.
E. V/Q scan.
Not all patients presenting with possible symptoms of pulmonary embolism (PE) need to undergo imaging tests such as computer tomography pulmonary angiography (CTPA), V/Q scan, Doppler ultrasound, etc. Decision as to whether this tests are performed depends on pretest probability of PE. A reasonable way to stratify patient risk is to use one of the validated clinical decision rules (CDR). simplified Wells Score (SWS) is one the most commonly used CDR for this purpose. It takes into account different variables to generate a score, based on which the probability of PE will be estimated to be low, moderate or high. The variables and their designated score are according to the following table: - See table below.
Clinical probability of PE based on Wells score: - See table below.
Or
- Wells score ≤ 4: PE unlikely
- Wells score >4: PE likely
Those with low or intermediate pretest probability should have a D-dimer assay as the most appropriate step. D-dimer, a degradation product of cross-linked fibrin, is elevated in the presence of clot because of the activation of fibrinolysis. A negative D-dimer using a quantitative enzyme- linked immunoabsorbent assay (ELISA) has a sensitivity of >95% and effectively excludes PE in low- and intermediate-probability groups. However, D-dimer levels are elevated after surgery, in cancer patients, and during pregnancy and cut-off levels considered for other patients may not be as reliable. In the presence of cancer D-dimer is not a useful tests and imaging studies should be considered.
CTPA and V/Q scan are used to confirm the diagnosis of PE. Diagnostic accuracy of CTPA and V/Q scan is similar. However, CTPA detects clots in smaller vessels. CTPA may have the advantage of widespread availability whereas V/Q scanning may not be available outside working hours. Radiation dose of V/Q is significantly less than CTPA, making V/Q scan preferable for women of reproductive age (< 55 years) to avoid the risk of breast cancer associated with higher radiation exposure in CTPA, Provided that the patient has a clear chest X-ray and no underlying lung pathology to make V/Q scan results equivocal.
NOTE - Although CXR is the initial test of choice for every patient with suspected PE, it is only used to exclude other causes of such presentation as well as eligibilty for V/Q scan. It is not diagnostic for PE. However, V/Q or CTPA are not used as first tests for every patient with suspected PE, unless there is a high index of suspicion based on pre-test probability.
A 34-year-old man presents to the Emergency Department with acute-onset shortness of breath. Medical history is only remarkable for essential thrombocytosis. On examination, he has a blood pressure of 110/70 mmHg, pulse rate of 90 bpm, respiratory rate of 22 breath per minute, and temperature of 37.1°C. He has a BMI of 24 kg/m2. Chest radiograph is significant for a prominent right hilum. With the provisional diagnosis of pulmonary embolism, a CT pulmonary angiogram (CTPA) is ordered which is shown in the following photograph. Which one of the following is the most appropriate treatment option for this patient?
A. Warfarin.
B. Unfractionated heparin or low-molecular weight heparin (LMWH).
C. Caval filter.
D. Thrombolytic therapy.
E. Dabigatran.
B. Unfractionated heparin or low-molecular weight heparin (LMWH).
The photograph shows a filling defect in the right branch of the pulmonary artery consistent with the diagnosis of pulmonary embolism (PE).
PE may only present with shortness of breath and tachypnea. However, other symptoms and signs such as pleuretic chest pain, cough, tachycardia and, in severe cases, hemodynamic instability may be present.
With confirmed PE, the patient should be started on unfractionated heparin or low-molecular weight heparin (LMWH) as the most appropriate next step in management.
Option A Warfarin should be commenced within 48 hours of heparin administration and continued for at least 3 months or more, depending on individual risk of recurrent PE or DVT in the future.
Option C Inferior vena cava (IVC) filters provide a screen in the inferior vena cava, allowing blood to pass through, while large emboli from the pelvis or lower extremities are blocked or fragmented before reaching the lung. Placement of an IVC filter is generally considered in patients who have contraindications to anticoagulation, failed anticoagulation, or developed a complication due to anticoagulation, or are non-adherent to treatment. Other indication is hemodynamic or respiratory compromise significant enough to make another PE may be fatal.
Option D Thrombolytic therapy may be considered for patients with PE associated with significant hemodynamic compromise. This patient does not have hemodynamic instabiliy justifying the use of thrombolytics.
Option E Dabigatran is a direct thrombin inhibitor, approved in Australia for stroke prevention in patients with non-valvular atrial fibrillation and at least one other risk factor for stroke. It is not recommended to substitute warfarin or heparin therapy in PE.
A 52-year-old woman presents to your GP clinic with severe upper arm pain and progressive shortness of breath for the past 6 months. She is non-smoker with a medical history significant only for an operation on her right thigh approximately 2 years ago for a strangulated right femoral hernia. On examination, weakness and muscle wasting of the right hand is noted, as well as an increased respiratory rate of 20 breaths per minute. A chest X-ray is obtained that is shown in the following photograph. Which one of the following would be the most appropriate next step in management?
A. Lung biopsy.
B. Electromyographic studies of the right arm.
C. Electromyographic studies of the right thigh.
D. Bronchoscopy.
E. Sputum cytology exam.
A. Lung biopsy.
The photograph shows a cap-like opacity covering the apex of the right lung. This finding in addition to hand weakness and muscular atrophy and upper arm pain is suggestive of Pancoast tumor as the most likely diagnosis.
The terms “Pancoast tumors”, “superior sulcus tumors”, or “superior pulmonary sulcus tumors” are used to describe neoplasms located at the apical pleuropulmonary groove, adjacent to the subclavian vessels.
Lesions in the superior sulcus can result in shoulder or arm pain in the distribution of the C8, T1, and T2 dermatomes. T1 involvement causes sensory disturbances in the medial forearm and hand and wasting of intrinsic hand muscles.
Horner’s syndrome can be another finding. It is caused by invasion to the stellate sympathetic ganglion in the neck. The constellation of Horner’s syndrome and weakness and atrophy of hand muscles is referred to as “Pancoast’s syndrome”.
The majority of patients with superior sulcus tumors present with one or more of the following:
Shoulder pain - The most common initial symptom of superior sulcus tumors is shoulder pain, present in 44%-96% of patients. Pain is produced by invasion to the brachial
plexus and/or extension of the tumor into the parietal pleura, endothoracic fascia, first and second ribs, or vertebral bodies. Pain can progress and radiate up to the head and neck, or down to the medial aspect of the scapula, axilla, anterior chest, or ipsilateral arm in the distribution of the ulnar nerve. Patients frequently receive treatment for presumed cervical osteoarthritis or shoulder bursitis and there is often a delay in diagnosis. Pain ultimately becomes persistent and often so severe that the patient may need to support the involved arm with the uninvolved hand for pain relief.
Horner’s syndrome - Horner’s syndrome consists of ipsilateral ptosis with narrowing of the palpebral fissure, miosis, enophthalmos, and anhidrosis. It is caused by the involvement of the paravertebral sympathetic chain and the inferior cervical (stellate) ganglion. It is seen in 14%-50%
Ipsilateral flushing and decreased sweating of the face may occur before the development of the full Horner’s syndrome, presumably due to irritation of the sympathetic chain by the tumor prior to frank invasion. Ipsilateral complex regional pain syndrome (reflex sympathetic dystrophy) and facial pain similar to paroxysmal hemicrania rarely may occur. Contralateral facial sweating and flushing, especially with exercise, due to an excessive response by the intact sympathetic pathway have also been reported; this phenomenon is known as the Harlequin sign.
Neurologic complications involving the upper extremity - Extension of the tumor to the C8 and T1 nerve roots results in upper extremity neurologic findings in approximately 8%-22% of cases. Involvement of these nerve roots may result in weakness and atrophy of the intrinsic hand muscles, or pain and paresthesia of the fourth and fifth digits and the medial aspect of the arm and forearm. Abnormal sensation and pain in the T2 territory (the axilla and medial aspect of the upper arm) may also be an early finding. The triceps reflex may be lost.
Superior sulcus tumors invade the intervertebral foramina early in the course of disease in approximately 5% of patients and may cause spinal cord compression and paraplegia. Approximately 25% of patients ultimately develop spinal cord compromise.
Other findings - Supraclavicular lymph node enlargement and prominent weight loss are seen in some patients. Superior sulcus tumors may produce a phrenic or recurrent laryngeal neuropathy or superior vena cava syndrome in 5%-10% of patients.
Radiologic findings include a unilateral cervical cap of more than 5 mm, asymmetry of bilateral cervical cap of more than 5 mm, an apical mass and local bone destruction.
Biopsy is used for definite diagnosis. The location of the superior sulcus tumors allows percutaneous needle biopsy in most cases. The technique can be performed via a posterior or cervical approach with the use of ultrasound or CT to localize the lesion. Video-assisted thoracoscopy (VATS) or thoracotomy can be performed if less invasive methods are non- diagnostic.
CT scanning of the chest is often used to provide additional information about a superior sulcus tumor and its extension, including the presence of satellite pulmonary nodules, parenchymal disease, and mediastinal lymphadenopathy. MRI is a better option for evaluation of brachial plexus, subclavian vein and artery and chest wall involvement. CT scan and MRI are often performed prior to biopsy and were the best choices if present among the given options. In their absence, lung biopsy would be the most appropriate next step and the correct option.
(Options B and C) Electromyographic studies do not add any useful infrmation regarding diagnosis or management plan.
(Options D and E) Due to the peripheral location of superior sulcus tumors, the diagnostic yields of bronchoscopy and sputum cytology are less desirable. Fiberoptic bronchoscopy with cytology and biopsies are diagnostic in only 30% to 40% of patients, but there is the benefit of detecting unexpected endobronchial tumors that will significantly change the management plan.
A 42-year-old woman sustained a motor vehicle accident (MVA) and had her femoral neck fractured which is surgically fixed. Five days after the surgery, she develops sudden-onset chest pain and dyspnea. She is on oral contraceptive pills. On examination, she is afebrile, has a heart rate of 100 bpm, BP of 110/70 mmHg, and respiratory rate of 24 breaths per minute. Lungs are clear to auscultation. Chest X-ray and ECG are normal. Which one of the following is the most appropriate next step in management?
A. Duplex doppler ultrasound scan of lower limbs.
B. D-dimer assay.
C. Computed tomography pulmonary angiography (CTPA). D. Arterial blood gas (ABG) analysis.
E. V/Q scan.
E. V/Q scan.
Orthopedic surgery is a strong risk factor for development of venous thromboembolism in the post- op period. For every patient with major surgery within the past 4 weeks, or immobilization longer than 3 days, who have signs and symptoms such as dyspnea, chest pain (especially pleuretic or sudden onset), cough, hemoptysis, or hypoxia, pulmonary embolism (PE) should always be suspected and promptly investigated.
CTPA and V/Q scan are confirmatory tests for PE if, through pretest probability assessment, PE is a likely diagnosis. There are rules referred to as Clinical Decision Rules (CDR) for this purpose. CDRs take into account different items to calculate the likelihood of PE as a diagnosis to
prevent unnecessary diagnostic testing or treatment.
One of the most recently validated and practical of these CDRs is Simplified Wells Score (SWS). SWS gives seven items one score each (if present). Patients with scores 2 or higher are likely to have PE and should undergo imaging studies either by CTPA or V/Q scan, while patients with scores 0 or 1 are unlikely to have PE. In this group, a D-dimer assay is used to safely exclude PE.
D-dimer is a fibrin degeneration product. High levels of D-dimer represent the presence of thrombus and triggers further confirmatory diagnostic tests for definite diagnosis. Negative results have high negative predictive value and are sensitive enough to exclude PE in patients with low to moderate pretest probability of PE. D-dimer levels are, however, elevated in post-surgery (first 2 weeks) period, pregnancy, inflammation, infection, and cancer, making a negative result less likely and the test less desirable where these conditions are present.
The following diagram shows the approach to patients with suspected PE bases on SWS: - See diagram below.
This patient has had a major surgery within the past four weeks (1 score). She also has a clear chest X-ray and a normal ECG, excluding other lung pathologies and cardiac problems as a cause to the presentation; hence, no other condition seems to be more likely (1 score). She has a SWS 2 and is likely to have PE.
When PE is likely, imaging tests follow. Generally, CTPA is preferred over V/Q scan because it is often readily available, easy to use and more convenient to the patient. Unlike V/Q scan, underlying lung disease evident on CXR does not significantly affect the specificity of the test. Moreover, it can detect smaller and more distal emboli in pulmonary arterial tree, as well as other conditions that may mimic PE. Drawbacks to this method are more radiation exposure and detection of clinically insignificant emboli which can trigger unnecessary anticoagulation.
CTPA is always the method of choice except in the following groups:
- Women of reproductive age (<55 years)
- Those with poor GFR (<40) or those with progressively declining renal function
- Those with known allergic reaction to contrast media
Since this patient is a female younger than 55 years, V/Q is scan is the preferred method, as radiation exposure is greater with CTPA and associated with higher rates of breast cancer in future, at least theoretically.
When leg symptoms are present (a minimum of leg swelling or tenderness of deep veins on palpation), a Doppler ultrasonography of the lower limbs can be used as an alternative. The usual source of PE is thrombosis in the deep veins (DVT) of the lower limbs or pelvis. If a clot is present in lower limb or pelvis on Doppler ultrasound, no further imaging is required, and treatment should be started. In the absence of leg symptoms, however, Doppler ultrasound is unlikely to be useful.
NOTE - Although ABG is an essential part of PE workup alongside the ECG and CXR, it is not the correct answer here because even with a normal ABG or an ABG inconsistent with expected result in PE (hypoxia and hypocarbia at the same time) is neither sensitive nor specific. ABG is never used to diagnose PE with certainty.
