Question 1

A 24-year-old woman is brought to the Emergency Department with thorax injuries after a road traffic accident. Her chest X-ray shows multiple rib fractures and a right-sided shadow suggestive of a haemothorax. Her O2 saturation is compromised at 91% on 10 litres of oxygen. What is the next step in her management?

Explanation

Correct Answer: C- Intercostal drain insertion Explanation Intercostal drain insertion A haemothorax is the result of bleeding into the pleural space, and is arbitrarily diagnosed on the basis of having a haematocrit that is more than half that of peripheral blood. This distinguishes it from a blood-stained effusion, which can be associated with a number of different pathological processes. The vast majority of haemothoraces are associated with penetrating or non- penetrating trauma, including iatrogenic procedures such as central venous catheterisation. Bleeding usually results from parenchymal laceration or damage to intercostal vessels. A pneumothorax is present in a high proportion of patients. The treatment of choice is to insert a large intercostal drain (28–32 F), allowing evacuation of blood and reducing the incidence of a subsequent fibrothorax. If this reveals continued bleeding, a thoracotomy might be required. Surgery is not indicated simply to remove any residual blood clots because there is spontaneous lysis with no residual damage in the majority of patients. Blood transfusion Blood transfusion is incorrect. A transfusion may or may not be required and would depend on the degree of blood loss and the patient’s hemoglobin, neither of which is revealed here. However, the priority on this case is to improve this lady’s oxygenation urgently by draining off the haemothorax. Computed tomography (CT) of the thorax Computed tomography (CT) of the thorax is incorrect. The priority here is to urgently improve this lady’s oxygenation. The diagnosis is clear here and requires urgent intervention to improve oxygenation. A CT thorax can be performed following stabilisation of the patient, if needs be. Intubation and ventilation Intubation and ventilation is incorrect. It would be appropriate to drain the hameothorax and reassess this lady’s oxygenation and clinical status, which is likely to improve significantly following drain insertion, before considering intubation and ventilation – which would worsen any untreated pneumothorax that may be present here. Surgical referral for thoracotomy Surgical referral for thoracotomy is incorrect. This may well be required, but the first line of intervention should be insertion of a chest drain.

Question 2

A 36-year-old woman with systemic sclerosis develops breathlessness on exertion. Her pulmonary function tests show normal spirometry but a decreased gas transfer factor (Tlco, transfer factor for carbon monoxide) and transfer coefficient (Kco). Which of the following is the most likely explanation for this abnormality?

Explanation

Correct Answer: C- Pulmonary vascular disease Explanation Pulmonary vascular disease Isolated decreases in gas transfer are typical of pulmonary vascular diseases such as vasculitis and recurrent pulmonary embolism. Interstitial lung disease Interstitial lung disease is incorrect. In interstitial lung disease you would also expect to see decreased lung volumes with a restrictive ratio (> 80%) on spirometry. Pleural involvement Pleural involvement is incorrect. In pleural involvement these investigations would give a picture of extrapulmonary restriction, with a restrictive ratio, low

Tlco but normal/high Kco (ie the same cardiac output is going through a smaller alveolar volume). Respiratory muscle weakness Respiratory muscle weakness is incorrect. In respiratory muscle weakness, these investigations would give a picture of extrapulmonary restriction, with a restrictive ratio, low Tlco but normal/high Kco (ie the same cardiac output is going through a smaller alveolar volume). Severe thoracic skin thickening Severe thoracic skin thickening is incorrect. In severe thoracic skin thickening these investigations would give a picture of extrapulmonary restriction, with a restrictive ratio, low Tlco but normal/high Kco (ie the same cardiac output is going through a smaller alveolar volume).

Question 3

A 24-year-old man with HIV and a CD4 lymphocyte count of 150/mm3 has been complaining of gradually worsening dyspnoea associated with a non-productive cough and fever for the last 2 weeks. A chest X-ray shows bilateral diffuse ground-glass opacities. What is the most appropriate therapy?

Explanation

Correct Answer: C- Co-trimoxazole Explanation Co-trimoxazole Pneumocystis jirovecii (formerly called P. carinii) pneumonia typically presents with gradually increasing dyspnoea and cough over a period of weeks, but it sometimes presents as an acute illness, with rapid deterioration occurring over a few days. Although the chest X-ray usually shows diffuse ground-glass opacities, which strongly suggests the diagnosis, it sometimes shows nodular opacities, lobar consolidation, or even a normal film. High-dose co-trimoxazole (120 mg/kg daily in divided doses) for 3 weeks is the first-line treatment for Pneumocystispneumonia. Oral therapy is often adequate, but in moderate and severe cases the drug should be given intravenously. Cystic abnormalities and spontaneous pneumothoraces in patients with known or suspected HIV infection are usually caused by Pneumocystis pneumonia. However, Pneumocystis pneumonia is unlikely in a patient who has had a CD4 cell count above 200 cells/mm3 in the preceding 2 months in the absence of other HIV-associated symptoms. Approximately 90% of patients with Pneumocystis pneumonia have an elevated serum lactate dehydrogenase, but this can occur with other pulmonary diseases. All HIV patients with a CD4 count below 200/mm3 should receive effective prophylaxis with low- dose suppressive therapy to prevent Pneumocystis pneumonia. Co-trimoxazole is the preferred agent. Dapsone and inhaled pentamidine are also used. Ampicillin Ampicillin is incorrect. Ampicillin would not be considered as first-line treatment for Pneumocystis pneumonia. Cefaclor Cefaclor is incorrect. Cefaclor would not be considered as first-line treatment for Pneumocystis pneumonia. Erythromycin Erythromycin is incorrect. Erythromycin would not be considered as first-line treatment for Pneumocystis pneumonia. Glucocorticoids Glucocorticoids is incorrect. Glucocorticoids would not be considered as first-line treatment for Pneumocystis pneumonia.

Question 4

Which of the following is the main limiting feature of spiral computed tomographic (CT) scanning for pulmonary embolism?

Explanation

Correct Answer: D- Low sensitivity for detecting pulmonary emboli in subsegmental pulmonary arteries Explanation Low sensitivity for detecting pulmonary emboli in subsegmental pulmonary arteries CT angiography is less accurate for imaging peripheral emboli in the subsegmental arteries. High incidence of artefacts due to unavoidable chest movement during respiration High incidence of artefacts due to unavoidable chest movement during respiration is incorrect. Spiral CT scanning allows imaging of the entire chest with the use of intravenous contrast enhancement during a single breath-hold. Long scanning time Long scanning time is incorrect. Spiral CT scanning allows imaging of the entire chest with the use of intravenous contrast enhancement during a single breath- hold. Low sensitivity for detecting pulmonary emboli in main pulmonary arteries Low sensitivity for detecting pulmonary emboli in main pulmonary arteries is incorrect. The majority of studies performed to date have shown CT angiography to be an accurate non-invasive tool in the diagnosis of pulmonary embolus at the main, lobar and segmental pulmonary artery levels. The sensitivity and specificity of this technique is generally regarded as being comparable to that of standard pulmonary angiography. Technical factors cause approximately 5–10% of CT angiography to be non-diagnostic, but this is a similar figure to the non-diagnostic rate for standard pulmonary angiography. Technical difficulty in passing a catheter into the pulmonary artery Technical difficulty in passing a catheter into the pulmonary artery is incorrect. Spiral CT uses intravenous contrast via a peripheral vein. No catheters are passed.

Question 5

A 39-year-old woman presented with sudden-onset pleuritic chest pain and shortness of breath. Her blood pressure was 89/50 mmHg, pulse 110 bpm, respiratory rate 30/min. The chest X-ray was normal and arterial blood gases showed Po2 6.74 kPa (the others all normal). Which of the following is the most appropriate initial management step?

Explanation

Correct Answer: E- Oxygen Explanation Oxygen This woman has type I respiratory failure. The normal chest X-ray excludes a pneumothorax. Acute asthma is a possibility, as is infection, but the sudden onset makes pulmonary embolus the most likely diagnosis. The most important initial management steps are oxygen and analgesia. Antibiotics Antibiotics is incorrect. This is a history suggestive of pulmonary embolus. Antibiotics and cultures would not be required empirically here when there is no mention of a fever or other signs of sepsis. Culture Culture is incorrect. This is a history suggestive of pulmonary embolus. Antibiotics and cultures would not be required empirically here when there is no mention of a fever or other signs of sepsis. Intravenous fluids Intravenous fluids is incorrect. Intravenous fluids to maintain the blood pressure and perfusion to organs are necessary, but oxygen therapy is the first treatment required. Low-molecular-weight heparin Low-molecular-weight heparin is incorrect. Most deaths from pulmonary embolus occur within the first few hours after presentation. If the patient does not respond quickly to supportive measures and her systolic blood pressure remains <90 mmHg, then thrombolysis with streptokinase should be considered rather than treatment with low-molecular-weight heparin.

Question 6

A 60-year-old man presents with inspiratory stridor. His chest X-ray reveals compression of the trachea by a retrosternal goitre. Which of the following investigations is the most useful to assess the severity of his airway obstruction?

Explanation

Correct Answer: A- Flow–volume loop Explanation Flow–volume loop Flow–volume loop examination is the best way to ascertain the effects of extrathoracic tracheal compression. Patients with retrosternal goitre show proportionally more reduction in the inspiratory flow rate than in the expiratory flow rate. The test is useful to differentiate these patients from patients who have severe airflow limitation or intrathoracic large-airway obstruction. Partial thyroidectomy might be considered where there is considerable inspiratory airflow restriction. Forced expiratory volume Forced expiratory volume is incorrect. Flow–volume loop would be a more useful measure to assess the severity of his airway obstruction. Forced vital capacity Forced vital capacity is incorrect. Flow–volume loop would be a more useful measure to assess the severity of his airway obstruction. Peak expiratory flow rate Peak expiratory flow rate is incorrect. Flow–volume loop would be a more useful measure to assess the severity of his airway obstruction. Residual volume Residual volume is incorrect. Flow–volume loop would be a more useful measure to assess the severity of his airway obstruction.

Question 7

A 45-year-old patient presents with shortness of breath. He has been referred by his GP to the renal clinic a few weeks earlier because his creatinine is elevated at 154 micromol/l. His transfer coefficient (Kco) is 160% of predicted. What is the most likely cause?

Explanation

Correct Answer: E- Pulmonary haemorrhage Explanation Pulmonary haemorrhage The transfer coefficient (Kco), which is obtained along with the Tlco, represents the uptake of carbon monoxide per litre of effective alveolar volume (Va):

Kco = Tlco/Va To a large extent, the Kco allows correction for any real or effective reduction of alveolar volume, tending to be normal after lung resection, when both Tlco and Va are reduced to roughly the same degree. In some conditions, the Kco can increase. This usually results from an increase in red blood cells in the lungs due to greater blood flow, haemorrhage, or polycythaemia. The Kco is also increased if (at full inflation) the density of pulmonary capillaries per unit alveolar volume is greater than normal. This occurs most commonly in patients with extrapulmonary volume restriction, when the density of pulmonary capillaries is unusually high in relation to the (restricted) lung volume at which the measurement is made. Acute exacerbation of asthma Acute exacerbation of asthma is incorrect. Acute exacerbation of asthma is associated with a reduced transfer factor. Interstitial lung disease Interstitial lung disease is incorrect. Interstitial lung disease is associated with a reduced transfer factor. Pneumonia Pneumonia is incorrect. Pneumonia is associated with a reduced transfer factor. Pulmonary embolus Pulmonary embolus is incorrect. Pulmonary embolus is associated with a reduced transfer factor.

Question 8

At the time of discharge of a 75-year-old non-smoker with known chronic obstructive pulmonary disease it was decided that, according to the criteria, he should be having long-term oxygen therapy (LTOT) at home. Which of the following options is not considered as a lone criterion for LTOT (where FVC = forced vital capacity; FEV1 = forced expiratory volume in 1 second)?

Explanation

Correct Answer: C- Cor pulmonale Explanation Cor pulmonale Cor plumonale in the absence of hypoxia may have a primary cardiological underlying cause and therefore may not require home oxygen therapy. • An MRC trial showed that if PaO2 was maintained > 8.0 kPa for > 15 hours a day, the 3-year survival improved by 50%. UK Department of Health guidelines suggest that long-term oxygen therapy (LTOT) should be provided for: Patients who are clinically stable and non- smokers with PaO2 < 7.3 kPa, FEV1 ≤ 1.5 l and FVC < 2 l despite maximal treatment. These values should be stable on two occasions more than 3 weeks apart. • Patients with a Pao2 of 7.3–8.0 kPa and pulmonary hypertension showing right ventricular hypertrophy and a loud S2 and features of cor pulmonale. Arterial blood gas showing Pao2 7.2 kPa Arterial blood gas showing Pao2 7.2 kPa is incorrect. This is in agreement with the prescription of LTOT. Arterial blood gas showing PaO2 7.8 kPa with pulmonary hypertension Arterial blood gas showing PaO2 7.8 kPa with pulmonary hypertension is incorrect. This is in agreement with the prescription of LTOT.

FEV1 < 1.5 l despite maximal treatment

FEV1 < 1.5 l despite maximal treatment is incorrect. This is in agreement with the prescription of LTOT.

FVC < 2 l despite maximal treatment

FVC < 2 l despite maximal treatment is incorrect. This is in agreement with the prescription of LTOT.

Question 9

You are trying to introduce d-dimer testing into your Emergency Department to reduce the number of patients who are admitted for suspected pulmonary embolus who are heparinised unnecessarily. Which of the following is true regarding the use of d-dimer measurement in the diagnosis of pulmonary embolus (PE)?

Explanation

Correct Answer: E- It is not useful for confirming PE when the clinical probability is high Explanation It is not useful for confirming PE when the clinical probability is high d- Dimer measurements should not be performed if:

1. An alternative diagnosis is likely 2. The clinical probability is high 3. There is a probable massive PE A d-dimer should be performed in patients with a probable massive PE A d-dimer should be performed in patients with a probable massive PE is incorrect. d-dimer measurements should not be performed if:

1. An alternative diagnosis is likely 2. The clinical probability is high 3. There is a probable massive PE A positive result is of more use clinically than a negative result A positive result is of more use clinically than a negative result is incorrect. The d-dimer test misses 10% of patients with pulmonary embolism, while only 30% of patients with positive d-dimer findings have a confirmatory diagnosis of pulmonary embolism (ie the negative predictive value is greater than the positive predictive value). It is a useful screening test for PE It is a useful screening test for PE is incorrect. d-dimer measurement can be very useful if used wisely. However, it should not be used as a screening test for pulmonary embolus (PE) because d-dimers can be positive:

• In hospitalised patients • In obstetric patients • In patients with peripheral vascular disease, cancer and inflammatory conditions • With increasing age It is likely to be useful in confirming PE for a patient with pleuritic chest pain, in the absence of breathlessness It is likely to be useful in confirming PE for a patient with pleuritic chest pain, in the absence of breathlessness is incorrect. Most patients with PE are breathless and/or tachypnoeic(> 20/min). In the absence of these signs, pleuritic chest pain or haemoptysis is usually caused by something else.

Question 10

Pneumonectomy for carcinoma of the lung is likely to be contraindicated in the presence of which one of the following?

Explanation

Correct Answer: B- Forced expiratory volume in 1 s (FEV1) of 1.6 l Explanation Forced expiratory volume in 1 s (FEV1) of 1.6 l Pulmonary function assessment does not provide clear- cut answers to the Question: of operability, but there are some simple rules for performing a thoracotomy. The

physician should keep in mind that the extent of resection can be determined only at operation, and pneumonectomy might be needed. The functional criteria for pneumonectomy are therefore:

• Forced expiratory volume in 1 s (FEV1) of > 2 l •

FEV1 > 50% of the observed forced vital capacity • Normal partial pressure of arterial CO2 (PaCO2) with the patient at rest. These form a starting point, backed up by global functional assessment. Adenocarcinoma Adenocarcinoma is incorrect. Localised adenocarcinoma may be surgically resected. Mediastinal lymph nodes < 1 cm diameter Mediastinal lymph nodes < 1 cm diameter is incorrect. Mediastinal lymph nodes < 1 cm are unlikely to be malignant and are therefore not a contraindication to surgical resection of lung cancer. Assessment of the likelihood of malignant disease affecting the lymph nodes is usually considered for example utilising PET scanning. Moderate pulmonary hypertension Moderate pulmonary hypertension is incorrect. Moderate pulmonary hypertension is not a contraindication to surgery and may be found in a significant percentage of patients with chronic obstructive pulmonary disease. Paraneoplastic syndrome Paraneoplastic syndrome is incorrect. Paraneoplastic syndromes are not a contraindication to surgery and may improve once pneumonectomy has occurred.

Question 11

A 45-year-old woman presents with progressive idiopathic pulmonary fibrosis. When performing lung function tests, which of the following parameters would you expect to be normal?

Explanation

Correct Answer: B- FEV1/FVC (ratio of the forced expiratory volume in 1 s to the forced vital capacity) Explanation

FEV1/FVC (ratio of the forced expiratory volume in 1 s to the forced vital capacity) Gas transfer is reduced by both the emphysematous and the fibrosing processes, whereas lung volumes will tend to be increased by emphysema but reduced by fibrosis. These two opposing influences result in relatively normal-sized lungs radiographically and physiologically. Carbon monoxide transfer factor Carbon monoxide transfer factor is incorrect. Carbon monoxide transfer factor (Dlco, a measure of diffusion capacity) is reduced and might be the only abnormality in early disease. In most patients the gas transfer measurement adjusted for alveolar volume (Kco) is also reduced, but less so than Dlco, indicating that the capacity to exchange gas is impaired in a lung that has not been destroyed. If there is significant coexisting emphysema, lung volumes will be well preserved in the face of a disproportionately depressed gas transfer measurement in both Dlco and Kco. Forced vital capacity Forced vital capacity is incorrect. Idiopathic pulmonary fibrosis is characterised by a restrictive ventilatory defect of mechanical function, resulting in reduced pulmonary compliance, vital capacity and total lung capacity. Residual volume is usually decreased, unless there is coincident airflow obstruction due to cigarette smoking, and lung recoil pressure is increased. Total lung capacity Total lung capacity is incorrect. Idiopathic pulmonary fibrosis is characterised by a restrictive ventilatory defect of mechanical function, resulting in reduced pulmonary compliance, vital capacity and total lung capacity. Residual volume is usually decreased, unless there is coincident airflow obstruction due to cigarette smoking, and lung recoil pressure is increased. Vital capacity Vital capacity is incorrect. Idiopathic pulmonary fibrosis is characterised by a restrictive ventilatory defect of mechanical function, resulting in reduced pulmonary compliance, vital capacity and total lung capacity. Residual volume is usually decreased, unless there is coincident airflow obstruction due to cigarette smoking, and lung recoil pressure is increased.

Question 12

A 26-year-old female intravenous drug user presents with a productive cough and fever of 2–3 days’ duration. She had flu last week. Other than a leucocytosis and a high C-reactive protein level, her blood results are normal. A chest X-ray shows bilateral cavitating pneumonia. Which of the following types of pneumonia is she most likely to have?

Explanation

Correct Answer: E- Staphylococcal pneumonia Explanation Staphylococcal pneumonia In general, staphylococcal pneumonia follows a viral infection – usually with flu-like symptoms. This type of pneumonia is often seen in intravenous drug abusers and in patients with a central line. It is also common in patients with an underlying disease, such as leukaemia, lymphoma or cystic fibrosis. X-rays show bilateral cavitating bronchopneumonia. Pneumothorax, effusion and empyema are common. Intravenous antibiotics should be administered properly. The drug of choice is flucloxacillin. Fungal pneumonia Fungal pneumonia is incorrect. Although the history of intravenous drug use indicates an increased risk of HIV infection and therefore fungal infection (which can caue cavitation), the typical pattern of fungal pneumonia is nodular consolidation. Although fungal pneumonias can cavitate, the lack of history to suggest this patient has a likely diagnosis of HIV, combined with the history of flu, make staphylococcal pneumonia more likely. Klebsiella pneumonia Klebsiella pneumonia is incorrect. Klebsiella spp. can cause cavitating pneumonia, particularly of the upper lobes, but the history of flu and intravenous drug use here makes staphylococcal pneumonia more likely. Pneumococcal pneumonia Pneumococcal pneumonia is incorrect. Streptococcus pneumoniae is the commonest cause of pneumonia in the general population; however, it is not associated with cavitation. Furthermore, the history of flu and intravenous drug use here makes staphylococcal pneumonia more likely. Pneumocystis jirovecii pneumonia Pneumocystis jirovecii pneumonia is incorrect. Although the history of intravenous drug use indicates an increased risk of HIV infection and therefore Pneumocystis jirovecii infection, the case described is not consistent with pneumocystis pneumonia, which does not frequently cause cavitation.

Question 13

A 62-year-old woman is brought to the Emergency Department with symptoms of a respiratory tract infection. According to her relatives she has had a cough for the past week, has become progressively more short of breath, and is now confused, convinced that her husband is trying to poison her. On examination she is pyrexial 38.2 °C, pulse is 95/min, her BP is 100/60 mmHg. There are clear signs of a right lower lobe pneumonia and her respiratory rate is 27/min. She tries to hit you during the consultation. Her urea is 5.2 mmol/l on arterial blood gas. Which of the following according to CURB 65 criteria is associated with a worse prognosis?

Explanation

Correct Answer: B- Confusion Explanation Confusion The CURB-65 criteria include age > 65, BP < 90 mmHg systolic or 60 mmHg diastolic, respiratory rate > 30/min, urea >7 mmol/l. Patients with 3 or more features are at high risk of death, and thus require urgent hospital admission with IV antibiotic therapy the preferred option. Scores of 1 or 2 are associated with increased risk of death and therefore expert assessment with respect to management is recommended. Age 62 Age 62 is incorrect. Age > 65 is associated with a worse prognosis in line with the CURB-65 criteria. Respiratory rate 27/min Respiratory rate 27/min is incorrect. Respiratory rate > 30/min is associated with a worse prognosis in line with the CURB-65 criteria. Systolic blood pressure 100 mmHg Systolic blood pressure is incorrect. Systolic blood pressure < 90 mmHg is associated with a worse prognosis in line with the CURB-65 criteria.

Urea 5.2 mmol/l

Urea 5.2 mmol/l is incorrect. Urea > 7 mmol/l is associated with a worse prognosis in line with the CURB-65 criteria.

Question 14

A 29-year-old woman noticed shortness of breath and a dry cough while jogging last winter. She now wakes up twice a week at 0400 h with a troublesome cough. What is the most likely cause?

Explanation

Correct Answer: A- Asthma Explanation Asthma The symptoms of asthma are non-specific: shortness of breath, wheezing, chest tightness and cough. These are manifestations of airway narrowing (which is usually variable in severity over short periods, but can be persistent) and of airway hyper-responsiveness. Asthma as the cause of these symptoms is suggested by the variability in their severity and distinguished by their periodicity (such as daily, weekly, monthly or seasonal), their provocation by specific (such as an allergen) and non-specific stimuli and their reversibility with bronchodilators or corticosteroids. Patients with asthma can be categorised, at any one time, by whether their symptoms are intermittent or persistent, and by the severity of their symptoms and underlying airway narrowing measured by lung function tests (even people with normally mild asthma can develop severe asthma). • Mild, intermittent asthma – symptoms occur less than weekly, with normal or near-normal lung function between episodes. • Mild persistent asthma – symptoms occur more than weekly but less than daily, with normal or near-normal lung function between episodes. • Moderate persistent asthma – symptoms occur daily, with mild to moderate variable airflow limitation. • Severe persistent asthma – symptoms occur daily and interfere with normal activities; there is frequent nocturnal waking and moderate to severe variable airflow limitation. • Severe asthma – severe distressing symptoms prevent sleep; severe airflow limitation responds poorly to inhaled bronchodilators and can be life-threatening. Bronchiectasis Bronchiectasis is incorrect. Cough in bronchiectasis is characteristically productive. Cardiac insufficiency Cardiac insufficiency is incorrect. This lady’s young age and lack of any cardiac history make alternative diagnoses more likely. Extrinsic allergic alveolitis Extrinsic allergic alveolitis is incorrect. There is no history given of a potential allergen. This, with the history of exercise-induced and nocturnal symptoms, makes asthma more likely. Mycoplasma pneumonia Mycoplasma pneumonia is incorrect. The history implies that this lady’s symptoms are chronic rather than acute, making an acute infection causing pneumonia unlikely.

Question 15

Which of the following is true in an acute exacerbation of chronic bronchitis?

Explanation

Correct Answer: B- An extensor plantar response is common Explanation An extensor plantar response is common Extensor plantar responses are seen in chronic obstructive pulmonary disease (COPD) due to carbon dioxide retention, which results in carbon dioxide narcosis. Aminophylline/theophylline combinations are the first- line treatments Aminophylline/Theophylline combinations are the first-line treatments is incorrect. Aminophylline and theophylline are indicated in patients with exacerbations of COPD only if nebulised bronchodilators and steroids are ineffective. Exacerbation is usually due to anaerobic infection Exacerbation is usually due to anaerobic infection is incorrect. Exacerbations of COPD are usually due to viral infections or Gram positive bacteria such as Streptococcus pneumoniae and Haemophilus influenzae. Oxygen therapy should be continued until the symptoms subside Oxygen therapy should be continued until the symptoms subside is incorrect. Oxygen therapy is indicated for treatment of hypoxia and should aim for a pO2 of 8 kPa (60 mmHg), particularly for ‘blue bloaters’ (with type II respiratory failure). Any further increase in at risk patients (ie patients with chronic type 2 respiratory failure) may result in carbon dioxide retention and respiratory acidosis. Respiratory acidosis is associated with a lowering of

bicarbonate levels Respiratory acidosis is associated with a lowering of

bicarbonate levels is incorrect. In respiratory acidosis the

bicarbonate and hydrogen levels are usually raised because of carbon dioxide retention and the renal retention of bicarbonate.

Question 16

A 64-year-old mechanic and lifelong smoker noticed haemoptysis a few days after he had a cold. Clinical examination is unremarkable. His chest X-ray shows predominantly left-sided hilar enlargement and mediastinal widening. What is the most likely diagnosis?

Explanation

Correct Answer: A- Bronchial carcinoma Explanation Bronchial carcinoma The value of the chest X-ray in the diagnosis and management of pulmonary neoplasm needs no emphasis. No initial examination is complete without a lateral film. Coned views of the ribs can help where rib invasion is suspected clinically. However, the finding of a normal X- ray of the chest does not exclude bronchial carcinoma, as patients presenting with haemoptysis and a normal chest X-ray are sometimes found to have a central tumour on bronchoscopy. The common appearance of a tumour arising from the main central airways (70% of all cases) is enlargement of one or other hilum. Even experienced observers sometimes have difficulty in deciding whether or not a hilar shadow is enlarged; if there is any suspicion,

investigation by bronchoscopy and/or computed tomography (CT) should be pursued. Consolidation and collapse distal to the tumour might have occurred by the time the patient presents, with the tumour itself often being obscured in the process. Collapse of the left lower lobe is often hard to identify, as is a tumour situated behind the heart. Apically located masses or superior sulcus tumours (Pancoast tumours) can be misdiagnosed as pleural caps, and patients often have a long history of pain in the distribution of the brachial nerve roots. Loss of the head of the first, second or third rib is not unusual. The mediastinum might be widened by enlarged nodes. Involvement of the phrenic nerve can lead to paralysis and elevation of the hemidiaphragm, which then moves paradoxically on sniffing. Tumour spread to the pleura causes effusion, but such an abnormality can also be secondary to infection beyond obstruction caused by a central tumour. The ribs and spine should be carefully examined for the presence of metastases. Spread of tumour from mediastinal nodes peripherally along the lymphatics gives the characteristic appearance of lymphangitis carcinomatosa – bilateral hilar enlargement with streaky shadows fanning out into the lung fields on either side. Rarely, localised obstructive emphysema is observed. Hilar metastases Hilar metastases is incorrect. Hilar metastases from an extrapulmonary primary malignancy is a reasonable differential diagnosis in this case. However, given the gentleman’s lifelong smoking status, absence of extrapulmonary symptoms, normal clinical examination and chest radiograph showing a hilar mass rather than multiple pulmonary lesions, a primary lung carcinoma is the most likely diagnosis of the options listed. Lung abscess Lung abscess is incorrect. Lung abscesses are seen on chest radiographs as cavities with an air/fluid level. Patients would usually have symptoms suggestive of pulmonary infection such as fevers, sweats and purulent sputum. Lymphoma Lymphoma is incorrect. Lymphoma is also a reasonable differential diagnosis in this case. However, hilar enlargenment would usually be bilateral on the chest radiograph, clinical examination would be likely to reveal lymphadenopathy +/- hepatoslenomegaly. This, combined with the lack of history of night sweats and weight loss, means that lymphoma is a less likely diagnosis than bronchial carcinoma. Tuberculosis Tuberculosis is incorrect. Tuberculosis would usually cause bilateral hilar lymphadenopathy and one would expect a history suggestive of potential contact with tuberculosis or presence of risk factors such as immunosuppression, malnutrition or alcoholism. There are no features in this history to suggest infection as the cause of lymphadenopathy.

Question 17

A 21-year-old medical student presents with confusion and dyspnoea 24 hours after fracturing his left femur in a ski competition. Which one of the following skin lesions would you expect to see on physical examination?

Explanation

Correct Answer: A- Multiple petechiae in both axillae and skin folds of the upper body Explanation Multiple petechiae in both axillae and skin folds of the upper body This is a ‘know it or you don’t’ sort of question. The appearance of showers of petechiae over the axillae or upper half of the body is characteristic of fat embolism syndrome, which occurs in patients with a history of recent traumatic fracture. Multiple vesicular lesions on the upper back Multiple vesicular lesions on the upper back is incorrect. This is not an expected finding of fat embolism. Palpable purpura on the buttock only Palpable purpura on the buttock only is incorrect. This is not an expected finding of fat embolism. Target lesions on the chest Target lesions on the chest is incorrect. This is not an expected finding of fat embolism. Tender red nodules on the shin Tender red nodules on the shin is incorrect. This is not an expected finding of fat embolism.

Question 18

A 32-year-old contract spray painter presents to the Respiratory Clinic for review. His asthma is becoming increasingly difficult to control and he now requires fluticasone 500 µg/day and salmeterol 100 µg/day just to perform reasonable activities of daily living. He reports that the only time he has felt well in recent months is when he spent 3 weeks on holiday at his mother’s house at the seaside. Chest X-ray reveals mild hyperinflation, and lung function reveals an obstructive defect. What is the diagnosis that best fits with his symptoms?

Explanation

Correct Answer: D- Occupational asthma Explanation Occupational asthma This patient works as a paint sprayer, and asthma is known to be associated with isocyanates, which can be a component of industrial paints or lacquers. Other people who can develop occupational asthma include:

• Welders • Laboratory animal workers • Farmers • Millers and grain handlers • Workers manufacturing biological washing powders • Workers involved in metal refining • Workers involved in the industrial coatings business. The clue to his condition is that he improved during his prolonged holiday. Workers who keep a peak-flow diary usually show marked deterioration in their peak flow associated with the working week. Proper assessment of industrial processes and safety equipment should take place to minimise any risk. α1-Antitrypsin deficiency α1-Antitrypsin deficiency is incorrect. α1-Antitrypsin deficiency is associated with emphysema, not asthma. The chest X-ray did not reveal any evidence of emphysema and the history is higly suggestive of occupational asthma. Bronchiectasis Bronchiectasis is incorrect. There is no mention of chronic productive cough, making bronchiectasis an unlikely diagnosis. Constitutional asthma Constitutional asthma is incorrect. Consitutional asthma would not improve when off work. His occupation and the improvement of symptoms when on holiday make occupational asthma more likely. Pulmonary fibrosis Pulmonary fibrosis is incorrect. The symptoms of interstitial lung disease would not improve when on holiday and the chest radiograph would likely show interstitial shadowing.

Question 19

A 17-year-old man has been complaining of shortness of breath for the last 2 days. On examination, bronchial breathing is heard over the right lower lobe. What is the most likely diagnosis for this clinical finding?

Explanation

Correct Answer: D- Pneumonia Explanation Pneumonia The classic presentation of pneumonia is of a cough and fever with the variable presence of sputum production, dyspnoea and pleurisy. Most patients have constitutional symptoms such as malaise, fatigue and asthenia, and many also have gastrointestinal symptoms. Although patients with pneumonia usually present with these characteristic clinical features, there can be major differences in presentation, depending on host factors and the aetiological agent. Bronchial breathing is heard over an airless lung, such as in consolidation, atelectasis or dense fibrosis. There is some resemblance to the sounds heard over the normal trachea, but, by comparison with normal breath sounds, bronchial breathing is higher in pitch and more blowing in quality. It does not have to be loud. Bronchial breath sounds are classically heard throughout both inspiration and expiration. Very quiet breath sounds are heard over hyperinflated lungs, as in emphysema, or when breath sounds are prevented from reaching the chest wall by a layer of air, fluid or fibrosis. Asthma Asthma is incorrect. Global expiratory wheeze or reduced air entry would be the classical finding in asthma. Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease (COPD) is incorrect. Global expiratory wheeze or reduced air entry would be the classical findings in COPD. Emphysema Emphysema is incorrect. Global expiratory wheeze or reduced air entry would be the classical findings in asthma or COPD including emphysema. Pneumothorax Pneumothorax is incorrect. Pneumothorax would be associated with an absence of breath sounds.

Question 20

A 58-year-old woman has been admitted with pulmonary embolism. After 7 days she develops an arterial thrombosis in her left leg. The platelet count is 40 × 109/l. Which drug is most likely to be responsible?

Explanation

Correct Answer: B- Intravenous heparin for acute treatment Explanation Intravenous heparin for acute treatment Heparin-induced thrombocytopenia (HIT) is caused by IgG antibodies that recognise multimolecular complexes of platelet factor 4 and heparin. HIT occurs in as many as 5% of certain high-risk populations. Typically, the fall in platelet count begins 5–10 days after starting heparin. However, in any patient who has received heparin within the past 100 days, the platelet count can fall abruptly on resuming heparin therapy, probably because of residual circulating HIT antibodies. Most patients with HIT develop venous or arterial thrombosis:

• Deep vein thrombosis • Pulmonary embolism • Major limb artery thrombosis • Stroke • Myocardial infarction • Bilateral adrenal haemorrhagic necrosis – leading to acute or chronic adrenal failure (much less common than the above, but has been described) The thrombocytopenia is typically moderate in severity (median platelet count nadir 60 × 109/l), and the platelet count falls to less than 20 × 109/l in only 10% of patients. In at least 10% of patients the platelet count never drops below 150 × 109/l. Bisacodyl for her constipation Bisacodyl for her constipation is incorrect. Bisacodyl is not associated with thrombocytopenia. Temazepam for night-time sleep Temazepam for night-time sleep is incorrect. Temazepam is not associated with thrombocytopenia. Tramadol for pain control Tramadol for pain control is incorrect. Tramadol is not associated with thrombocytopenia. Warfarin for continuous outpatient treatment Warfarin for continuous outpatient treatment is incorrect. Warfarin is not associated with thrombocytopenia.

Question 21

A 45-year-old man falls from a height and sustains an L1 burst fracture. His neurological examination is normal. A CT scan demonstrates 30% canal compromise, and MRI confirms an intact posterior ligamentous complex. His Thoracolumbar Injury Classification and Severity (TLICS) score is calculated as 2. What is the most appropriate management?

Explanation

A burst fracture with intact neurological status and an intact posterior ligamentous complex typically scores a 2 on the TLICS system. The standard of care for a neurologically intact patient with a stable burst fracture is nonoperative management with a TLSO.

Question 22

A 30-year-old polytrauma patient sustains an anteroposterior compression (APC) type III pelvic ring injury. Despite the application of a pelvic binder, 2 liters of crystalloid, and 2 units of packed red blood cells, he remains hypotensive. He is currently in the operating room undergoing an emergency laparotomy for an associated bowel perforation. What is the most appropriate next step in managing his pelvic hemorrhage?

Explanation

In a hemodynamically unstable patient with a pelvic ring injury who is already in the operating room for laparotomy, pre-peritoneal pelvic packing is the most rapid and effective direct intervention for venous bleeding. Angiography is indicated if bleeding persists post-packing, typically targeting arterial sources.

Question 23

A 9-year-old girl with a BMI in the 95th percentile presents with right knee pain and an antalgic gait. Radiographs reveal a severe but stable slipped capital femoral epiphysis (SCFE). Given her atypical age for this condition, she is evaluated for an underlying metabolic condition associated with bilateral involvement. Which endocrine disorder is most strongly associated with her presentation?

Explanation

While typical SCFE occurs in overweight adolescents due to mechanical forces, bilateral presentations in atypical age groups (under 10 or over 16 years) strongly suggest an underlying endocrine disorder. Hypothyroidism is the most common endocrinopathy associated with SCFE in this demographic.

Question 24

A 65-year-old woman undergoes a total hip arthroplasty (THA) via a posterior approach. Postoperatively, she suffers recurrent posterior dislocations. Radiographs reveal the acetabular cup is placed in 30 degrees of inclination and 5 degrees of retroversion. Which surgical adjustment is most appropriate to stabilize the joint?

Explanation

A cup placed in retroversion predisposes the patient to posterior instability following a THA. The most appropriate surgical adjustment is to revise the component to increase its anteversion, targeting the Lewinnek safe zone of 15 (+/- 10) degrees.

Question 25

A 25-year-old male presents with chronic wrist pain years after an unrecognized fall onto an outstretched hand. X-rays show a scaphoid nonunion with advanced radioscaphoid arthritis and early scaphocapitate arthritis, but a preserved radiolunate joint (SNAC stage II). What is the most appropriate surgical management?

Explanation

SNAC stage II involves arthritis between the scaphoid and the radial styloid, as well as the scaphocapitate joint, while sparing the radiolunate joint. Because the radiolunate articulation is intact, a proximal row carpectomy or a four-corner fusion are the standard salvage procedures.

Question 26

A collegiate football player sustains a hyperplantarflexion injury to his midfoot. Weight-bearing radiographs show widening of the space between the first and second metatarsal bases. What is the primary ligamentous structure disrupted in this injury?

Explanation

The Lisfranc ligament is an interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. It is the primary stabilizer of the tarsometatarsal joint complex, and its disruption leads to midfoot instability.

Question 27

A 15-year-old boy presents with severe thigh pain and swelling. Radiographs reveal a permeative lytic lesion in the femoral diaphysis with an "onion skin" periosteal reaction. Biopsy reveals uniform small round blue cells. What is the most common chromosomal translocation associated with this tumor?

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. The t(11;22) chromosomal translocation, resulting in the EWS-FLI1 fusion protein, is present in approximately 85% to 90% of Ewing sarcoma cases.

Question 28

A 22-year-old female soccer player undergoes ACL reconstruction using a bone-patellar tendon-bone (BTB) autograft. Compared to a multi-strand hamstring autograft, what is the most significant disadvantage of utilizing this specific graft?

Explanation

BTB autografts offer excellent initial fixation and reliable bone-to-bone healing. However, their primary disadvantage compared to hamstring autografts is a significantly higher incidence of donor site morbidity, notably anterior knee pain and kneeling discomfort.

Question 29

A 35-year-old man sustains a closed high-energy tibial shaft fracture. Hours later, he develops excruciating pain out of proportion to the injury, pain with passive toe stretch, and a tense compartment. In borderline cases requiring intra-compartmental pressure monitoring, which delta pressure threshold universally dictates the need for a fasciotomy?

Explanation

Acute compartment syndrome is primarily a clinical diagnosis, but tissue pressure monitoring is useful in equivocal cases or obtunded patients. A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the accepted threshold for performing an emergency fasciotomy.

Question 30

A 45-year-old man is brought to the trauma bay after a high-speed motorcycle collision. He is hypotensive with a blood pressure of 80/50 mmHg. An AP pelvis radiograph reveals an anteroposterior compression type III (APC III) pelvic ring injury. A pelvic binder is applied, and a FAST scan is negative. His blood pressure remains 75/40 mmHg after 2 liters of crystalloid. What is the most appropriate next step in management?

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST scan, the source of bleeding is likely pelvic. After applying a pelvic binder, the next most appropriate step is preperitoneal pelvic packing or pelvic angiography to control venous or arterial hemorrhage.

Question 31

A 68-year-old woman presents with her third posterior dislocation of a total hip arthroplasty (THA) performed 6 weeks ago via a posterior approach. Radiographs demonstrate well-fixed components with the acetabular cup in 45 degrees of abduction and 0 degrees of anteversion. What is the most likely primary cause of her recurrent instability?

Explanation

The patient's recurrent posterior dislocations are primarily due to inadequate acetabular anteversion (0 degrees). The safe zone for acetabular component placement is generally considered to be 15 +/- 10 degrees of anteversion and 40 +/- 10 degrees of abduction.

Question 32

A 13-year-old obese boy presents with a 3-week history of right groin pain and a limp. On examination, he has obligatory external rotation of the right hip with passive flexion. AP and frog-leg lateral radiographs show a widened right proximal femoral physis, and a line drawn along the superior neck does not intersect the epiphysis. What is the standard of care for this condition?

Explanation

This patient has a slipped capital femoral epiphysis (SCFE). The standard treatment for a stable SCFE is in situ fixation using a single, centrally placed cannulated screw to prevent further slippage and promote early physeal closure.

Question 33

A 28-year-old man sustains a closed diaphyseal tibia fracture. Twelve hours post-admission, he develops severe, unrelenting leg pain out of proportion to the injury, significantly worsened by passive stretch of the toes. Which of the following compartment pressure measurements is the most accepted threshold for performing an emergency four-compartment fasciotomy?

Explanation

A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the most reliable objective threshold for diagnosing acute compartment syndrome. Relying on absolute pressures alone can lead to unnecessary fasciotomies or missed diagnoses depending on systemic blood pressure.

Question 34

A 42-year-old woman presents with acute onset severe lower back pain, bilateral sciatica, and perineal numbness. Which of the following clinical findings is considered the most sensitive indicator for the diagnosis of cauda equina syndrome?

Explanation

Urinary retention (often with post-void residual > 100-200 mL) is the most sensitive symptom and sign of cauda equina syndrome. If a patient does not have urinary retention, a complete cauda equina syndrome is highly unlikely.

Question 35

A 35-year-old man undergoes open reduction and internal fixation of a transverse radial shaft fracture using a 3.5mm dynamic compression plate to achieve absolute stability. Which of the following best describes the predominant mechanism of bone healing expected in this scenario?

Explanation

When absolute stability is achieved with compression plating, the fracture heals via primary bone healing (direct contact healing) without the formation of a provisional callus. This process relies entirely on the direct progression of cutting cones and Haversian remodeling across the fracture site.

Question 36

A 16-year-old boy presents with worsening distal thigh pain. Radiographs reveal a mixed lytic and blastic metaphyseal lesion with a 'sunburst' periosteal reaction. Biopsy confirms a conventional high-grade intramedullary osteosarcoma. What is the most appropriate management sequence?

Explanation

The standard of care for conventional high-grade osteosarcoma is neoadjuvant chemotherapy, followed by wide surgical resection (limb salvage when possible), and concluding with adjuvant chemotherapy. Osteosarcoma is generally radioresistant, making radiation therapy a poor primary option.

Question 37

A 35-year-old male is brought to the trauma bay following a high-speed motorcycle collision. He is hemodynamically unstable with a suspected pelvic ring disruption. Where is the most appropriate anatomical level to apply a pelvic circumferential compression device (pelvic binder)?

Explanation

Pelvic binders should be placed at the level of the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests is incorrect and can exacerbate rotational deformities.

Question 38

A 28-year-old male presents with a closed tibial shaft fracture following a skiing accident. Six hours post-admission, he complains of worsening leg pain that is not relieved by intravenous opioids. Which of the following is the most sensitive early clinical sign of acute compartment syndrome?

Explanation

Pain with passive stretch of the muscles within the affected compartment is typically the most sensitive and earliest clinical sign of acute compartment syndrome. Pulselessness and paralysis are late, irreversible signs.

Question 39

A 60-year-old female undergoes a total hip arthroplasty. During cement pressurization and insertion of the femoral stem, she experiences a sudden drop in end-tidal CO2 and oxygen saturation, accompanied by hypotension. Which of the following is the primary pathophysiological mechanism for this event?

Explanation

Bone cement implantation syndrome is primarily caused by the embolization of fat, bone marrow, and cement into the venous circulation during pressurization. This leads to sudden right heart strain, hypoxia, and hypotension.

Question 40

A 22-year-old male sustains a vertically oriented, displaced femoral neck fracture (Pauwels type III). Open reduction and internal fixation are planned. Which of the following fixation constructs provides superior biomechanical stability for this high-shear fracture pattern?

Explanation

Pauwels type III (vertical) femoral neck fractures have high shear forces and a high rate of failure with parallel screws alone. A sliding hip screw (with or without a derotation screw) provides a fixed-angle construct that offers superior biomechanical stability.

Question 41

A 45-year-old male presents with an open segmental fracture of his right tibia with a 12 cm soft tissue defect and exposed stripped bone, but intact distal pulses. After initial stabilization and antibiotics, he undergoes debridement and external fixation. According to the Gustilo-Anderson classification, what is the optimal timing for soft tissue coverage?

Explanation

This is a Gustilo-Anderson IIIB fracture requiring flap coverage. Evidence suggests that early soft tissue coverage with a local or free flap within 5 to 7 days minimizes the risk of deep infection and osteomyelitis.

Question 42

A 19-year-old male sustains a scaphoid proximal pole fracture. Which of the following anatomical characteristics of the scaphoid is most responsible for the high rate of avascular necrosis and nonunion seen in this specific fracture pattern?

Explanation

The primary blood supply to the scaphoid enters distally from branches of the radial artery and flows retrograde to the proximal pole. Proximal pole fractures disrupt this supply, leading to a high risk of avascular necrosis.

Question 43

A 12-year-old overweight boy presents with a 4-week history of left knee pain and a limp. Examination reveals obligate external rotation of the left hip during passive flexion. Radiographs confirm a Slipped Capital Femoral Epiphysis (SCFE). Which of the following accurately describes the true displacement of the epiphysis relative to the femoral neck?

Explanation

In SCFE, the femoral neck typically displaces anteriorly and superiorly relative to the epiphysis. Consequently, the epiphysis itself remains in the acetabulum and relatively displaces posteriorly and inferiorly.

Question 44

A 6-week-old female infant is being treated with a Pavlik harness for Developmental Dysplasia of the Hip (DDH). During follow-up, the parents report the infant has stopped kicking her legs, and the examiner notes absent active knee extension on the treated side. Which of the following is the most likely cause?

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by excessive flexion of the hip. Treatment involves loosening the anterior straps or temporarily discontinuing the harness until function returns.

Question 45

An 18-year-old male presents with a painful, enlarging mass about the right knee. Radiographs reveal a mixed lytic and sclerotic lesion in the distal femoral metaphysis with a Codman triangle. If a biopsy is planned to confirm the suspected diagnosis of osteosarcoma, what is the most critical principle of the biopsy technique?

Explanation

The biopsy tract must be placed longitudinally and in line with the planned definitive surgical incision so that the entire tract can be excised en bloc with the tumor. Exsanguination with an Esmarch bandage is contraindicated to prevent tumor spread.

Question 46

A 42-year-old female presents to the Emergency Department with severe low back pain, bilateral sciatica, and perineal numbness. She reports difficulty initiating micturition. A post-void residual bladder volume is measured. What residual volume threshold is most indicative of early Cauda Equina Syndrome?

Explanation

In the context of suspected Cauda Equina Syndrome, a post-void residual (PVR) bladder volume greater than 200 mL is highly sensitive for urinary retention secondary to sacral root compression. Urgent MRI and surgical decompression are indicated.

Question 47

A 26-year-old male undergoes arthroscopic anterior stabilization for recurrent shoulder dislocations. Intraoperatively, he is noted to have a large, engaging Hill-Sachs lesion. Which of the following adjunctive procedures is most appropriate to prevent recurrent anterior instability?

Explanation

The Remplissage procedure involves tenodesis of the infraspinatus tendon and posterior capsule into the Hill-Sachs defect. This converts an intra-articular defect into an extra-articular one, preventing the lesion from engaging the anterior glenoid rim.

Question 48

A 25-year-old female professional soccer player undergoes anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone (BPTB) autograft. Compared to hamstring autograft, the BPTB autograft is associated with a statistically higher incidence of which of the following?

Explanation

Bone-patellar tendon-bone (BPTB) autografts are historically associated with a higher incidence of anterior knee pain and kneeling pain compared to hamstring autografts. Rates of graft rupture and infection are generally comparable.

Question 49

A 6-year-old boy is diagnosed with Legg-Calvé-Perthes disease. The treating surgeon uses the Herring lateral pillar classification to determine prognosis. Which radiographic feature defines a Herring Group C classification?

Explanation

The Herring classification evaluates the height of the lateral pillar of the femoral head during the fragmentation phase. Group C is defined by less than 50% maintenance of the lateral pillar height and carries the worst prognosis.

Question 50

A 5-year-old girl sustains a widely displaced extension-type supracondylar humerus fracture. On presentation, her hand is pink, but the radial pulse is absent. After closed reduction and percutaneous pinning, her hand remains pink and well-perfused, but the radial pulse remains unpalpable. What is the most appropriate next step?

Explanation

The 'pink, pulseless hand' following reduction and pinning of a supracondylar humerus fracture indicates adequate collateral circulation. Current guidelines recommend close observation and monitoring rather than immediate vascular exploration.

Question 51

A 45-year-old man sustains a Schatzker type II lateral tibial plateau fracture. Which of the following is the most widely accepted indication for operative intervention in this specific injury pattern?

Explanation

Operative indications for a lateral tibial plateau fracture include valgus instability >10 degrees in near-full extension, articular step-off >3-5 mm, or an open fracture.

Question 52

A 6-year-old boy presents with a Gartland type III extension-type supracondylar humerus fracture with posteromedial displacement of the distal fragment. Which nerve is at the highest risk of injury?

Explanation

Posteromedial displacement of the distal fragment forces the proximal spike anterolaterally, directly risking stretch or entrapment of the radial nerve.

Question 53

A 35-year-old man is brought in after a severe motorcycle crash. Pelvic radiographs demonstrate an Anteroposterior Compression (APC) Type III pelvic ring injury. Which of the following ligamentous complexes is disrupted in this injury pattern but remains intact in an APC Type II injury?

Explanation

APC III injuries involve complete disruption of the pelvic ring, including both anterior and posterior sacroiliac ligaments. APC II injuries spare the strong posterior SI ligaments.

Question 54

In an adult patient with a displaced intracapsular femoral neck fracture, which artery provides the predominant blood supply to the femoral head and is at greatest risk of catastrophic disruption?

Explanation

The lateral epiphyseal branches of the medial femoral circumflex artery provide the main blood supply to the adult femoral head and are highly vulnerable to tearing in displaced neck fractures.

Question 55

A 28-year-old farmer sustains an open tibial shaft fracture with a 4 cm wound, moderate soft tissue damage, and gross agricultural soil contamination. According to the Gustilo-Anderson classification, what is the most appropriate initial antibiotic regimen?

Explanation

Farm injuries heavily contaminated with soil are at high risk for Clostridium infections. They demand the addition of penicillin to the standard cephalosporin and aminoglycoside regimen.

Question 56

A 15-year-old boy presents with knee pain and a destructive lesion in the distal femoral metaphysis exhibiting a "sunburst" periosteal reaction. Biopsy confirms high-grade osteosarcoma. What is the standard sequence of treatment?

Explanation

The gold standard treatment for high-grade osteosarcoma is neoadjuvant multi-agent chemotherapy, followed by definitive wide surgical resection and adjuvant chemotherapy.

Question 57

A 65-year-old man presents with progressive hand clumsiness, difficulty buttoning his shirts, and a broad-based, unsteady gait. Physical examination reveals a positive Hoffmann sign bilaterally and hyperreflexia. MRI shows multilevel cervical spondylosis. What is the most likely diagnosis?

Explanation

Cervical spondylotic myelopathy classically presents with upper motor neuron signs (Hoffmann sign, hyperreflexia) and progressive upper extremity clumsiness due to cord compression.

Question 58

A 25-year-old chef sustains a knife laceration over the volar proximal phalanx of his index finger. He is unable to flex the proximal interphalangeal (PIP) or distal interphalangeal (DIP) joints. This injury corresponds to which flexor tendon zone?

Explanation

Flexor tendon Zone II, historically called "no man's land", extends from the proximal aspect of the A1 pulley to the insertion of the flexor digitorum superficialis tendon.

Question 59

During an anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone autograft, the surgeon inadvertently places the femoral tunnel too anteriorly. What is the most likely postoperative clinical consequence?

Explanation

Placing the femoral tunnel anterior to the native ACL footprint causes the graft to become excessively tight in flexion, severely restricting motion, while remaining loose in extension.

Question 60

A 72-year-old woman undergoes a posterior approach total hip arthroplasty for severe osteoarthritis. Postoperatively, she is noted to have a foot drop, weak ankle dorsiflexion, and decreased sensation over the first web space. Which nerve was most likely injured intraoperatively?

Explanation

The common peroneal division of the sciatic nerve is highly susceptible to traction injury during total hip arthroplasty, especially with leg lengthening or overzealous posterior retractor placement.

Question 61

A 32-year-old man sustains a closed high-energy tibial shaft fracture. Twelve hours later, he complains of severe leg pain out of proportion to the injury, unrelieved by narcotics. What is the most sensitive and reliable clinical indicator for diagnosing acute compartment syndrome in this patient?

Explanation

Pain out of proportion to the injury and severe pain on passive stretch of ischemic muscles are the most sensitive early clinical signs of acute compartment syndrome. Pulselessness and pallor are unreliable late signs.

Question 62

A 13-year-old obese boy presents with a 3-week history of right thigh and knee pain. Physical examination reveals an obligatory external rotation of the right hip when it is passively flexed. Radiographs confirm a slipped capital femoral epiphysis (SCFE). What is the most appropriate definitive management?

Explanation

In situ fixation with a single, centrally placed, partially threaded cannulated screw is the gold standard definitive treatment for a stable slipped capital femoral epiphysis.

Question 63

Which specific mode of bone healing occurs under conditions of absolute biomechanical stability, such as following anatomic open reduction and internal fixation with a dynamic compression plate?

Explanation

Primary (Haversian) bone healing requires absolute stability. It directly remodels the fracture site via osteoclastic cutting cones and osteoblastic bone formation without an intermediate soft callus.

Question 64

A 40-year-old male feels a sudden pop in his right heel while playing basketball. Examination reveals a positive Thompson test and a palpable gap in the tendon. If non-operative management is selected, what is the most appropriate initial immobilization position?

Explanation

Non-operative management of acute Achilles tendon ruptures begins with immobilization in plantar flexion (equinus) to approximate the torn tendon ends and facilitate fibrous healing.

Question 65

A 55-year-old man presents with chronic right shoulder pain. On examination, he has notable weakness in external rotation with the arm abducted to 90 degrees, demonstrating a positive hornblower's sign. Which rotator cuff tendon is predominantly pathological?

Explanation

A positive hornblower's sign indicates significant weakness of external rotation in abduction, which specifically isolates pathology of the teres minor muscle and tendon.

Orthopedic Prometric MCQs - Chapter 4 Part 1

Orthopedic Prometric MCQs - Chapter 4 Part 6

Orthopedic Prometric MCQs - Chapter 4 Part 6

Chapter Index