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  • Question 1 - A 65-year-old man visited his family doctor with a persistent cough that has...

    Correct

    • A 65-year-old man visited his family doctor with a persistent cough that has been bothering him for the last six months. He complains of coughing up clear sputum and how it has been affecting his daily life. He has also noticed that he gets short of breath more easily and cannot keep up with his grandchildren. He has a medical history of well-controlled diabetes and dyslipidemia. He attended a smoking cessation program a few months ago, but he finds it challenging to quit smoking after smoking a pack of cigarettes a day for the past 40 years. During the examination, the doctor hears bilateral wheezing with some crackles. The doctor expresses concerns about a possible lung disease due to his long history of smoking and refers him for a pulmonary function test. What is likely to be found during the test?

      Your Answer: The FEV1/FVC ratio is lower than normal as there is a larger decrease in FEV1 than FVC

      Explanation:

      The patient’s prolonged smoking history and current symptoms suggest a diagnosis of chronic bronchitis and possibly emphysema, both of which are obstructive lung diseases. These conditions cause air to become trapped in the lungs, making it difficult to breathe out. Pulmonary function tests typically show a greater decrease in FEV1 than FVC in obstructive lung diseases, resulting in a lower FEV1/FVC ratio (also known as the Tiffeneau-Pinelli index). This is different from restrictive lung diseases, which may sometimes show an increase in the FEV1/FVC ratio due to a larger decrease in FVC than FEV1. Chest X-rays may reveal hyperinflated lungs in patients with obstructive lung diseases. An increase in FEV1 may occur in healthy individuals after exercise training or in patients with conditions like asthma after taking medication. Restrictive lung diseases, such as pneumoconioses, hypersensitivity pneumonitis, and idiopathic pulmonary fibrosis, are typically associated with a decrease in the FEV1/FVC ratio.

      Understanding Pulmonary Function Tests

      Pulmonary function tests are a useful tool in determining whether a respiratory disease is obstructive or restrictive. These tests measure various aspects of lung function, such as forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). By analyzing the results of these tests, doctors can diagnose and monitor conditions such as asthma, COPD, pulmonary fibrosis, and neuromuscular disorders.

      In obstructive lung diseases, such as asthma and COPD, the FEV1 is significantly reduced, while the FVC may be reduced or normal. The FEV1% (FEV1/FVC) is also reduced. On the other hand, in restrictive lung diseases, such as pulmonary fibrosis and asbestosis, the FEV1 is reduced, but the FVC is significantly reduced. The FEV1% (FEV1/FVC) may be normal or increased.

      It is important to note that there are many conditions that can affect lung function, and pulmonary function tests are just one tool in diagnosing and managing respiratory diseases. However, understanding the results of these tests can provide valuable information for both patients and healthcare providers.

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      • Respiratory System
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  • Question 2 - A 65-year-old woman comes to the COPD clinic complaining of increasing breathlessness over...

    Incorrect

    • A 65-year-old woman comes to the COPD clinic complaining of increasing breathlessness over the past 3 months. She is currently receiving long-term oxygen therapy at home.

      During the examination, the patient's face appears plethoric, but there is no evidence of dyspnea at rest.

      The patient's FEV1/FVC ratio remains unchanged at 0.4, and her peak flow is 50% of the predicted value. However, her transfer factor is unexpectedly elevated.

      What could be the possible cause of this unexpected finding?

      Your Answer: Exacerbation of COPD

      Correct Answer: Polycythaemia

      Explanation:

      The transfer factor is typically low in most conditions that impair alveolar diffusion, except for polycythaemia, asthma, haemorrhage, and left-to-right shunts, which can cause an increased transfer of carbon monoxide. In this case, the patient’s plethoric facies suggest polycythaemia as the cause of their increased transfer factor. It’s important to note that exacerbations of COPD, pneumonia, and pulmonary fibrosis typically result in a low transfer factor, not an increased one.

      Understanding Transfer Factor in Lung Function Testing

      The transfer factor is a measure of how quickly a gas diffuses from the alveoli into the bloodstream. This is typically tested using carbon monoxide, and the results can be given as either the total gas transfer (TLCO) or the transfer coefficient corrected for lung volume (KCO). A raised TLCO may be caused by conditions such as asthma, pulmonary haemorrhage, left-to-right cardiac shunts, polycythaemia, hyperkinetic states, male gender, or exercise. On the other hand, a lower TLCO may be indicative of pulmonary fibrosis, pneumonia, pulmonary emboli, pulmonary oedema, emphysema, anaemia, or low cardiac output.

      KCO tends to increase with age, and certain conditions may cause an increased KCO with a normal or reduced TLCO. These conditions include pneumonectomy/lobectomy, scoliosis/kyphosis, neuromuscular weakness, and ankylosis of costovertebral joints (such as in ankylosing spondylitis). Understanding transfer factor is important in lung function testing, as it can provide valuable information about a patient’s respiratory health and help guide treatment decisions.

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      • Respiratory System
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  • Question 3 - An 87-year-old man with a history of interstitial lung disease is admitted with...

    Incorrect

    • An 87-year-old man with a history of interstitial lung disease is admitted with fever, productive cough, and difficulty breathing. His inflammatory markers are elevated, and a chest x-ray reveals focal patchy consolidation in the right lung. He requires oxygen supplementation as his oxygen saturation level is 87% on room air. What factor causes a decrease in haemoglobin's affinity for oxygen?

      Your Answer: Increase in pH

      Correct Answer: Increase in temperature

      Explanation:

      What effect does pyrexia have on the oxygen dissociation curve?

      Understanding the Oxygen Dissociation Curve

      The oxygen dissociation curve is a graphical representation of the relationship between the percentage of saturated haemoglobin and the partial pressure of oxygen in the blood. It is not influenced by the concentration of haemoglobin. The curve can shift to the left or right, indicating changes in oxygen delivery to tissues. When the curve shifts to the left, there is increased saturation of haemoglobin with oxygen, resulting in decreased oxygen delivery to tissues. Conversely, when the curve shifts to the right, there is reduced saturation of haemoglobin with oxygen, leading to enhanced oxygen delivery to tissues.

      The L rule is a helpful mnemonic to remember the factors that cause a shift to the left, resulting in lower oxygen delivery. These factors include low levels of hydrogen ions (alkali), low partial pressure of carbon dioxide, low levels of 2,3-diphosphoglycerate, and low temperature. On the other hand, the mnemonic ‘CADET, face Right!’ can be used to remember the factors that cause a shift to the right, leading to raised oxygen delivery. These factors include carbon dioxide, acid, 2,3-diphosphoglycerate, exercise, and temperature.

      Understanding the oxygen dissociation curve is crucial in assessing the oxygen-carrying capacity of the blood and the delivery of oxygen to tissues. By knowing the factors that can shift the curve to the left or right, healthcare professionals can make informed decisions in managing patients with respiratory and cardiovascular diseases.

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      • Respiratory System
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  • Question 4 - Which of the following paraneoplastic manifestations is the LEAST frequent in individuals diagnosed...

    Incorrect

    • Which of the following paraneoplastic manifestations is the LEAST frequent in individuals diagnosed with squamous cell lung carcinoma?

      Your Answer: Hypertrophic pulmonary osteoarthropathy

      Correct Answer: Lambert-Eaton syndrome

      Explanation:

      Small cell lung cancer is strongly associated with Lambert-Eaton syndrome, while squamous cell lung cancer is more commonly associated with paraneoplastic features such as PTHrp, clubbing, and HPOA.

      Lung cancer can present with paraneoplastic features, which are symptoms caused by the cancer but not directly related to the tumor itself. Small cell lung cancer can cause the secretion of ADH and, less commonly, ACTH, which can lead to hypertension, hyperglycemia, hypokalemia, alkalosis, and muscle weakness. Lambert-Eaton syndrome is also associated with small cell lung cancer. Squamous cell lung cancer can cause the secretion of parathyroid hormone-related protein, leading to hypercalcemia, as well as clubbing and hypertrophic pulmonary osteoarthropathy. Adenocarcinoma can cause gynecomastia and hypertrophic pulmonary osteoarthropathy. Hypertrophic pulmonary osteoarthropathy is a painful condition involving the proliferation of periosteum in the long bones. Although traditionally associated with squamous cell carcinoma, some studies suggest that adenocarcinoma is the most common cause.

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      • Respiratory System
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  • Question 5 - A 48-year-old male presents for a preoperative evaluation for an inguinal hernia repair....

    Incorrect

    • A 48-year-old male presents for a preoperative evaluation for an inguinal hernia repair. During the assessment, you observe a loculated left pleural effusion on his chest x-ray. Upon further inquiry, the patient discloses that he worked as a builder three decades ago. What is the probable reason for the effusion?

      Your Answer: Silicosis

      Correct Answer: Mesothelioma

      Explanation:

      Due to his profession as a builder, this individual is at risk of being exposed to asbestos. Given the 30-year latent period and the presence of a complex effusion, it is highly probable that the underlying cause is mesothelioma.

      Understanding Mesothelioma

      Mesothelioma is a type of cancer that affects the mesothelial layer of the pleural cavity, which is commonly linked to asbestos exposure. Although it is rare, other mesothelial layers in the abdomen may also be affected. Symptoms of mesothelioma include dyspnoea, weight loss, chest wall pain, and clubbing. In some cases, patients may present with painless pleural effusion. It is important to note that only 20% of patients have pre-existing asbestosis, but 85-90% have a history of asbestos exposure, with a latent period of 30-40 years.

      Diagnosis of mesothelioma is typically made through a chest x-ray, which may show pleural effusion or pleural thickening. A pleural CT is then performed to confirm the diagnosis. If a pleural effusion is present, fluid is sent for MC&S, biochemistry, and cytology. However, cytology is only helpful in 20-30% of cases. Local anaesthetic thoracoscopy is increasingly used to investigate cytology negative exudative effusions as it has a high diagnostic yield of around 95%. If an area of pleural nodularity is seen on CT, an image-guided pleural biopsy may be used.

      Management of mesothelioma is mainly symptomatic, with industrial compensation available for those who have been exposed to asbestos. Chemotherapy and surgery may be options for those who are operable. Unfortunately, the prognosis for mesothelioma is poor, with a median survival of only 12 months.

    • This question is part of the following fields:

      • Respiratory System
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  • Question 6 - A 67-year-old woman presents to the clinic with a gradual onset of dyspnea...

    Correct

    • A 67-year-old woman presents to the clinic with a gradual onset of dyspnea on exertion over the past 6 months. She has a medical history of severe COPD and is currently receiving long-term oxygen therapy. During the examination, you observe pitting edema up to the mid-thighs, an elevated JVP with a prominent V wave, a precordial heave, and a loud P2. What is the most probable mechanism involved in this diagnosis?

      Your Answer: Pulmonary arteries vasoconstriction due to hypoxia

      Explanation:

      Hypoxia causes vasoconstriction of pulmonary arteries, leading to a diagnosis of right heart failure secondary to hypoxic lung disease, also known as cor pulmonale.

      The Effects of Hypoxia on Pulmonary Arteries

      When the partial pressure of oxygen in the blood decreases, the pulmonary arteries undergo vasoconstriction. This means that the blood vessels narrow, allowing blood to be redirected to areas of the lung that are better aerated. This response is a natural mechanism that helps to improve the efficiency of gaseous exchange in the lungs. By diverting blood to areas with more oxygen, the body can ensure that the tissues receive the oxygen they need to function properly. Overall, hypoxia triggers a physiological response that helps to maintain homeostasis in the body.

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      • Respiratory System
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  • Question 7 - A 49-year-old man experiences blunt force trauma to the head and subsequently experiences...

    Incorrect

    • A 49-year-old man experiences blunt force trauma to the head and subsequently experiences respiratory distress, leading to hypercapnia. What is the most probable consequence of this condition?

      Your Answer: None of the above

      Correct Answer: Cerebral vasodilation

      Explanation:

      Cerebral vasodilation is a common result of hypercapnia, which can be problematic for patients with cranial trauma due to the potential increase in intracranial pressure.

      Understanding the Monro-Kelly Doctrine and Autoregulation in the CNS

      The Monro-Kelly doctrine governs the pressure within the cranium by considering the skull as a closed box. The loss of cerebrospinal fluid (CSF) can accommodate increases in mass until a critical point is reached, usually at 100-120ml of CSF lost. Beyond this point, intracranial pressure (ICP) rises sharply, and pressure will eventually equate with mean arterial pressure (MAP), leading to neuronal death and herniation.

      The central nervous system (CNS) has the ability to autoregulate its own blood supply through vasoconstriction and dilation of cerebral blood vessels. However, extreme blood pressure levels can exceed this capacity, increasing the risk of stroke. Additionally, metabolic factors such as hypercapnia can cause vasodilation, which is crucial in ventilating head-injured patients.

      It is important to note that the brain can only metabolize glucose, and a decrease in glucose levels can lead to impaired consciousness. Understanding the Monro-Kelly doctrine and autoregulation in the CNS is crucial in managing intracranial pressure and preventing neurological damage.

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      • Respiratory System
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  • Question 8 - A seven-year-old boy who was born in Germany presents to paediatrics with a...

    Correct

    • A seven-year-old boy who was born in Germany presents to paediatrics with a history of recurrent chest infections, steatorrhoea, and poor growth. He has a significant medical history of meconium ileus. Following a thorough evaluation, the suspected diagnosis is confirmed through a chloride sweat test. The paediatrician informs the parents that their son will have an elevated risk of infertility in adulthood. What is the pathophysiological basis for the increased risk of infertility in this case?

      Your Answer: Absent vas deferens

      Explanation:

      Men with cystic fibrosis are at risk of infertility due to the absence of vas deferens. Unfortunately, this condition often goes undetected in infancy as Germany does not perform neonatal testing for it. Hypogonadism, which can cause infertility, is typically caused by genetic factors like Kallmann syndrome, but not cystic fibrosis. Retrograde ejaculation is most commonly associated with complicated urological surgery, while an increased risk of testicular cancer can be caused by factors like cryptorchidism. However, cystic fibrosis is also a risk factor for testicular cancer.

      Understanding Cystic Fibrosis: Symptoms and Other Features

      Cystic fibrosis is a genetic disorder that affects various organs in the body, particularly the lungs and digestive system. The symptoms of cystic fibrosis can vary from person to person, but some common presenting features include recurrent chest infections, malabsorption, and liver disease. In some cases, infants may experience meconium ileus or prolonged jaundice. It is important to note that while many patients are diagnosed during newborn screening or early childhood, some may not be diagnosed until adulthood.

      Aside from the presenting features, there are other symptoms and features associated with cystic fibrosis. These include short stature, diabetes mellitus, delayed puberty, rectal prolapse, nasal polyps, and infertility. It is important for individuals with cystic fibrosis to receive proper medical care and management to address these symptoms and improve their quality of life.

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      • Respiratory System
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  • Question 9 - A 25-year-old female patient visits your clinic complaining of hearing loss. According to...

    Incorrect

    • A 25-year-old female patient visits your clinic complaining of hearing loss. According to her, her hearing has been declining for about two years, with her left ear being worse than the right. She struggles to hear her partner when he is on her left side. Additionally, she has been experiencing tinnitus in her left ear for a year. She mentions that her mother also has hearing difficulties and uses hearing aids on both ears. During the examination, the Rinne test shows a negative result on the left and a positive result on the right. On the other hand, the Weber test indicates that the sound is louder on the left. What is the probable impairment?

      Your Answer: Sensorineural hearing loss on the left.

      Correct Answer: Conductive hearing loss on the left.

      Explanation:

      Based on the results of the Weber and Rinne tests, the patient in the question is likely experiencing conductive hearing loss on the left side. The Weber test revealed that the patient hears sound better on the left side, which could indicate a conductive hearing loss or sensorineural hearing loss on the right side. However, the Rinne test was negative on the left side, indicating a conductive hearing loss. This is further supported by the patient’s reported symptoms of hearing loss in the left ear. This presentation, along with a family history of hearing loss, suggests a possible diagnosis of otosclerosis, a condition that affects the stapes bone and can lead to severe or total hearing loss.

      Understanding the Different Causes of Deafness

      Deafness can be caused by various factors, with ear wax, otitis media, and otitis externa being the most common. However, there are other conditions that can lead to hearing loss, each with its own characteristic features. Presbycusis, for instance, is age-related sensorineural hearing loss that often makes it difficult for patients to follow conversations. Otosclerosis, on the other hand, is an autosomal dominant condition that replaces normal bone with vascular spongy bone, causing conductive deafness, tinnitus, and a flamingo tinge in the tympanic membrane. Glue ear, also known as otitis media with effusion, is the most common cause of conductive hearing loss in children, while Meniere’s disease is characterized by recurrent episodes of vertigo, tinnitus, and sensorineural hearing loss. Drug ototoxicity, noise damage, and acoustic neuroma are other factors that can lead to deafness.

      Understanding the different causes of deafness is crucial in diagnosing and treating the condition. By knowing the characteristic features of each condition, healthcare professionals can determine the appropriate interventions to help patients manage their hearing loss. It is also important for individuals to protect their hearing by avoiding exposure to loud noises and seeking medical attention when they experience any symptoms of hearing loss. With proper care and management, people with deafness can still lead fulfilling lives.

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      • Respiratory System
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  • Question 10 - A 35-year-old pregnant woman undergoes an ABG test. What is the anticipated outcome...

    Incorrect

    • A 35-year-old pregnant woman undergoes an ABG test. What is the anticipated outcome for a healthy pregnant woman?

      Your Answer: Compensated metabolic acidosis

      Correct Answer: Compensated respiratory alkalosis

      Explanation:

      During pregnancy, a woman’s increased tidal volume leads to a decrease in carbon dioxide levels, resulting in alkalosis. This is because carbon dioxide generates acid, and reduced levels of it lead to a decrease in acid. The kidneys eventually adapt to this change by reducing the amount of alkaline bicarbonate in the body. Therefore, pregnancy causes a compensated respiratory alkalosis.

      If a woman’s bicarbonate levels remain normal, she would have simple respiratory alkalosis.

      On the other hand, if a woman produces excess acid, she would have metabolic acidosis, which is the opposite of what occurs during pregnancy.

      Arterial Blood Gas Interpretation: A 5-Step Approach

      Arterial blood gas interpretation is a crucial aspect of patient care, particularly in critical care settings. The Resuscitation Council (UK) recommends a 5-step approach to interpreting arterial blood gas results. The first step is to assess the patient’s overall condition. The second step is to determine if the patient is hypoxaemic, with a PaO2 on air of less than 10 kPa. The third step is to assess if the patient is acidaemic (pH <7.35) or alkalaemic (pH >7.45).

      The fourth step is to evaluate the respiratory component of the arterial blood gas results. A PaCO2 level greater than 6.0 kPa suggests respiratory acidosis, while a PaCO2 level less than 4.7 kPa suggests respiratory alkalosis. The fifth step is to assess the metabolic component of the arterial blood gas results. A bicarbonate level less than 22 mmol/l or a base excess less than -2mmol/l suggests metabolic acidosis, while a bicarbonate level greater than 26 mmol/l or a base excess greater than +2mmol/l suggests metabolic alkalosis.

      To remember the relationship between pH, PaCO2, and bicarbonate, the acronym ROME can be used. Respiratory acidosis or alkalosis is opposite to the pH level, while metabolic acidosis or alkalosis is equal to the pH level. This 5-step approach and the ROME acronym can aid healthcare professionals in interpreting arterial blood gas results accurately and efficiently.

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      • Respiratory System
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  • Question 11 - During a neck dissection, a nerve is observed to pass behind the medial...

    Incorrect

    • During a neck dissection, a nerve is observed to pass behind the medial aspect of the second rib. Which nerve from the list below is the most probable?

      Your Answer: Nerve to subclavius

      Correct Answer: Phrenic nerve

      Explanation:

      The crucial aspect to note is that the phrenic nerve travels behind the inner side of the first rib. Towards the top, it is situated on the exterior of scalenus anterior.

      The Phrenic Nerve: Origin, Path, and Supplies

      The phrenic nerve is a crucial nerve that originates from the cervical spinal nerves C3, C4, and C5. It supplies the diaphragm and provides sensation to the central diaphragm and pericardium. The nerve passes with the internal jugular vein across scalenus anterior and deep to the prevertebral fascia of the deep cervical fascia.

      The right phrenic nerve runs anterior to the first part of the subclavian artery in the superior mediastinum and laterally to the superior vena cava. In the middle mediastinum, it is located to the right of the pericardium and passes over the right atrium to exit the diaphragm at T8. On the other hand, the left phrenic nerve passes lateral to the left subclavian artery, aortic arch, and left ventricle. It passes anterior to the root of the lung and pierces the diaphragm alone.

      Understanding the origin, path, and supplies of the phrenic nerve is essential in diagnosing and treating conditions that affect the diaphragm and pericardium.

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      • Respiratory System
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  • Question 12 - Which one of the following muscles is supplied by the external laryngeal nerve?...

    Incorrect

    • Which one of the following muscles is supplied by the external laryngeal nerve?

      Your Answer: Posterior crico-arytenoid

      Correct Answer: Cricothyroid

      Explanation:

      Anatomy of the Larynx

      The larynx is located in the front of the neck, between the third and sixth cervical vertebrae. It is made up of several cartilaginous segments, including the paired arytenoid, corniculate, and cuneiform cartilages, as well as the single thyroid, cricoid, and epiglottic cartilages. The cricoid cartilage forms a complete ring. The laryngeal cavity extends from the laryngeal inlet to the inferior border of the cricoid cartilage and is divided into three parts: the laryngeal vestibule, the laryngeal ventricle, and the infraglottic cavity.

      The vocal folds, also known as the true vocal cords, control sound production. They consist of the vocal ligament and the vocalis muscle, which is the most medial part of the thyroarytenoid muscle. The glottis is composed of the vocal folds, processes, and rima glottidis, which is the narrowest potential site within the larynx.

      The larynx is also home to several muscles, including the posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid, transverse and oblique arytenoids, vocalis, and cricothyroid muscles. These muscles are responsible for various actions, such as abducting or adducting the vocal folds and relaxing or tensing the vocal ligament.

      The larynx receives its arterial supply from the laryngeal arteries, which are branches of the superior and inferior thyroid arteries. Venous drainage is via the superior and inferior laryngeal veins. Lymphatic drainage varies depending on the location within the larynx, with the vocal cords having no lymphatic drainage and the supraglottic and subglottic parts draining into different lymph nodes.

      Overall, understanding the anatomy of the larynx is important for proper diagnosis and treatment of various conditions affecting this structure.

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      • Respiratory System
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  • Question 13 - An 80-year-old man visits the GP clinic for a routine hearing examination. He...

    Incorrect

    • An 80-year-old man visits the GP clinic for a routine hearing examination. He reports a decline in hearing ability in his left ear for the past few months. After conducting Rinne and Weber tests, you determine that he has conductive hearing loss in the left ear. Upon otoscopy, you observe cerumen impaction.

      What are the test findings for this patient?

      Your Answer: Rinne: bone conduction > air conduction in left ear; Weber: lateralising to left ear

      Correct Answer: Rinne: bone conduction > air conduction in right ear; Weber: lateralising to right ear

      Explanation:

      Rinne’s and Weber’s Test for Differentiating Conductive and Sensorineural Deafness

      Rinne’s and Weber’s tests are used to differentiate between conductive and sensorineural deafness. Rinne’s test involves placing a tuning fork over the mastoid process until the sound is no longer heard, then repositioning it just over the external acoustic meatus. A positive test indicates that air conduction (AC) is better than bone conduction (BC), while a negative test indicates that BC is better than AC, suggesting conductive deafness.

      Weber’s test involves placing a tuning fork in the middle of the forehead equidistant from the patient’s ears and asking the patient which side is loudest. In unilateral sensorineural deafness, sound is localized to the unaffected side, while in unilateral conductive deafness, sound is localized to the affected side.

      The table below summarizes the interpretation of Rinne and Weber tests. A normal result indicates that AC is greater than BC bilaterally and the sound is midline. Conductive hearing loss is indicated by BC being greater than AC in the affected ear and AC being greater than BC in the unaffected ear, with the sound lateralizing to the affected ear. Sensorineural hearing loss is indicated by AC being greater than BC bilaterally, with the sound lateralizing to the unaffected ear.

      Overall, Rinne’s and Weber’s tests are useful tools for differentiating between conductive and sensorineural deafness, allowing for appropriate management and treatment.

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      • Respiratory System
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  • Question 14 - A 25-year-old woman visits the outpatient department with concerns of eyelid drooping, double...

    Incorrect

    • A 25-year-old woman visits the outpatient department with concerns of eyelid drooping, double vision, shortness of breath, and rapid breathing. These symptoms typically occur in the evening or after physical activity.

      What respiratory condition could be causing her symptoms?

      Your Answer: Pulmonary embolism

      Correct Answer: Restrictive lung disease

      Explanation:

      The presence of myasthenia gravis can result in a restrictive pattern of lung disease due to weakened chest wall muscles, leading to incomplete expansion during inhalation.

      Occupational lung disease, also known as pneumoconioses, is caused by inhaling specific types of dust particles in the workplace, resulting in a restrictive pattern of lung disease. However, symptoms such as drooping eyelids and double vision are typically not associated with this condition.

      Pneumonia is an infection of the lung tissue that typically presents with symptoms such as coughing, chest pain, fever, and difficulty breathing.

      Pulmonary embolism is an acute condition that presents with symptoms such as chest pain, shortness of breath, and coughing up blood.

      Understanding the Differences between Obstructive and Restrictive Lung Diseases

      Obstructive and restrictive lung diseases are two distinct categories of respiratory conditions that affect the lungs in different ways. Obstructive lung diseases are characterized by a reduction in the flow of air through the airways due to narrowing or blockage, while restrictive lung diseases are characterized by a decrease in lung volume or capacity, making it difficult to breathe in enough air.

      Spirometry is a common diagnostic tool used to differentiate between obstructive and restrictive lung diseases. In obstructive lung diseases, the ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) is less than 80%, indicating a reduced ability to exhale air. In contrast, restrictive lung diseases are characterized by an FEV1/FVC ratio greater than 80%, indicating a reduced ability to inhale air.

      Examples of obstructive lung diseases include chronic obstructive pulmonary disease (COPD), chronic bronchitis, and emphysema, while asthma and bronchiectasis are also considered obstructive. Restrictive lung diseases include intrapulmonary conditions such as idiopathic pulmonary fibrosis, extrinsic allergic alveolitis, and drug-induced fibrosis, as well as extrapulmonary conditions such as neuromuscular diseases, obesity, and scoliosis.

      Understanding the differences between obstructive and restrictive lung diseases is important for accurate diagnosis and appropriate treatment. While both types of conditions can cause difficulty breathing, the underlying causes and treatment approaches can vary significantly.

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      • Respiratory System
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  • Question 15 - A 65-year-old male with a diagnosis of lung cancer presents with fatigue and...

    Incorrect

    • A 65-year-old male with a diagnosis of lung cancer presents with fatigue and lightheadedness. Upon examination, the following results are obtained:

      Plasma sodium concentration 115 mmol/L (137-144)
      Potassium 3.5 mmol/L (3.5-4.9)
      Urea 3.2 mmol/L (2.5-7.5)
      Creatinine 67 ”mol/L (60-110)

      What is the probable reason for his symptoms based on these findings?

      Your Answer: Malignant nephrotic syndrome

      Correct Answer: Syndrome of inappropriate ADH secretion

      Explanation:

      Syndrome of Inappropriate ADH Secretion

      Syndrome of inappropriate ADH secretion (SIADH) is a condition characterized by low levels of sodium in the blood. This is caused by the overproduction of antidiuretic hormone (ADH) by the posterior pituitary gland. Tumors such as bronchial carcinoma can cause the ectopic elaboration of ADH, leading to dilutional hyponatremia. The diagnosis of SIADH is one of exclusion, but it can be supported by a high urine sodium concentration with high urine osmolality.

      Hypoadrenalism is less likely to cause hyponatremia, as it is usually associated with hyperkalemia and mild hyperuricemia. On the other hand, diabetes insipidus is a condition where the kidneys are unable to reabsorb water, leading to excessive thirst and urination.

      It is important to diagnose and treat SIADH promptly to prevent complications such as seizures, coma, and even death. Treatment options include fluid restriction, medications to block the effects of ADH, and addressing the underlying cause of the condition.

      In conclusion, SIADH is a condition that can cause low levels of sodium in the blood due to the overproduction of ADH. It is important to differentiate it from other conditions that can cause hyponatremia and to treat it promptly to prevent complications.

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      • Respiratory System
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  • Question 16 - A 68-year-old woman has been diagnosed with laryngeal cancer and has quit smoking....

    Correct

    • A 68-year-old woman has been diagnosed with laryngeal cancer and has quit smoking. Surgery is planned to remove the cancer through a laryngectomy. What vertebral level/levels will the organ be located during the procedure?

      Your Answer: C3 to C6

      Explanation:

      The larynx is situated in the front of the neck at the level of the C3-C6 vertebrae. This is the correct location for accessing the larynx during a laryngectomy. The larynx is not located at the C1-C2 level, as these are the atlas bones. It is also not located at the C2-C3 level, which is where the hyoid bone can be found. The C7 level is where the isthmus of the thyroid gland is located, not the larynx.

      Anatomy of the Larynx

      The larynx is located in the front of the neck, between the third and sixth cervical vertebrae. It is made up of several cartilaginous segments, including the paired arytenoid, corniculate, and cuneiform cartilages, as well as the single thyroid, cricoid, and epiglottic cartilages. The cricoid cartilage forms a complete ring. The laryngeal cavity extends from the laryngeal inlet to the inferior border of the cricoid cartilage and is divided into three parts: the laryngeal vestibule, the laryngeal ventricle, and the infraglottic cavity.

      The vocal folds, also known as the true vocal cords, control sound production. They consist of the vocal ligament and the vocalis muscle, which is the most medial part of the thyroarytenoid muscle. The glottis is composed of the vocal folds, processes, and rima glottidis, which is the narrowest potential site within the larynx.

      The larynx is also home to several muscles, including the posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid, transverse and oblique arytenoids, vocalis, and cricothyroid muscles. These muscles are responsible for various actions, such as abducting or adducting the vocal folds and relaxing or tensing the vocal ligament.

      The larynx receives its arterial supply from the laryngeal arteries, which are branches of the superior and inferior thyroid arteries. Venous drainage is via the superior and inferior laryngeal veins. Lymphatic drainage varies depending on the location within the larynx, with the vocal cords having no lymphatic drainage and the supraglottic and subglottic parts draining into different lymph nodes.

      Overall, understanding the anatomy of the larynx is important for proper diagnosis and treatment of various conditions affecting this structure.

    • This question is part of the following fields:

      • Respiratory System
      15.1
      Seconds
  • Question 17 - A 45-year-old woman is undergoing consent for a thyroidectomy due to failed medical...

    Incorrect

    • A 45-year-old woman is undergoing consent for a thyroidectomy due to failed medical treatment for Grave's disease. Radioiodine was not an option as she is the sole caregiver for her three young children. During the consent process, she is informed of the potential complications of thyroidectomy, including the risk of injury to the sensory branch of the superior laryngeal nerve. Can you identify which nerve branches off from the superior laryngeal nerve and is responsible for sensory function?

      Your Answer: Right recurrent laryngeal nerve

      Correct Answer: Internal laryngeal nerve

      Explanation:

      The superior laryngeal nerve, a branch of the vagus nerve, has two branches: the external laryngeal nerve, which is a motor nerve, and the internal laryngeal nerve, which is a sensory nerve. The recurrent laryngeal nerve, also a branch of the vagus nerve, supplies all intrinsic muscles of the larynx except for the cricothyroid muscles.

      Anatomy of the Larynx

      The larynx is located in the front of the neck, between the third and sixth cervical vertebrae. It is made up of several cartilaginous segments, including the paired arytenoid, corniculate, and cuneiform cartilages, as well as the single thyroid, cricoid, and epiglottic cartilages. The cricoid cartilage forms a complete ring. The laryngeal cavity extends from the laryngeal inlet to the inferior border of the cricoid cartilage and is divided into three parts: the laryngeal vestibule, the laryngeal ventricle, and the infraglottic cavity.

      The vocal folds, also known as the true vocal cords, control sound production. They consist of the vocal ligament and the vocalis muscle, which is the most medial part of the thyroarytenoid muscle. The glottis is composed of the vocal folds, processes, and rima glottidis, which is the narrowest potential site within the larynx.

      The larynx is also home to several muscles, including the posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid, transverse and oblique arytenoids, vocalis, and cricothyroid muscles. These muscles are responsible for various actions, such as abducting or adducting the vocal folds and relaxing or tensing the vocal ligament.

      The larynx receives its arterial supply from the laryngeal arteries, which are branches of the superior and inferior thyroid arteries. Venous drainage is via the superior and inferior laryngeal veins. Lymphatic drainage varies depending on the location within the larynx, with the vocal cords having no lymphatic drainage and the supraglottic and subglottic parts draining into different lymph nodes.

      Overall, understanding the anatomy of the larynx is important for proper diagnosis and treatment of various conditions affecting this structure.

    • This question is part of the following fields:

      • Respiratory System
      40.5
      Seconds
  • Question 18 - A woman in her 30s is stabbed in the chest to the right...

    Incorrect

    • A woman in her 30s is stabbed in the chest to the right of the manubriosternal angle. Which structure is least likely to be injured in this scenario?

      Your Answer: The trachea

      Correct Answer: Right recurrent laryngeal nerve

      Explanation:

      The right vagus nerve gives rise to the right recurrent laryngeal nerve at a more proximal location, which then curves around the subclavian artery in a posterior direction. Therefore, out of the given structures, it is the least susceptible to injury.

      The mediastinum is the area located between the two pulmonary cavities and is covered by the mediastinal pleura. It extends from the thoracic inlet at the top to the diaphragm at the bottom. The mediastinum is divided into four regions: the superior mediastinum, middle mediastinum, posterior mediastinum, and anterior mediastinum.

      The superior mediastinum is the area between the manubriosternal angle and T4/5. It contains important structures such as the superior vena cava, brachiocephalic veins, arch of aorta, thoracic duct, trachea, oesophagus, thymus, vagus nerve, left recurrent laryngeal nerve, and phrenic nerve. The anterior mediastinum contains thymic remnants, lymph nodes, and fat. The middle mediastinum contains the pericardium, heart, aortic root, arch of azygos vein, and main bronchi. The posterior mediastinum contains the oesophagus, thoracic aorta, azygos vein, thoracic duct, vagus nerve, sympathetic nerve trunks, and splanchnic nerves.

      In summary, the mediastinum is a crucial area in the thorax that contains many important structures and is divided into four regions. Each region contains different structures that are essential for the proper functioning of the body.

    • This question is part of the following fields:

      • Respiratory System
      39.3
      Seconds
  • Question 19 - A 55-year-old man comes to the hospital complaining of lethargy, headache, and shortness...

    Incorrect

    • A 55-year-old man comes to the hospital complaining of lethargy, headache, and shortness of breath. Upon examination, he is found to be cyanotic and hypoxic, and is admitted to the respiratory ward for oxygen therapy.

      Following some initial tests, the consultant informs the patient that his hemoglobin has a high affinity for oxygen, resulting in reduced oxygen delivery to the tissues.

      What is the probable reason for this alteration in the oxygen dissociation curve?

      Your Answer: Hyperglycaemia

      Correct Answer: Low 2,3-DPG

      Explanation:

      The correct answer is low 2,3-DPG. The professor’s description refers to a left shift in the oxygen dissociation curve, which indicates that haemoglobin has a high affinity for oxygen and is less likely to release it to the tissues. Factors that cause a left shift include low temperature, high pH, low PCO2, and low 2,3-DPG. 2,3-DPG is a substance that helps release oxygen from haemoglobin, so low levels of it result in less oxygen being released, causing a left shift in the oxygen dissociation curve.

      The answer high temperature is incorrect because it causes a right shift in the oxygen dissociation curve, promoting oxygen delivery to the tissues. Hypercapnoea also causes a right shift in the curve, promoting oxygen delivery. Hyperglycaemia has no effect on haemoglobin’s ability to release oxygen, so it is also incorrect.

      Understanding the Oxygen Dissociation Curve

      The oxygen dissociation curve is a graphical representation of the relationship between the percentage of saturated haemoglobin and the partial pressure of oxygen in the blood. It is not influenced by the concentration of haemoglobin. The curve can shift to the left or right, indicating changes in oxygen delivery to tissues. When the curve shifts to the left, there is increased saturation of haemoglobin with oxygen, resulting in decreased oxygen delivery to tissues. Conversely, when the curve shifts to the right, there is reduced saturation of haemoglobin with oxygen, leading to enhanced oxygen delivery to tissues.

      The L rule is a helpful mnemonic to remember the factors that cause a shift to the left, resulting in lower oxygen delivery. These factors include low levels of hydrogen ions (alkali), low partial pressure of carbon dioxide, low levels of 2,3-diphosphoglycerate, and low temperature. On the other hand, the mnemonic ‘CADET, face Right!’ can be used to remember the factors that cause a shift to the right, leading to raised oxygen delivery. These factors include carbon dioxide, acid, 2,3-diphosphoglycerate, exercise, and temperature.

      Understanding the oxygen dissociation curve is crucial in assessing the oxygen-carrying capacity of the blood and the delivery of oxygen to tissues. By knowing the factors that can shift the curve to the left or right, healthcare professionals can make informed decisions in managing patients with respiratory and cardiovascular diseases.

    • This question is part of the following fields:

      • Respiratory System
      43.8
      Seconds
  • Question 20 - What is the carrier rate of cystic fibrosis in the United Kingdom? ...

    Incorrect

    • What is the carrier rate of cystic fibrosis in the United Kingdom?

      Your Answer: 1 in 100

      Correct Answer: 1 in 25

      Explanation:

      Understanding Cystic Fibrosis

      Cystic fibrosis is a genetic disorder that causes thickened secretions in the lungs and pancreas. It is an autosomal recessive condition that occurs due to a defect in the cystic fibrosis transmembrane conductance regulator gene (CFTR), which regulates a chloride channel. In the UK, 80% of CF cases are caused by delta F508 on chromosome 7, and the carrier rate is approximately 1 in 25.

      CF patients are at risk of colonization by certain organisms, including Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia (previously known as Pseudomonas cepacia), and Aspergillus. These organisms can cause infections and exacerbate symptoms in CF patients. It is important for healthcare providers to monitor and manage these infections to prevent further complications.

      Overall, understanding cystic fibrosis and its associated risks can help healthcare providers provide better care for patients with this condition.

    • This question is part of the following fields:

      • Respiratory System
      16.4
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  • Question 21 - A 44-year-old woman is scheduled for a thyroidectomy due to symptomatic tracheal compression....

    Incorrect

    • A 44-year-old woman is scheduled for a thyroidectomy due to symptomatic tracheal compression. She has a history of hyperthyroidism that was controlled with carbimazole. However, she was deemed a suitable candidate for thyroidectomy after presenting to the emergency department with dyspnoea and stridor.

      As a surgical resident assisting the ENT surgeon, you need to ligate the superior thyroid artery before removing the thyroid glands to prevent excessive bleeding. However, the superior laryngeal artery, a branch of the superior thyroid artery, is closely related to a structure that, if injured, can lead to loss of sensation in the laryngeal mucosa.

      What is the correct identification of this structure?

      Your Answer: Right recurrent laryngeal nerve

      Correct Answer: Internal laryngeal nerve

      Explanation:

      The internal laryngeal nerve and the superior laryngeal artery are closely associated with each other. The superior laryngeal artery travels alongside the internal laryngeal branch of the superior laryngeal nerve, beneath the thyrohyoid muscle. It originates from the superior thyroid artery near its separation from the external carotid artery.

      If the internal laryngeal nerve is damaged, it can result in a loss of sensation to the laryngeal mucosa. The nerve is situated beneath the mucous membrane of the piriform recess, making it vulnerable to injury from sharp objects like fish and chicken bones that may become stuck in the recess.

      Anatomy of the Larynx

      The larynx is located in the front of the neck, between the third and sixth cervical vertebrae. It is made up of several cartilaginous segments, including the paired arytenoid, corniculate, and cuneiform cartilages, as well as the single thyroid, cricoid, and epiglottic cartilages. The cricoid cartilage forms a complete ring. The laryngeal cavity extends from the laryngeal inlet to the inferior border of the cricoid cartilage and is divided into three parts: the laryngeal vestibule, the laryngeal ventricle, and the infraglottic cavity.

      The vocal folds, also known as the true vocal cords, control sound production. They consist of the vocal ligament and the vocalis muscle, which is the most medial part of the thyroarytenoid muscle. The glottis is composed of the vocal folds, processes, and rima glottidis, which is the narrowest potential site within the larynx.

      The larynx is also home to several muscles, including the posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid, transverse and oblique arytenoids, vocalis, and cricothyroid muscles. These muscles are responsible for various actions, such as abducting or adducting the vocal folds and relaxing or tensing the vocal ligament.

      The larynx receives its arterial supply from the laryngeal arteries, which are branches of the superior and inferior thyroid arteries. Venous drainage is via the superior and inferior laryngeal veins. Lymphatic drainage varies depending on the location within the larynx, with the vocal cords having no lymphatic drainage and the supraglottic and subglottic parts draining into different lymph nodes.

      Overall, understanding the anatomy of the larynx is important for proper diagnosis and treatment of various conditions affecting this structure.

    • This question is part of the following fields:

      • Respiratory System
      55.5
      Seconds
  • Question 22 - A 28-year-old female patient presents to your clinic seeking help to quit smoking....

    Correct

    • A 28-year-old female patient presents to your clinic seeking help to quit smoking. Despite several attempts in the past, she has been unsuccessful. She has a medical history of bipolar disorder and well-managed epilepsy, for which she takes lamotrigine. She currently smokes 15 cigarettes per day and is especially interested in the health benefits of quitting smoking since she has recently found out that she is pregnant. As her physician, you decide to prescribe a suitable medication to assist her in her efforts. What would be the most appropriate treatment option?

      Your Answer: Nicotine gum

      Explanation:

      Standard treatments for nicotine dependence do not include amitriptyline, fluoxetine, or gabapentin. Nicotine replacement therapy (NRT) can be helpful for motivated patients, but it is not a cure for addiction and may require multiple attempts. Bupropion and varenicline are other smoking cessation aids, but they have multiple side effects and may not be suitable for all patients. NICE guidelines recommend discussing the best method of smoking cessation with the patient, but NRT is considered safer in pregnancy.

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      • Respiratory System
      32.9
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  • Question 23 - A man in his early fifties comes in with a painful rash caused...

    Incorrect

    • A man in his early fifties comes in with a painful rash caused by herpes on the external auditory meatus. He also has facial palsy on the same side, along with deafness, tinnitus, and vertigo. What is the probable diagnosis?

      Your Answer: Bell's palsy

      Correct Answer: Ramsay Hunt syndrome

      Explanation:

      Ramsay Hunt syndrome is characterized by a combination of Bell’s palsy facial paralysis, along with symptoms such as a herpetic rash, deafness, tinnitus, and vertigo. It is important to note that the rash may not always be visible, despite being present.

      While Bell’s palsy may present with facial paralysis, it does not typically involve the presence of herpetic rashes.

      Understanding Ramsay Hunt Syndrome

      Ramsay Hunt syndrome, also known as herpes zoster oticus, is a condition that occurs when the varicella zoster virus reactivates in the geniculate ganglion of the seventh cranial nerve. The first symptom of this syndrome is often auricular pain, followed by facial nerve palsy and a vesicular rash around the ear. Other symptoms may include vertigo and tinnitus.

      To manage Ramsay Hunt syndrome, doctors typically prescribe oral acyclovir and corticosteroids. These medications can help reduce the severity of symptoms and prevent complications.

    • This question is part of the following fields:

      • Respiratory System
      10.2
      Seconds
  • Question 24 - A 60-year-old male patient complains of chronic productive cough and difficulty breathing. He...

    Incorrect

    • A 60-year-old male patient complains of chronic productive cough and difficulty breathing. He has been smoking 10 cigarettes per day for the past 30 years. What is the number of pack years equivalent to his smoking history?

      Your Answer: 30

      Correct Answer: 15

      Explanation:

      Pack Year Calculation

      Pack year calculation is a tool used to estimate the risk of tobacco exposure. It is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years of smoking. One pack of cigarettes contains 20 cigarettes. For instance, if a person smoked half a pack of cigarettes per day for 30 years, their pack year history would be 15 (1/2 x 30 = 15).

      The pack year calculation is a standardized method of measuring tobacco exposure. It helps healthcare professionals to estimate the risk of developing smoking-related diseases such as lung cancer, chronic obstructive pulmonary disease (COPD), and heart disease. The higher the pack year history, the greater the risk of developing these diseases. Therefore, it is important for individuals who smoke or have a history of smoking to discuss their pack year history with their healthcare provider to determine appropriate screening and prevention measures.

    • This question is part of the following fields:

      • Respiratory System
      17.1
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  • Question 25 - A patient in their 60s presents to surgical outpatients with diffuse abdominal pain....

    Incorrect

    • A patient in their 60s presents to surgical outpatients with diffuse abdominal pain. As a second-line imaging investigation, a CT scan is requested. The radiologist looks through the images to write the report. Which of the following would they expect to find at the level of the transpyloric plane (L1)?

      Your Answer: Origin of the inferior mesenteric artery

      Correct Answer: Hila of the kidneys

      Explanation:

      The hila of the kidneys are at the level of the transpyloric plane, with the left kidney slightly higher than the right. The adrenal glands sit just above the kidneys at the level of T12. The neck of the pancreas, not the body, is at the level of the transpyloric plane. The coeliac trunk originates at the level of T12 and the inferior mesenteric artery originates at L3.

      The Transpyloric Plane and its Anatomical Landmarks

      The transpyloric plane is an imaginary horizontal line that passes through the body of the first lumbar vertebrae (L1) and the pylorus of the stomach. It is an important anatomical landmark used in clinical practice to locate various organs and structures in the abdomen.

      Some of the structures that lie on the transpyloric plane include the left and right kidney hilum (with the left one being at the same level as L1), the fundus of the gallbladder, the neck of the pancreas, the duodenojejunal flexure, the superior mesenteric artery, and the portal vein. The left and right colic flexure, the root of the transverse mesocolon, and the second part of the duodenum also lie on this plane.

      In addition, the upper part of the conus medullaris (the tapered end of the spinal cord) and the spleen are also located on the transpyloric plane. Knowing the location of these structures is important for various medical procedures, such as abdominal surgeries and diagnostic imaging.

      Overall, the transpyloric plane serves as a useful reference point for clinicians to locate important anatomical structures in the abdomen.

    • This question is part of the following fields:

      • Respiratory System
      21.6
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  • Question 26 - A 20-year-old man presents to the emergency department with diabetic ketoacidosis. After early...

    Correct

    • A 20-year-old man presents to the emergency department with diabetic ketoacidosis. After early treatment, an arterial blood gas is taken, which shows the following results.

      ABG result - temperature 35.0 ÂșC:

      pH 7.30 (7.35 - 7.45)
      PaCO2 3.5 kPa (4.7 - 6.0)
      PaO2 10 kPa (11 - 13)
      HCO3- 16 mEq/L (22 - 26)
      Na+ 138 mmol/L (135 - 145)
      K+ 3.3 mmol/L (3.5 - 5.0)

      What physiological change is occurring in this patient?

      Your Answer: Metabolic acidosis is causing a decreased affinity of haemoglobin for oxygen

      Explanation:

      In acidosis, the oxyhaemoglobin dissociation curve shifts to the right, indicating a decrease in affinity of haemoglobin for oxygen. This is due to an increase in the number of [H+] ions, reflecting greater metabolic activity. Low [H+] levels cause a shift to the left. The low HCO3- in this patient can be explained by metabolic acidosis, but it does not cause a shift in the oxyhaemoglobin dissociation curve. Hypokalaemia may be a result of treatment for diabetic ketoacidosis, but it does not cause a shift in the oxygen dissociation curve. When temperature increases, the oxyhaemoglobin dissociation curve also shifts to the right, causing a decrease in haemoglobin affinity for oxygen. Hypothermia causes a shift to the left, indicating an increased affinity of haemoglobin for oxygen.

      Understanding the Oxygen Dissociation Curve

      The oxygen dissociation curve is a graphical representation of the relationship between the percentage of saturated haemoglobin and the partial pressure of oxygen in the blood. It is not influenced by the concentration of haemoglobin. The curve can shift to the left or right, indicating changes in oxygen delivery to tissues. When the curve shifts to the left, there is increased saturation of haemoglobin with oxygen, resulting in decreased oxygen delivery to tissues. Conversely, when the curve shifts to the right, there is reduced saturation of haemoglobin with oxygen, leading to enhanced oxygen delivery to tissues.

      The L rule is a helpful mnemonic to remember the factors that cause a shift to the left, resulting in lower oxygen delivery. These factors include low levels of hydrogen ions (alkali), low partial pressure of carbon dioxide, low levels of 2,3-diphosphoglycerate, and low temperature. On the other hand, the mnemonic ‘CADET, face Right!’ can be used to remember the factors that cause a shift to the right, leading to raised oxygen delivery. These factors include carbon dioxide, acid, 2,3-diphosphoglycerate, exercise, and temperature.

      Understanding the oxygen dissociation curve is crucial in assessing the oxygen-carrying capacity of the blood and the delivery of oxygen to tissues. By knowing the factors that can shift the curve to the left or right, healthcare professionals can make informed decisions in managing patients with respiratory and cardiovascular diseases.

    • This question is part of the following fields:

      • Respiratory System
      45.3
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  • Question 27 - A 27-year-old male admitted to the ICU after a car accident has a...

    Correct

    • A 27-year-old male admitted to the ICU after a car accident has a pneumothorax. Using a bedside spirometer, his inspiratory and expiratory volumes were measured. What is the typical tidal volume for a male of his age?

      Your Answer: 500ml

      Explanation:

      The amount of air that is normally breathed in and out without any extra effort is called tidal volume, which is 500ml in males and 350ml in females.

      Understanding Lung Volumes in Respiratory Physiology

      In respiratory physiology, lung volumes can be measured to determine the amount of air that moves in and out of the lungs during breathing. The diagram above shows the different lung volumes that can be measured.

      Tidal volume (TV) refers to the amount of air that is inspired or expired with each breath at rest. In males, the TV is 500ml while in females, it is 350ml.

      Inspiratory reserve volume (IRV) is the maximum volume of air that can be inspired at the end of a normal tidal inspiration. The inspiratory capacity is the sum of TV and IRV. On the other hand, expiratory reserve volume (ERV) is the maximum volume of air that can be expired at the end of a normal tidal expiration.

      Residual volume (RV) is the volume of air that remains in the lungs after maximal expiration. It increases with age and can be calculated by subtracting ERV from FRC. Speaking of FRC, it is the volume in the lungs at the end-expiratory position and is equal to the sum of ERV and RV.

      Vital capacity (VC) is the maximum volume of air that can be expired after a maximal inspiration. It decreases with age and can be calculated by adding inspiratory capacity and ERV. Lastly, total lung capacity (TLC) is the sum of vital capacity and residual volume.

      Physiological dead space (VD) is calculated by multiplying tidal volume by the difference between arterial carbon dioxide pressure (PaCO2) and end-tidal carbon dioxide pressure (PeCO2) and then dividing the result by PaCO2.

    • This question is part of the following fields:

      • Respiratory System
      14.9
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  • Question 28 - A 63-year-old man visits his GP complaining of worsening shortness of breath. He...

    Correct

    • A 63-year-old man visits his GP complaining of worsening shortness of breath. He was diagnosed with COPD six years ago and has been frequently admitted to the emergency department due to lower respiratory tract infections, especially in the past year. He has a smoking history of 50 pack-years and currently smokes 20 cigarettes per day.

      During the examination, the patient appears to be struggling to breathe even at rest and is in the tripod position. His heart rate is 78/min, blood pressure is 140/88 mmHg, oxygen saturation is 88% on air, respiratory rate is 26 breaths per minute, and temperature is 36.4ÂșC. His chest expansion is symmetrical, and breath sounds are equal throughout the lung fields.

      Recent spirometry results show that his FEV1 was 47% a week ago, 53% a month ago, and 67% six months ago. What intervention would be most effective in slowing the decline of his FEV1?

      Your Answer: Smoking cessation

      Explanation:

      Slowing the decrease in FEV1 in COPD can be most effectively achieved by quitting smoking.

      The National Institute for Health and Care Excellence (NICE) updated its guidelines on the management of chronic obstructive pulmonary disease (COPD) in 2018. The guidelines recommend general management strategies such as smoking cessation advice, annual influenzae vaccination, and one-off pneumococcal vaccination. Pulmonary rehabilitation is also recommended for patients who view themselves as functionally disabled by COPD.

      Bronchodilator therapy is the first-line treatment for patients who remain breathless or have exacerbations despite using short-acting bronchodilators. The next step is determined by whether the patient has asthmatic features or features suggesting steroid responsiveness. NICE suggests several criteria to determine this, including a previous diagnosis of asthma or atopy, a higher blood eosinophil count, substantial variation in FEV1 over time, and substantial diurnal variation in peak expiratory flow.

      If the patient does not have asthmatic features or features suggesting steroid responsiveness, a long-acting beta2-agonist (LABA) and long-acting muscarinic antagonist (LAMA) should be added. If the patient is already taking a short-acting muscarinic antagonist (SAMA), it should be discontinued and switched to a short-acting beta2-agonist (SABA). If the patient has asthmatic features or features suggesting steroid responsiveness, a LABA and inhaled corticosteroid (ICS) should be added. If the patient remains breathless or has exacerbations, triple therapy (LAMA + LABA + ICS) should be offered.

      NICE only recommends theophylline after trials of short and long-acting bronchodilators or to people who cannot use inhaled therapy. Azithromycin prophylaxis is recommended in select patients who have optimised standard treatments and continue to have exacerbations. Mucolytics should be considered in patients with a chronic productive cough and continued if symptoms improve.

      Cor pulmonale features include peripheral oedema, raised jugular venous pressure, systolic parasternal heave, and loud P2. Loop diuretics should be used for oedema, and long-term oxygen therapy should be considered. Smoking cessation, long-term oxygen therapy in eligible patients, and lung volume reduction surgery in selected patients may improve survival in patients with stable COPD. NICE does not recommend the use of ACE-inhibitors, calcium channel blockers, or alpha blockers

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      • Respiratory System
      28.4
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  • Question 29 - A 59-year-old woman visits the respiratory clinic for spirometry testing. As part of...

    Incorrect

    • A 59-year-old woman visits the respiratory clinic for spirometry testing. As part of the testing, what is the definition of functional residual capacity?

      Your Answer: Functional residual capacity = inspiratory capacity - inspiratory reserve volume

      Correct Answer: Functional residual capacity = expiratory reserve volume + residual volume

      Explanation:

      To calculate the volume of air in the lungs after a normal relaxed expiration, one can use the formula for functional residual capacity (FRC), which is determined by the balance between the lungs’ tendency to recoil inwards and the chest wall’s tendency to pull outwards. FRC can be calculated by adding the expiratory reserve volume and the residual volume. In individuals with tetraplegia, decreases in FRC are primarily caused by a reduction in the outward pull of the chest wall, which occurs over time due to the inability to regularly expand the chest wall to large lung volumes. This reduction in FRC can increase the risk of atelectasis.

      Understanding Lung Volumes in Respiratory Physiology

      In respiratory physiology, lung volumes can be measured to determine the amount of air that moves in and out of the lungs during breathing. The diagram above shows the different lung volumes that can be measured.

      Tidal volume (TV) refers to the amount of air that is inspired or expired with each breath at rest. In males, the TV is 500ml while in females, it is 350ml.

      Inspiratory reserve volume (IRV) is the maximum volume of air that can be inspired at the end of a normal tidal inspiration. The inspiratory capacity is the sum of TV and IRV. On the other hand, expiratory reserve volume (ERV) is the maximum volume of air that can be expired at the end of a normal tidal expiration.

      Residual volume (RV) is the volume of air that remains in the lungs after maximal expiration. It increases with age and can be calculated by subtracting ERV from FRC. Speaking of FRC, it is the volume in the lungs at the end-expiratory position and is equal to the sum of ERV and RV.

      Vital capacity (VC) is the maximum volume of air that can be expired after a maximal inspiration. It decreases with age and can be calculated by adding inspiratory capacity and ERV. Lastly, total lung capacity (TLC) is the sum of vital capacity and residual volume.

      Physiological dead space (VD) is calculated by multiplying tidal volume by the difference between arterial carbon dioxide pressure (PaCO2) and end-tidal carbon dioxide pressure (PeCO2) and then dividing the result by PaCO2.

    • This question is part of the following fields:

      • Respiratory System
      19
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  • Question 30 - A 29-year-old man comes to the clinic with a complaint of ear pain....

    Incorrect

    • A 29-year-old man comes to the clinic with a complaint of ear pain. He mentions that the pain started yesterday and has been preventing him from working. He also reports experiencing dizziness and muffled sounds on the affected side. During the examination, you notice that he has a fever and a bulging tympanic membrane with visible fluid. Based on these symptoms, you suspect that he has a middle ear infection. Now, you wonder which ossicle the tensor tympani muscle inserts into.

      Which ossicle does the tensor tympani muscle insert into?

      Your Answer: Stapes

      Correct Answer: Malleus

      Explanation:

      The tensor tympani muscle is located in a bony canal above the pharyngotympanic tube and originates from the cartilaginous portion of the tube, the bony canal, and the greater wing of the sphenoid bone. Its function is to reduce the magnitude of vibrations transmitted into the middle ear by pulling the handle of the malleus medially when contracted. This muscle is innervated by the nerve to tensor tympani, which arises from the mandibular nerve.

      The middle ear contains three ossicles, which are the malleus, incus, and stapes. The malleus is the most lateral and attaches to the tympanic membrane, while the incus lies between and articulates with the other two ossicles. The stapes is the most medial and is connected to the oval window of the cochlea. The stapedius muscle is associated with the stapes. The lunate and trapezium are not bones of the middle ear but are carpal bones.

      A patient with ear pain, difficulty hearing, dizziness, and fever may have otitis media, which is confirmed on otoscopy by a bulging tympanic membrane and visible fluid level.

      Anatomy of the Ear

      The ear is divided into three distinct regions: the external ear, middle ear, and internal ear. The external ear consists of the auricle and external auditory meatus, which are innervated by the greater auricular nerve and auriculotemporal branch of the trigeminal nerve. The middle ear is the space between the tympanic membrane and cochlea, and is connected to the nasopharynx by the eustachian tube. The tympanic membrane is composed of three layers and is approximately 1 cm in diameter. The middle ear is innervated by the glossopharyngeal nerve. The ossicles, consisting of the malleus, incus, and stapes, transmit sound vibrations from the tympanic membrane to the inner ear. The internal ear contains the cochlea, which houses the organ of corti, the sense organ of hearing. The vestibule accommodates the utricule and saccule, which contain endolymph and are surrounded by perilymph. The semicircular canals, which share a common opening into the vestibule, lie at various angles to the petrous temporal bone.

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