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  • Question 1 - A 9-month-old girl is brought to the emergency department by her mother due...

    Correct

    • A 9-month-old girl is brought to the emergency department by her mother due to difficulty in breathing. The mother reports that her daughter has been restless, with a runny nose, feeling warm and a dry cough for the past 4 days. However, the mother is now quite worried because her daughter has not eaten since last night and her breathing seems to have worsened throughout the morning.

      During the examination, the infant has a respiratory rate of 70/min, heart rate of 155/min, oxygen saturation of 92% and a temperature of 37.9ºC. The infant shows signs of nasal flaring and subcostal recession while breathing. On auscultation, widespread wheezing is heard. The infant is admitted, treated with humidified oxygen via nasal cannula and discharged home after 2 days.

      What is the probable causative agent of this infant's illness?

      Your Answer: Respiratory syncytial virus

      Explanation:

      Bronchiolitis typically presents with symptoms such as coryza and increased breathing effort, leading to feeding difficulties in children under one year of age. The majority of cases of bronchiolitis are caused by respiratory syncytial virus, while adenovirus is a less frequent culprit. On the other hand, croup is most commonly caused by parainfluenza virus.

      Understanding Bronchiolitis

      Bronchiolitis is a condition that is characterized by inflammation of the bronchioles. It is a serious lower respiratory tract infection that is most common in children under the age of one year. The pathogen responsible for 75-80% of cases is respiratory syncytial virus (RSV), while other causes include mycoplasma and adenoviruses. Bronchiolitis is more serious in children with bronchopulmonary dysplasia, congenital heart disease, or cystic fibrosis.

      The symptoms of bronchiolitis include coryzal symptoms, dry cough, increasing breathlessness, and wheezing. Fine inspiratory crackles may also be present. Children with bronchiolitis may experience feeding difficulties associated with increasing dyspnoea, which is often the reason for hospital admission.

      Immediate referral to hospital is recommended if the child has apnoea, looks seriously unwell to a healthcare professional, has severe respiratory distress, central cyanosis, or persistent oxygen saturation of less than 92% when breathing air. Clinicians should consider referring to hospital if the child has a respiratory rate of over 60 breaths/minute, difficulty with breastfeeding or inadequate oral fluid intake, or clinical dehydration.

      The investigation for bronchiolitis involves immunofluorescence of nasopharyngeal secretions, which may show RSV. Management of bronchiolitis is largely supportive, with humidified oxygen given via a head box if oxygen saturations are persistently < 92%. Nasogastric feeding may be needed if children cannot take enough fluid/feed by mouth, and suction is sometimes used for excessive upper airway secretions.

    • This question is part of the following fields:

      • Respiratory System
      13.4
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  • Question 2 - 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.

    • This question is part of the following fields:

      • Respiratory System
      34
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  • Question 3 - A 25-year-old man is shot in the chest during a robbery. The right...

    Correct

    • A 25-year-old man is shot in the chest during a robbery. The right lung is lacerated and is bleeding. An emergency thoracotomy is performed. The surgeons place a clamp over the hilum of the right lung. Which one of the following structures lies most anteriorly at this level?

      Your Answer: Phrenic nerve

      Explanation:

      At this location, the phrenic nerve is situated in front. The vagus nerve runs in front and then curves backwards just above the base of the left bronchus, releasing the recurrent laryngeal nerve as it curves.

      Anatomy of the Lungs

      The lungs are a pair of organs located in the chest cavity that play a vital role in respiration. The right lung is composed of three lobes, while the left lung has two lobes. The apex of both lungs is approximately 4 cm superior to the sternocostal joint of the first rib. The base of the lungs is in contact with the diaphragm, while the costal surface corresponds to the cavity of the chest. The mediastinal surface contacts the mediastinal pleura and has the cardiac impression. The hilum is a triangular depression above and behind the concavity, where the structures that form the root of the lung enter and leave the viscus. The right main bronchus is shorter, wider, and more vertical than the left main bronchus. The inferior borders of both lungs are at the 6th rib in the mid clavicular line, 8th rib in the mid axillary line, and 10th rib posteriorly. The pleura runs two ribs lower than the corresponding lung level. The bronchopulmonary segments of the lungs are divided into ten segments, each with a specific function.

    • This question is part of the following fields:

      • Respiratory System
      305.4
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  • Question 4 - A 70-year-old man visits a respiratory clinic complaining of shortness of breath even...

    Correct

    • A 70-year-old man visits a respiratory clinic complaining of shortness of breath even with minimal activity. Upon conducting a thorough assessment, you suspect that he may have idiopathic pulmonary fibrosis. To aid in your diagnosis, you decide to review his previous medical records. You come across the following spirometry results:

      Measurement volume (ml)
      Vital Capacity (VC) 4400
      Inspiratory Reserve Volume (IRV) 3000
      Functional Residual Capacity (FRC) 2800
      Residual Volume (RV) 1200

      What is the total lung capacity (TLC) of this patient?

      Your Answer: 5600ml

      Explanation:

      The correct answer is 5600ml, which represents the total lung capacity. This value is obtained by adding the vital capacity, which is the maximum amount of air that can be breathed out after a deep inhalation, to the residual volume, which is the amount of air that remains in the lungs after a maximal exhalation. The vital capacity is composed of three volumes: the inspiratory reserve volume, the tidal volume, and the expiratory reserve volume. Other formulas are available to calculate different lung volumes, but they are not as commonly used.

      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
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  • Question 5 - A 67-year-old man with a suspected ruptured abdominal aortic aneurysm is brought to...

    Incorrect

    • A 67-year-old man with a suspected ruptured abdominal aortic aneurysm is brought to the emergency department. Upon arrival, the patient appears pale, cold, and clammy. His vital signs are as follows: temperature 35.3 degrees Celsius, respiratory rate 40, heart rate 116bpm, and blood pressure 90/65mmHg.

      When there is a decrease in the concentration of oxygen in the blood, the inspiratory center is stimulated, and any voluntary cortical control of breathing pattern is overridden. Where are the peripheral chemoreceptors located that detect these changes?

      Your Answer: Internal carotid artery

      Correct Answer: Aortic arch

      Explanation:

      The peripheral chemoreceptors, found in the aortic and carotid bodies, are capable of detecting alterations in the levels of carbon dioxide in the arterial blood. These receptors are located in the aortic arch and at the bifurcation of the common carotid artery. However, they are not as sensitive as the central chemoreceptors in the medulla oblongata, which monitor the cerebrospinal fluid. It is important to note that there are no peripheral chemoreceptors present in veins.

      The Control of Ventilation in the Human Body

      The control of ventilation in the human body is a complex process that involves various components working together to regulate the respiratory rate and depth of respiration. The respiratory centres, chemoreceptors, lung receptors, and muscles all play a role in this process. The automatic, involuntary control of respiration occurs from the medulla, which is responsible for controlling the respiratory rate and depth of respiration.

      The respiratory centres consist of the medullary respiratory centre, apneustic centre, and pneumotaxic centre. The medullary respiratory centre has two groups of neurons, the ventral group, which controls forced voluntary expiration, and the dorsal group, which controls inspiration. The apneustic centre, located in the lower pons, stimulates inspiration and activates and prolongs inhalation. The pneumotaxic centre, located in the upper pons, inhibits inspiration at a certain point and fine-tunes the respiratory rate.

      Ventilatory variables, such as the levels of pCO2, are the most important factors in ventilation control, while levels of O2 are less important. Peripheral chemoreceptors, located in the bifurcation of carotid arteries and arch of the aorta, respond to changes in reduced pO2, increased H+, and increased pCO2 in arterial blood. Central chemoreceptors, located in the medulla, respond to increased H+ in brain interstitial fluid to increase ventilation. It is important to note that the central receptors are not influenced by O2 levels.

      Lung receptors also play a role in the control of ventilation. Stretch receptors respond to lung stretching, causing a reduced respiratory rate, while irritant receptors respond to smoke, causing bronchospasm. J (juxtacapillary) receptors are also involved in the control of ventilation. Overall, the control of ventilation is a complex process that involves various components working together to regulate the respiratory rate and depth of respiration.

    • This question is part of the following fields:

      • Respiratory System
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  • Question 6 - A 29-year-old man visits his GP with a complaint of a persistent cough....

    Incorrect

    • A 29-year-old man visits his GP with a complaint of a persistent cough. He reports coughing up large amounts of yellow sputum and occasionally blood on a daily basis for the past few years. Lately, he has noticed that his clothes seem loose on him and he frequently feels fatigued.

      What is the most probable underlying condition responsible for this patient's symptoms?

      Your Answer: Goodpasture's disease

      Correct Answer: Kartagener's syndrome

      Explanation:

      Kartagener’s syndrome is a condition that can lead to bronchiectasis due to a defect in the cilia, which impairs the lungs’ ability to clear mucus. Bronchiectasis is diagnosed when a person produces large amounts of sputum daily, experiences haemoptysis, and loses weight. While other conditions may cause tiredness, weight loss, or haemoptysis, they are not typically associated with bronchiectasis.

      Understanding Kartagener’s Syndrome

      Kartagener’s syndrome, also known as primary ciliary dyskinesia, is a rare genetic disorder that was first described in 1933. It is often associated with dextrocardia, which can be detected through quiet heart sounds and small volume complexes in lateral leads during examinations. The pathogenesis of Kartagener’s syndrome is caused by a dynein arm defect, which results in immotile cilia.

      The features of Kartagener’s syndrome include dextrocardia or complete situs inversus, bronchiectasis, recurrent sinusitis, and subfertility. The latter is due to diminished sperm motility and defective ciliary action in the fallopian tubes. It is important to note that Kartagener’s syndrome is a rare disorder, and diagnosis can be challenging. However, early detection and management can help improve the quality of life for those affected by this condition.

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      • Respiratory System
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  • Question 7 - A 75-year-old man visits his doctor complaining of weight loss and feeling full...

    Correct

    • A 75-year-old man visits his doctor complaining of weight loss and feeling full quickly. During the abdominal examination, the doctor notices a swollen lymph node in the left supraclavicular region. The doctor suspects that this could be a sign of gastric cancer with the spread of tumor emboli through the thoracic duct as it ascends from the abdomen into the mediastinum. Can you name the two other structures that pass through the diaphragm along with the thoracic duct?

      Your Answer: Aorta and azygous vein

      Explanation:

      The point at which the aorta, thoracic duct, and azygous vein cross the diaphragm is at T12, specifically at the aortic opening. This is also where the oesophageal branches of the left gastric veins, the vagal trunk, and the oesophagus pass through the diaphragm, at the oesophageal opening located at T10. The left phrenic nerve and sympathetic trunk have their own separate openings in the diaphragm. A lymph node in the left supraclavicular fossa, known as Virchow’s node, is a characteristic sign of early gastric carcinoma.

      Structures Perforating the Diaphragm

      The diaphragm is a dome-shaped muscle that separates the thoracic and abdominal cavities. It plays a crucial role in breathing by contracting and relaxing to create negative pressure in the lungs. However, there are certain structures that perforate the diaphragm, allowing them to pass through from the thoracic to the abdominal cavity. These structures include the inferior vena cava at the level of T8, the esophagus and vagal trunk at T10, and the aorta, thoracic duct, and azygous vein at T12.

      To remember these structures and their corresponding levels, a helpful mnemonic is I 8(ate) 10 EGGS AT 12. This means that the inferior vena cava is at T8, the esophagus and vagal trunk are at T10, and the aorta, thoracic duct, and azygous vein are at T12. Knowing these structures and their locations is important for medical professionals, as they may need to access or treat them during surgical procedures or diagnose issues related to them.

    • This question is part of the following fields:

      • Respiratory System
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  • Question 8 - A father brings his 5-year-old daughter to the GP with a 72-hour history...

    Incorrect

    • A father brings his 5-year-old daughter to the GP with a 72-hour history of left ear pain. She has had a cough with coryzal symptoms for the past four days. She has no past medical history, allergies or current medications, and she is up-to-date with her vaccinations. Her temperature is 38.5ºC. No abnormality is detected on examination of the oral cavity. Following otoscopy, what is the most likely causative pathogen for her diagnosis of otitis media?

      Your Answer: Candida albicans

      Correct Answer: Streptococcus pneumoniae

      Explanation:

      Otitis media is primarily caused by bacteria, with viral URTIs often preceding the infection. The majority of cases are secondary to bacterial infections, with the most common culprit being…

      Acute otitis media is a common condition in young children, often caused by bacterial infections following viral upper respiratory tract infections. Symptoms include ear pain, fever, and hearing loss, and diagnosis is based on criteria such as the presence of a middle ear effusion and inflammation of the tympanic membrane. Antibiotics may be prescribed in certain cases, and complications can include perforation of the tympanic membrane, hearing loss, and more serious conditions such as meningitis and brain abscess.

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      • Respiratory System
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  • Question 9 - An 83-year-old man is on the stroke ward after suffering a total anterior...

    Incorrect

    • An 83-year-old man is on the stroke ward after suffering a total anterior circulation stroke of the left hemisphere. He is receiving assistance from the physiotherapists to mobilize, but the speech and language team has determined that he has an unsafe swallow. On the 6th day of his hospital stay, he begins to feel unwell.

      Upon examination, his temperature is 38.4ºC, heart rate of 112/min, respiratory rate of 18, and his blood pressure is 100/76 mmHg. Aspiration pneumonia is suspected. Which area of the body is most likely affected?

      Your Answer: Left lower lobe

      Correct Answer: Right middle lobe

      Explanation:

      Aspiration pneumonia is a common occurrence in stroke patients during the recovery phase, with a higher likelihood of affecting the right lung due to the steeper course of the right bronchus. This type of pneumonia is often caused by unsafe swallowing and can lead to prolonged hospital stays and increased mortality rates. The right middle and lower lobes are the most susceptible to aspirated gastric contents, while the right upper lobe is less likely due to gravity. It’s important to consider aspiration pneumonia as a differential diagnosis when assessing stroke patients, especially those with severe pathology.

      Aspiration pneumonia is a type of pneumonia that occurs when foreign substances, such as food or saliva, enter the bronchial tree. This can lead to inflammation and a chemical pneumonitis, as well as the introduction of bacterial pathogens. The condition is often caused by an impaired swallowing mechanism, which can be a result of neurological disease or injury, intoxication, or medical procedures such as intubation. Risk factors for aspiration pneumonia include poor dental hygiene, swallowing difficulties, prolonged hospitalization or surgery, impaired consciousness, and impaired mucociliary clearance. The right middle and lower lung lobes are typically the most affected areas. The bacteria involved in aspiration pneumonia can be aerobic or anaerobic, with examples including Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa, Klebsiella, Bacteroides, Prevotella, Fusobacterium, and Peptostreptococcus.

    • This question is part of the following fields:

      • Respiratory System
      90.3
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  • Question 10 - What is the anatomical level of the transpyloric plane? ...

    Incorrect

    • What is the anatomical level of the transpyloric plane?

      Your Answer: L4

      Correct Answer: L1

      Explanation:

      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
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  • Question 11 - A 24-year-old male patient arrives at the Emergency Department complaining of abdominal pain,...

    Incorrect

    • A 24-year-old male patient arrives at the Emergency Department complaining of abdominal pain, nausea, vomiting, and a decreased level of consciousness. Upon examination, the patient exhibits Kussmaul respiration and an acetone-like breath odor.

      What type of metabolic disturbance is most consistent with the symptoms and presentation of this patient?

      Your Answer: Respiratory acidosis, oxygen dissociation curve shifts to the right

      Correct Answer: Metabolic acidosis, oxygen dissociation curve shifts to the right

      Explanation:

      The correct answer is that metabolic acidosis shifts the oxygen dissociation curve to the right. This is seen in the condition described in the question, diabetic ketoacidosis, which is associated with metabolic acidosis. Acidosis causes more oxygen to be unloaded from haemoglobin, leading to a rightward shift in the curve. The other answer options are incorrect, as they either describe a different type of acidosis or an incorrect direction of the curve shift.

      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
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  • Question 12 - A father brings his 9-year-old daughter to your general practice, as he is...

    Incorrect

    • A father brings his 9-year-old daughter to your general practice, as he is worried about her hearing. He notices that he has to repeat himself when talking to her, and thinks she is often 'in her own little world'. During the examination, the Rinne test is positive on the left and negative on the right. What conclusions can be drawn from this?

      Your Answer: Conductive hearing loss on the left.

      Correct Answer: Can not tell if both sides are affected.

      Explanation:

      The Rinne and Weber tests are used to diagnose hearing loss. The Rinne test involves comparing air and bone conduction, with a positive result indicating a healthy or sensorineural loss and a negative result indicating a conductive loss. The Weber test involves placing a tuning fork on the forehead and determining if the sound is symmetrical or louder on one side, with a conductive loss resulting in louder sound on the affected side and a sensorineural loss resulting in louder sound on the non-affected side. When used together, these tests can provide more information about the type and affected side of hearing loss.

      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 13 - An 80-year-old man with metastatic lung cancer arrives at the acute medical unit...

    Incorrect

    • An 80-year-old man with metastatic lung cancer arrives at the acute medical unit with sudden shortness of breath. A chest x-ray shows a malignant pleural effusion encasing the right lung. The medical registrar intends to perform a pleural tap to drain the effusion and send a sample to the lab. The registrar takes into account the effusion's position around the lung. What is the minimum level of the effusion in the mid-axillary line?

      Your Answer: 8th rib

      Correct Answer: 10th rib

      Explanation:

      The parietal pleura can be found at the 10th rib in the mid-axillary line, while the visceral pleura is closely attached to the lung tissue and can be considered as one. The location of the parietal pleura is more inferior than that of the visceral pleura, with the former being at the 8th rib in the midclavicular line and the 10th rib in the midaxillary line. The location of the parietal pleura in the scapular line is not specified.

      Anatomy of the Lungs

      The lungs are a pair of organs located in the chest cavity that play a vital role in respiration. The right lung is composed of three lobes, while the left lung has two lobes. The apex of both lungs is approximately 4 cm superior to the sternocostal joint of the first rib. The base of the lungs is in contact with the diaphragm, while the costal surface corresponds to the cavity of the chest. The mediastinal surface contacts the mediastinal pleura and has the cardiac impression. The hilum is a triangular depression above and behind the concavity, where the structures that form the root of the lung enter and leave the viscus. The right main bronchus is shorter, wider, and more vertical than the left main bronchus. The inferior borders of both lungs are at the 6th rib in the mid clavicular line, 8th rib in the mid axillary line, and 10th rib posteriorly. The pleura runs two ribs lower than the corresponding lung level. The bronchopulmonary segments of the lungs are divided into ten segments, each with a specific function.

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      • Respiratory System
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  • Question 14 - Sophie is a 15-year-old girl who has been brought to your GP clinic...

    Correct

    • Sophie is a 15-year-old girl who has been brought to your GP clinic by her father. She has not yet started to develop breasts or have her first period. She does not seem worried, but her father is concerned. Sophie has a history of eczema and has been using topical steroids for several years. When her father leaves the room, she also admits to occasionally using tanning beds.

      What could be a possible cause of delayed puberty in Sophie?

      Your Answer: Cystic fibrosis

      Explanation:

      Delayed puberty can be caused by various factors, with constitutional delay being the most common cause. However, other causes must be ruled out before diagnosing constitutional delay. Some of these causes include chronic illnesses like kidney disease and Crohn’s disease, malnutrition from conditions such as anorexia nervosa, cystic fibrosis, and coeliac disease, excessive physical exercise, psychosocial deprivation, steroid therapy, hypothyroidism, tumours near the hypothalamo-pituitary axis, congenital anomalies like septo-optic dysplasia and congenital panhypopituitarism, irradiation treatment, and trauma such as surgery or head injury.

      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.

    • This question is part of the following fields:

      • Respiratory System
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  • Question 15 - A 25-year-old female presents to the emergency department with complaints of shortness of...

    Incorrect

    • A 25-year-old female presents to the emergency department with complaints of shortness of breath that started 2 hours ago. She has no medical history. The results of her arterial blood gas (ABG) test are as follows:

      Normal range
      pH: 7.49 (7.35 - 7.45)
      pO2: 12.2 (10 - 14)kPa
      pCO2: 3.4 (4.5 - 6.0)kPa
      HCO3: 22 (22 - 26)mmol/l
      BE: +2 (-2 to +2)mmol/l

      Her temperature is 37ºC, and her pulse is 98 beats/minute and regular. Based on this information, what is the most likely diagnosis?

      Your Answer: Asthma exacerbation

      Correct Answer: Anxiety hyperventilation

      Explanation:

      The patient is exhibiting symptoms and ABG results consistent with respiratory alkalosis. However, it is important to conduct a thorough history and physical examination to rule out any underlying pulmonary pathology or infection. Based on the patient’s history, anxiety-induced hyperventilation is the most probable cause of her condition.

      Respiratory Alkalosis: Causes and Examples

      Respiratory alkalosis is a condition that occurs when the blood pH level rises above the normal range due to excessive breathing. This can be caused by various factors, including anxiety, pulmonary embolism, CNS disorders, altitude, and pregnancy. Salicylate poisoning can also lead to respiratory alkalosis, but it may also cause metabolic acidosis in the later stages. In this case, the respiratory centre is stimulated early, leading to respiratory alkalosis, while the direct acid effects of salicylates combined with acute renal failure may cause acidosis later on. It is important to identify the underlying cause of respiratory alkalosis to determine the appropriate treatment. Proper management can help prevent complications and improve the patient’s overall health.

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      • Respiratory System
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  • Question 16 - A 32-year-old woman arrives at the emergency department complaining of sudden shortness of...

    Incorrect

    • A 32-year-old woman arrives at the emergency department complaining of sudden shortness of breath and a sharp pain on the right side of her chest that worsens with inspiration. Upon examination, the doctor observes hyper-resonance and reduced breath sounds on the right side of her chest.

      What is a risk factor for this condition, considering the probable diagnosis?

      Your Answer: Female sex

      Correct Answer: Cystic fibrosis

      Explanation:

      Pneumothorax can be identified by reduced breath sounds and a hyper-resonant chest on the same side as the pain. Cystic fibrosis is a significant risk factor for pneumothorax due to the frequent chest infections, lung remodeling, and air trapping associated with the disease. While tall, male smokers are also at increased risk, Marfan’s syndrome, not Turner syndrome, is a known risk factor.

      Pneumothorax: Characteristics and Risk Factors

      Pneumothorax is a medical condition characterized by the presence of air in the pleural cavity, which is the space between the lungs and the chest wall. This condition can occur spontaneously or as a result of trauma or medical procedures. There are several risk factors associated with pneumothorax, including pre-existing lung diseases such as COPD, asthma, cystic fibrosis, lung cancer, and Pneumocystis pneumonia. Connective tissue diseases like Marfan’s syndrome and rheumatoid arthritis can also increase the risk of pneumothorax. Ventilation, including non-invasive ventilation, can also be a risk factor.

      Symptoms of pneumothorax tend to come on suddenly and can include dyspnoea, chest pain (often pleuritic), sweating, tachypnoea, and tachycardia. In some cases, catamenial pneumothorax can be the cause of spontaneous pneumothoraces occurring in menstruating women. This type of pneumothorax is thought to be caused by endometriosis within the thorax. Early diagnosis and treatment of pneumothorax are crucial to prevent complications and improve outcomes.

    • This question is part of the following fields:

      • Respiratory System
      53.2
      Seconds
  • Question 17 - Which of the following paraneoplastic manifestations is the LEAST frequent in individuals diagnosed...

    Correct

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

      Your 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.

    • This question is part of the following fields:

      • Respiratory System
      21
      Seconds
  • Question 18 - A 43-year-old woman comes to the respiratory clinic for an outpatient appointment. She...

    Incorrect

    • A 43-year-old woman comes to the respiratory clinic for an outpatient appointment. She has been experiencing increased breathlessness, particularly at night. Her medical history includes long-standing COPD, heart failure, and previous breast cancer that was treated with a mastectomy and radiotherapy. She used to smoke 20 cigarettes a day for 22 years but has since quit.

      During the examination, her respiratory rate is 23/min, oxygen saturation is 93%, blood pressure is 124/98mmHg, and temperature is 37.2ºC. A gas transfer test is performed, and her transfer factor is found to be low.

      What is the most likely diagnosis?

      Your Answer: Asthma

      Correct Answer: Pulmonary oedema

      Explanation:

      TLCO, also known as transfer factor, is a measurement of how quickly gas can move from a person’s lungs into their bloodstream. To test TLCO, a patient inhales a mixture of carbon monoxide and a tracer gas, holds their breath for 10 seconds, and then exhales forcefully. The exhaled gas is analyzed to determine how much tracer gas was absorbed during the 10-second period.

      A high TLCO value is associated with conditions such as asthma, pulmonary hemorrhage, left-to-right cardiac shunts, polycythemia, hyperkinetic states, male gender, and exercise. Conversely, most other conditions result in a low TLCO value, including pulmonary fibrosis, pneumonia, pulmonary emboli, pulmonary edema, emphysema, and anemia.

      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.

    • This question is part of the following fields:

      • Respiratory System
      101.3
      Seconds
  • Question 19 - A 9-year-old boy is rushed to the emergency department following a fish bone...

    Correct

    • A 9-year-old boy is rushed to the emergency department following a fish bone choking incident during dinner. The patient is not experiencing any airway obstruction and has been given sufficient pain relief.

      After being referred for laryngoscopy, a fish bone is discovered in the piriform recess. What is the potential structure that could be harmed due to the location of the fish bone?

      Your Answer: Internal laryngeal nerve

      Explanation:

      Foreign objects lodged in the piriform recess can cause damage to the internal laryngeal nerve, which is in close proximity to this area. The internal laryngeal nerve is responsible for providing sensation to the laryngeal mucosa. The ansa cervicalis, external laryngeal nerve, glossopharyngeal nerve, and superior laryngeal nerve are not at high risk of injury from foreign bodies in the piriform 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
      17.7
      Seconds
  • Question 20 - A middle-aged woman with myasthenia gravis experiences a myasthenic crisis leading to respiratory...

    Incorrect

    • A middle-aged woman with myasthenia gravis experiences a myasthenic crisis leading to respiratory failure. Which nerve root is most commonly affected in this scenario?

      Your Answer: C2

      Correct Answer: C4

      Explanation:

      The phrenic nerve receives input from C3, C4, and C5, which is essential for keeping the diaphragm functioning properly. In cases of medical emergencies, mechanical ventilation is often the first-line management. C2 primarily innervates muscles in the neck, while C7 and T1 are part of the brachial plexus and contribute to the formation of nerves in the upper limb.

      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.

    • This question is part of the following fields:

      • Respiratory System
      14.6
      Seconds
  • Question 21 - Which one of the following is true regarding the phrenic nerves? ...

    Incorrect

    • Which one of the following is true regarding the phrenic nerves?

      Your Answer: None of the above

      Correct Answer: They both lie anterior to the hilum of the lungs

      Explanation:

      The phrenic nerves, located in the anterior region of the lung’s hilum, play a crucial role in keeping the diaphragm functioning properly. These nerves have both sensory and motor functions, and any issues in the sub diaphragmatic area may result in referred pain in the shoulder.

      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.

    • This question is part of the following fields:

      • Respiratory System
      24.3
      Seconds
  • Question 22 - A 50-year-old man with laryngeal cancer is undergoing a challenging laryngectomy. During the...

    Incorrect

    • A 50-year-old man with laryngeal cancer is undergoing a challenging laryngectomy. During the procedure, the surgeons cut the thyrocervical trunk. What vessel does this structure typically originate from?

      Your Answer: Internal carotid artery

      Correct Answer: Subclavian artery

      Explanation:

      The subclavian artery gives rise to the thyrocervical trunk, which emerges from the first part of the artery located between the inner border of scalenus anterior and the subclavian artery. The thyrocervical trunk branches off from the subclavian artery after the vertebral artery.

      Thoracic Outlet: Where the Subclavian Artery and Vein and Brachial Plexus Exit the Thorax

      The thoracic outlet is the area where the subclavian artery and vein and the brachial plexus exit the thorax and enter the arm. This passage occurs over the first rib and under the clavicle. The subclavian vein is the most anterior structure and is located immediately in front of scalenus anterior and its attachment to the first rib. Scalenus anterior has two parts, and the subclavian artery leaves the thorax by passing over the first rib and between these two portions of the muscle. At the level of the first rib, the lower cervical nerve roots combine to form the three trunks of the brachial plexus. The lowest trunk is formed by the union of C8 and T1, and this trunk lies directly posterior to the artery and is in contact with the superior surface of the first rib.

      Thoracic outlet obstruction can cause neurovascular compromise.

    • This question is part of the following fields:

      • Respiratory System
      31.5
      Seconds
  • Question 23 - A 23-year-old woman comes to your clinic complaining of difficulty hearing her partner...

    Incorrect

    • A 23-year-old woman comes to your clinic complaining of difficulty hearing her partner at home. She has been experiencing a high-pitched ringing in her left ear for the past 6 months. She attributes this to attending loud concerts frequently and has not sought medical attention until now. She reports that she can hear better when she is outside but struggles in quiet environments. Upon examination, there are no abnormalities seen during otoscopy. One of the possible diagnoses for this patient is otosclerosis, a condition that primarily affects the stapes bone. Which structure does the stapes bone come into contact with in the cochlea?

      Your Answer: Tectorial membrane

      Correct Answer: Oval window

      Explanation:

      The oval window is where the stapes connects with the cochlea, and it is the most inner of the ossicles. The stapes has a stirrup-like shape, with a head that articulates with the incus and two limbs that connect it to the base. The base of the stapes is in contact with the oval window, which is one of the only two openings between the middle and inner ear. The organ of Corti, which is responsible for hearing, is located on the basilar membrane within the cochlear duct. The round window is the other opening between the middle and inner ear, and it allows the fluid within the cochlea to move, transmitting sound to the hair cells. The helicotrema is the point where the scala tympani and scala vestibuli meet at the apex of the cochlear labyrinth. The tectorial membrane is a membrane that extends along the entire length of the cochlea. A female in her third decade of life with unilateral conductive hearing loss and a family history of hearing loss is likely to have otosclerosis, a condition that affects the stapes and can cause severe or total hearing loss due to abnormal bone growth and fusion with the cochlea.

      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.

    • This question is part of the following fields:

      • Respiratory System
      29
      Seconds
  • Question 24 - Which of the structures listed below are not located within the mediastinum? ...

    Incorrect

    • Which of the structures listed below are not located within the mediastinum?

      Your Answer: Arch of azygos vein

      Correct Answer: Vertebral bodies

      Explanation:

      Both the lungs and vertebral bodies are located outside of the mediastinum.

      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
      37.2
      Seconds
  • Question 25 - Which one of the following nerves conveys sensory information from the nasal mucosa?...

    Incorrect

    • Which one of the following nerves conveys sensory information from the nasal mucosa?

      Your Answer: Laryngeal branches of the trigeminal

      Correct Answer: Laryngeal branches of the vagus

      Explanation:

      The larynx receives sensory information from the laryngeal branches of the vagus.

      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
      53
      Seconds
  • Question 26 - During a clinical trial examining oxygen consumption during exercise, participants aged 50 and...

    Incorrect

    • During a clinical trial examining oxygen consumption during exercise, participants aged 50 and above engage in high-intensity interval training exercises for 20 minutes while physiological measurements are recorded. What is the primary factor that is likely to restrict oxygen supply to tissues after the training session?

      Your Answer: Raised 2,3-DPG

      Correct Answer: Low pCO2

      Explanation:

      When the pCO2 is low, the oxygen dissociation curve shifts to the left, which increases the affinity of haemoglobin for oxygen. This can limit the amount of oxygen available to tissues. On the other hand, high levels of pCO2 (hypercarbia) shift the curve to the right, decreasing the affinity of haemoglobin for oxygen and increasing oxygen availability to tissues.

      In acidosis, the concentration of 2,3-diphosphoglycerate (DPG) increases, which binds to deoxyhaemoglobin and shifts the oxygen dissociation curve to the right. This results in increased oxygen release from the blood into tissues.

      Hyperthermia also shifts the oxygen dissociation curve to the right, while the performance-enhancing substance myo-inositol trispyrophosphate (ITPP) has a similar effect.

      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
      29.4
      Seconds
  • Question 27 - A 49-year-old woman of African descent visits her primary care physician with concerns...

    Correct

    • A 49-year-old woman of African descent visits her primary care physician with concerns about a lump in her neck that has been present for a week. She reports no significant increase in size and denies any pain or difficulty swallowing. The patient has no notable medical history, except for a visit to the eye doctor last year for a red-eye that required treatment with topical steroid drops. During the examination, the doctor observes some red, tender nodules on the patient's shin, which the patient says come and go and do not cause much discomfort. A chest x-ray reveals bilateral hilar lymphadenopathy with no other significant findings. What is typically linked to this patient's condition?

      Your Answer: Elevated angiotensin-converting enzyme levels

      Explanation:

      Sarcoidosis is likely in this patient based on their symptoms and examination findings, including a neck lump, tender nodules on the shin, and a history of red-eye. Bilateral lymphadenopathy on chest X-ray further supports the diagnosis, as does the presence of elevated angiotensin-converting enzyme levels, which are commonly seen in sarcoidosis. Hypercalcemia, fatigue, and uveitis are also associated with sarcoidosis, while exposure to silica is not supported by this patient’s presentation.

      Investigating Sarcoidosis

      Sarcoidosis is a disease that does not have a single diagnostic test, and therefore, diagnosis is mainly based on clinical observations. Although ACE levels may be used to monitor disease activity, they are not reliable in diagnosing sarcoidosis due to their low sensitivity and specificity. Routine blood tests may show hypercalcemia and a raised ESR.

      A chest x-ray is a common investigation for sarcoidosis and may reveal different stages of the disease. Stage 0 is normal, stage 1 shows bilateral hilar lymphadenopathy (BHL), stage 2 shows BHL and interstitial infiltrates, stage 3 shows diffuse interstitial infiltrates only, and stage 4 shows diffuse fibrosis. Other investigations, such as spirometry, may show a restrictive defect, while a tissue biopsy may reveal non-caseating granulomas. However, the Kveim test, which involves injecting part of the spleen from a patient with known sarcoidosis under the skin, is no longer performed due to concerns about cross-infection.

      In addition, a gallium-67 scan is not routinely used to investigate sarcoidosis. CT scans may also be used to investigate sarcoidosis, and they may show diffuse areas of nodularity predominantly in a peribronchial distribution with patchy areas of consolidation, particularly in the upper lobes. Ground glass opacities may also be present, but there are no gross reticular changes to suggest fibrosis.

      Overall, investigating sarcoidosis involves a combination of clinical observations, blood tests, chest x-rays, and other investigations such as spirometry and tissue biopsy. CT scans may also be used to provide more detailed information about the disease.

    • This question is part of the following fields:

      • Respiratory System
      61.1
      Seconds
  • Question 28 - A 65-year-old man presents with a persistent dry cough and unintentional weight loss...

    Incorrect

    • A 65-year-old man presents with a persistent dry cough and unintentional weight loss of 5kg over the past 3 months. He denies experiencing chest pain, dyspnoea, fever or haemoptysis. The patient has a history of smoking 10 cigarettes a day for the last 50 years and has been diagnosed with COPD. A nodule is detected on chest x-ray, and biopsy results indicate a tumour originating from the bronchial glands.

      What is the most probable diagnosis?

      Your Answer: Small cell carcinoma of the lung

      Correct Answer: Adenocarcinoma of the lung

      Explanation:

      Adenocarcinoma has become the most prevalent form of lung cancer, originating from the bronchial glands as a type of non-small-cell lung cancer.

      While a bronchogenic cyst may cause chest pain and dysphagia, it is typically diagnosed during childhood and does not stem from the bronchial glands.

      Sarcoidosis may result in a persistent cough and weight loss, but it typically affects multiple systems and does not involve nodules originating from the bronchial glands.

      Small cell carcinoma of the lung is a significant consideration, but given the description of a tumor originating from the bronchial glands, adenocarcinoma is the more probable diagnosis.

      Lung cancer can be classified into two main types: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). SCLC is less common, accounting for only 15% of cases, but has a worse prognosis. NSCLC, on the other hand, is more prevalent and can be further broken down into different subtypes. Adenocarcinoma is now the most common type of lung cancer, likely due to the increased use of low-tar cigarettes. It is often seen in non-smokers and accounts for 62% of cases in ‘never’ smokers. Squamous cell carcinoma is another subtype, and cavitating lesions are more common in this type of lung cancer. Large cell carcinoma, alveolar cell carcinoma, bronchial adenoma, and carcinoid are other subtypes of NSCLC. Differentiating between these subtypes is crucial as different drugs are available to treat each subtype.

    • This question is part of the following fields:

      • Respiratory System
      59
      Seconds
  • Question 29 - A 26-year-old man has been referred to ENT by his doctor as he...

    Correct

    • A 26-year-old man has been referred to ENT by his doctor as he has swallowed a small chicken bone that feels stuck in his throat. During laryngoscopy, a chicken bone is observed lodged in the piriform recess. Which of the following nerves is most likely to be affected by the chicken bone?

      Your Answer: Internal laryngeal nerve

      Explanation:

      When foreign objects get stuck in the piriform recess, particularly sharp items like bones from fish or chicken, they can harm the internal laryngeal nerve that lies beneath the mucous membrane in that area. Retrieving these objects also poses a risk of damaging the internal laryngeal nerve. However, the other nerves are not likely to be impacted.

      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
      9.5
      Seconds
  • Question 30 - A 72-year-old woman is brought to the stroke unit with a suspected stroke....

    Incorrect

    • A 72-year-old woman is brought to the stroke unit with a suspected stroke. She has a medical history of hypertension, type II diabetes, and hypothyroidism. Additionally, she experienced a myocardial infarction 4 years ago. Upon arrival, the patient exhibited a positive FAST result and an irregular breathing pattern. An urgent brain CT scan was performed and is currently under review. What region of the brainstem is responsible for regulating the fundamental breathing rhythm?

      Your Answer: Upper pons

      Correct Answer: Medulla oblongata

      Explanation:

      The medullary rhythmicity area in the medullary oblongata controls the basic rhythm of breathing through its inspiratory and expiratory neurons. During quiet breathing, the inspiratory area is active for approximately 2 seconds, causing the diaphragm and external intercostals to contract, followed by a period of inactivity lasting around 3 seconds as the muscles relax and there is elastic recoil. Additional brainstem regions can be stimulated to regulate various aspects of breathing, such as extending inspiration in the apneustic area (refer to the table below).

      The Control of Ventilation in the Human Body

      The control of ventilation in the human body is a complex process that involves various components working together to regulate the respiratory rate and depth of respiration. The respiratory centres, chemoreceptors, lung receptors, and muscles all play a role in this process. The automatic, involuntary control of respiration occurs from the medulla, which is responsible for controlling the respiratory rate and depth of respiration.

      The respiratory centres consist of the medullary respiratory centre, apneustic centre, and pneumotaxic centre. The medullary respiratory centre has two groups of neurons, the ventral group, which controls forced voluntary expiration, and the dorsal group, which controls inspiration. The apneustic centre, located in the lower pons, stimulates inspiration and activates and prolongs inhalation. The pneumotaxic centre, located in the upper pons, inhibits inspiration at a certain point and fine-tunes the respiratory rate.

      Ventilatory variables, such as the levels of pCO2, are the most important factors in ventilation control, while levels of O2 are less important. Peripheral chemoreceptors, located in the bifurcation of carotid arteries and arch of the aorta, respond to changes in reduced pO2, increased H+, and increased pCO2 in arterial blood. Central chemoreceptors, located in the medulla, respond to increased H+ in brain interstitial fluid to increase ventilation. It is important to note that the central receptors are not influenced by O2 levels.

      Lung receptors also play a role in the control of ventilation. Stretch receptors respond to lung stretching, causing a reduced respiratory rate, while irritant receptors respond to smoke, causing bronchospasm. J (juxtacapillary) receptors are also involved in the control of ventilation. Overall, the control of ventilation is a complex process that involves various components working together to regulate the respiratory rate and depth of respiration.

    • This question is part of the following fields:

      • Respiratory System
      132.2
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Respiratory System (10/30) 33%
Passmed