-
Question 1
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
-
-
Question 2
Incorrect
-
Which of the following laryngeal tumors is unlikely to spread to the cervical lymph nodes?
Your Answer: Subglottic
Correct Answer: Glottic
Explanation:The area of the vocal cords lacks lymphatic drainage, making it a lymphatic boundary. The upper portion above the vocal cords drains to the deep cervical nodes through vessels that penetrate the thyrohyoid membrane. The lower portion below the vocal cords drains to the pre-laryngeal, pre-tracheal, and inferior deep cervical nodes. The aryepiglottic and vestibular folds have a significant lymphatic drainage and are prone to early metastasis.
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
-
-
Question 3
Incorrect
-
A 65-year-old man visits his doctor complaining of a productive cough and difficulty breathing for the past 10 days. The doctor prescribes antibiotics, but after a week, the patient's symptoms persist and he develops a fever and pain when breathing in. The doctor orders a chest x-ray, which indicates the presence of an empyema. What is the probable causative agent responsible for this condition?
Your Answer: Mycobacterium tuberculosis
Correct Answer: Streptococcus pneumoniae
Explanation:An accumulation of pus in the pleural space, known as empyema, is a possible complication of pneumonia and is responsible for the patient’s pleurisy. Streptococcus pneumoniae, the most frequent cause of pneumonia, is also the leading cause of empyema.
Pneumonia is a common condition that affects the alveoli of the lungs, usually caused by a bacterial infection. Other causes include viral and fungal infections. Streptococcus pneumoniae is the most common organism responsible for pneumonia, accounting for 80% of cases. Haemophilus influenzae is common in patients with COPD, while Staphylococcus aureus often occurs in patients following influenzae infection. Mycoplasma pneumoniae and Legionella pneumophilia are atypical pneumonias that present with dry cough and other atypical symptoms. Pneumocystis jiroveci is typically seen in patients with HIV. Idiopathic interstitial pneumonia is a group of non-infective causes of pneumonia.
Patients who develop pneumonia outside of the hospital have community-acquired pneumonia (CAP), while those who develop it within hospitals are said to have hospital-acquired pneumonia. Symptoms of pneumonia include cough, sputum, dyspnoea, chest pain, and fever. Signs of systemic inflammatory response, tachycardia, reduced oxygen saturations, and reduced breath sounds may also be present. Chest x-ray is used to diagnose pneumonia, with consolidation being the classical finding. Blood tests, such as full blood count, urea and electrolytes, and CRP, are also used to check for infection.
Patients with pneumonia require antibiotics to treat the underlying infection and supportive care, such as oxygen therapy and intravenous fluids. Risk stratification is done using a scoring system called CURB-65, which stands for confusion, respiration rate, blood pressure, age, and is used to determine the management of patients with community-acquired pneumonia. Home-based care is recommended for patients with a CRB65 score of 0, while hospital assessment is recommended for all other patients, particularly those with a CRB65 score of 2 or more. The CURB-65 score also correlates with an increased risk of mortality at 30 days.
-
This question is part of the following fields:
- Respiratory System
-
-
Question 4
Correct
-
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: 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.
-
This question is part of the following fields:
- Respiratory System
-
-
Question 5
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
-
-
Question 6
Incorrect
-
A 25-year-old woman presents to the Emergency department with sudden onset of difficulty breathing. She has a history of asthma but is otherwise healthy. Upon admission, she is observed to be breathing rapidly, using her accessory muscles, and is experiencing cold and clammy skin. Upon chest auscultation, widespread wheezing is detected.
An arterial blood gas analysis reveals:
pH 7.46
pO2 13 kPa
pCO2 2.7 kPa
HCO3- 23 mmol/l
Which aspect of the underlying disease is affected in this patient?Your Answer: Forced Vital Capacity
Correct Answer: Forced Expiratory Volume
Explanation:It is probable that this individual is experiencing an acute episode of asthma. Asthma is a condition that results in the constriction of the airways, known as an obstructive airway disease. Its distinguishing feature is its ability to be reversed. The forced expiratory volume is the most impacted parameter in asthma and other obstructive airway diseases.
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
-
-
Question 7
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: External 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
-
-
Question 8
Correct
-
A 35-year-old man is stabbed in the right chest and requires a thoracotomy. During the procedure, the right lung is mobilized and the pleural reflection at the lung hilum is opened. Which of the following structures is not located in this area?
Your Answer: Azygos vein
Explanation:The pulmonary ligament extends from the pleural reflections surrounding the hilum of the lung and covers the pulmonary vessels and bronchus. However, it does not contain the azygos vein.
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
-
-
Question 9
Incorrect
-
A 15-year-old boy presents to his GP with a painless swelling in his neck. The mass is located centrally just below the hyoid bone and does not cause any difficulty in swallowing or breathing. Upon examination, the GP notes that the mass moves with protrusion of the tongue and with swallowing. The GP diagnoses the boy with a benign thyroglossal cyst, which is caused by a persistent thyroglossal duct, and advises surgical removal. Where is the thyroglossal duct attached to the tongue?
Your Answer: Terminal sulcus of the tongue
Correct Answer: Foramen cecum
Explanation:The thyroglossal duct connects the thyroid gland to the tongue via the foramen caecum during embryonic development. The terminal sulcus, median sulcus, palatoglossal arch, and epiglottis are not connected to the thyroid gland.
Understanding Thyroglossal Cysts
Thyroglossal cysts are named after the thyroid and tongue, which are the two structures involved in their development. During embryology, the thyroid gland develops from the floor of the pharynx and descends into the neck, connected to the tongue by the thyroglossal duct. The foramen cecum is the point of attachment of the thyroglossal duct to the tongue. Normally, the thyroglossal duct atrophies, but in some people, it may persist and give rise to a thyroglossal duct cyst.
Thyroglossal cysts are more common in patients under 20 years old and are usually midline, between the isthmus of the thyroid and the hyoid bone. They move upwards with protrusion of the tongue and may be painful if infected. Understanding the embryology and presentation of thyroglossal cysts is important for proper diagnosis and treatment.
-
This question is part of the following fields:
- Respiratory System
-
-
Question 10
Incorrect
-
A 20-year-old male arrives at the emergency department with a sudden worsening of his asthma symptoms. He is experiencing difficulty in speaking and breathing, with cyanosis of the lips and a respiratory rate of 33 breaths per minute. He reports feeling lightheaded. Although his airways are open, his chest sounds are faint upon auscultation. The patient is administered oxygen, nebulized salbutamol, and intravenous aminophylline.
What is the mechanism of action of aminophylline?Your Answer: Inhibits prostaglandin synthesis and reduces thromboxane A2 associated inflammation
Correct Answer: Binds to adenosine receptors and blocks adenosine-mediated bronchoconstriction
Explanation:Aminophylline works by binding to adenosine receptors and preventing adenosine-induced bronchoconstriction. This mode of action is different from antihistamines like loratadine, which is an incorrect option. Theophylline, a shorter acting form of aminophylline, competitively inhibits type III and type IV phosphodiesterase enzymes responsible for breaking down cyclic AMP in smooth muscle cells, leading to possible bronchodilation. Additionally, theophylline binds to the adenosine A2B receptor and blocks adenosine-mediated bronchoconstriction. In inflammatory conditions, theophylline activates histone deacetylase, which prevents the transcription of inflammatory genes that require histone acetylation for transcription to begin. Therefore, the last three options are incorrect. (Source: Drugbank)
Aminophylline infusions are utilized to manage acute asthma and COPD. In patients who have not received xanthines (theophylline or aminophylline) before, a loading dose of 5 mg/kg is administered through a slow intravenous injection lasting at least 20 minutes. For the maintenance infusion, 1g of aminophylline is mixed with 1 litre of normal saline to create a solution of 1 mg/ml. The recommended dose is 500-700 mcg/kg/hour, or 300 mcg/kg/hour for elderly patients. It is important to monitor plasma theophylline concentrations.
-
This question is part of the following fields:
- Respiratory System
-
00
Correct
00
Incorrect
00
:
00
:
00
Session Time
00
:
00
Average Question Time (
Secs)