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Question 1
Incorrect
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A 49-year-old man comes to the clinic with recent onset of asthma and frequent nosebleeds. Laboratory results reveal elevated eosinophil counts and a positive pANCA test.
What is the probable diagnosis?Your Answer: Temporal arteritis
Correct Answer: Eosinophilic granulomatosis with polyangiitis (EGPA)
Explanation:The presence of adult-onset asthma, eosinophilia, and a positive pANCA test strongly suggests a diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA) in this patient.
Although GPA can cause epistaxis, the absence of other characteristic symptoms such as saddle-shaped nose deformity, haemoptysis, renal failure, and positive cANCA make EGPA a more likely diagnosis.
Polyarteritis Nodosa, Temporal Arteritis, and Toxic Epidermal Necrolysis have distinct clinical presentations that do not match the symptoms exhibited by this patient.
Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss Syndrome)
Eosinophilic granulomatosis with polyangiitis (EGPA), previously known as Churg-Strauss syndrome, is a type of small-medium vessel vasculitis that is associated with ANCA. It is characterized by asthma, blood eosinophilia (more than 10%), paranasal sinusitis, mononeuritis multiplex, and pANCA positivity in 60% of cases.
Compared to granulomatosis with polyangiitis, EGPA is more likely to have blood eosinophilia and asthma as prominent features. Additionally, leukotriene receptor antagonists may trigger the onset of the disease.
Overall, EGPA is a rare but serious condition that requires prompt diagnosis and treatment to prevent complications.
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This question is part of the following fields:
- Respiratory System
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Question 2
Incorrect
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A 75-year-old man is having a left pneumonectomy for bronchial carcinoma. When the surgeons reach the root of the lung, which structure will be the most anterior in the anatomical plane?
Your Answer: Pulmonary artery
Correct Answer: Phrenic nerve
Explanation:The lung root contains two nerves, with the phrenic nerve positioned in the most anterior location and the vagus nerve situated in the most posterior location.
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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This question is part of the following fields:
- Respiratory System
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Question 3
Correct
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A 10-year-old girl has been diagnosed with asthma. Her father asks you about the cause of her symptoms. What is the best response?
Inflammation of the lining of the bronchioles causes obstruction of the flow of air out from the lungs. This inflammation is reversible so symptoms of asthma may be intermittent. There may also be increased mucus production and bronchial muscle constriction.Your Answer: Reversible inflammation of the lining of the small airways causing them to become narrower
Explanation:The bronchioles’ lining inflammation obstructs the outflow of air from the lungs, leading to asthma symptoms that may come and go. Additionally, there could be heightened mucus production and constriction of bronchial muscles.
Asthma is a common respiratory disorder that affects both children and adults. It is characterized by chronic inflammation of the airways, resulting in reversible bronchospasm and airway obstruction. While asthma can develop at any age, it typically presents in childhood and may improve or resolve with age. However, it can also persist into adulthood and cause significant morbidity, with around 1,000 deaths per year in the UK.
Several risk factors can increase the likelihood of developing asthma, including a personal or family history of atopy, antenatal factors such as maternal smoking or viral infections, low birth weight, not being breastfed, exposure to allergens and air pollution, and the hygiene hypothesis. Patients with asthma may also suffer from other atopic conditions such as eczema and hay fever, and some may be sensitive to aspirin. Occupational asthma is also a concern for those exposed to allergens in the workplace.
Symptoms of asthma include coughing, dyspnea, wheezing, and chest tightness, with coughing often worse at night. Signs may include expiratory wheezing on auscultation and reduced peak expiratory flow rate. Diagnosis is typically made through spirometry, which measures the volume and speed of air during exhalation and inhalation.
Management of asthma typically involves the use of inhalers to deliver drug therapy directly to the airways. Short-acting beta-agonists such as salbutamol are the first-line treatment for relieving symptoms, while inhaled corticosteroids like beclometasone dipropionate and fluticasone propionate are used for daily maintenance therapy. Long-acting beta-agonists like salmeterol and leukotriene receptor antagonists like montelukast may also be used in combination with other medications. Maintenance and reliever therapy (MART) is a newer approach that combines ICS and a fast-acting LABA in a single inhaler for both daily maintenance and symptom relief. Recent guidelines recommend offering a leukotriene receptor antagonist instead of a LABA for patients on SABA + ICS whose asthma is not well controlled, and considering MART for those with poorly controlled asthma.
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This question is part of the following fields:
- Respiratory System
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Question 4
Correct
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A 70-year-old man presents with haemoptysis and undergoes a bronchoscopy. The carina is noted to be widened. Where does the trachea bifurcate?
Your Answer: T5
Explanation:The trachea divides into two branches at the fifth thoracic vertebrae, or sometimes the sixth in individuals who are tall.
Anatomy of the Trachea
The trachea, also known as the windpipe, is a tube-like structure that extends from the C6 vertebrae to the upper border of the T5 vertebrae where it bifurcates into the left and right bronchi. It is supplied by the inferior thyroid arteries and the thyroid venous plexus, and innervated by branches of the vagus, sympathetic, and recurrent nerves.
In the neck, the trachea is anterior to the isthmus of the thyroid gland, inferior thyroid veins, and anastomosing branches between the anterior jugular veins. It is also surrounded by the sternothyroid, sternohyoid, and cervical fascia. Posteriorly, it is related to the esophagus, while laterally, it is in close proximity to the common carotid arteries, right and left lobes of the thyroid gland, inferior thyroid arteries, and recurrent laryngeal nerves.
In the thorax, the trachea is anterior to the manubrium, the remains of the thymus, the aortic arch, left common carotid arteries, and the deep cardiac plexus. Laterally, it is related to the pleura and right vagus on the right side, and the left recurrent nerve, aortic arch, and left common carotid and subclavian arteries on the left side.
Overall, understanding the anatomy of the trachea is important for various medical procedures and interventions, such as intubation and tracheostomy.
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This question is part of the following fields:
- Respiratory System
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Question 5
Correct
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John, a 55-year-old man, arrives at the emergency department complaining of chest pain that is relieved by leaning forward. He also mentions that the pain spreads to his left shoulder. The diagnosis is pericarditis.
Which nerve is accountable for the referred pain in this case?Your Answer: Phrenic nerve
Explanation:The phrenic nerve provides motor innervation to the diaphragm and sensory innervation to the pleura and pericardium. Pericarditis can cause referred pain to the shoulder due to the supraclavicular nerves originating at C3-4. It is important to note that there are no pericardial nerves. The spinal accessory nerve innervates the trapezius and sternocleidomastoid muscles, while the trochlear nerve supplies the superior oblique muscle. Although the vagus nerve has various functions, it does not supply the pericardium.
The Phrenic Nerve: Origin, Path, and Supplies
The phrenic nerve is a crucial nerve that originates from the cervical spinal nerves C3, C4, and C5. It supplies the diaphragm and provides sensation to the central diaphragm and pericardium. The nerve passes with the internal jugular vein across scalenus anterior and deep to the prevertebral fascia of the deep cervical fascia.
The right phrenic nerve runs anterior to the first part of the subclavian artery in the superior mediastinum and laterally to the superior vena cava. In the middle mediastinum, it is located to the right of the pericardium and passes over the right atrium to exit the diaphragm at T8. On the other hand, the left phrenic nerve passes lateral to the left subclavian artery, aortic arch, and left ventricle. It passes anterior to the root of the lung and pierces the diaphragm alone.
Understanding the origin, path, and supplies of the phrenic nerve is essential in diagnosing and treating conditions that affect the diaphragm and pericardium.
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This question is part of the following fields:
- Respiratory System
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Question 6
Incorrect
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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: 9th 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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This question is part of the following fields:
- Respiratory System
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Question 7
Correct
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A 35-year-old female patient presents to the GP with complaints of headaches, nasal congestion, and facial pain that worsens upon leaning forward. Sinusitis is suspected. Which sinus is typically affected in this condition?
Your Answer: Maxillary
Explanation:The maxillary sinus is susceptible to infections due to its drainage from the top. This sinus is the most frequently affected in cases of sinusitis. While frontal sinusitis can lead to intracranial complications, it is still less common than maxillary sinusitis.
The petrosal sinus is not a bone cavity, but rather a venous structure situated beneath the brain.
Acute sinusitis is a condition where the mucous membranes of the paranasal sinuses become inflamed. This inflammation is usually caused by infectious agents such as Streptococcus pneumoniae, Haemophilus influenzae, and rhinoviruses. Certain factors can predispose individuals to this condition, including nasal obstruction, recent local infections, swimming/diving, and smoking. Symptoms of acute sinusitis include facial pain, nasal discharge, and nasal obstruction. Treatment options include analgesia, intranasal decongestants or nasal saline, and intranasal corticosteroids. Oral antibiotics may be necessary for severe presentations, but they are not typically required. In some cases, an initial viral sinusitis can worsen due to secondary bacterial infection, which is known as double-sickening.
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This question is part of the following fields:
- Respiratory System
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Question 8
Incorrect
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A 56-year-old man has been diagnosed with small cell lung carcinoma. The tumor measures 4 centimeters in its largest dimension and is not invading any surrounding structures. However, there are metastases in the ipsilateral hilar lymph nodes, and no distant metastases have been found. What is the TNM score for this patient, considering the primary tumor (T), regional lymph nodes (N), and distant metastases (M)?
Your Answer: T3 N1 M1
Correct Answer: T2 N1 M0
Explanation:It is crucial to have knowledge about the TNM system for staging lung cancer. The absence of distant metastases eliminates one of the options immediately (as M must be 0).
The size and invasion of the tumor are significant factors:
– T1 is less than 3 cm
– T2 is between 3 cm and 7 cm
– T3 is more than 7 cm and/or involves invasion of the chest wall, parietal pleura, diaphragm, phrenic nerve, mediastinal pleura, or parietal pericardium
– T4 can be any size but involves invasion of other structuresTo differentiate between N1 and N2, remember that N1 involves ipsilateral hilar or peribronchial lymph nodes, while N2 involves ipsilateral mediastinal and/or subcarinal lymph nodes.
Small Cell Lung Cancer: Characteristics and Management
Small cell lung cancer is a type of lung cancer that usually develops in the central part of the lungs and arises from APUD cells. This type of cancer is often associated with the secretion of hormones such as ADH and ACTH, which can cause hyponatremia and Cushing’s syndrome, respectively. In addition, ACTH secretion can lead to bilateral adrenal hyperplasia and hypokalemic alkalosis due to high levels of cortisol. Patients with small cell lung cancer may also experience Lambert-Eaton syndrome, which is characterized by antibodies to voltage-gated calcium channels causing a myasthenic-like syndrome.
Management of small cell lung cancer depends on the stage of the disease. Patients with very early stage disease may be considered for surgery, while those with limited disease typically receive a combination of chemotherapy and radiotherapy. Patients with more extensive disease are offered palliative chemotherapy. Unfortunately, most patients with small cell lung cancer are diagnosed with metastatic disease, making treatment more challenging.
Overall, small cell lung cancer is a complex disease that requires careful management and monitoring. Early detection and treatment can improve outcomes, but more research is needed to better understand the underlying mechanisms of this type of cancer.
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This question is part of the following fields:
- Respiratory System
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Question 9
Correct
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A 65-year-old male with a diagnosis of lung cancer presents with fatigue and lightheadedness. Upon examination, the following results are obtained:
Plasma sodium concentration 115 mmol/L (137-144)
Potassium 3.5 mmol/L (3.5-4.9)
Urea 3.2 mmol/L (2.5-7.5)
Creatinine 67 ”mol/L (60-110)
What is the probable reason for his symptoms based on these findings?Your Answer: Syndrome of inappropriate ADH secretion
Explanation:Syndrome of Inappropriate ADH Secretion
Syndrome of inappropriate ADH secretion (SIADH) is a condition characterized by low levels of sodium in the blood. This is caused by the overproduction of antidiuretic hormone (ADH) by the posterior pituitary gland. Tumors such as bronchial carcinoma can cause the ectopic elaboration of ADH, leading to dilutional hyponatremia. The diagnosis of SIADH is one of exclusion, but it can be supported by a high urine sodium concentration with high urine osmolality.
Hypoadrenalism is less likely to cause hyponatremia, as it is usually associated with hyperkalemia and mild hyperuricemia. On the other hand, diabetes insipidus is a condition where the kidneys are unable to reabsorb water, leading to excessive thirst and urination.
It is important to diagnose and treat SIADH promptly to prevent complications such as seizures, coma, and even death. Treatment options include fluid restriction, medications to block the effects of ADH, and addressing the underlying cause of the condition.
In conclusion, SIADH is a condition that can cause low levels of sodium in the blood due to the overproduction of ADH. It is important to differentiate it from other conditions that can cause hyponatremia and to treat it promptly to prevent complications.
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This question is part of the following fields:
- Respiratory System
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Question 10
Incorrect
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A 60-year-old diabetic patient presents to the clinic with a chief complaint of hearing loss. After conducting a Webberâs and Rinneâs test, the following results were obtained:
- Webberâs test: lateralizes to the left ear
- Rinneâs test (left ear): bone conduction > air conduction
- Rinneâs test (right ear): air conduction > bone conduction
Based on these findings, what is the probable cause of the patient's hearing loss?Your Answer: Diabetic sensory neuropathy
Correct Answer: Otitis media with effusion
Explanation:The Weber test lateralises to the side with bone conduction > air conduction, indicating conductive hearing loss on that side. The options given include acoustic neuroma (sensorineural hearing loss), otitis media with effusion (conductive hearing loss), temporal lobe epilepsy (no conductive hearing loss), and Meniere’s disease (vertigo, tinnitus, and fluctuating hearing loss). The correct answer is otitis media with effusion.
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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This question is part of the following fields:
- Respiratory System
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Question 11
Incorrect
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A 78-year-old man comes to your clinic with a complaint of hoarseness in his voice for the past 2 months. He is unsure if he had a viral infection prior to this and has attempted using over-the-counter remedies with no improvement. How would you approach managing this patient?
Your Answer: Routine referral to ENT
Correct Answer: Red flag referral to ENT
Explanation:An urgent referral to an ENT specialist is necessary when a person over the age of 45 experiences persistent hoarseness without any apparent cause. In this case, the patient has been suffering from a hoarse voice for 8 weeks, which warrants an urgent referral. A routine referral would not be sufficient as it may not be quick enough to address the issue. Although it could be a viral or bacterial infection, the duration of the hoarseness suggests that there may be an underlying serious condition. Merely informing the patient that their voice may not return is not helpful and may overlook the possibility of a more severe problem.
Hoarseness can be caused by various factors such as overusing the voice, smoking, viral infections, hypothyroidism, gastro-oesophageal reflux, laryngeal cancer, and lung cancer. It is important to investigate the underlying cause of hoarseness, and a chest x-ray may be necessary to rule out any apical lung lesions.
If laryngeal cancer is suspected, it is recommended to refer the patient to an ENT specialist through a suspected cancer pathway. This referral should be considered for individuals who are 45 years old and above and have persistent unexplained hoarseness or an unexplained lump in the neck. Early detection and treatment of laryngeal cancer can significantly improve the patient’s prognosis.
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This question is part of the following fields:
- Respiratory System
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Question 12
Incorrect
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A 25-year-old female patient visits your clinic complaining of hearing loss. According to her, her hearing has been declining for about two years, with her left ear being worse than the right. She struggles to hear her partner when he is on her left side. Additionally, she has been experiencing tinnitus in her left ear for a year. She mentions that her mother also has hearing difficulties and uses hearing aids on both ears. During the examination, the Rinne test shows a negative result on the left and a positive result on the right. On the other hand, the Weber test indicates that the sound is louder on the left. What is the probable impairment?
Your Answer: Sensorineural hearing loss on the right.
Correct Answer: Conductive hearing loss on the left.
Explanation:Based on the results of the Weber and Rinne tests, the patient in the question is likely experiencing conductive hearing loss on the left side. The Weber test revealed that the patient hears sound better on the left side, which could indicate a conductive hearing loss or sensorineural hearing loss on the right side. However, the Rinne test was negative on the left side, indicating a conductive hearing loss. This is further supported by the patient’s reported symptoms of hearing loss in the left ear. This presentation, along with a family history of hearing loss, suggests a possible diagnosis of otosclerosis, a condition that affects the stapes bone and can lead to severe or total hearing loss.
Understanding the Different Causes of Deafness
Deafness can be caused by various factors, with ear wax, otitis media, and otitis externa being the most common. However, there are other conditions that can lead to hearing loss, each with its own characteristic features. Presbycusis, for instance, is age-related sensorineural hearing loss that often makes it difficult for patients to follow conversations. Otosclerosis, on the other hand, is an autosomal dominant condition that replaces normal bone with vascular spongy bone, causing conductive deafness, tinnitus, and a flamingo tinge in the tympanic membrane. Glue ear, also known as otitis media with effusion, is the most common cause of conductive hearing loss in children, while Meniere’s disease is characterized by recurrent episodes of vertigo, tinnitus, and sensorineural hearing loss. Drug ototoxicity, noise damage, and acoustic neuroma are other factors that can lead to deafness.
Understanding the different causes of deafness is crucial in diagnosing and treating the condition. By knowing the characteristic features of each condition, healthcare professionals can determine the appropriate interventions to help patients manage their hearing loss. It is also important for individuals to protect their hearing by avoiding exposure to loud noises and seeking medical attention when they experience any symptoms of hearing loss. With proper care and management, people with deafness can still lead fulfilling lives.
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This question is part of the following fields:
- Respiratory System
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Question 13
Incorrect
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A 27-year-old male admitted to the ICU after a car accident has a pneumothorax. Using a bedside spirometer, his inspiratory and expiratory volumes were measured. What is the typical tidal volume for a male of his age?
Your Answer: 600ml
Correct Answer: 500ml
Explanation:The amount of air that is normally breathed in and out without any extra effort is called tidal volume, which is 500ml in males and 350ml in females.
Understanding Lung Volumes in Respiratory Physiology
In respiratory physiology, lung volumes can be measured to determine the amount of air that moves in and out of the lungs during breathing. The diagram above shows the different lung volumes that can be measured.
Tidal volume (TV) refers to the amount of air that is inspired or expired with each breath at rest. In males, the TV is 500ml while in females, it is 350ml.
Inspiratory reserve volume (IRV) is the maximum volume of air that can be inspired at the end of a normal tidal inspiration. The inspiratory capacity is the sum of TV and IRV. On the other hand, expiratory reserve volume (ERV) is the maximum volume of air that can be expired at the end of a normal tidal expiration.
Residual volume (RV) is the volume of air that remains in the lungs after maximal expiration. It increases with age and can be calculated by subtracting ERV from FRC. Speaking of FRC, it is the volume in the lungs at the end-expiratory position and is equal to the sum of ERV and RV.
Vital capacity (VC) is the maximum volume of air that can be expired after a maximal inspiration. It decreases with age and can be calculated by adding inspiratory capacity and ERV. Lastly, total lung capacity (TLC) is the sum of vital capacity and residual volume.
Physiological dead space (VD) is calculated by multiplying tidal volume by the difference between arterial carbon dioxide pressure (PaCO2) and end-tidal carbon dioxide pressure (PeCO2) and then dividing the result by PaCO2.
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This question is part of the following fields:
- Respiratory System
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Question 14
Incorrect
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A 75-year-old man presents to the Emergency Department with acute shortness of breath following a 4-day febrile illness. On initial assessment, his oxygen saturation is 70% on room air with a PaO2 of 4.2kpa on an arterial blood gas.
What would be the anticipated physiological response in this patient?Your Answer: Reduced tidal volume with increased respiratory rate
Correct Answer: Pulmonary artery vasoconstriction
Explanation:When faced with hypoxia, the pulmonary arteries undergo vasoconstriction, which redirects blood flow away from poorly oxygenated areas of the lungs and towards well-oxygenated regions. In cases where patients remain hypoxic despite optimal mechanical ventilation, inhaled nitric oxide can be used to induce pulmonary vasodilation and reverse this response.
The statement that increased tidal volume with decreased respiratory rate is a response to hypoxia is incorrect. While an increase in tidal volume may occur, it is typically accompanied by an increase in respiratory rate.
Pulmonary artery vasodilation is also incorrect. Hypoxia actually induces vasoconstriction in the pulmonary vasculature, as explained above.
Similarly, reduced tidal volume with increased respiratory rate is not a direct response to hypoxia. While respiratory rate may increase, tidal volumes typically increase in response to hypoxia.
In contrast to the pulmonary vessels, the systemic vasculature vasodilates in response to hypoxia.
The Effects of Hypoxia on Pulmonary Arteries
When the partial pressure of oxygen in the blood decreases, the pulmonary arteries undergo vasoconstriction. This means that the blood vessels narrow, allowing blood to be redirected to areas of the lung that are better aerated. This response is a natural mechanism that helps to improve the efficiency of gaseous exchange in the lungs. By diverting blood to areas with more oxygen, the body can ensure that the tissues receive the oxygen they need to function properly. Overall, hypoxia triggers a physiological response that helps to maintain homeostasis in the body.
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This question is part of the following fields:
- Respiratory System
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Question 15
Correct
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A 70-year-old man with lung cancer is having a left pneumonectomy. The left main bronchus is being divided. Which thoracic vertebrae is located behind this structure?
Your Answer: T6
Explanation: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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This question is part of the following fields:
- Respiratory System
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Question 16
Incorrect
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A 54-year-old man comes to the emergency department complaining of difficulty breathing. The results of his pulmonary function tests are as follows:
Reference Range
FVC (% predicted) 102 80-120
FEV1 (% predicted) 62 80-120
FEV1/FVC (%) 60.1 >70
TCLO (% predicted) 140 60-120
What is the probable reason for his symptoms?Your Answer: COPD exacerbation
Correct Answer: Asthma exacerbation
Explanation:The raised transfer factor suggests that the patient is experiencing an exacerbation of asthma. This condition can cause obstructive patterns on pulmonary function tests, leading to reduced FEV1 and FEV1/FVC, as well as hypoxia and wheezing. However, other conditions such as COPD exacerbation, idiopathic pulmonary fibrosis, and pulmonary embolism would result in a low transfer factor, and are therefore unlikely explanations for the patient’s symptoms.
Understanding Transfer Factor in Lung Function Testing
The transfer factor is a measure of how quickly a gas diffuses from the alveoli into the bloodstream. This is typically tested using carbon monoxide, and the results can be given as either the total gas transfer (TLCO) or the transfer coefficient corrected for lung volume (KCO). A raised TLCO may be caused by conditions such as asthma, pulmonary haemorrhage, left-to-right cardiac shunts, polycythaemia, hyperkinetic states, male gender, or exercise. On the other hand, a lower TLCO may be indicative of pulmonary fibrosis, pneumonia, pulmonary emboli, pulmonary oedema, emphysema, anaemia, or low cardiac output.
KCO tends to increase with age, and certain conditions may cause an increased KCO with a normal or reduced TLCO. These conditions include pneumonectomy/lobectomy, scoliosis/kyphosis, neuromuscular weakness, and ankylosis of costovertebral joints (such as in ankylosing spondylitis). Understanding transfer factor is important in lung function testing, as it can provide valuable information about a patient’s respiratory health and help guide treatment decisions.
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This question is part of the following fields:
- Respiratory System
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Question 17
Incorrect
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A 67-year-old woman presents to the clinic with a gradual onset of dyspnea on exertion over the past 6 months. She has a medical history of severe COPD and is currently receiving long-term oxygen therapy. During the examination, you observe pitting edema up to the mid-thighs, an elevated JVP with a prominent V wave, a precordial heave, and a loud P2. What is the most probable mechanism involved in this diagnosis?
Your Answer: Pulmonary veins vasodilation due to hypoxia
Correct Answer: Pulmonary arteries vasoconstriction due to hypoxia
Explanation:Hypoxia causes vasoconstriction of pulmonary arteries, leading to a diagnosis of right heart failure secondary to hypoxic lung disease, also known as cor pulmonale.
The Effects of Hypoxia on Pulmonary Arteries
When the partial pressure of oxygen in the blood decreases, the pulmonary arteries undergo vasoconstriction. This means that the blood vessels narrow, allowing blood to be redirected to areas of the lung that are better aerated. This response is a natural mechanism that helps to improve the efficiency of gaseous exchange in the lungs. By diverting blood to areas with more oxygen, the body can ensure that the tissues receive the oxygen they need to function properly. Overall, hypoxia triggers a physiological response that helps to maintain homeostasis in the body.
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This question is part of the following fields:
- Respiratory System
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Question 18
Correct
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A 12-year-old girl is referred to a respiratory specialist due to persistent episodes of shortness of breath. She also suffers from severe hay fever and eczema. After undergoing a peak expiratory flow test, signs of outflow obstruction of her lungs are detected. The doctor prescribes beclomethasone and salbutamol for her and advises her mother to keep her away from dust, as asthma is often linked to hypersensitivity to dust. Which type of hypersensitivity is associated with asthma?
Your Answer: Type 1 hypersensitivity
Explanation:Asthma is linked to type 1 hypersensitivity, which is caused by the binding of IgE to Mast cells, resulting in an inflammatory reaction. Other types of hypersensitivity include type 2, which involves the binding of IgG or IgM to cell surface antigens, type 3, which is immune complex-mediated, and type 4, which is T-cell mediated.
Asthma is a common respiratory disorder that affects both children and adults. It is characterized by chronic inflammation of the airways, resulting in reversible bronchospasm and airway obstruction. While asthma can develop at any age, it typically presents in childhood and may improve or resolve with age. However, it can also persist into adulthood and cause significant morbidity, with around 1,000 deaths per year in the UK.
Several risk factors can increase the likelihood of developing asthma, including a personal or family history of atopy, antenatal factors such as maternal smoking or viral infections, low birth weight, not being breastfed, exposure to allergens and air pollution, and the hygiene hypothesis. Patients with asthma may also suffer from other atopic conditions such as eczema and hay fever, and some may be sensitive to aspirin. Occupational asthma is also a concern for those exposed to allergens in the workplace.
Symptoms of asthma include coughing, dyspnea, wheezing, and chest tightness, with coughing often worse at night. Signs may include expiratory wheezing on auscultation and reduced peak expiratory flow rate. Diagnosis is typically made through spirometry, which measures the volume and speed of air during exhalation and inhalation.
Management of asthma typically involves the use of inhalers to deliver drug therapy directly to the airways. Short-acting beta-agonists such as salbutamol are the first-line treatment for relieving symptoms, while inhaled corticosteroids like beclometasone dipropionate and fluticasone propionate are used for daily maintenance therapy. Long-acting beta-agonists like salmeterol and leukotriene receptor antagonists like montelukast may also be used in combination with other medications. Maintenance and reliever therapy (MART) is a newer approach that combines ICS and a fast-acting LABA in a single inhaler for both daily maintenance and symptom relief. Recent guidelines recommend offering a leukotriene receptor antagonist instead of a LABA for patients on SABA + ICS whose asthma is not well controlled, and considering MART for those with poorly controlled asthma.
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This question is part of the following fields:
- Respiratory System
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Question 19
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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: 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.
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This question is part of the following fields:
- Respiratory System
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Question 20
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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 37.9ÂșC. 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.
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This question is part of the following fields:
- Respiratory System
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