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Question 1
Correct
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A 14-year-old girl presents to her GP with complaints of earache and hearing difficulty in her left ear. Upon examination, her GP observes a bulging tympanic membrane and diagnoses her with acute otitis media. The GP prescribes a course of oral antibiotics.
However, after a few days, the girl's fever persists and her pain worsens, prompting her to visit the emergency department. Upon examination, the girl has a tender and erythematous retro-auricular swelling with a temperature of 38.9ÂșC. She has no ear discharge, and the rest of her examination is unremarkable.
What complication has developed in this case?Your Answer: Mastoiditis
Explanation:Mastoiditis is a potential complication of acute otitis media, which can cause pain and swelling behind the ear over the mastoid bone. However, there is no evidence of tympanic membrane perforation, neurological symptoms or signs of meningitis or brain abscess, or facial nerve injury in this case.
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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This question is part of the following fields:
- Respiratory System
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Question 2
Incorrect
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During a schoolyard brawl a boy is hit in the chest. The stick passes through the posterior mediastinum (from left to right). Which one of the following structures is least likely to be injured?
Your Answer: Vagus nerve
Correct Answer: Arch of the azygos vein
Explanation:The azygos vein’s arch is located within the middle 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.
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This question is part of the following fields:
- Respiratory System
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Question 3
Incorrect
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Cystic fibrosis is caused by a mutation in the CFTR gene. On which chromosome is this gene located?
Your Answer: Chromosome 3
Correct Answer: Chromosome 7
Explanation:Understanding Cystic Fibrosis
Cystic fibrosis is a genetic disorder that causes thickened secretions in the lungs and pancreas. It is an autosomal recessive condition that occurs due to a defect in the cystic fibrosis transmembrane conductance regulator gene (CFTR), which regulates a chloride channel. In the UK, 80% of CF cases are caused by delta F508 on chromosome 7, and the carrier rate is approximately 1 in 25.
CF patients are at risk of colonization by certain organisms, including Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia (previously known as Pseudomonas cepacia), and Aspergillus. These organisms can cause infections and exacerbate symptoms in CF patients. It is important for healthcare providers to monitor and manage these infections to prevent further complications.
Overall, understanding cystic fibrosis and its associated risks can help healthcare providers provide better care for patients with this condition.
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This question is part of the following fields:
- Respiratory System
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Question 4
Incorrect
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A 65-year-old man presents with respiratory symptoms and is referred to his primary care physician for pulmonary function testing. The estimated vital capacity is 3.5 liters. What does the measurement of vital capacity involve?
Your Answer: Tidal volume + Functional residual capacity
Correct Answer: Inspiratory reserve volume + Tidal volume + Expiratory reserve volume
Explanation: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 5
Incorrect
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A 55-year-old man presents to his doctor with complaints of vertigo, which worsens when he rolls over in bed. The doctor diagnoses him with benign paroxysmal positional vertigo.
What treatment options are available to alleviate the symptoms of this condition?Your Answer: Dix-Hallpike manoeuvre
Correct Answer: Epley manoeuvre
Explanation:The Epley manoeuvre is a treatment for BPPV, while the Dix-Hallpike manoeuvre is used for diagnosis. The Epley manoeuvre aims to move fluid in the inner ear to dislodge otoliths, while the Dix-Hallpike manoeuvre involves observing the patient for nystagmus when swiftly lowered from a sitting to supine position. Tinel’s sign is positive in those with carpal tunnel syndrome, where tapping the median nerve over the flexor retinaculum causes paraesthesia. The Trendelenburg test is used to assess venous valve competency in patients with varicose veins.
Benign paroxysmal positional vertigo (BPPV) is a common cause of vertigo that occurs suddenly when there is a change in head position. It is more prevalent in individuals over the age of 55 and is less common in younger patients. Symptoms of BPPV include dizziness and vertigo, which can be accompanied by nausea. Each episode typically lasts for 10-20 seconds and can be triggered by rolling over in bed or looking upwards. A positive Dix-Hallpike manoeuvre, which is indicated by vertigo and rotatory nystagmus, can confirm the diagnosis of BPPV.
Fortunately, BPPV has a good prognosis and usually resolves on its own within a few weeks to months. Treatment options include the Epley manoeuvre, which is successful in around 80% of cases, and vestibular rehabilitation exercises such as the Brandt-Daroff exercises. While medication such as Betahistine may be prescribed, it tends to have limited effectiveness. However, it is important to note that around half of individuals with BPPV may experience a recurrence of symptoms 3-5 years after their initial diagnosis.
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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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A patient on the medical ward was waiting for a cardiac procedure. On discussing the procedure with the consultant before the procedure, the patient started to feel anxious and had difficulty breathing. The resident obtained an arterial blood gas:
pH 7.55
pCO2 2.7kPa
pO2 11.2kPa
HCO3 24mmol/l
What is the most appropriate interpretation of these results?Your Answer: Mixed respiratory and metabolic alkalosis
Correct Answer: Respiratory alkalosis
Explanation:The respiratory alkalosis observed in the arterial blood gas results is most likely a result of hyperventilation, as indicated by the patient’s medical history.
Arterial Blood Gas Interpretation: A 5-Step Approach
Arterial blood gas interpretation is a crucial aspect of patient care, particularly in critical care settings. The Resuscitation Council (UK) recommends a 5-step approach to interpreting arterial blood gas results. The first step is to assess the patient’s overall condition. The second step is to determine if the patient is hypoxaemic, with a PaO2 on air of less than 10 kPa. The third step is to assess if the patient is acidaemic (pH <7.35) or alkalaemic (pH >7.45).
The fourth step is to evaluate the respiratory component of the arterial blood gas results. A PaCO2 level greater than 6.0 kPa suggests respiratory acidosis, while a PaCO2 level less than 4.7 kPa suggests respiratory alkalosis. The fifth step is to assess the metabolic component of the arterial blood gas results. A bicarbonate level less than 22 mmol/l or a base excess less than -2mmol/l suggests metabolic acidosis, while a bicarbonate level greater than 26 mmol/l or a base excess greater than +2mmol/l suggests metabolic alkalosis.
To remember the relationship between pH, PaCO2, and bicarbonate, the acronym ROME can be used. Respiratory acidosis or alkalosis is opposite to the pH level, while metabolic acidosis or alkalosis is equal to the pH level. This 5-step approach and the ROME acronym can aid healthcare professionals in interpreting arterial blood gas results accurately and efficiently.
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This question is part of the following fields:
- Respiratory System
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Question 7
Incorrect
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A 10-year-old boy comes to your clinic with a complaint of ear pain that started last night and kept him awake. He missed school today because of the pain and reports muffled sounds on the affected side. During otoscopy, you observe a bulging tympanic membrane with visible fluid behind it, indicating a middle ear infection. Can you identify which nerves pass through the middle ear?
Your Answer:
Correct Answer: Chorda tympani
Explanation:The chorda tympani is the correct answer. It is a branch of the seventh cranial nerve, the facial nerve, and carries parasympathetic and taste fibers. It passes through the middle ear before exiting and joining with the lingual nerve to reach the tongue and salivary glands.
The vestibulocochlear nerve is the eighth cranial nerve and carries balance and hearing information.
The maxillary nerve is the second division of the fifth cranial nerve and carries sensation from the upper teeth, nasal cavity, and skin.
The mandibular nerve is the third division of the fifth cranial nerve and carries sensation from the lower teeth, tongue, mandible, and skin. It also carries motor fibers to certain muscles.
The glossopharyngeal nerve is the ninth cranial nerve and carries taste and sensation from the posterior one-third of the tongue, as well as sensation from various areas. It also carries motor and parasympathetic fibers.
The patient in the question has ear pain, likely due to otitis media, as evidenced by a bulging tympanic membrane and fluid level on otoscopy.
Anatomy of the Ear
The ear is divided into three distinct regions: the external ear, middle ear, and internal ear. The external ear consists of the auricle and external auditory meatus, which are innervated by the greater auricular nerve and auriculotemporal branch of the trigeminal nerve. The middle ear is the space between the tympanic membrane and cochlea, and is connected to the nasopharynx by the eustachian tube. The tympanic membrane is composed of three layers and is approximately 1 cm in diameter. The middle ear is innervated by the glossopharyngeal nerve. The ossicles, consisting of the malleus, incus, and stapes, transmit sound vibrations from the tympanic membrane to the inner ear. The internal ear contains the cochlea, which houses the organ of corti, the sense organ of hearing. The vestibule accommodates the utricule and saccule, which contain endolymph and are surrounded by perilymph. The semicircular canals, which share a common opening into the vestibule, lie at various angles to the petrous temporal bone.
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This question is part of the following fields:
- Respiratory System
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Question 8
Incorrect
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A 65-year-old man with uncontrolled diabetes complains of severe otalgia and headaches. During examination, granulation tissue is observed in the external auditory meatus. What is the probable causative agent of the infection?
Your Answer:
Correct Answer: Pseudomonas aeruginosa
Explanation:The primary cause of malignant otitis externa is typically Pseudomonas aeruginosa. Symptoms of this condition include intense pain, headaches, and the presence of granulation tissue in the external auditory meatus. Individuals with diabetes mellitus are at a higher risk for developing this condition.
Malignant Otitis Externa: A Rare but Serious Infection
Malignant otitis externa is a type of ear infection that is uncommon but can be serious. It is typically found in individuals who are immunocompromised, with 90% of cases occurring in diabetics. The infection starts in the soft tissues of the external auditory meatus and can progress to involve the soft tissues and bony ear canal, eventually leading to temporal bone osteomyelitis.
Key features in the patient’s history include diabetes or immunosuppression, severe and persistent ear pain, temporal headaches, and purulent otorrhea. In some cases, patients may also experience dysphagia, hoarseness, and facial nerve dysfunction.
Diagnosis is typically done through a CT scan, and non-resolving otitis externa with worsening pain should be referred urgently to an ENT specialist. Treatment involves intravenous antibiotics that cover pseudomonal infections.
In summary, malignant otitis externa is a rare but serious infection that requires prompt diagnosis and treatment. Patients with diabetes or immunosuppression should be particularly vigilant for symptoms and seek medical attention if they experience persistent ear pain or other related symptoms.
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This question is part of the following fields:
- Respiratory System
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Question 9
Incorrect
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A 63-year-old man visits his GP complaining of worsening shortness of breath. He was diagnosed with COPD six years ago and has been frequently admitted to the emergency department due to lower respiratory tract infections, especially in the past year. He has a smoking history of 50 pack-years and currently smokes 20 cigarettes per day.
During the examination, the patient appears to be struggling to breathe even at rest and is in the tripod position. His heart rate is 78/min, blood pressure is 140/88 mmHg, oxygen saturation is 88% on air, respiratory rate is 26 breaths per minute, and temperature is 36.4ÂșC. His chest expansion is symmetrical, and breath sounds are equal throughout the lung fields.
Recent spirometry results show that his FEV1 was 47% a week ago, 53% a month ago, and 67% six months ago. What intervention would be most effective in slowing the decline of his FEV1?Your Answer:
Correct Answer: Smoking cessation
Explanation:Slowing the decrease in FEV1 in COPD can be most effectively achieved by quitting smoking.
The National Institute for Health and Care Excellence (NICE) updated its guidelines on the management of chronic obstructive pulmonary disease (COPD) in 2018. The guidelines recommend general management strategies such as smoking cessation advice, annual influenzae vaccination, and one-off pneumococcal vaccination. Pulmonary rehabilitation is also recommended for patients who view themselves as functionally disabled by COPD.
Bronchodilator therapy is the first-line treatment for patients who remain breathless or have exacerbations despite using short-acting bronchodilators. The next step is determined by whether the patient has asthmatic features or features suggesting steroid responsiveness. NICE suggests several criteria to determine this, including a previous diagnosis of asthma or atopy, a higher blood eosinophil count, substantial variation in FEV1 over time, and substantial diurnal variation in peak expiratory flow.
If the patient does not have asthmatic features or features suggesting steroid responsiveness, a long-acting beta2-agonist (LABA) and long-acting muscarinic antagonist (LAMA) should be added. If the patient is already taking a short-acting muscarinic antagonist (SAMA), it should be discontinued and switched to a short-acting beta2-agonist (SABA). If the patient has asthmatic features or features suggesting steroid responsiveness, a LABA and inhaled corticosteroid (ICS) should be added. If the patient remains breathless or has exacerbations, triple therapy (LAMA + LABA + ICS) should be offered.
NICE only recommends theophylline after trials of short and long-acting bronchodilators or to people who cannot use inhaled therapy. Azithromycin prophylaxis is recommended in select patients who have optimised standard treatments and continue to have exacerbations. Mucolytics should be considered in patients with a chronic productive cough and continued if symptoms improve.
Cor pulmonale features include peripheral oedema, raised jugular venous pressure, systolic parasternal heave, and loud P2. Loop diuretics should be used for oedema, and long-term oxygen therapy should be considered. Smoking cessation, long-term oxygen therapy in eligible patients, and lung volume reduction surgery in selected patients may improve survival in patients with stable COPD. NICE does not recommend the use of ACE-inhibitors, calcium channel blockers, or alpha blockers
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This question is part of the following fields:
- Respiratory System
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Question 10
Incorrect
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Which one of the following is not a cause of increased anion gap acidosis?
Your Answer:
Correct Answer: Acetazolamide
Explanation:Causes of anion gap acidosis can be remembered using the acronym MUDPILES, which stands for Methanol, Uraemia, DKA/AKA, Paraldehyde/phenformin, Iron/INH, Lactic acidosis, Ethylene glycol, and Salicylates.
Disorders of Acid-Base Balance
The acid-base nomogram is a useful tool for categorizing the various disorders of acid-base balance. Metabolic acidosis is the most common surgical acid-base disorder, characterized by a reduction in plasma bicarbonate levels. This can be caused by a gain of strong acid or loss of base, and is classified according to the anion gap. A normal anion gap indicates hyperchloraemic metabolic acidosis, which can be caused by gastrointestinal bicarbonate loss, renal tubular acidosis, drugs, or Addison’s disease. A raised anion gap indicates lactate, ketones, urate, or acid poisoning. Metabolic alkalosis, on the other hand, is usually caused by a rise in plasma bicarbonate levels due to a loss of hydrogen ions or a gain of bicarbonate. It is mainly caused by problems of the kidney or gastrointestinal tract. Respiratory acidosis is characterized by a rise in carbon dioxide levels due to alveolar hypoventilation, while respiratory alkalosis is caused by hyperventilation resulting in excess loss of carbon dioxide. These disorders have various causes, such as COPD, sedative drugs, anxiety, hypoxia, and pregnancy.
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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 53-year-old man arrives at the Emergency Department with jaundice and a distended abdomen. He has a history of alcoholism and has been hospitalized before for acute alcohol withdrawal. During the examination, you observe spider naevi on his upper chest wall and detect a shifting dullness on abdominal percussion, indicating ascites. Further imaging and investigation reveal portal vein hypertension and cirrhosis.
Where does this vessel start?Your Answer:
Correct Answer: L1
Explanation:Portal hypertension is commonly caused by liver cirrhosis, often due to alcohol abuse. The causes of this condition can be categorized as pre-hepatic, hepatic, or post-hepatic, depending on the location of the underlying pathology. The primary factors contributing to portal hypertension are increased vascular resistance in the portal venous system and elevated blood flow in the portal veins. The portal vein originates at the transpyloric plane, which is situated at the level of the body of L1. Other significant structures found at this location include the neck of the pancreas, the spleen, the duodenojejunal flexure, and the superior mesenteric artery.
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.
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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 24-year-old man is admitted to the emergency department after a car accident. During the initial evaluation, he complains of difficulty breathing. A portable chest X-ray shows a 3 cm gap between the right lung margin and the chest wall, indicating a significant traumatic pneumothorax. The medical team administers high-flow oxygen and performs a right-sided chest drain insertion to drain the pneumothorax.
What is a potential negative outcome that could arise from the insertion of a chest drain?Your Answer:
Correct Answer: Winging of the scapula
Explanation:Insertion of a chest drain poses a risk of damaging the long thoracic nerve, which runs from the neck to the serratus anterior muscle. This can result in weakness or paralysis of the muscle, causing a winged scapula that is noticeable along the medial border of the scapula. It is important to use aseptic technique during the procedure to prevent hospital-acquired pleural infection. Chylothorax, pneumothorax, and pyothorax are all conditions that may require chest drain insertion, but they are not known complications of the procedure. Therefore, these options are not applicable.
Anatomy of Chest Drain Insertion
Chest drain insertion is necessary for various medical conditions such as trauma, haemothorax, pneumothorax, and pleural effusion. The size of the chest drain used depends on the specific condition being treated. While ultrasound guidance is an option, the anatomical method is typically tested in exams.
It is recommended that chest drains are placed in the safe triangle, which is located in the mid axillary line of the 5th intercostal space. This triangle is bordered by the anterior edge of the latissimus dorsi, the lateral border of pectoralis major, a line superior to the horizontal level of the nipple, and the apex below the axilla. Another triangle, known as the triangle of auscultation, is situated behind the scapula and is bounded by the trapezius, latissimus dorsi, and vertebral border of the scapula. By folding the arms across the chest and bending forward, parts of the sixth and seventh ribs and the interspace between them become subcutaneous and available for auscultation.
References:
– Prof Harold Ellis. The applied anatomy of chest drains insertions. British Journal of hospital medicine 2007; (68): 44-45.
– Laws D, Neville E, Duffy J. BTS guidelines for insertion of chest drains. Thorax, 2003; (58): 53-59. -
This question is part of the following fields:
- Respiratory System
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Question 13
Incorrect
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Sophie, a 4-year-old patient with Down's syndrome, is brought to the general practitioner by her father. He is worried as Sophie has been crying more than usual and has started holding her right ear. She is diagnosed with acute bacterial otitis media.
What is the most probable bacteria responsible for this infection?Your Answer:
Correct Answer: Haemophilus influenzae
Explanation:Haemophilus influenzae is a frequent culprit behind bacterial otitis media, a common ear infection.
The majority of cases of acute bacterial otitis media are caused by Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella.
Genital gonorrhoeae is caused by N. gonorrhoeae, a sexually transmitted infection that presents with discharge and painful urination.
Meningococcal sepsis, a life-threatening condition, is caused by N. meningitides.
Staph. aureus is responsible for superficial skin infections like impetigo.
Syphilis, which typically manifests as a painless genital sore called a chancre, is caused by T. pallidum.
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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This question is part of the following fields:
- Respiratory System
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Question 14
Incorrect
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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:
Correct 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.
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This question is part of the following fields:
- Respiratory System
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Question 15
Incorrect
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A 70-year-old man is admitted to the respiratory ward with an exacerbation of COPD. He has been experiencing increased breathlessness and a productive cough for the past week. He is currently on day three of his rescue medication regimen consisting of amoxicillin and prednisolone. According to his previous discharge summary, this patient has a history of carbon dioxide retention. He is currently receiving controlled oxygen therapy via a 28% venturi mask. What is the target oxygen saturation level for this patient?
Your Answer:
Correct Answer: 88%-92%
Explanation:As a junior doctor, you will often encounter patients who retain carbon dioxide and depend on their hypoxic drive to breathe. When using Venturi masks to deliver controlled oxygen, it is important to set a target that balances the patient’s need for oxygen with their reliance on hypoxia to stimulate breathing. Answer 4 is the correct choice in this scenario. Providing too much oxygen, as in answers 2 and 3, can cause the patient to lose their hypoxic drive and become drowsy or confused. Answer 5 does not provide enough oxygen to properly perfuse the tissues. Failing to set a target for these patients is not good clinical practice.
Guidelines for Oxygen Therapy in Emergency Situations
In 2017, the British Thoracic Society updated its guidelines for emergency oxygen therapy. The guidelines state that in critically ill patients, such as those experiencing anaphylaxis or shock, oxygen should be administered through a reservoir mask at a rate of 15 liters per minute. However, certain conditions, such as stable myocardial infarction, are excluded from this recommendation.
The guidelines also provide specific oxygen saturation targets for different patient populations. Acutely ill patients should have a saturation level between 94-98%, while patients at risk of hypercapnia, such as those with COPD, should have a saturation level between 88-92%. Oxygen levels should be reduced in stable patients with satisfactory oxygen saturation.
For COPD patients, a 28% Venturi mask at 4 liters per minute should be used prior to the availability of blood gases. The target oxygen saturation level for these patients should be 88-92% if they have risk factors for hypercapnia but no prior history of respiratory acidosis. If the patient’s pCO2 is normal, the target range should be adjusted to 94-98%.
The guidelines also state that oxygen therapy should not be used routinely in certain situations where there is no evidence of hypoxia, such as in cases of myocardial infarction, acute coronary syndromes, stroke, obstetric emergencies, and anxiety-related hyperventilation.
Overall, these guidelines provide important recommendations for the appropriate use of oxygen therapy in emergency situations, taking into account the specific needs of different patient populations.
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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 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:
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.
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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 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 37ÂșC, and her pulse is 98 beats/minute and regular. Based on this information, what is the most likely diagnosis?Your Answer:
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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This question is part of the following fields:
- Respiratory System
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Question 18
Incorrect
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A 28-year-old female patient presents to your clinic seeking help to quit smoking. Despite several attempts in the past, she has been unsuccessful. She has a medical history of bipolar disorder and well-managed epilepsy, for which she takes lamotrigine. She currently smokes 15 cigarettes per day and is especially interested in the health benefits of quitting smoking since she has recently found out that she is pregnant. As her physician, you decide to prescribe a suitable medication to assist her in her efforts. What would be the most appropriate treatment option?
Your Answer:
Correct Answer: Nicotine gum
Explanation:Standard treatments for nicotine dependence do not include amitriptyline, fluoxetine, or gabapentin. Nicotine replacement therapy (NRT) can be helpful for motivated patients, but it is not a cure for addiction and may require multiple attempts. Bupropion and varenicline are other smoking cessation aids, but they have multiple side effects and may not be suitable for all patients. NICE guidelines recommend discussing the best method of smoking cessation with the patient, but NRT is considered safer in pregnancy.
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This question is part of the following fields:
- Respiratory System
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Question 19
Incorrect
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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:
Correct 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.
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This question is part of the following fields:
- Respiratory System
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Question 20
Incorrect
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A 29-year-old man visits his primary care physician with complaints of a malodorous discharge from his right ear for the past 3 weeks. The patient also reports experiencing ear pain for the past 2 weeks and occasional mild dizziness. Upon examination, the skin around the ear and pinna appear normal, but the ear canal is filled with debris. After removing the debris, a small perforation and waxy debris are observed on the tympanic membrane.
The Rinne test indicates that bone conduction is better than air conduction on the right, and the Weber test shows sound lateralization to the right. The patient has no significant medical history and has never presented with an ear problem before.
What is the most likely condition based on this patient's clinical presentation?Your Answer:
Correct Answer: Cholesteatoma
Explanation:Cholesteatoma is a growth of non-cancerous squamous epithelium that can be observed as an ‘attic crust’ during otoscopy. This patient is displaying symptoms consistent with cholesteatoma, including ear discharge, earache, conductive hearing loss, and dizziness, which suggests that the inner ear has also been affected. It is important to distinguish cholesteatoma from otitis externa, as failure to diagnose cholesteatoma can lead to serious complications. Cholesteatoma can erode the ossicles bones, damage the inner ear and vestibulocochlear nerve, and even result in brain infections if it erodes through the skull bone.
Otitis externa is an inflammation of the outer ear canal that causes ear pain, which worsens with movement of the outer ear. It is often caused by the use of earplugs or swimming in unclean water. Otitis media is an inflammation of the middle ear that can lead to fluid accumulation and perforation of the tympanic membrane. It is common in children and often follows a viral upper respiratory tract infection. Myringitis is a condition associated with otitis media that causes small vesicles or cysts to form on the surface of the eardrum, resulting in severe pain and hearing impairment. It is caused by viral or bacterial infections and is treated with pain relief and antibiotics.
Understanding Cholesteatoma
Cholesteatoma is a benign growth of squamous epithelium that can cause damage to the skull base. It is most commonly found in individuals between the ages of 10 and 20 years old. Those born with a cleft palate are at a higher risk of developing cholesteatoma, with a 100-fold increase in risk.
The main symptoms of cholesteatoma include a persistent discharge with a foul odor and hearing loss. Other symptoms may occur depending on the extent of the growth, such as vertigo, facial nerve palsy, and cerebellopontine angle syndrome.
During otoscopy, a characteristic attic crust may be seen in the uppermost part of the eardrum.
Management of cholesteatoma involves referral to an ear, nose, and throat specialist for surgical removal. Early detection and treatment are important to prevent further damage to the skull base and surrounding structures.
In summary, cholesteatoma is a non-cancerous growth that can cause significant damage if left untreated. It is important to be aware of the symptoms and seek medical attention promptly if they occur.
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This question is part of the following fields:
- Respiratory System
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