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Question 1
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A 39-year-old man of South Asian descent is experiencing a productive cough with occasional pink-coloured sputum for the past two weeks. He has also been having a fever, night sweats, and unintentional weight loss during this period. Upon examination, a chest x-ray confirms the diagnosis, revealing cavitary patterns in the superior lobe of the right lung, with more radiopaque walls of the air-filled cavities. What serum electrolyte is most likely to be elevated in this patient?
Your Answer: Ca2+
Explanation:The Link Between Granulomatous Diseases and Hypercalcaemia
In diseases such as tuberculosis and sarcoidosis, where granuloma formation is the main pathological mechanism, activated macrophages increase serum levels of calcium. This is due to the production of calcitriol or the active form of vitamin D, which increases calcium absorption in the small intestine and reabsorption in the renal parenchyma.
Normally, hypercalcaemia inhibits the release of parathyroid hormone (PTH), which reduces osteoclastic activity and decreases the amount of calcitriol being released. However, in granulomatous diseases, sustained activation of macrophages produces increased amounts of calcitriol without regard to the negative feedback mechanism. As a result, the walls of air-filled cavities become calcified due to the sustained hypercalcaemia, making them more radiopaque.
In summary, granulomatous diseases can lead to hypercalcaemia due to sustained activation of macrophages and increased production of calcitriol. This can result in calcification of air-filled cavities and increased radiopacity.
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This question is part of the following fields:
- Clinical Sciences
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Question 2
Incorrect
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A 67-year-old patient is being evaluated after being admitted for treatment of a persistent Clostridium difficile infection. The patient had received treatment for a previous infection three weeks ago, but the symptoms did not subside, and she continued to experience diarrhoea. The patient was hospitalized three days ago due to a life-threatening Clostridium difficile infection.
The patient has been receiving oral vancomycin and IV metronidazole for the past few days, but there has been no improvement in her symptoms. What would be the venous blood gas results in this case?Your Answer: Metabolic acidosis + hyperkalaemia
Correct Answer: Metabolic acidosis + hypokalaemia
Explanation:If a patient experiences prolonged diarrhoea, they may develop metabolic acidosis and hypokalaemia. This is likely the case for a patient with a history of prolonged Clostridium difficile infection, as the loss of bicarbonate ions from the GI tract during diarrhoea can lead to metabolic acidosis. Prolonged diarrhoea can also result in hypokalaemia due to the direct loss of potassium from the GI tract, which the body may be unable to compensate for. Therefore, metabolic acidosis and hypokalaemia are the expected outcomes in this scenario.
Understanding Metabolic Acidosis
Metabolic acidosis is a condition that can be classified based on the anion gap, which is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium. The normal range for anion gap is 10-18 mmol/L. If a question provides the chloride level, it may be an indication to calculate the anion gap.
Hyperchloraemic metabolic acidosis is a type of metabolic acidosis with a normal anion gap. It can be caused by gastrointestinal bicarbonate loss, prolonged diarrhea, ureterosigmoidostomy, fistula, renal tubular acidosis, drugs like acetazolamide, ammonium chloride injection, and Addison’s disease. On the other hand, raised anion gap metabolic acidosis is caused by lactate, ketones, urate, acid poisoning, and other factors.
Lactic acidosis is a type of metabolic acidosis that is caused by high lactate levels. It can be further classified into two types: lactic acidosis type A, which is caused by sepsis, shock, hypoxia, and burns, and lactic acidosis type B, which is caused by metformin. Understanding the different types and causes of metabolic acidosis is important in diagnosing and treating the condition.
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This question is part of the following fields:
- Renal System
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Question 3
Incorrect
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Which one of the following statements relating to the Cavernous Sinus is not true?
Your Answer: The internal carotid artery passes through it
Correct Answer: The mandibular branch of the trigeminal and optic nerve lie on the lateral wall
Explanation:The veins that empty into the sinus play a crucial role in preventing cavernous sinus thrombosis, which can result from sepsis. It is worth noting that the maxillary branch of the trigeminal nerve, rather than the mandibular branches, traverses the sinus.
Understanding the Cavernous Sinus
The cavernous sinuses are a pair of structures located on the sphenoid bone, running from the superior orbital fissure to the petrous temporal bone. They are situated between the pituitary fossa and the sphenoid sinus on the medial side, and the temporal lobe on the lateral side. The cavernous sinuses contain several important structures, including the oculomotor, trochlear, ophthalmic, and maxillary nerves, as well as the internal carotid artery and sympathetic plexus, and the abducens nerve.
The lateral wall components of the cavernous sinuses include the oculomotor, trochlear, ophthalmic, and maxillary nerves, while the contents of the sinus run from medial to lateral and include the internal carotid artery and sympathetic plexus, and the abducens nerve. The blood supply to the cavernous sinuses comes from the ophthalmic vein, superficial cortical veins, and basilar plexus of veins posteriorly. The cavernous sinuses drain into the internal jugular vein via the superior and inferior petrosal sinuses.
In summary, the cavernous sinuses are important structures located on the sphenoid bone that contain several vital nerves and blood vessels. Understanding their location and contents is crucial for medical professionals in diagnosing and treating various conditions that may affect these structures.
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This question is part of the following fields:
- Neurological System
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Question 4
Incorrect
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A 29-year-old man with a prolonged history of alcoholism is brought to the emergency department after experiencing a prolonged seizure. Despite a thorough examination, no underlying causes of seizures are found. The attending consultant suspects that the seizure may be due to a deficiency in which vitamin, as a result of the patient's chronic alcohol consumption?
Your Answer: Vitamin B5
Correct Answer: Vitamin B6
Explanation:The Importance of Vitamin B6 in the Body
Vitamin B6 is a type of water-soluble vitamin that belongs to the B complex group. Once it enters the body, it is converted into pyridoxal phosphate (PLP), which acts as a cofactor for various biochemical reactions such as transamination, deamination, and decarboxylation. These reactions are essential for the proper functioning of the body.
However, a deficiency in vitamin B6 can lead to various health problems such as peripheral neuropathy and sideroblastic anemia. One of the common causes of vitamin B6 deficiency is isoniazid therapy, which is used to treat tuberculosis. Therefore, it is important to ensure that the body receives an adequate amount of vitamin B6 to maintain optimal health.
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This question is part of the following fields:
- General Principles
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Question 5
Correct
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A 50-year-old man with a history of rate-controlled atrial fibrillation (AF) presents with chest pain, palpitations, and dizziness. The patient has a past medical history of a transient ischemic episode and is taking warfarin to prevent further ischemic episodes. He also has a history of gout, low back pain, depression, and polymyalgia rheumatica.
Upon immediate ECG, the patient is found to have an irregularly irregular rhythm consistent with fast AF. You decide to perform electrical cardioversion and prescribe a course of amiodarone to prevent recurrence.
What drug interaction should you be cautious of in this patient?Your Answer: Warfarin and amiodarone
Explanation:The metabolism of warfarin is reduced by amiodarone, which can increase the risk of bleeding. However, there are no known interactions between amiodarone and naproxen, paracetamol, codeine, or allopurinol. It should be noted that the patient in question is not diabetic and therefore should not be taking metformin.
Amiodarone is a medication used to treat various types of abnormal heart rhythms. It works by blocking potassium channels, which prolongs the action potential and helps to regulate the heartbeat. However, it also has other effects, such as blocking sodium channels. Amiodarone has a very long half-life, which means that loading doses are often necessary. It should ideally be given into central veins to avoid thrombophlebitis. Amiodarone can cause proarrhythmic effects due to lengthening of the QT interval and can interact with other drugs commonly used at the same time. Long-term use of amiodarone can lead to various adverse effects, including thyroid dysfunction, corneal deposits, pulmonary fibrosis/pneumonitis, liver fibrosis/hepatitis, peripheral neuropathy, myopathy, photosensitivity, a ‘slate-grey’ appearance, thrombophlebitis, injection site reactions, and bradycardia. Patients taking amiodarone should be monitored regularly with tests such as TFT, LFT, U&E, and CXR.
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This question is part of the following fields:
- Cardiovascular System
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Question 6
Incorrect
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A 47-year-old patient visits his doctor complaining of a cough, fever and coryzal symptoms. The doctor notes a temperature of 38.1ºC. What is the primary effector responsible for these symptoms?
Your Answer: IL-10
Correct Answer: IL-1
Explanation:IL-1 is primarily responsible for inducing fever, which is likely the cause of the patient’s fever in the context of an upper respiratory tract infection. This cytokine is produced by macrophages as part of the acute inflammatory response. Other cytokines, such as IL-5 and IL-8, have different functions, such as eosinophil activation and neutrophil chemotaxis, respectively. However, they are not the main effector responsible for the fever in this case. Additionally, von Willebrand factor is a blood glycoprotein that plays a crucial role in primary and secondary haemostasis.
Overview of Cytokines and Their Functions
Cytokines are signaling molecules that play a crucial role in the immune system. Interleukins are a type of cytokine that are produced by various immune cells and have specific functions. IL-1, produced by macrophages, induces acute inflammation and fever. IL-2, produced by Th1 cells, stimulates the growth and differentiation of T cell responses. IL-3, produced by activated T helper cells, stimulates the differentiation and proliferation of myeloid progenitor cells. IL-4, produced by Th2 cells, stimulates the proliferation and differentiation of B cells. IL-5, also produced by Th2 cells, stimulates the production of eosinophils. IL-6, produced by macrophages and Th2 cells, stimulates the differentiation of B cells and induces fever. IL-8, produced by macrophages, promotes neutrophil chemotaxis. IL-10, produced by Th2 cells, inhibits Th1 cytokine production and is known as an anti-inflammatory cytokine. IL-12, produced by dendritic cells, macrophages, and B cells, activates NK cells and stimulates the differentiation of naive T cells into Th1 cells.
In addition to interleukins, there are other cytokines with specific functions. Tumor necrosis factor-alpha, produced by macrophages, induces fever and promotes neutrophil chemotaxis. Interferon-gamma, produced by Th1 cells, activates macrophages. Understanding the functions of cytokines is important in developing treatments for various immune-related diseases.
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This question is part of the following fields:
- General Principles
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Question 7
Incorrect
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A 45-year-old male patient complains of haemoptysis and is diagnosed with tuberculosis. What type of cells typically internalize the tubercle bacillus?
Your Answer: Fibroblast
Correct Answer: Macrophage
Explanation:M. Tuberculosis has the tendency to survive within macrophages.
Understanding Tuberculosis: The Pathophysiology and Risk Factors
Tuberculosis is a bacterial infection caused by Mycobacterium tuberculosis. The pathophysiology of tuberculosis involves the migration of macrophages to regional lymph nodes, forming a Ghon complex. This complex leads to the formation of a granuloma, which is a collection of epithelioid histiocytes with caseous necrosis in the center. The inflammatory response is mediated by a type 4 hypersensitivity reaction. While healthy individuals can contain the disease, immunocompromised individuals are at risk of developing disseminated (miliary) TB.
Several risk factors increase the likelihood of developing tuberculosis. These include having lived in Asia, Latin America, Eastern Europe, or Africa for years, exposure to an infectious TB case, and being infected with HIV. Immunocompromised individuals, such as diabetics, patients on immunosuppressive therapy, malnourished individuals, or those with haematological malignancies, are also at risk. Additionally, silicosis and apical fibrosis increase the likelihood of developing tuberculosis. Understanding the pathophysiology and risk factors of tuberculosis is crucial in preventing and treating this infectious disease.
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This question is part of the following fields:
- General Principles
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Question 8
Incorrect
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A 15-year-old girl arrives at the Emergency Department after ingesting a handful of her father's anxiety medication. He takes lorazepam 1 mg TID for generalized anxiety disorder which has not responded well to other treatments.
She has consumed 8 mg lorazepam and is now unresponsive, with a respiratory rate of eight per minute and oxygen saturation of 90% on room air.
The patient does not react to verbal stimuli, but responds to a painful sternal rub and attempts to push the examiner's hand away.
Given that the half-life of lorazepam is approximately 10-20 hours, how long will it take for the medication to be eliminated from her system?Your Answer: 320 hours
Correct Answer: 200 hours
Explanation:Clonazepam and Flumazenil in Benzodiazepine Overdose
Conventionally, a drug is considered to be eliminated from the system after four or five half-lives, leaving only a small fraction of the original amount. However, this does not necessarily mean that the drug’s clinical effects have disappeared. For instance, a person who has taken clonazepam, a potent benzodiazepine used to treat certain seizure disorders, may still feel relatively alert even after only one half-life has passed.
Clonazepam is a long-acting benzodiazepine that is approximately 20 times more potent than diazepam. In cases of benzodiazepine overdose, flumazenil may be a useful antidote. Flumazenil is particularly effective in uncomplicated cases of benzodiazepine overdose, and it works by reversing the effects of benzodiazepines on the central nervous system. Therefore, it may be considered as a treatment option for individuals who have taken an excessive amount of clonazepam or other benzodiazepines.
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This question is part of the following fields:
- Pharmacology
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Question 9
Incorrect
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A child undergoes a challenging craniotomy for fulminant mastoiditis and abscess. While performing the surgery, the trigeminal nerve is severely affected in Meckel's cave. What is the least probable deficit that the child will experience?
Your Answer: Anaesthesia of the anterior aspect of the lip
Correct Answer: Anaesthesia over the entire ipsilateral side of the face
Explanation:The sensory fibres of the trigeminal nerve do not provide innervation to the angle of the jaw, which means that this area is not affected by this type of injury. However, since the trigeminal nerve is responsible for providing motor innervation to the muscles of mastication, an injury in close proximity to the motor fibres may result in some degree of compromise in muscle function.
The trigeminal nerve is the main sensory nerve of the head and also innervates the muscles of mastication. It has sensory distribution to the scalp, face, oral cavity, nose and sinuses, and dura mater, and motor distribution to the muscles of mastication, mylohyoid, anterior belly of digastric, tensor tympani, and tensor palati. The nerve originates at the pons and has three branches: ophthalmic, maxillary, and mandibular. The ophthalmic and maxillary branches are sensory only, while the mandibular branch is both sensory and motor. The nerve innervates various muscles, including the masseter, temporalis, and pterygoids.
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This question is part of the following fields:
- Neurological System
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Question 10
Incorrect
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A 3-year-old girl is brought to the emergency department with mouth pain and bruising on her chest and left arm. According to her father, she fell off the monkey bars while playing at the park. During the examination, a torn maxillary frenum is discovered.
Which healthcare professional should be prioritized for involvement in the child's care?Your Answer:
Correct Answer: Safeguarding Officer
Explanation:When a child experiences a torn maxillary frenum, it is a rare injury that should be taken seriously. If other bruises are present, it may indicate non-accidental injury, which requires immediate attention. In such cases, the designated safeguarding officer of the hospital trust should be involved to determine the appropriate course of action in consultation with the local safeguarding children board.
To assess suspected non-accidental injury, a thorough medical examination and history should be conducted, and all injuries should be documented and photographed with consent. The child’s interaction with their parent should also be noted. A full skeletal survey, including oblique views of the ribs, should be ordered to identify any fractures that may not be visible during a physical examination.
If abuse is suspected or confirmed, the safeguarding officer will help determine whether the child needs further protection from harm. This may involve admitting the child to the hospital or involving the police.
The National Institute for Health and Care Excellence (NICE) released guidelines in 2009 to help healthcare professionals identify when a child may be experiencing maltreatment. Child abuse can take many forms, including physical, emotional, and sexual abuse, neglect, and fabricated or induced illness. The guidelines provide a comprehensive list of features that may indicate abuse, but only selected features are highlighted here. Neglect may be suspected if a child has severe and persistent infestations, is not receiving essential prescribed treatment, has poor hygiene, or is not being dressed appropriately. Sexual abuse may be suspected if a child has persistent dysuria or anogenital discomfort, a gaping anus during examination, or is exhibiting sexualized behavior. Physical abuse may be suspected if a child has unexplained serious or unusual injuries, cold injuries, hypothermia, oral injuries, bruises, lacerations, burns, human bite marks, or fractures with unsuitable explanations.
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This question is part of the following fields:
- General Principles
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