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Question 1
Incorrect
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A 55-year-old man from Hong Kong complains of fatigue, weight loss, and recurrent nosebleeds. During clinical examination, left-sided cervical lymphadenopathy is observed, and an ulcerated mass is found in the nasopharynx upon oropharyngeal examination. Which viral agent is typically associated with the development of this condition?
Your Answer: Coxsackie virus
Correct Answer: Epstein Barr virus
Explanation:Nasopharyngeal carcinoma is typically diagnosed through Trotter’s triad, which includes unilateral conductive hearing loss, ipsilateral facial and ear pain, and ipsilateral paralysis of the soft palate. This condition is commonly associated with previous Epstein Barr Virus infection, but there is no known link between the development of nasopharyngeal carcinoma and the other viruses mentioned.
Understanding Nasopharyngeal Carcinoma
Nasopharyngeal carcinoma is a type of squamous cell carcinoma that affects the nasopharynx. It is a rare form of cancer that is more common in individuals from Southern China and is associated with Epstein Barr virus infection. The presenting features of nasopharyngeal carcinoma include cervical lymphadenopathy, otalgia, unilateral serous otitis media, nasal obstruction, discharge, and/or epistaxis, and cranial nerve palsies such as III-VI.
To diagnose nasopharyngeal carcinoma, a combined CT and MRI scan is typically used. The first line of treatment for this type of cancer is radiotherapy. It is important to catch nasopharyngeal carcinoma early to increase the chances of successful treatment.
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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 35-year-old woman presents to your clinic complaining of increased joint pain and fatigue. She reports no significant medical history but mentions that her sister was recently diagnosed with systemic lupus erythematosus (SLE). On examination, there are no notable findings. Laboratory tests reveal the following results:
- Hemoglobin: 118 g/L (normal range for females: 115-160 g/L)
- Platelets: 260 * 109/L (normal range: 150-400 * 109/L)
- White blood cells: 7.5 * 109/L (normal range: 4.0-11.0 * 109/L)
- ANA: Negative
- ANCA: Negative
- Anti-La antibody: Negative
- Rheumatoid factor: Positive
Which blood test result is the most reliable indicator that SLE is unlikely in this patient?Your Answer: ANCA (antineutrophil cytoplasmic antibodies)
Correct Answer: ANA (antinuclear antibodies)
Explanation:Systemic lupus erythematosus (SLE) can be investigated through various tests, including antibody tests. ANA testing is highly sensitive and useful for ruling out SLE, but it has low specificity. About 99% of SLE patients are ANA positive. Rheumatoid factor testing is positive in 20% of SLE patients. Anti-dsDNA testing is highly specific (>99%) but less sensitive (70%). Anti-Smith testing is also highly specific (>99%) but has a lower sensitivity (30%). Other antibody tests that can be used include anti-U1 RNP, SS-A (anti-Ro), and SS-B (anti-La).
Monitoring of SLE can be done through various markers, including inflammatory markers such as ESR. During active disease, CRP levels may be normal, and a raised CRP may indicate an underlying infection. Complement levels (C3, C4) are low during active disease due to the formation of complexes that lead to the consumption of complement. Anti-dsDNA titres can also be used for disease monitoring, but it is important to note that they are not present in all SLE patients. Overall, these investigations can help diagnose and monitor SLE, allowing for appropriate management and treatment.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 3
Incorrect
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A 21-year-old male visits the GP complaining of a sore and itchy eye upon waking up. Upon examination, the right eye appears red with a discharge of mucopurulent nature. The patient has a medical history of asthma and eczema and is currently using a salbutamol inhaler. Based on this information, what is the most probable diagnosis?
Your Answer: Corneal ulcer
Correct Answer: Bacterial conjunctivitis
Explanation:A mucopurulent discharge is indicative of bacterial conjunctivitis, which is likely in this patient presenting with an itchy, red eye. Although the patient has a history of asthma and eczema, allergic rhinitis would not produce a mucopurulent discharge. Viral conjunctivitis, the most common type of conjunctivitis, is associated with a watery discharge. A corneal ulcer, on the other hand, is characterized by pain and a watery eye.
Infective conjunctivitis is a common eye problem that is often seen in primary care. It is characterized by red, sore eyes that are accompanied by a sticky discharge. There are two types of infective conjunctivitis: bacterial and viral. Bacterial conjunctivitis is identified by a purulent discharge and eyes that may be stuck together in the morning. On the other hand, viral conjunctivitis is characterized by a serous discharge and recent upper respiratory tract infection, as well as preauricular lymph nodes.
In most cases, infective conjunctivitis is a self-limiting condition that resolves on its own within one to two weeks. However, patients are often offered topical antibiotic therapy, such as Chloramphenicol or topical fusidic acid. Chloramphenicol drops are given every two to three hours initially, while chloramphenicol ointment is given four times a day initially. Topical fusidic acid is an alternative and should be used for pregnant women. For contact lens users, topical fluoresceins should be used to identify any corneal staining, and treatment should be the same as above. It is important to advise patients not to share towels and to avoid wearing contact lenses during an episode of conjunctivitis. School exclusion is not necessary.
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This question is part of the following fields:
- Neurological System
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Question 4
Correct
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A 26-year-old 38/40 primigravida woman arrives in labour and reports a familial condition. She inquires about the possibility of her baby being affected due to consanguinity. What is the condition that poses the highest risk to the child?
Your Answer: Cystic fibrosis
Explanation:Consanguinity and Inherited Defects
Consanguinity refers to the practice of marrying within the same family or bloodline. When couples who are related marry, the risk of inherited defects is approximately double that of a non-related couple. This is because the genetic material passed down from both parents is more likely to contain the same harmful mutations. However, when second cousins marry, the risk of inherited defects is reduced to that of a non-related couple. This is because second cousins share a smaller percentage of their genetic material compared to first cousins or closer relatives. It is important for couples who are considering marriage to be aware of the potential risks associated with consanguinity and to seek genetic counseling if necessary. By understanding the risks and taking appropriate measures, couples can make informed decisions about their future together.
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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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What is the highest level of evidence in the hierarchy of evidence based medicine?
Your Answer: A well-conducted meta-analysis of randomised controlled trials
Explanation:The Hierarchy of Evidence in Healthcare
In healthcare, evidence-based practice is crucial in making informed decisions about patient care. The hierarchy of evidence is a framework used to determine the strength and reliability of research studies. At the top of the hierarchy is a meta-analysis, which combines data from multiple studies to provide the most comprehensive and reliable evidence. Randomised controlled trials follow, which are considered the gold standard in clinical research. Cohort studies and case-control studies are next in the hierarchy, followed by case series. At the bottom of the hierarchy is expert opinion, which is based on the experience and knowledge of healthcare professionals.
It is important to note that an evidence-based guideline is not included in the hierarchy of evidence, as it relies on the hierarchy to determine the strength of the evidence used to create the guideline. By following the hierarchy of evidence, healthcare professionals can make informed decisions about patient care based on the most reliable and trustworthy evidence available.
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This question is part of the following fields:
- Clinical Sciences
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Question 6
Incorrect
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As a new resident on the medical assessment unit, you are attending a consultant-led ward round. A 45-year-old male with a history of alcohol-related liver failure becomes agitated and threatens to punch the consultant. He displays coarse tremors in both hands and appears highly anxious.
The patient is a chronic alcoholic.
What is the preferred medication for managing his symptoms?Your Answer: Naloxone
Correct Answer: Lorazepam
Explanation:To prevent increased sedation, lorazepam is the preferred medication for alcohol withdrawal syndrome in patients with hepatic failure, rather than chlordiazepoxide. Naloxone is used for opioid overdose and respiratory depression caused by opioids, while flumazenil is not used for alcohol withdrawal management as it counteracts the effects of benzodiazepines.
Alcohol withdrawal occurs when an individual who has been consuming alcohol chronically suddenly stops or reduces their intake. This is due to the fact that chronic alcohol consumption enhances GABA-mediated inhibition in the central nervous system (CNS), similar to benzodiazepines, and inhibits NMDA-type glutamate receptors. When alcohol consumption is stopped, the opposite occurs, resulting in decreased inhibitory GABA and increased NMDA glutamate transmission.
Symptoms of alcohol withdrawal typically start within 6-12 hours and include tremors, sweating, tachycardia, and anxiety. Seizures are most likely to occur at around 36 hours, while delirium tremens, which is characterized by coarse tremors, confusion, delusions, auditory and visual hallucinations, fever, and tachycardia, is most likely to occur at around 48-72 hours.
Patients with a history of complex withdrawals from alcohol, such as delirium tremens, seizures, or blackouts, should be admitted to the hospital for monitoring until their withdrawals stabilize. The first-line treatment for alcohol withdrawal is long-acting benzodiazepines, such as chlordiazepoxide or diazepam, which are typically given as part of a reducing dose protocol. Lorazepam may be preferable in patients with hepatic failure. Carbamazepine is also effective in treating alcohol withdrawal, while phenytoin is said not to be as effective in the treatment of alcohol withdrawal seizures.
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This question is part of the following fields:
- Psychiatry
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Question 7
Incorrect
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A 28-year-old man comes to the hospital after experiencing two instances of bright red urine in the morning. He is extremely anxious and informs the doctor that he has never had such an occurrence before. The man has recently started working at an engineering firm and is preparing to get married in a few months. He has been feeling fatigued for the past few months but attributed it to his job, which requires him to travel to construction sites daily. He has no significant medical history except for an appendectomy during childhood. A blood test shows a hemoglobin concentration of 11.5 g/dL and a reticulocyte count of 14% of red blood cells. What is the most probable finding that will be reported after flow cytometry of a blood sample from this patient?
Your Answer: CD59 negative cells
Correct Answer: CD55 and CD59 negative cells
Explanation:Paroxysmal nocturnal hemoglobinuria (PNH) is a chronic form of intrinsic hemolytic anemia that can present with symptoms such as hematuria, anemia, and venous thrombosis. The classic triad of PNH includes hemolytic anemia, pancytopenia, and venous thrombosis. The gold standard test for PNH is flow cytometry for CD59 and CD55, which shows a deficiency of these proteins on red and white blood cells.
A deficiency of C3 is a complement deficiency disorder that increases the risk of recurrent bacterial infections. While a deficiency of CD59 or CD55 may be present in this patient, PNH patients typically have a deficiency of both proteins. Terminal complement deficiency, indicated by a deficiency of complements forming the membrane attack membrane, confers a high risk of infection with Neisseria organisms. Eculizumab, a humanized monoclonal antibody, is approved for the treatment of PNH and works by inhibiting the terminal complement cascade.
Understanding Paroxysmal Nocturnal Haemoglobinuria
Paroxysmal nocturnal haemoglobinuria (PNH) is a condition that causes the breakdown of haematological cells, mainly intravascular haemolysis. It is believed to be caused by a lack of glycoprotein glycosyl-phosphatidylinositol (GPI), which acts as an anchor that attaches surface proteins to the cell membrane. This leads to the improper binding of complement-regulating surface proteins, such as decay-accelerating factor (DAF), to the cell membrane. As a result, patients with PNH are more prone to venous thrombosis.
PNH can affect red blood cells, white blood cells, platelets, or stem cells, leading to pancytopenia. Patients may also experience haemoglobinuria, which is characterized by dark-coloured urine in the morning. Thrombosis, such as Budd-Chiari syndrome, is also a common feature of PNH. In some cases, patients may develop aplastic anaemia.
To diagnose PNH, flow cytometry of blood is used to detect low levels of CD59 and CD55. This has replaced Ham’s test as the gold standard investigation for PNH. Ham’s test involves acid-induced haemolysis, which normal red cells would not undergo.
Management of PNH involves blood product replacement, anticoagulation, and stem cell transplantation. Eculizumab, a monoclonal antibody directed against terminal protein C5, is currently being trialled and is showing promise in reducing intravascular haemolysis. Understanding PNH is crucial in managing this condition and improving patient outcomes.
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This question is part of the following fields:
- Haematology And Oncology
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Question 8
Incorrect
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A 25-day-old girl is brought in with jaundice and inadequate weight gain. She presents with a swollen tongue, thick skin, and elevated unconjugated bilirubin levels. It is noted that she did not receive the heel prick blood test on day 5.
What condition is the most probable diagnosis?Your Answer: MCAD deficiency
Correct Answer: Hypothyroidism
Explanation:Congenital Hypothyroidism and Other Conditions Screened for in the UK
Congenital hypothyroidism is a rare condition in the United Kingdom, often caused by inherited metabolic defects. It is important to diagnose and treat early, as untreated cases can lead to serious long-term consequences such as learning difficulties and growth restriction. Symptoms of congenital hypothyroidism include poor weight gain, a large tongue, thick skin, constipation, and coarse facies.
In the UK, the Guthrie test is used to screen for five conditions on days four to five after birth. These conditions include cystic fibrosis, sickle cell disease, phenylketonuria (PKU), MCAD deficiency, and congenital hypothyroidism. Galactosaemia is another severe metabolic condition that affects neonates from their first milk feed.
Cystic fibrosis is an autosomal recessive condition that results in thick bodily secretions due to a mutation in the chloride ion channel transporter proteins. MCAD deficiency leads to symptoms of hypotonia, hypoglycemia, and vomiting. PKU leads to symptoms of cognitive dysfunction, learning disability, and seizures. By screening for these conditions, healthcare professionals can identify and treat affected infants early, improving their long-term outcomes.
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This question is part of the following fields:
- Paediatrics
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Question 9
Incorrect
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A 33-year-old female visits her doctor complaining of a red rash on her hands. She first noticed the rash a few weeks ago after moving into her new apartment with her partner. However, in the past few days, the rash has become extremely itchy and is keeping her up at night. Despite using her regular moisturizer cream, the rash has not improved. Upon examination, the doctor observes a bilateral erythematous rash on both hands that extends into the interdigital spaces, with multiple excoriation marks. The rash is not present anywhere else, and there are no other significant findings.
What is the likely diagnosis, and what is the underlying mechanism behind this patient's presentation?Your Answer: Antigen-antibody complexes depositing in the epidermis
Correct Answer: Delayed-type IV hypersensitivity reaction
Explanation:The severe itching caused by scabies is a result of a delayed-type IV hypersensitivity reaction to the mites and their eggs, which occurs around 30 days after infestation. This type of reaction involves T-cells and antigen-presenting cells, leading to an inflammatory response. Scabies is typically spread through close skin-to-skin contact with an infected person. An allergic reaction to the patient’s regular moisturizer would be a type I hypersensitivity reaction, which causes acute itching. Antigen-antibody complex deposition in the epidermis would be a type III hypersensitivity reaction, while psoriasis is caused by hyperproliferation of epidermal keratinocytes and presents with red, scaly patches on extensor surfaces. Bacterial skin infections like cellulitis cause warm, swollen, and red skin with systemic symptoms like fever.
Scabies: Causes, Symptoms, and Treatment
Scabies is a skin condition caused by the mite Sarcoptes scabiei, which is spread through prolonged skin contact. It is most commonly seen in children and young adults. The mite burrows into the skin, laying its eggs in the outermost layer. The resulting intense itching is due to a delayed hypersensitivity reaction to the mites and eggs, which occurs about a month after infection. Symptoms include widespread itching, linear burrows on the fingers and wrists, and secondary features such as excoriation and infection.
The first-line treatment for scabies is permethrin 5%, followed by malathion 0.5% if necessary. Patients should be advised to avoid close physical contact until treatment is complete and to treat all household and close contacts, even if asymptomatic. Clothing, bedding, and towels should be laundered, ironed, or tumble-dried on the first day of treatment to kill off mites. The insecticide should be applied to all areas, including the face and scalp, and left on for 8-12 hours for permethrin or 24 hours for malathion before washing off. Treatment should be repeated after 7 days.
Crusted scabies, also known as Norwegian scabies, is a severe form of the condition seen in patients with suppressed immunity, particularly those with HIV. The skin is covered in hundreds of thousands of mites, and isolation is essential. Ivermectin is the treatment of choice.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 10
Correct
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A 50-year-old man with type 2 diabetes mellitus, who is currently on metformin, visits for his diabetic check-up. His blood sugar levels are not well-controlled and the doctor decides to prescribe gliclazide in addition to his current medication. During the consultation, the doctor discusses the potential side effects of sulfonylureas. What is a possible side effect of sulfonylureas?
Your Answer: Hypoglycaemia
Explanation:Hypoglycaemia is a significant adverse effect of sulfonylureas, including gliclazide, which stimulate insulin secretion from the pancreas. Patients taking sulfonylureas should be educated about the possibility of hypoglycaemia and instructed on how to manage it if it occurs. Acarbose commonly causes flatulence, while PPAR agonists (glitazones) can lead to fluid retention, and metformin may cause nausea and diarrhoea.
Sulfonylureas are a type of medication used to treat type 2 diabetes mellitus. They work by increasing the amount of insulin produced by the pancreas, but only if the beta cells in the pancreas are functioning properly. Sulfonylureas bind to a specific channel on the cell membrane of pancreatic beta cells, known as the ATP-dependent K+ channel (KATP).
While sulfonylureas can be effective in managing diabetes, they can also cause some adverse effects. The most common side effect is hypoglycemia, which is more likely to occur with long-acting preparations like chlorpropamide. Another common side effect is weight gain. However, there are also rarer side effects that can occur, such as hyponatremia (low sodium levels) due to inappropriate ADH secretion, bone marrow suppression, hepatotoxicity (liver damage), and peripheral neuropathy.
It is important to note that sulfonylureas should not be used during pregnancy or while breastfeeding.
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This question is part of the following fields:
- Endocrine System
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