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Question 1
Incorrect
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A man in his 50s arrives at the emergency department with bleeding following a car accident. Despite significant blood loss, his blood pressure has remained stable. What can be said about the receptors responsible for regulating his blood pressure?
Your Answer: Baroreceptor impulses travel via the sympathetic nervous system
Correct Answer: Baroreceptors are stimulated by arterial stretch
Explanation:Arterial stretch stimulates baroreceptors, which are located at the aortic arch and carotid sinus. The baroreceptor reflex acts on the medulla to regulate parasympathetic and sympathetic activity. When baroreceptors are more stimulated, there is an increase in parasympathetic discharge to the SA node and a decrease in sympathetic discharge. Conversely, reduced stimulation of baroreceptors leads to decreased parasympathetic discharge and increased sympathetic discharge. Baroreceptors are always active, and changes in arterial stretch can either increase or decrease their level of stimulation.
The heart has four chambers and generates pressures of 0-25 mmHg on the right side and 0-120 mmHg on the left. The cardiac output is the product of heart rate and stroke volume, typically 5-6L per minute. The cardiac impulse is generated in the sino atrial node and conveyed to the ventricles via the atrioventricular node. Parasympathetic and sympathetic fibers project to the heart via the vagus and release acetylcholine and noradrenaline, respectively. The cardiac cycle includes mid diastole, late diastole, early systole, late systole, and early diastole. Preload is the end diastolic volume and afterload is the aortic pressure. Laplace’s law explains the rise in ventricular pressure during the ejection phase and why a dilated diseased heart will have impaired systolic function. Starling’s law states that an increase in end-diastolic volume will produce a larger stroke volume up to a point beyond which stroke volume will fall. Baroreceptor reflexes and atrial stretch receptors are involved in regulating cardiac output.
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This question is part of the following fields:
- Cardiovascular System
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Question 2
Incorrect
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A 43-year-old woman presents to the clinic with a 4-month history of fatigue and constipation. Upon examination, no significant findings were observed except for the following blood results:
- Hb: 125 g/L (Female: 115-160)
- Platelets: 162 * 109/L (150-400)
- WBC: 6.8 * 109/L (4.0-11.0)
- Na+: 142 mmol/L (135-145)
- K+: 3.8 mmol/L (3.5-5.0)
- Urea: 6.2 mmol/L (2.0-7.0)
- Creatinine: 105 µmol/L (55-120)
- CRP: 2 mg/L (<5)
- TSH: 105.5 mU/L (0.5-5.5)
- Free thyroxine (T4): 6.8 pmol/L (9.0-18)
The appropriate medication was prescribed to treat the underlying condition. What is the receptor targeted by this drug?Your Answer: G-protein coupled receptors (GPCRs)
Correct Answer: Nuclear
Explanation:Levothyroxine functions by binding to nuclear receptors, while drugs such as lidocaine primarily act on ion channels, specifically voltage-gated sodium channels. G-protein coupled receptors are more intricate, with drugs binding to the receptor causing a series of events within the G-protein subunits, ultimately leading to the production of secondary messengers like cyclic AMP or protein phosphorylation cascades. Adrenoreceptors are an example of G-protein coupled receptors.
Pharmacodynamics refers to the effects of drugs on the body, as opposed to pharmacokinetics which is concerned with how the body processes drugs. Drugs typically interact with a target, which can be a protein located either inside or outside of cells. There are four main types of cellular targets: ion channels, G-protein coupled receptors, tyrosine kinase receptors, and nuclear receptors. The type of target determines the mechanism of action of the drug. For example, drugs that work on ion channels cause the channel to open or close, while drugs that activate tyrosine kinase receptors lead to cell growth and differentiation.
It is also important to consider whether a drug has a positive or negative impact on the receptor. Agonists activate the receptor, while antagonists block the receptor preventing activation. Antagonists can be competitive or non-competitive, depending on whether they bind at the same site as the agonist or at a different site. The binding affinity of a drug refers to how readily it binds to a specific receptor, while efficacy measures how well an agonist produces a response once it has bound to the receptor. Potency is related to the concentration at which a drug is effective, while the therapeutic index is the ratio of the dose of a drug resulting in an undesired effect compared to that at which it produces the desired effect.
The relationship between the dose of a drug and the response it produces is rarely linear. Many drugs saturate the available receptors, meaning that further increased doses will not cause any more response. Some drugs do not have a significant impact below a certain dose and are considered sub-therapeutic. Dose-response graphs can be used to illustrate the relationship between dose and response, allowing for easy comparison of different drugs. However, it is important to remember that dose-response varies between individuals.
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This question is part of the following fields:
- General Principles
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Question 3
Incorrect
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A 30-year-old male presents to the emergency department after vomiting blood. He had been out drinking heavily with friends and had vomited multiple times, with the last episode containing a significant amount of blood.
Upon examination, the patient appeared intoxicated and had a pulse of 96 bpm and a blood pressure of 120/74 mmHg. Abdominal examination revealed no abnormalities.
What is the probable diagnosis?Your Answer: Duodenal ulceration
Correct Answer: Mallory-Weiss tear
Explanation:Mallory Weiss Tear and Alcoholic Gastritis
Repeated episodes of vomiting due to alcohol consumption can lead to a Mallory Weiss tear, which is a mucosal tear in the esophagus. This tear can cause hematemesis, which is vomiting of blood. This is a common occurrence in habitual drinkers who suffer from alcoholic gastritis. Along with upper abdominal pain, this condition can cause a rise in esophageal pressures, leading to mucosal tears. However, most patients only lose small amounts of blood, and symptoms can often be resolved with minimal intervention. It is important to seek medical attention if symptoms persist or worsen.
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This question is part of the following fields:
- Gastrointestinal System
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Question 4
Incorrect
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An 68-year-old woman is presented to the vascular clinic with a painful ulcer on the anterior aspect of her shin. She reports experiencing pain in the same leg at night and while sitting in a chair.
The patient has a medical history of diabetes for 11 years, hypertension for 12 years, and has been a smoker for over 50 years.
Upon examination, a pale ulcer with a 'punched out' appearance is observed. The patient declines further examination.
Based on the given clinical scenario, what is the most probable type of ulcer?Your Answer: Marjolin ulcer
Correct Answer: Arterial ulcer
Explanation:The correct answer is arterial ulcer. These types of leg ulcers are typically pale, painful, and have a punched-out appearance. They are often associated with peripheral vascular disease, which is likely in this patient given her cardiovascular risk factors and claudication pain. The fact that she experiences pain while sitting down suggests critical ischemia. Venous ulcers, on the other hand, appear red and oozing with irregular margins and are usually associated with varicose veins, edema, or lipodermatosclerosis. Marjolin ulcers are a malignant transformation of chronic ulcers into squamous cell carcinoma, while neuropathic ulcers typically occur over pressure areas such as the sole of the foot and are associated with a sensory neuropathy. Although this patient has diabetes, the history and appearance of the ulcer are more consistent with an arterial ulcer.
Venous leg ulcers are caused by venous hypertension and can be managed with compression banding. Marjolin’s ulcers are a type of squamous cell carcinoma that occur at sites of chronic inflammation. Arterial ulcers are painful and occur on the toes and heel, while neuropathic ulcers commonly occur over the plantar surface of the metatarsal head and hallux. Pyoderma gangrenosum is associated with inflammatory bowel disease and can present as erythematous nodules or pustules that ulcerate.
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This question is part of the following fields:
- Cardiovascular System
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Question 5
Incorrect
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A 65-year-old man is admitted after experiencing an acute coronary syndrome. He is prescribed aspirin, clopidogrel, nitrates, and morphine. Due to his high 6-month risk score, percutaneous coronary intervention is planned and he is given intravenous tirofiban. What is the mechanism of action of this medication?
Your Answer: Coronary vasodilator
Correct Answer: Glycoprotein IIb/IIIa receptor antagonist
Explanation:Glycoprotein IIb/IIIa Receptor Antagonists
Glycoprotein IIb/IIIa receptor antagonists are a class of drugs that inhibit the function of the glycoprotein IIb/IIIa receptor, which is found on the surface of platelets. These drugs are used to prevent blood clots from forming in patients with acute coronary syndrome, unstable angina, or during percutaneous coronary intervention (PCI).
Examples of glycoprotein IIb/IIIa receptor antagonists include abciximab, eptifibatide, and tirofiban. These drugs work by blocking the binding of fibrinogen to the glycoprotein IIb/IIIa receptor, which prevents platelet aggregation and the formation of blood clots.
Glycoprotein IIb/IIIa receptor antagonists are typically administered intravenously and are used in combination with other antiplatelet agents, such as aspirin and clopidogrel. While these drugs are effective at preventing blood clots, they can also increase the risk of bleeding. Therefore, careful monitoring of patients is necessary to ensure that the benefits of these drugs outweigh the risks.
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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 42-year-old woman visits the clinic to discuss her treatment options after being diagnosed with Huntington's disease. The physician informs her that excess triplets of nucleotides are responsible for causing this condition. Can you identify the biochemical makeup of these DNA units?
Your Answer: One sugar, two amines and two phosphates molecules
Correct Answer: One sugar, one amine and one phosphate molecules
Explanation:A man with Kearns-Sayer syndrome, a mitochondrial disease, will not pass on the condition to any of his children. This disease is characterized by ptosis, external ophthalmoplegia, retinitis pigmentosa, cardiac conduction defects, and a proximal myopathy. Diagnosis is confirmed through muscle biopsy and polymerase chain reaction analysis of mitochondrial DNA. Mitochondrial diseases are inherited through defects in DNA present in the mitochondria, which are only passed down through the maternal line. Other examples of mitochondrial diseases include MERRF, MELAS, and MIDD.
Mitochondrial diseases are caused by a small amount of double-stranded DNA present in the mitochondria, which encodes protein components of the respiratory chain and some special types of RNA. These diseases are inherited only via the maternal line, as the sperm contributes no cytoplasm to the zygote. None of the children of an affected male will inherit the disease, while all of the children of an affected female will inherit it. Mitochondrial diseases generally encode rare neurological diseases, and there is poor genotype-phenotype correlation due to heteroplasmy, which means that within a tissue or cell, there can be different mitochondrial populations. Muscle biopsy typically shows red, ragged fibers due to an increased number of mitochondria. Examples of mitochondrial diseases include Leber’s optic atrophy, MELAS syndrome, MERRF syndrome, Kearns-Sayre syndrome, and sensorineural hearing loss.
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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 group of teachers in the kindergarten team want to establish the levels of literacy skills among their students.
They collect data over the course of a month and compare their results against the National Association for the Education of Young Children (NAEYC) guidelines for kindergarten literacy skills and find that they recommend all students should have basic literacy skills.
After the first month, they find that only 25% of their students have basic literacy skills.
They go on to develop a literacy program and repeat the data collection one month later. They find the levels of basic literacy skills have now improved to 75%.
What type of project is this?Your Answer: Service evaluation and service improvement
Correct Answer: Clinical audit
Explanation:The purpose of a clinical audit is to identify areas where clinical practice falls short of the required standard and to implement interventions to improve these shortcomings. Developing interventions, such as electronic prompts, is a crucial aspect of clinical audits.
A case-control study is not applicable in this scenario. Case-control studies compare two groups based on different outcomes and retrospectively look for possible causal factors. However, in this case, there is only one group being evaluated, and the team is not looking for cause and effect.
Similarly, a cohort study is not appropriate. Cohort studies compare two groups with different characteristics over time to observe differing outcomes. This is a type of research study, which is not the aim of the clinical audit.
A risk assessment is also not relevant. Risk assessments evaluate the potential risks of an activity and are not appropriate for this scenario. A risk assessment may be conducted to assess the safety of oxygen delivery systems or the harms of not delivering oxygen to patients. However, the purpose of a clinical audit is to identify areas for improvement in clinical practice.
Likewise, a service evaluation is not the correct option. Service evaluations review clinical services for performance and outcomes, but not against any defined standards. Improving a service is an inherent part of a clinical audit and does not need to be explicitly mentioned.
Understanding Clinical Audit
Clinical audit is a process that aims to improve the quality of patient care and outcomes by systematically reviewing care against specific criteria and implementing changes. It is a quality improvement process that involves the collection and analysis of data to identify areas where improvements can be made. The process involves reviewing current practices, identifying areas for improvement, and implementing changes to improve patient care and outcomes.
Clinical audit is an essential tool for healthcare professionals to ensure that they are providing the best possible care to their patients. It helps to identify areas where improvements can be made and provides a framework for implementing changes. The process involves a team of healthcare professionals working together to review current practices and identify areas for improvement. Once areas for improvement have been identified, changes can be implemented to improve patient care and outcomes.
In summary, clinical audit is a quality improvement process that seeks to improve patient care and outcomes through systematic review of care against explicit criteria and the implementation of change. It is an essential tool for healthcare professionals to ensure that they are providing the best possible care to their patients. By identifying areas for improvement and implementing changes, clinical audit helps to improve patient care and outcomes.
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This question is part of the following fields:
- General Principles
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Question 8
Correct
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A 25-year-old man has recently come back from travelling around South America, particularly Brazil. He reports experiencing fever and sweating every few days, along with a headache and joint pain. Upon further inquiry, he confesses to having multiple mosquito bites during his vacation. What is the probable pathogen responsible for his symptoms?
Your Answer: Plasmodium falciparum
Explanation:The patient is exhibiting symptoms that are characteristic of falciparum malaria, including fluctuating temperatures over a period of three days, arthralgia, headache, and sweating. The key piece of information in the patient’s history is their exposure to mosquito bites in an area where malaria is prevalent. Based on these factors, the likely causative organism is falciparum malaria.
Understanding Falciparum Malaria and its Complications
Falciparum malaria is the most common and severe type of malaria. It is characterized by schizonts on a blood film, parasitaemia greater than 2%, hypoglycaemia, acidosis, temperature above 39°C, severe anaemia, and various complications. Complications of falciparum malaria include cerebral malaria, acute renal failure, acute respiratory distress syndrome, hypoglycaemia, and disseminated intravascular coagulation.
In areas where strains resistant to chloroquine are prevalent, the 2010 WHO guidelines recommend artemisinin-based combination therapies (ACTs) as first-line therapy for uncomplicated falciparum malaria. Examples of ACTs include artemether plus lumefantrine, artesunate plus amodiaquine, artesunate plus mefloquine, artesunate plus sulfadoxine-pyrimethamine, and dihydroartemisinin plus piperaquine.
For severe falciparum malaria, a parasite count of more than 2% usually requires parenteral treatment regardless of clinical state. The WHO now recommends intravenous artesunate over intravenous quinine. If the parasite count is greater than 10%, exchange transfusion should be considered. Shock may indicate coexistent bacterial septicaemia, as malaria rarely causes haemodynamic collapse.
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This question is part of the following fields:
- General Principles
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Question 9
Incorrect
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A 62-year-old male with type 2 diabetes is urgently referred by his GP due to poor glycaemic control for the past three days, with home blood glucose readings around 25 mmol/L. He is currently being treated with metformin and lisinopril. Yesterday, his GP checked his U+E and found that his serum sodium was 138 mmol/L (137-144), serum potassium was 5.8 mmol/L (3.5-4.9), serum urea was 20 mmol/L (2.5-7.5), and serum creatinine was 350 µmol/L (60-110). On examination, he has a temperature of 39°C, a pulse of 108 bpm, a blood pressure of 96/60 mmHg, a respiratory rate of 32/min, and oxygen saturations of 99% on air. His cardiovascular, respiratory, and abdominal examination are otherwise normal. Further investigations reveal a plasma glucose level of 17 mmol/L (3.0-6.0) and urine analysis showing blood ++ and protein ++, but ketones are negative. What is the likely diagnosis?
Your Answer: Type 4 renal tubular acidosis
Correct Answer: Sepsis
Explanation:The causes of septic shock are important to understand in order to provide appropriate treatment and improve patient outcomes. Septic shock can cause fever, hypotension, and renal failure, as well as tachypnea due to metabolic acidosis. However, it is crucial to rule out other conditions such as hyperosmolar hyperglycemic state or diabetic ketoacidosis, which have different symptoms and diagnostic criteria.
While metformin can contribute to acidosis, it is unlikely to be the primary cause in this case. Diabetic patients may be prone to renal tubular acidosis, but this is not likely to be the cause of an acute presentation. Instead, a type IV renal tubular acidosis, characterized by hyporeninaemic hypoaldosteronism, may be a more likely association.
Overall, it is crucial to carefully evaluate patients with septic shock and consider all possible causes of their symptoms. By ruling out other conditions and identifying the underlying cause of the acidosis, healthcare providers can provide targeted treatment and improve patient outcomes. Further research and education on septic shock and its causes can also help to improve diagnosis and treatment in the future.
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This question is part of the following fields:
- Endocrine System
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Question 10
Incorrect
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A 45-year-old woman, gravida 2 para 1, has been referred to the medical assessment unit by her family physician due to persistent pelvic pain and discomfort with radiation to her lower back, hips and groin. This has significantly impacted her day-to-day activities, family and social life. She has a past medical history of atrial fibrillation and type II diabetes. She is currently 34 weeks into her second pregnancy, and ultrasound scans have reported a fairly large baby. Despite her symptoms, her bladder and bowel function remain normal. Upon assessment, her pulse is 78 beats per minute, blood pressure is 123/78 mmHg, temperature is 37.5ºC, respiratory rate is 16 breaths per minute, and CRP is less than 5 mg/L. What is the most likely cause of her pain?
Your Answer: Ectopic pregnancy
Correct Answer: Pubic symphysis dysfunction
Explanation:During pregnancy, it is common to experience pubic symphysis dysfunction due to increased ligament laxity caused by hormonal changes. This can result in pain over the pubic symphysis that may radiate to the groins and inner thighs. It is important to differentiate this from more serious conditions such as cauda equina syndrome, which is a surgical emergency and presents with low back pain, leg pain, numbness around the anus, and loss of bowel or bladder control. While slipped lumbar vertebrae can also cause similar symptoms, it is less common than pubic symphysis dysfunction during pregnancy. Ultrasound scans can confirm a normal fetus, ruling out ectopic pregnancy and miscarriage as potential causes of the symptoms.
Understanding Symphysis Pubis Dysfunction in Pregnancy
Symphysis pubis dysfunction (SPD), also known as pelvic girdle pain, is a common condition experienced by pregnant women. It is caused by the hormone relaxin, which affects the laxity of ligaments in the pelvic girdle and other parts of the body. This increased laxity can result in pain and instability in the symphysis pubis joint and/or sacroiliac joint. Around 20% of women suffer from SPD by 33 weeks of gestation, and it can occur at any time during pregnancy or in the postnatal period.
Multiple risk factors have been identified, including a previous history of low back pain, multiparity, previous trauma to the back or pelvis, heavy workload, higher levels of stress, and job dissatisfaction. Patients typically present with discomfort and pain in the suprapubic or low back area, which may radiate to the upper thighs and perineum. Pain can range from mild to severe and is often exacerbated by walking, climbing stairs, turning in bed, standing on one leg, or weight-bearing activities.
Physical examination may reveal tenderness of the symphysis pubis and/or sacroiliac joint, pain on hip abduction, pain at the symphysis when standing on one leg, and a waddling gait. Positive Faber and active straight leg raise tests, as well as palpation of the anterior surface of the symphysis pubis, can also indicate SPD. Imaging, such as ultrasound or MRI, is necessary to confirm separation of the symphysis pubis.
Conservative management with physiotherapy is the primary treatment for SPD. Understanding the risk factors and symptoms of SPD can help healthcare providers provide appropriate care and support for pregnant women experiencing this condition.
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This question is part of the following fields:
- Reproductive System
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