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Question 1
Incorrect
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A 22-year-old man is discovered unresponsive in his apartment after intentionally overdosing on barbiturates. He is rushed to the hospital with sirens blaring.
Upon being transported, he awakens and is evaluated with a Glasgow Coma Scale (GCS) score of 11 (E3V3M5).
What is the primary type of ion channel that this medication targets to produce its sedative properties?Your Answer: Potassium
Correct Answer: Chloride
Explanation:Barbiturates prolong the opening of chloride channels
Barbiturates are strong sedatives that have been used in the past as anesthetics and anti-epileptic drugs. They work in the central nervous system by binding to a subunit of the GABA receptor, which opens chloride channels. This results in an influx of chloride ions and hyperpolarization of the neuronal resting potential.
The passage of calcium, magnesium, potassium, and sodium ions through channels, both actively and passively, is crucial for neuronal and peripheral function and is also targeted by other pharmacological agents.
Barbiturates are commonly used in the treatment of anxiety and seizures, as well as for inducing anesthesia. They work by enhancing the action of GABAA, a neurotransmitter that helps to calm the brain. Specifically, barbiturates increase the duration of chloride channel opening, which allows more chloride ions to enter the neuron and further inhibit its activity. This is in contrast to benzodiazepines, which increase the frequency of chloride channel opening. A helpful mnemonic to remember this difference is Frequently Bend – During Barbeque or Barbiturates increase duration & Benzodiazepines increase frequency. Overall, barbiturates are an important class of drugs that can help to manage a variety of conditions by modulating the activity of GABAA in the brain.
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This question is part of the following fields:
- Neurological System
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Question 2
Incorrect
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A 67-year-old man with a history of atrial fibrillation presents with an embolus in his lower leg. The medical team decides to perform an embolectomy using a trans popliteal approach. Upon incising the deep fascia, what will be the first structure encountered by the surgeons as they explore the central region of the popliteal fossa?
Your Answer:
Correct Answer: Tibial nerve
Explanation:The inferior aspect of the popliteal fossa houses the tibial nerve, which is positioned above the vessels. Initially, the nerve is located laterally to the vessels in the upper part of the fossa, but it eventually moves to a medial position by passing over them. The popliteal artery is the most deeply situated structure in the popliteal fossa.
Anatomy of the Popliteal Fossa
The popliteal fossa is a diamond-shaped space located at the back of the knee joint. It is bound by various muscles and ligaments, including the biceps femoris, semimembranosus, semitendinosus, and gastrocnemius. The floor of the popliteal fossa is formed by the popliteal surface of the femur, posterior ligament of the knee joint, and popliteus muscle, while the roof is made up of superficial and deep fascia.
The popliteal fossa contains several important structures, including the popliteal artery and vein, small saphenous vein, common peroneal nerve, tibial nerve, posterior cutaneous nerve of the thigh, genicular branch of the obturator nerve, and lymph nodes. These structures are crucial for the proper functioning of the lower leg and foot.
Understanding the anatomy of the popliteal fossa is important for healthcare professionals, as it can help in the diagnosis and treatment of various conditions affecting the knee joint and surrounding structures.
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This question is part of the following fields:
- Cardiovascular System
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Question 3
Incorrect
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A 20 year old intravenous drug abuser is recuperating after a surgical drainage of a psoas abscess. Suddenly, he is discovered collapsed in the restroom of the ward, unresponsive, and with pinpoint pupils. What is the best immediate course of action?
Your Answer:
Correct Answer: Intravenous naloxone
Explanation:To treat opiate overdose, the patient requires intravenous naloxone which has the fastest onset of action. However, it is crucial to note that naloxone has a short duration of action and may require additional administration. Additionally, there is a possibility of rebound pain following the administration of naloxone.
Understanding Opioid Misuse and its Management
Opioid misuse is a serious problem that can lead to various complications and health risks. Opioids are substances that bind to opioid receptors, including natural opiates like morphine and synthetic opioids like buprenorphine and methadone. Signs of opioid misuse include rhinorrhoea, needle track marks, pinpoint pupils, drowsiness, watering eyes, and yawning.
Complications of opioid misuse can range from viral and bacterial infections to venous thromboembolism and overdose, which can lead to respiratory depression and death. Psychological and social problems such as craving, crime, prostitution, and homelessness can also arise.
In case of an opioid overdose, emergency management involves administering IV or IM naloxone, which has a rapid onset and relatively short duration of action. Harm reduction interventions such as needle exchange and testing for HIV, hepatitis B & C may also be offered.
Patients with opioid dependence are usually managed by specialist drug dependence clinics or GPs with a specialist interest. Treatment options may include maintenance therapy or detoxification, with methadone or buprenorphine recommended as the first-line treatment by NICE. Compliance is monitored using urinalysis, and detoxification can last up to 4 weeks in an inpatient/residential setting and up to 12 weeks in the community. Understanding opioid misuse and its management is crucial in addressing this growing public health concern.
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This question is part of the following fields:
- General Principles
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Question 4
Incorrect
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The upper and lower limit of normal, of a cognitive test in the research study, is two standard deviations of the population. What percentage of the population is encompassed by two standard deviations?
Your Answer:
Correct Answer: 95%
Explanation:Normal Distribution and Standard Deviation
Normal distribution is a statistical concept that assumes that data is distributed in a bell-shaped curve. This means that most of the data falls within a certain range, with fewer data points at the extremes. Standard deviation is a measure of how spread out the data is from the mean. If we assume that there is a normal distribution of a test in the population, we can use standard deviation to understand how much of the population falls within certain ranges.
For example, one standard deviation from the mean includes 68% of the population. This means that if we were to plot the test scores on a graph, 68% of the scores would fall within one standard deviation of the mean. Two standard deviations from the mean include approximately 95% of the population. This means that if we were to plot the test scores on a graph, 95% of the scores would fall within two standard deviations of the mean. Finally, three standard deviations from the mean include 99.7% of the population. This means that if we were to plot the test scores on a graph, 99.7% of the scores would fall within three standard deviations of the mean.
normal distribution and standard deviation is important in many fields, including finance, science, and social sciences. By knowing how much of the population falls within certain ranges, we can make more informed decisions and draw more accurate conclusions from our data.
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This question is part of the following fields:
- Clinical Sciences
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Question 5
Incorrect
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Mr. Johnson is a 72-year-old man who was diagnosed with chronic lymphocytic leukaemia (CLL) 18 months ago. His disease has been stable, however he has now presented with fatigue and splenomegaly. His blood results are shown below.
Hb 85 g/dL
WCC 41 x 109 cells/L
Plts 210 x 109 cells/L
MCV 88 fl
Haptoglobin 115 mg/dL (30-200 mg/dL)
Direct Coombs test Positive
What is the most likely diagnosis?Your Answer:
Correct Answer: Warm autoimmune haemolytic anaemia
Explanation:CLL is linked to warm autoimmune haemolytic anaemia.
Complications of Chronic Lymphocytic Leukaemia
Chronic lymphocytic leukaemia (CLL) is a type of cancer that affects the blood and bone marrow. It can lead to various complications, including anaemia, hypogammaglobulinaemia, and warm autoimmune haemolytic anaemia. Patients with CLL may also experience recurrent infections due to their weakened immune system. However, one of the most severe complications of CLL is Richter’s transformation.
Richter’s transformation occurs when CLL cells transform into a high-grade, fast-growing non-Hodgkin’s lymphoma. This transformation can happen when the leukaemia cells enter the lymph nodes. Patients with Richter’s transformation often become unwell very suddenly and may experience symptoms such as lymph node swelling, fever without infection, weight loss, night sweats, nausea, and abdominal pain.
It is essential for patients with CLL to be aware of the potential complications and to seek medical attention if they experience any concerning symptoms. Regular check-ups and monitoring can also help detect any changes in the condition early on, allowing for prompt treatment and management.
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This question is part of the following fields:
- Haematology And Oncology
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Question 6
Incorrect
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A 65-year-old man with critical limb ischaemia is having a femoro-distal bypass graft. When mobilizing the proximal part of the posterior tibial artery, what is the most vulnerable structure to injury?
Your Answer:
Correct Answer: Tibial nerve
Explanation:The posterior tibial artery and tibial nerve are in close proximity to each other. The nerve passes behind the vessel about 2.5cm below where it begins. Initially, the nerve is positioned on the medial side of the artery, but it shifts to the lateral side after crossing it.
Anatomy of the Posterior Tibial Artery
The posterior tibial artery is a major branch of the popliteal artery that terminates by dividing into the medial and lateral plantar arteries. It is accompanied by two veins throughout its length and its position corresponds to a line drawn from the lower angle of the popliteal fossa to a point midway between the medial malleolus and the most prominent part of the heel.
The artery is located anteriorly to the tibialis posterior and flexor digitorum longus muscles, and posteriorly to the surface of the tibia and ankle joint. The posterior tibial nerve is located 2.5 cm distal to its origin. The proximal part of the artery is covered by the gastrocnemius and soleus muscles, while the distal part is covered by skin and fascia. The artery is also covered by the fascia overlying the deep muscular layer.
Understanding the anatomy of the posterior tibial artery is important for medical professionals, as it plays a crucial role in the blood supply to the foot and ankle. Any damage or blockage to this artery can lead to serious complications, such as peripheral artery disease or even amputation.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 7
Incorrect
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A 65-year-old woman presents with microcytic anaemia on routine blood tests. She reports feeling fatigued and experiencing occasional episodes of fresh red blood in her stool. Despite passing stool less frequently, she expresses no concern to her physician. What is the probable diagnosis?
Your Answer:
Correct Answer: Rectal cancer
Explanation:Rectal cancer is characterized by symptoms such as passing fresh blood, which distinguishes it from duodenal cancer that presents with upper gastrointestinal bleeding. Inflammatory bowel disease typically includes abdominal pain, fever, and passing bloody stools, and may have more severe presentations, but microcytic anemia is not a common feature. Irritable bowel syndrome does not involve passing bloody stools and is associated with vague symptoms like bloating, backache, and urinary problems. Gastroenteritis is unlikely as it is accompanied by vomiting, diarrhea, and fever, which the patient has not reported.
Colorectal cancer is a prevalent type of cancer in the UK, ranking third in terms of frequency and second in terms of cancer-related deaths. Every year, approximately 150,000 new cases are diagnosed, and 50,000 people die from the disease. The cancer can occur in different parts of the colon, with the rectum being the most common location, accounting for 40% of cases. The sigmoid colon follows closely, with 30% of cases, while the descending colon has only 5%. The transverse colon has 10% of cases, and the ascending colon and caecum have 15%.
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This question is part of the following fields:
- Gastrointestinal System
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Question 8
Incorrect
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A 65-year-old woman with hypocalcaemia has elevated parathyroid hormone levels. Is it a typical physiological response to increase calcium levels? In the kidney, where does parathyroid hormone act to enhance calcium reabsorption?
Your Answer:
Correct Answer: Distal convoluted tubule
Explanation:Understanding Parathyroid Hormone and Its Effects
Parathyroid hormone is a hormone produced by the chief cells of the parathyroid glands. Its main function is to increase the concentration of calcium in the blood by stimulating the PTH receptors in the kidney and bone. This hormone has a short half-life of only 4 minutes.
The effects of parathyroid hormone are mainly seen in the bone, kidney, and intestine. In the bone, PTH binds to osteoblasts, which then signal to osteoclasts to resorb bone and release calcium. In the kidney, PTH promotes the active reabsorption of calcium and magnesium from the distal convoluted tubule, while decreasing the reabsorption of phosphate. In the intestine, PTH indirectly increases calcium absorption by increasing the activation of vitamin D, which in turn increases calcium absorption.
Overall, understanding the role of parathyroid hormone is important in maintaining proper calcium levels in the body. Any imbalances in PTH secretion can lead to various disorders such as hyperparathyroidism or hypoparathyroidism.
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This question is part of the following fields:
- Endocrine System
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Question 9
Incorrect
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A 10-year-old boy has been referred to a pediatric neurologist due to a persistent headache for the past two months. Initially, his mother thought it was due to school stress, but the boy has also been experiencing accidents while riding his bike. He has reported an inability to see his friends when they ride next to him. The boy was born via C-section and has had normal development and is doing well in school. Upon examination, the doctor discovered a visual defect where the boy cannot perceive the two temporal visual fields. If this boy undergoes surgery for his condition, which part of his hypothalamus would be affected, causing weight gain after surgery?
Your Answer:
Correct Answer: Ventromedial area of the hypothalamus
Explanation:The child displayed symptoms consistent with a craniopharyngioma, a common brain tumor in children that can be mistaken for a pituitary adenoma due to the presence of bitemporal hemianopia. Craniopharyngiomas originate from the Rathke’s pouch and often invade the pituitary and hypothalamus, particularly the ventromedial area.
1: The ventromedial area of the hypothalamus, along with the paraventricular nucleus, is responsible for synthesizing antidiuretic hormone and oxytocin, which are then stored and released from the posterior hypothalamus.
2: The posterior hypothalamus generates heat to maintain core body temperature.
3: The anterior hypothalamus dissipates heat to cool down the body and prevent a rise in temperature that could harm the body’s internal environment.
4: If the ventromedial area of the hypothalamus is removed during surgery to treat a craniopharyngioma, the patient may experience uninhibited hunger and significant weight gain, as this area controls the satiety center.
5: The supraoptic nucleus, along with the aforementioned ventromedial area, is responsible for synthesizing antidiuretic hormone and oxytocin, which are stored and released from the posterior hypothalamus.Understanding Visual Field Defects
Visual field defects can occur due to various reasons, including lesions in the optic tract, optic radiation, or occipital cortex. A left homonymous hemianopia indicates a visual field defect to the left, which is caused by a lesion in the right optic tract. On the other hand, homonymous quadrantanopias can be categorized into PITS (Parietal-Inferior, Temporal-Superior) and can be caused by lesions in the inferior or superior optic radiations in the temporal or parietal lobes.
When it comes to congruous and incongruous defects, the former refers to complete or symmetrical visual field loss, while the latter indicates incomplete or asymmetric visual field loss. Incongruous defects are caused by optic tract lesions, while congruous defects are caused by optic radiation or occipital cortex lesions. In cases where there is macula sparing, it is indicative of a lesion in the occipital cortex.
Bitemporal hemianopia, on the other hand, is caused by a lesion in the optic chiasm. The type of defect can indicate the location of the compression, with an upper quadrant defect being more common in inferior chiasmal compression, such as a pituitary tumor, and a lower quadrant defect being more common in superior chiasmal compression, such as a craniopharyngioma.
Understanding visual field defects is crucial in diagnosing and treating various neurological conditions. By identifying the type and location of the defect, healthcare professionals can provide appropriate interventions to improve the patient’s quality of life.
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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 35-year-old woman visits her GP with a complaint of oligomenorrhoea that has persisted for the past year. The GP orders blood tests to evaluate her baseline hormone profile. The results are as follows:
FSH 5 U/L (2-8)
LH 15 mmol/L (3-16)
Oestradiol 210 mmol/L (70-600)
Based on these findings, what is the probable underlying cause of her anovulation?Your Answer:
Correct Answer: Polycystic ovary syndrome
Explanation:Polycystic ovary syndrome leads to anovulation with normal levels of FSH and estrogen, known as normogonadotropic normoestrogenic anovulation. LH levels may be elevated or normal in this condition.
Hypogonadotropic hypogonadal anovulation is caused by hypopituitarism or hyperprolactinemia, resulting in low levels of gonadotropins and estrogen. However, hyperprolactinemia can be ruled out based on gonadotropin and estrogen levels alone.
Hypothalamic amenorrhea is a functional cause of hypogonadotropic hypogonadal anovulation, often due to factors such as low BMI, stress, or excessive exercise.
Understanding Ovulation Induction and Its Categories
Ovulation induction is a common treatment for couples who have difficulty conceiving naturally due to ovulation disorders. The process of ovulation requires a balance of hormones and feedback loops between the hypothalamus, pituitary gland, and ovaries. Anovulation can occur due to alterations in this balance, which can be classified into three categories: hypogonadotropic hypogonadal anovulation, normogonadotropic normoestrogenic anovulation, and hypergonadotropic hypoestrogenic anovulation. The goal of ovulation induction is to induce mono-follicular development and subsequent ovulation, leading to a singleton pregnancy.
There are various forms of ovulation induction, starting with the least invasive and simplest management option first. Exercise and weight loss are typically the first-line treatment for patients with polycystic ovarian syndrome, as ovulation can spontaneously return with even a modest 5% weight loss. Letrozole is now considered the first-line medical therapy for patients with PCOS due to its reduced risk of adverse effects on endometrial and cervical mucous compared to clomiphene citrate. Clomiphene citrate is a selective estrogen receptor modulator that acts primarily at the hypothalamus, blocking the negative feedback effect of estrogens. Gonadotropin therapy tends to be the treatment used mostly for women with hypogonadotropic hypogonadism.
One potential side effect of ovulation induction is ovarian hyperstimulation syndrome (OHSS), which can be life-threatening if not identified and managed promptly. OHSS occurs when ovarian enlargement with multiple cystic spaces form, and an increase in the permeability of capillaries leads to a fluid shift from the intravascular to the extra-vascular space. The severity of OHSS varies, with the risk of severe OHSS occurring in less than 1% of all women undergoing ovarian induction. Management includes fluid and electrolyte replacement, anticoagulation therapy, abdominal ascitic paracentesis, and pregnancy termination to prevent further hormonal imbalances.
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This question is part of the following fields:
- Reproductive System
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Question 11
Incorrect
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An 82-year-old man arrives at the emergency department with sepsis of unknown origin. During a thorough examination, it is discovered that his big toe is swollen, black, and tender. A fluid collection is also present at the nail bed. The patient has a history of uncontrolled type 1 diabetes mellitus. An MRI confirms the diagnosis of osteomyelitis. What is the probable causative organism?
Your Answer:
Correct Answer: Staphylococcus aureus
Explanation:The most common cause of osteomyelitis is Staphylococcus aureus, a bacteria that is normally found on the skin and mucus membranes but can become pathogenic in individuals who are immunocompromised or have risk factors for infections. Clostridium perfringens, Pseudomonas aeruginosa, and Staphylococcus epidermidis are not common causes of osteomyelitis, although they may cause other types of infections.
Understanding Osteomyelitis: Types, Causes, and Treatment
Osteomyelitis is a bone infection that can be classified into two types: haematogenous and non-haematogenous. Haematogenous osteomyelitis is caused by bacteria in the bloodstream and is usually monomicrobial. It is more common in children and can be caused by risk factors such as sickle cell anaemia, intravenous drug use, immunosuppression, and infective endocarditis. On the other hand, non-haematogenous osteomyelitis is caused by the spread of infection from adjacent soft tissues or direct injury to the bone. It is often polymicrobial and more common in adults, with risk factors such as diabetic foot ulcers, pressure sores, diabetes mellitus, and peripheral arterial disease.
Staphylococcus aureus is the most common cause of osteomyelitis, except in patients with sickle-cell anaemia where Salmonella species are more prevalent. To diagnose osteomyelitis, MRI is the imaging modality of choice, with a sensitivity of 90-100%.
The treatment for osteomyelitis involves a course of antibiotics for six weeks. Flucloxacillin is the preferred antibiotic, but clindamycin can be used for patients who are allergic to penicillin. Understanding the types, causes, and treatment of osteomyelitis is crucial in managing this bone infection.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 12
Incorrect
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A 60-year-old woman presents to her physician complaining of upper abdominal pain, fatigue, and unintentional weight loss over the past 4 months. During the physical examination, a mass is palpated in the epigastric region. The doctor suspects gastric cancer and refers the patient for an endoscopy. What type of cell would confirm the diagnosis?
Your Answer:
Correct Answer: Signet ring
Explanation:The patient is diagnosed with gastric adenocarcinoma, which is a type of cancer that originates in the stomach lining. The presence of signet ring cells in the biopsy is a concerning feature, indicating an aggressive form of adenocarcinoma.
Chief cells are normal cells found in the stomach lining and are not indicative of any pathology in this case.
Megaloblast cells are abnormally large red blood cells that are not expected to be present in a gastric biopsy. They are typically associated with conditions such as leukaemia.
Merkel cells are benign cells found in the skin that play a role in the sensation of touch.
Mucous cells are normal cells found in the stomach lining that produce mucus.
Gastric cancer is a relatively uncommon type of cancer, accounting for only 2% of all cancer diagnoses in developed countries. It is more prevalent in older individuals, with half of patients being over the age of 75, and is more common in males than females. Several risk factors have been identified, including Helicobacter pylori infection, atrophic gastritis, certain dietary habits, smoking, and blood group. Symptoms of gastric cancer can include abdominal pain, weight loss, nausea, vomiting, and dysphagia. In some cases, lymphatic spread may result in the appearance of nodules in the left supraclavicular lymph node or periumbilical area. Diagnosis is typically made through oesophago-gastro-duodenoscopy with biopsy, and staging is done using CT. Treatment options depend on the extent and location of the cancer and may include endoscopic mucosal resection, partial or total gastrectomy, and chemotherapy.
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This question is part of the following fields:
- Gastrointestinal System
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Question 13
Incorrect
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After a myocardial infarction (MI), a 65-year-old patient is initiated on a regimen of medications for secondary prevention. The regimen includes aspirin, clopidogrel, perindopril, bisoprolol, and simvastatin. However, the patient experiences poor tolerance to clopidogrel, leading to a prescription of ticagrelor instead.
Your Answer:
Correct Answer: Inhibits ADP binding to platelet receptors
Explanation:Ticagrelor and clopidogrel have a similar mechanism of action in that they both inhibit ADP binding to platelet receptors, thereby preventing platelet aggregation. However, ticagrelor specifically targets the glycoprotein GPIIb/IIIa complex, while clopidogrel inhibits the P2Y12 receptor.
Aspirin, on the other hand, irreversibly binds to cyclooxygenase (COX), an enzyme that plays a key role in the production of thromboxane A2, a potent vasoconstrictor and platelet aggregator.
Direct oral anticoagulants (DOACs) like rivaroxaban work by directly inhibiting clotting factor Xa, which is necessary for the formation of thrombin and subsequent clotting. Unlike warfarin, DOACs require less monitoring.
Warfarin, on the other hand, inhibits the production of vitamin K-dependent clotting factors, including factors II, VII, IX, and X. It also inhibits some pro-thrombotic molecules, which initially increases the risk of thrombosis.
Dabigatran, another form of DOAC, is a thrombin inhibitor and currently the only one with a reversal agent available.
ADP receptor inhibitors, such as clopidogrel, prasugrel, ticagrelor, and ticlopidine, work by inhibiting the P2Y12 receptor, which leads to sustained platelet aggregation and stabilization of the platelet plaque. Clinical trials have shown that prasugrel and ticagrelor are more effective than clopidogrel in reducing short- and long-term ischemic events in high-risk patients with acute coronary syndrome or undergoing percutaneous coronary intervention. However, ticagrelor may cause dyspnea due to impaired clearance of adenosine, and there are drug interactions and contraindications to consider for each medication. NICE guidelines recommend dual antiplatelet treatment with aspirin and ticagrelor for 12 months as a secondary prevention strategy for ACS.
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This question is part of the following fields:
- Cardiovascular System
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Question 14
Incorrect
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A 39-year-old woman comes to the clinic with her concerned partner due to her recent bizarre behavior. The partner reports an increase in confusion, hypersexuality, putting objects in her mouth, constant eating, and difficulty recognizing her parents. The neurological exam shows only mild neck stiffness, and routine observations are normal except for a high temperature of 38ºC. A CT scan is normal, but a lumbar puncture reveals a high lymphocyte count and slightly elevated protein. T2 weighted MRI shows hyperintensities in which area of the temporal lobe is likely affected?
Your Answer:
Correct Answer: Amygdala
Explanation:The correct option for the brain area affected in the case of herpes simplex meningoencephalitis with Kluver-Bucy syndrome is the amygdala. Lesions in this area may cause Kluver-Bucy syndrome, which can be diagnosed if the patient presents with three or more of the following symptoms: docility, dietary changes and hyperphagia, hyperorality, hypersexuality, and visual agnosia.
The caudate nucleus, hippocampus, and internal capsule are incorrect options as they are not associated with Kluver-Bucy syndrome. The caudate nucleus is involved in motor function and learning processes, the hippocampus is involved in memory, and the internal capsule provides passage to ascending and descending fibres running to and from the cerebral cortex.
Brain lesions can be localized based on the neurological disorders or features that are present. The gross anatomy of the brain can provide clues to the location of the lesion. For example, lesions in the parietal lobe can result in sensory inattention, apraxias, astereognosis, inferior homonymous quadrantanopia, and Gerstmann’s syndrome. Lesions in the occipital lobe can cause homonymous hemianopia, cortical blindness, and visual agnosia. Temporal lobe lesions can result in Wernicke’s aphasia, superior homonymous quadrantanopia, auditory agnosia, and prosopagnosia. Lesions in the frontal lobes can cause expressive aphasia, disinhibition, perseveration, anosmia, and an inability to generate a list. Lesions in the cerebellum can result in gait and truncal ataxia, intention tremor, past pointing, dysdiadokinesis, and nystagmus.
In addition to the gross anatomy, specific areas of the brain can also provide clues to the location of a lesion. For example, lesions in the medial thalamus and mammillary bodies of the hypothalamus can result in Wernicke and Korsakoff syndrome. Lesions in the subthalamic nucleus of the basal ganglia can cause hemiballism, while lesions in the striatum (caudate nucleus) can result in Huntington chorea. Parkinson’s disease is associated with lesions in the substantia nigra of the basal ganglia, while lesions in the amygdala can cause Kluver-Bucy syndrome, which is characterized by hypersexuality, hyperorality, hyperphagia, and visual agnosia. By identifying these specific conditions, doctors can better localize brain lesions and provide appropriate treatment.
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This question is part of the following fields:
- Neurological System
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Question 15
Incorrect
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As a medical student in the memory clinic, I recently encountered an 84-year-old female patient who was taking memantine. Can you explain the mechanism of action of this medication?
Your Answer:
Correct Answer: NMDA antagonist
Explanation:Memantine, an NMDA receptor antagonist, is a drug commonly used in the treatment of various neurological disorders, such as Alzheimer’s disease. Its primary mode of action is thought to involve the inhibition of current flow through NMDA receptor channels, which are a type of glutamate receptor subfamily that plays a significant role in brain function.
Management of Alzheimer’s Disease
Alzheimer’s disease is a type of dementia that progressively affects the brain and is the most common form of dementia in the UK. There are both non-pharmacological and pharmacological management options available for patients with Alzheimer’s disease.
Non-pharmacological management involves offering activities that promote wellbeing and are tailored to the patient’s preferences. Group cognitive stimulation therapy, group reminiscence therapy, and cognitive rehabilitation are some of the options that can be considered.
Pharmacological management options include acetylcholinesterase inhibitors such as donepezil, galantamine, and rivastigmine for managing mild to moderate Alzheimer’s disease. Memantine, an NMDA receptor antagonist, is a second-line treatment option that can be used for patients with moderate Alzheimer’s who are intolerant of or have a contraindication to acetylcholinesterase inhibitors. It can also be used as an add-on drug to acetylcholinesterase inhibitors for patients with moderate or severe Alzheimer’s or as monotherapy in severe Alzheimer’s.
When managing non-cognitive symptoms, NICE does not recommend the use of antidepressants for mild to moderate depression in patients with dementia. Antipsychotics should only be used for patients at risk of harming themselves or others or when the agitation, hallucinations, or delusions are causing them severe distress.
It is important to note that donepezil is relatively contraindicated in patients with bradycardia, and adverse effects may include insomnia. Proper management of Alzheimer’s disease can improve the quality of life for patients and their caregivers.
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This question is part of the following fields:
- Neurological System
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Question 16
Incorrect
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A 67-year-old widower is brought to the acute psychiatric ward due to treatment-resistant severe depression. Upon physical examination, the patient displays slow movements and rigid limbs. Their body is bent, and they have a sad expression on their face with slow speech. All tests show no evidence of organic disorder, and the patient is not taking any psychotropic medication. What term best describes this presentation?
Your Answer:
Correct Answer: Psychomotor retardation
Explanation:Psychomotor Retardation in Depression
Psychomotor retardation is a common manifestation of depression, characterized by slow movement, speech, and rigidity in limbs. Patients may also exhibit a bent body posture and feelings of emptiness and hopelessness. It is crucial to rule out other potential causes, such as medication side effects or neurological disorders like Parkinson’s disease.
In severe cases, psychomotor retardation can progress to catatonia, where the patient is unresponsive to external stimuli despite being awake. It is essential to recognize and address these symptoms promptly to ensure proper diagnosis and treatment. By the signs and symptoms of psychomotor retardation, healthcare professionals can provide appropriate care and support to individuals experiencing depression.
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This question is part of the following fields:
- Psychiatry
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Question 17
Incorrect
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Lauren formulates a null hypothesis that taking aspirin every day decreases the risk of a heart attack in individuals over the age of 50. When testing this hypothesis, she wants to determine the likelihood of avoiding a type II error.
What is the term used to describe this probability and how can it be improved?Your Answer:
Correct Answer: Power - increasing the sample size
Explanation:Power refers to the likelihood of correctly rejecting the null hypothesis when it is false, which is also the probability of avoiding a type II error. In contrast, a type II error occurs when the null hypothesis is accepted despite being false, resulting in a false negative. The sample size, or the number of subjects analyzed, plays a crucial role in determining power. Increasing the sample size leads to more precise results and a higher probability of correctly rejecting the null hypothesis, while decreasing the sample size results in less accurate results and a lower power. It is important to note that a type I error refers to rejecting the null hypothesis when it is actually true, while a type III error is not a recognized term in statistics.
Significance tests are used to determine the likelihood of a null hypothesis being true. The null hypothesis states that two treatments are equally effective, while the alternative hypothesis suggests that there is a difference between the two treatments. The p value is the probability of obtaining a result by chance that is at least as extreme as the observed result, assuming the null hypothesis is true. Two types of errors can occur during significance testing: type I, where the null hypothesis is rejected when it is true, and type II, where the null hypothesis is accepted when it is false. The power of a study is the probability of correctly rejecting the null hypothesis when it is false, and it can be increased by increasing the sample size.
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This question is part of the following fields:
- General Principles
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Question 18
Incorrect
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What is the more commonly recognized name for the compound referred to as vitamin E?
Your Answer:
Correct Answer: Alpha tocopherol
Explanation:Vitamin E and Other Essential Nutrients
Vitamin E is a group of compounds that includes alpha tocopherol, beta tocopherol, gamma tocopherol, and delta tocopherol. While each of these compounds contains vitamin E activity, alpha tocopherol is the most biologically active and abundant form of vitamin E in the diet. Vitamin E plays a crucial role in protecting cells and proteins from oxidative damage by removing free radicals. It also has antithrombotic effects, which means it impairs the action of thromboxane and thrombin, reducing blood clotting and platelet aggregation.
Adults are recommended to consume at least 15 mg of vitamin E daily, but larger quantities may also be beneficial. Good sources of vitamin E in the diet include sunflower oil, wheatgerm, and unprocessed cereals. In addition to vitamin E, other essential nutrients include alpha 1 antitrypsin, which prevents alveolar damage and lung dysfunction, beta carotene, which is responsible for vision development, boron, which is important for bone health, and thiamine, which can lead to polyneuropathy and heart failure if deficient. these essential nutrients and their roles in the body can help individuals make informed decisions about their diet and overall health.
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This question is part of the following fields:
- Clinical Sciences
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Question 19
Incorrect
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A 25-year-old male presents with a recent onset of vomiting and diarrhoea. Upon further inquiry, he reports consuming undercooked meat at a barbecue three days ago. What is the probable pathological mechanism responsible for his diarrhoea?
Your Answer:
Correct Answer: Endotoxins stimulating secretion of electrolytes into intestinal lumen
Explanation:Two Main Pathological Processes that Cause Diarrhoea
There are two main pathological processes that typically cause diarrhoea: secretory diarrhoea and osmotic diarrhoea. Secretory diarrhoea is often caused by bacteria such as E. coli and V. cholerae, which produce A-B type endotoxins that activate and increase cyclic AMP. This leads to an increase in the amounts of Na+, K+, bicarbonate, and nutrients into the apical side of the lumen, which in turn draws water into the lumen as well. On the other hand, osmotic diarrhoea occurs when osmotically active nutrients within the lumen pull water in through osmotic gradients. This is often seen in patients with pancreatic insufficiency or coeliac disease.
Laxatives work in the same manner as osmotic diarrhoea, as they increase the water content in the large bowel by exerting osmotic effects. However, in this case, laxative use is unlikely as it does not fit with the clinical history. It is important to note that diarrhoea is defined as 200 ml of water per daily excrement. the underlying pathological processes that cause diarrhoea can help in the diagnosis and treatment of this common condition.
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This question is part of the following fields:
- Infectious Diseases
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Question 20
Incorrect
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A patient presents with difficulties with swallowing, muscle cramps, tiredness and fasciculations. A diagnosis of a motor neuron disease is made. Which is the most common type?
Your Answer:
Correct Answer: Amyotrophic lateral sclerosis
Explanation:The majority of individuals diagnosed with motor neuron disease suffer from amyotrophic lateral sclerosis, which is the prevailing form of the condition.
Understanding the Different Types of Motor Neuron Disease
Motor neuron disease is a neurological condition that affects both upper and lower motor neurons. It is a rare condition that usually occurs after the age of 40. There are different patterns of the disease, including amyotrophic lateral sclerosis, primary lateral sclerosis, progressive muscular atrophy, and progressive bulbar palsy. Some patients may also have a combination of these patterns.
Amyotrophic lateral sclerosis is the most common type of motor neuron disease, accounting for 50% of cases. It typically presents with lower motor neuron signs in the arms and upper motor neuron signs in the legs. In familial cases, the gene responsible for the disease is located on chromosome 21 and codes for superoxide dismutase.
Primary lateral sclerosis, on the other hand, presents with upper motor neuron signs only. Progressive muscular atrophy affects only the lower motor neurons and usually starts in the distal muscles before progressing to the proximal muscles. It carries the best prognosis among the different types of motor neuron disease.
Finally, progressive bulbar palsy affects the muscles of the tongue, chewing and swallowing, and facial muscles due to the loss of function of brainstem motor nuclei. It carries the worst prognosis among the different types of motor neuron disease. Understanding the different types of motor neuron disease is crucial in providing appropriate treatment and care for patients.
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This question is part of the following fields:
- Neurological System
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