-
Question 1
Incorrect
-
A 82-year-old woman named Mrs. Smith visits her GP complaining of constant fatigue. She has a medical history of hypothyroidism and takes oral levothyroxine. Her routine blood tests reveal the following results: Hb 87 g/L (115-160), MCV 108 fL (76-96), Platelets 136 ×109/L (150-400), TSH 3.6 (0.3-5), and T4 88 (70-150). What is the appropriate treatment plan for Mrs. Smith?
Your Answer: Encourage to eat more iron-containing foods
Correct Answer: Vitamin supplementation
Explanation:Pernicious Anaemia: An Autoimmune Disease
Pernicious anaemia is an autoimmune disease that occurs when the body produces antibodies against gastric parietal cells. These cells are responsible for producing intrinsic factor, which is necessary for the absorption of vitamin B12 in the terminal ileum. Vitamin B12 is essential for the synthesis of thymine, which is required for effective DNA synthesis. As a result, patients with pernicious anaemia may experience symptoms related to other cell lines, such as diarrhoea caused by gut mucosa turnover.
The failure of DNA synthesis leads to a large mean cell volume in erythrocytes as they mature through the erythroid cell line. Treatment for pernicious anaemia involves the replacement of vitamin B12, usually through hydroxycobalamin injections. Blood transfusions are unnecessary unless the patient is severely compromised, as they do not address the underlying problem.
-
This question is part of the following fields:
- Clinical Sciences
-
-
Question 2
Incorrect
-
A soon-to-be mother is advised on the significance of screening for Rhesus incompatibility between her and her unborn child. What maternal and fetal Rh status combination could potentially lead to Rhesus disease?
Your Answer: There is a 15% risk regardless of Rh statuses
Correct Answer: Rh-negative mother and Rh-positive baby
Explanation:When the baby has Rh-positive blood and the mother has Rh-negative blood, their blood supplies can mix during pregnancy. This can lead to the mother producing antibodies that may harm the baby by passing through the placenta and causing conditions like hydrops fetalis. Additionally, subsequent pregnancies may also be impacted.
Rhesus negative mothers can develop anti-D IgG antibodies if they deliver a Rh +ve child, which can cause haemolysis in future pregnancies. Prevention involves testing for D antibodies and giving anti-D prophylaxis at 28 and 34 weeks. Anti-D should also be given in various situations, such as delivery of a Rh +ve infant or amniocentesis. Tests include cord blood FBC, blood group, direct Coombs test, and Kleihauer test. Affected fetuses may experience oedema, jaundice, anaemia, hepatosplenomegaly, heart failure, and kernicterus, and may require transfusions and UV phototherapy.
-
This question is part of the following fields:
- Reproductive System
-
-
Question 3
Incorrect
-
A 39-year-old man visits his GP with a recent cut on his left forearm surrounded by erythema. The GP prescribes a short course of antibiotics. However, after 5 days, the man goes to the local hospital with a 24-hour history of progressive fatigue, headaches, and fevers. On examination, his vital signs are within normal limits except for a temperature of 38.2 ºC. The erythema has spread to his left axilla. Blood cultures reveal the presence of a bacterium containing beta-lactamase. Which antibiotic was most likely prescribed by the GP?
Your Answer: Co-amoxiclav
Correct Answer: Amoxicillin
Explanation:The resistance mechanism of penicillins involves the production of beta-lactamase, an enzyme that breaks down the beta-lactam ring present in the antibiotic. This confers resistance to bacteria that possess the enzyme, rendering the antimicrobial therapy ineffective. In this case, the patient’s infection worsened due to the breakdown of amoxicillin by beta-lactamase. However, co-amoxiclav, a combination of amoxicillin and clavulanic acid, can protect amoxicillin from beta-lactamase activity. On the other hand, ciprofloxacin, doxycycline, and minocycline belong to different classes of antibiotics and are not affected by beta-lactamase activity.
Antibiotic Resistance Mechanisms
Antibiotics are drugs that are used to treat bacterial infections. However, over time, bacteria have developed mechanisms to resist the effects of antibiotics. These mechanisms vary depending on the type of antibiotic being used.
For example, penicillins are often rendered ineffective by bacterial penicillinase, an enzyme that cleaves the β-lactam ring in the antibiotic. Cephalosporins, another type of antibiotic, can become ineffective due to changes in the penicillin-binding-proteins (PBPs) that they target. Macrolides, on the other hand, can be resisted by bacteria that have undergone post-transcriptional methylation of the 23S bacterial ribosomal RNA.
Fluoroquinolones can be resisted by bacteria that have mutations to DNA gyrase or efflux pumps that reduce the concentration of the antibiotic within the cell. Tetracyclines can be resisted by bacteria that have increased efflux through plasmid-encoded transport pumps or ribosomal protection. Aminoglycosides can be resisted by bacteria that have plasmid-encoded genes for acetyltransferases, adenyltransferases, and phosphotransferases.
Sulfonamides can be resisted by bacteria that increase the synthesis of PABA or have mutations in the gene encoding dihydropteroate synthetase. Vancomycin can be resisted by bacteria that have altered the terminal amino acid residues of the NAM/NAG-peptide subunits to which the antibiotic binds. Rifampicin can be resisted by bacteria that have mutations altering residues of the rifampicin binding site on RNA polymerase. Finally, isoniazid and pyrazinamide can be resisted by bacteria that have mutations in the katG and pncA genes, respectively, which reduce the ability of the catalase-peroxidase to activate the pro-drug.
In summary, bacteria have developed various mechanisms to resist the effects of antibiotics, making it increasingly difficult to treat bacterial infections.
-
This question is part of the following fields:
- General Principles
-
-
Question 4
Incorrect
-
A 23-year-old man is in a physical altercation resulting in a skull fracture and damage to the middle meningeal artery. After undergoing a craniotomy, the bleeding from the artery is successfully stopped through ligation near its origin. What sensory impairment is the patient most likely to experience after the operation?
Your Answer: Loss of taste from the posterior two thirds of the tongue
Correct Answer: Parasthesia of the ipsilateral external ear
Explanation:The middle meningeal artery is in close proximity to the auriculotemporal nerve, which could potentially be harmed in this situation. This nerve is responsible for providing sensation to the outer ear and the outer layer of the tympanic membrane. The C2,3 roots innervate the jaw angle and would not be impacted. The glossopharyngeal nerve is responsible for supplying the tongue.
The Middle Meningeal Artery: Anatomy and Clinical Significance
The middle meningeal artery is a branch of the maxillary artery, which is one of the two terminal branches of the external carotid artery. It is the largest of the three arteries that supply the meninges, the outermost layer of the brain. The artery runs through the foramen spinosum and supplies the dura mater. It is located beneath the pterion, where the skull is thin, making it vulnerable to injury. Rupture of the artery can lead to an Extradural hematoma.
In the dry cranium, the middle meningeal artery creates a deep indentation in the calvarium. It is intimately associated with the auriculotemporal nerve, which wraps around the artery. This makes the two structures easily identifiable in the dissection of human cadavers and also easily damaged in surgery.
Overall, understanding the anatomy and clinical significance of the middle meningeal artery is important for medical professionals, particularly those involved in neurosurgery.
-
This question is part of the following fields:
- Neurological System
-
-
Question 5
Incorrect
-
An older gentleman is brought to the acute psychiatric ward. He has ceased eating and drinking as he believes that his intestines are dead and decaying and that he cannot consume anything orally. He is experiencing severe depression. He denies auditory hallucinations.
What is the probable characterization of his delusions?Your Answer: Hypochondriacal delusions
Correct Answer: Nihilistic delusions
Explanation:Nihilistic Delusions and Cotard Syndrome
Nihilistic delusions are a severe form of negative thinking often experienced by depressed patients. These delusions are characterized by an exaggerated belief that all or part of the patient’s body, mind, or the world has ceased to exist. Patients may report that they do not have a brain or bowel, or that their body has died and they are awaiting a burial. This type of thinking is associated with a lack of insight and can be dangerous, particularly if the patient refuses to eat or drink. Urgent treatment, such as electroconvulsive therapy (ECT), may be necessary.
Nihilistic delusions are not limited to depression and can also occur in psychotic disorders like schizophrenia and organic disorders like delirium. Cotard syndrome is a specific type of nihilistic delusion where the patient believes that they are dead. This syndrome is often associated with depression and can be a sign of severe mental illness.
-
This question is part of the following fields:
- Psychiatry
-
-
Question 6
Incorrect
-
A 65-year-old man visits his doctor complaining of a productive cough and difficulty breathing for the past 10 days. The doctor prescribes antibiotics, but after a week, the patient's symptoms persist and he develops a fever and pain when breathing in. The doctor orders a chest x-ray, which indicates the presence of an empyema. What is the probable causative agent responsible for this condition?
Your Answer: Haemophilus influenzae
Correct Answer: Streptococcus pneumoniae
Explanation:An accumulation of pus in the pleural space, known as empyema, is a possible complication of pneumonia and is responsible for the patient’s pleurisy. Streptococcus pneumoniae, the most frequent cause of pneumonia, is also the leading cause of empyema.
Pneumonia is a common condition that affects the alveoli of the lungs, usually caused by a bacterial infection. Other causes include viral and fungal infections. Streptococcus pneumoniae is the most common organism responsible for pneumonia, accounting for 80% of cases. Haemophilus influenzae is common in patients with COPD, while Staphylococcus aureus often occurs in patients following influenzae infection. Mycoplasma pneumoniae and Legionella pneumophilia are atypical pneumonias that present with dry cough and other atypical symptoms. Pneumocystis jiroveci is typically seen in patients with HIV. Idiopathic interstitial pneumonia is a group of non-infective causes of pneumonia.
Patients who develop pneumonia outside of the hospital have community-acquired pneumonia (CAP), while those who develop it within hospitals are said to have hospital-acquired pneumonia. Symptoms of pneumonia include cough, sputum, dyspnoea, chest pain, and fever. Signs of systemic inflammatory response, tachycardia, reduced oxygen saturations, and reduced breath sounds may also be present. Chest x-ray is used to diagnose pneumonia, with consolidation being the classical finding. Blood tests, such as full blood count, urea and electrolytes, and CRP, are also used to check for infection.
Patients with pneumonia require antibiotics to treat the underlying infection and supportive care, such as oxygen therapy and intravenous fluids. Risk stratification is done using a scoring system called CURB-65, which stands for confusion, respiration rate, blood pressure, age, and is used to determine the management of patients with community-acquired pneumonia. Home-based care is recommended for patients with a CRB65 score of 0, while hospital assessment is recommended for all other patients, particularly those with a CRB65 score of 2 or more. The CURB-65 score also correlates with an increased risk of mortality at 30 days.
-
This question is part of the following fields:
- Respiratory System
-
-
Question 7
Incorrect
-
A 78-year-old woman is diagnosed with a femoral hernia and requires surgery. What structure forms the posterior wall of the femoral canal?
Your Answer: Sartorius
Correct Answer: Pectineal ligament
Explanation:Understanding the Femoral Canal
The femoral canal is a fascial tunnel located at the medial aspect of the femoral sheath. It contains both the femoral artery and femoral vein, with the canal lying medial to the vein. The borders of the femoral canal include the femoral vein laterally, the lacunar ligament medially, the inguinal ligament anteriorly, and the pectineal ligament posteriorly.
The femoral canal plays a significant role in allowing the femoral vein to expand, which facilitates increased venous return to the lower limbs. However, it can also be a site of femoral hernias, which occur when abdominal contents protrude through the femoral canal. The relatively tight neck of the femoral canal places these hernias at high risk of strangulation, making it important to understand the anatomy and function of this structure. Overall, understanding the femoral canal is crucial for medical professionals in diagnosing and treating potential issues related to this area.
-
This question is part of the following fields:
- Gastrointestinal System
-
-
Question 8
Incorrect
-
A 57-year-old woman arrives at the emergency department after experiencing a generalized tonic clonic seizure. Routine laboratory tests come back normal, but a CT scan of the brain with contrast shows a densely enhancing, well-defined extra-axial mass attached to the dural layer. If a biopsy of the mass were to be performed, what is the most probable histological finding?
Your Answer: Pleomorphic tumour cells border necrotic areas
Correct Answer: Spindle cells in concentric whorls and calcified psammoma bodies
Explanation:The characteristic histological findings of spindle cells in concentric whorls and calcified psammoma bodies are indicative of meningiomas, which are the most likely brain tumor in the given scenario. Meningiomas are typically asymptomatic due to their location outside the brain tissue, and are more commonly found in middle-aged females. They are described as masses with distinct margins, homogenous contrast uptake, and dural attachment. Psammoma bodies can also be found in other tumors such as papillary thyroid cancer, serous cystadenomas of the ovary, and mesotheliomas. The other answer choices are incorrect as they are associated with different types of brain tumors such as vestibular schwannomas, oligodendrogliomas, ependymomas, and glioblastoma multiform.
Brain tumours can be classified into different types based on their location, histology, and clinical features. Metastatic brain cancer is the most common form of brain tumours, which often cannot be treated with surgical intervention. Glioblastoma multiforme is the most common primary tumour in adults and is associated with a poor prognosis. Meningioma is the second most common primary brain tumour in adults, which is typically benign and arises from the arachnoid cap cells of the meninges. Vestibular schwannoma is a benign tumour arising from the eighth cranial nerve, while pilocytic astrocytoma is the most common primary brain tumour in children. Medulloblastoma is an aggressive paediatric brain tumour that arises within the infratentorial compartment, while ependymoma is commonly seen in the 4th ventricle and may cause hydrocephalus. Oligodendroma is a benign, slow-growing tumour common in the frontal lobes, while haemangioblastoma is a vascular tumour of the cerebellum. Pituitary adenoma is a benign tumour of the pituitary gland that can be either secretory or non-secretory, while craniopharyngioma is a solid/cystic tumour of the sellar region that is derived from the remnants of Rathke’s pouch.
-
This question is part of the following fields:
- Neurological System
-
-
Question 9
Incorrect
-
A 77-year-old man is admitted to a geriatric ward from his care home with new-onset confusion and agitation secondary to a urinary tract infection. His past medical history is significant for COPD, type 2 diabetes mellitus, hypertension, and systemic lupus erythematosus.
His regular medications include a combination inhaler, metformin, candesartan, and prednisolone.
As a result of a prescribing error, the medical team responsible for his admission fail to administer prednisolone during his hospital stay.
What potential adverse event does this prescribing error put the patient at risk of?Your Answer: Hypokalaemia
Correct Answer: Addisonian crisis
Explanation:Long-term use of systemic corticosteroids can suppress the body’s natural production of steroids. Therefore, sudden withdrawal of these steroids can lead to an Addisonian crisis, which is characterized by vomiting, hypotension, hyperkalemia, and hyponatremia. It is important to gradually taper off the steroids to avoid this crisis. Dyslipidemia, hyperkalemia, and immunosuppression are not consequences of abrupt withdrawal of steroids.
Corticosteroids are commonly prescribed medications that can be taken orally or intravenously, or applied topically. They mimic the effects of natural steroids in the body and can be used to replace or supplement them. However, the use of corticosteroids is limited by their numerous side effects, which are more common with prolonged and systemic use. These side effects can affect various systems in the body, including the endocrine, musculoskeletal, gastrointestinal, ophthalmic, and psychiatric systems. Some of the most common side effects include impaired glucose regulation, weight gain, osteoporosis, and increased susceptibility to infections. Patients on long-term corticosteroids should have their doses adjusted during intercurrent illness, and the medication should not be abruptly withdrawn to avoid an Addisonian crisis. Gradual withdrawal is recommended for patients who have received high doses or prolonged treatment.
-
This question is part of the following fields:
- Endocrine System
-
-
Question 10
Incorrect
-
A 53-year-old male presents to an endocrinology clinic with recurring symptoms of painful fingers and hands that seem to be enlarging. He was previously diagnosed with acromegaly eight months ago and underwent transsphenoidal surgery six months ago to remove the pituitary adenoma responsible. During examination, his facial features appear rough, and his hands are large and spade-like. You opt to manage this patient's symptoms with medication and initiate a trial of octreotide.
What physiological function is linked to this medication?Your Answer: Stimulation of growth hormone (hGH) secretion from the anterior pituitary
Correct Answer: Inhibition of glucagon secretion from the pancreas
Explanation:Somatostatin analogues, such as octreotide, are used to treat acromegaly in patients who have not responded well to surgery. Somatostatin is a hormone that has various functions, including inhibiting the secretion of growth hormone from the anterior pituitary gland and insulin and glucagon from the pancreas. Therefore, the correct answer is that somatostatin inhibits the secretion of glucagon.
The secretion of ACTH by the pancreas is regulated by a negative feedback loop involving cortisol and corticotropin-releasing hormone (CRH). When blood cortisol levels decrease, CRH is secreted from the hypothalamus, which then stimulates the secretion of ACTH from the anterior pituitary gland.
Somatostatin analogues typically do not affect the secretion of aldosterone from the pancreas, which is primarily stimulated by angiotensin-II.
Somatostatin analogues inhibit the secretion of growth hormone from the anterior pituitary gland. The hormone responsible for stimulating the secretion of growth hormone is growth hormone-releasing hormone (GHRH).
The secretion of insulin by pancreatic β-cells is inhibited by somatostatin analogues. The primary stimulus for insulin secretion is low blood glucose levels, but other substances such as arginine and leucine, acetylcholine, sulfonylurea, cholecystokinin, and incretins can also stimulate insulin release.
Somatostatin: The Inhibitor Hormone
Somatostatin, also known as growth hormone inhibiting hormone (GHIH), is a hormone produced by delta cells found in the pancreas, pylorus, and duodenum. Its main function is to inhibit the secretion of growth hormone, insulin, and glucagon. It also decreases acid and pepsin secretion, as well as pancreatic enzyme secretion. Additionally, somatostatin inhibits the trophic effects of gastrin and stimulates gastric mucous production.
Somatostatin analogs are commonly used in the management of acromegaly, a condition characterized by excessive growth hormone secretion. These analogs work by inhibiting growth hormone secretion, thereby reducing the symptoms associated with acromegaly.
The secretion of somatostatin is regulated by various factors. Its secretion increases in response to fat, bile salts, and glucose in the intestinal lumen, as well as glucagon. On the other hand, insulin decreases the secretion of somatostatin.
In summary, somatostatin plays a crucial role in regulating the secretion of various hormones and enzymes in the body. Its inhibitory effects on growth hormone, insulin, and glucagon make it an important hormone in the management of certain medical conditions.
-
This question is part of the following fields:
- Endocrine System
-
-
Question 11
Incorrect
-
A young woman with Crohn's disease has been experiencing severe exacerbations of her condition over the past year, despite standard medication. You have decided to prescribe Infliximab, a biologic drug.
What tests should be ordered before prescribing this medication?Your Answer:
Correct Answer: Interferon-gamma release assay
Explanation:Before prescribing any biologic medication, it is important to check the patient’s tuberculosis status by performing an interferon-gamma release assay. This test is used to detect TB latency and prevent reactivation of TB as a complication of biologic therapy. Other tests such as alpha-fetoprotein, spirometry, and brain-natriuretic peptide are not necessary before starting biologic treatment.
Biological Agents and Their Uses
Biological agents are substances that are used to target specific molecules or receptors in the body to treat various diseases. Adalimumab, infliximab, and etanercept are biological agents that inhibit TNF alpha, a molecule that plays a role in inflammation. These agents are used to treat Crohn’s disease and rheumatoid disease. Bevacizumab is an anti-VEGF agent that targets the growth of blood vessels in tumors. It is used to treat colorectal cancer, renal cancer, and glioblastoma. Trastuzumab is a biological agent that targets the HER receptor and is used to treat breast cancer. Imatinib is a tyrosine kinase inhibitor that is used to treat gastrointestinal stromal tumors and chronic myeloid leukemia. Basiliximab targets the IL2 binding site and is used in renal transplants. Cetuximab is an epidermal growth factor inhibitor that is used to treat EGF positive colorectal cancers. Biological agents have revolutionized the treatment of many diseases and continue to be an important area of research and development in medicine.
-
This question is part of the following fields:
- Gastrointestinal System
-
-
Question 12
Incorrect
-
An 82-year-old male patient visits their GP with a swollen and red knee joint that has been hot for the past 3 days. The patient has a medical history of diabetes and osteoarthritis, leading the GP to suspect septic arthritis. During the humoral response to an infection, what receptor is present on Helper T cells that allows them to interact with MHC II molecules on antigen-presenting cells to eliminate pathogens?
Your Answer:
Correct Answer: CD4
Explanation:Helper T cells express CD4, which interacts with MHC II molecules on antigen presenting cells. CD20 is present on B cells from late pro-B cells through memory cells, but not on early pro-B cells or plasma cells. CD8 is expressed on cytotoxic T cells and binds with MHC I molecules.
The adaptive immune response involves several types of cells, including helper T cells, cytotoxic T cells, B cells, and plasma cells. Helper T cells are responsible for the cell-mediated immune response and recognize antigens presented by MHC class II molecules. They express CD4, CD3, TCR, and CD28 and are a major source of IL-2. Cytotoxic T cells also participate in the cell-mediated immune response and recognize antigens presented by MHC class I molecules. They induce apoptosis in virally infected and tumor cells and express CD8 and CD3. Both helper T cells and cytotoxic T cells mediate acute and chronic organ rejection.
B cells are the primary cells of the humoral immune response and act as antigen-presenting cells. They also mediate hyperacute organ rejection. Plasma cells are differentiated from B cells and produce large amounts of antibody specific to a particular antigen. Overall, these cells work together to mount a targeted and specific immune response to invading pathogens or abnormal cells.
-
This question is part of the following fields:
- General Principles
-
-
Question 13
Incorrect
-
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.
-
This question is part of the following fields:
- General Principles
-
-
Question 14
Incorrect
-
A 79-year-old woman is admitted after a fall resulting in a wrist fracture. After diagnosis, she is prescribed a medication to increase bone density in accordance with NICE guidance. What is the mechanism of action of this drug?
Your Answer:
Correct Answer: Inhibits osteoclasts
Explanation:Bisphosphonates work by inhibiting osteoclasts, the cells responsible for bone resorption. Therefore, NICE recommends discharging patients on bisphosphonates after fragility fractures without the need for a DEXA scan. While vitamin D and calcium supplementation increase calcium availability to bone, bisphosphonates are the first-line treatment for fragility fractures. Inhibiting osteoblasts would decrease bone density, so promoting osteoclasts would lead to increased bone resorption, which is incorrect.
Bisphosphonates: Uses, Adverse Effects, and Patient Counselling
Bisphosphonates are drugs that mimic the action of pyrophosphate, a molecule that helps prevent bone demineralization. They work by inhibiting osteoclasts, the cells responsible for breaking down bone tissue. Bisphosphonates are commonly used to prevent and treat osteoporosis, hypercalcemia, Paget’s disease, and pain from bone metastases.
However, bisphosphonates can cause adverse effects such as oesophageal reactions, osteonecrosis of the jaw, and an increased risk of atypical stress fractures of the proximal femoral shaft in patients taking alendronate. Patients may also experience an acute phase response, which includes fever, myalgia, and arthralgia following administration. Hypocalcemia may also occur due to reduced calcium efflux from bone, but this is usually clinically unimportant.
To minimize the risk of adverse effects, patients taking oral bisphosphonates should swallow the tablets whole with plenty of water while sitting or standing. They should take the medication on an empty stomach at least 30 minutes before breakfast or another oral medication and remain upright for at least 30 minutes after taking the tablet. Hypocalcemia and vitamin D deficiency should be corrected before starting bisphosphonate treatment. However, calcium supplements should only be prescribed if dietary intake is inadequate when starting bisphosphonate treatment for osteoporosis. Vitamin D supplements are usually given.
The duration of bisphosphonate treatment varies depending on the level of risk. Some experts recommend stopping bisphosphonates after five years if the patient is under 75 years old, has a femoral neck T-score of more than -2.5, and is at low risk according to FRAX/NOGG.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 15
Incorrect
-
A 16-year-old boy visits his doctor with a complaint of dark brown urine for the past 2 days. He mentions feeling unwell for the past week with a fever and a sore throat. The doctor conducts a urinalysis and finds the following results:
- Glucose: Negative
- Ketones: Negative
- Blood: Positive
- Protein: Negative
- Leucocytes: Negative
- Nitrites: Negative
The doctor explains to the patient that he likely had an upper respiratory tract infection last week. The most commonly produced immunoglobulin in his body has combined with infection cells and deposited in his kidneys, causing blood in his urine.
What type of immunoglobulin is responsible for this patient's condition, based on the given information?Your Answer:
Correct Answer: IgA
Explanation:The most commonly produced immunoglobulin in the body is IgA, which is also associated with Berger’s disease or IgA nephropathy. This condition is often characterized by macroscopic haematuria following an upper respiratory tract strep infection, with urinalysis revealing blood and sometimes protein. IgA is frequently involved in type 3 immune-complex mediated hypersensitivity reactions, along with IgG.
IgD’s specific role in immunology is still being studied, but it is believed to activate B cells. Meanwhile, IgE is primarily known for its role in preventing parasites, although it is also associated with type 1 hypersensitivity reactions like asthma, eczema, and hay-fever. IgG, on the other hand, is the immunoglobulin with the highest concentration in the blood, but it is not produced as much as IgA and is not implicated in Berger’s disease.
Immunoglobulins, also known as antibodies, are proteins produced by the immune system to help fight off infections and diseases. There are five types of immunoglobulins found in the body, each with their own unique characteristics.
IgG is the most abundant type of immunoglobulin in blood serum and plays a crucial role in enhancing phagocytosis of bacteria and viruses. It also fixes complement and can be passed to the fetal circulation.
IgA is the most commonly produced immunoglobulin in the body and is found in the secretions of digestive, respiratory, and urogenital tracts and systems. It provides localized protection on mucous membranes and is transported across the interior of the cell via transcytosis.
IgM is the first immunoglobulin to be secreted in response to an infection and fixes complement, but does not pass to the fetal circulation. It is also responsible for producing anti-A, B blood antibodies.
IgD’s role in the immune system is largely unknown, but it is involved in the activation of B cells.
IgE is the least abundant type of immunoglobulin in blood serum and is responsible for mediating type 1 hypersensitivity reactions. It provides immunity to parasites such as helminths and binds to Fc receptors found on the surface of mast cells and basophils.
-
This question is part of the following fields:
- General Principles
-
-
Question 16
Incorrect
-
A 25-year-old man is in a physical altercation and sustains a stab wound to his upper arm, resulting in transection of the ulnar nerve. Which muscle among the following options will remain unaffected by this injury?
Your Answer:
Correct Answer: Pronator teres
Explanation:The ulnar nerve innervates several intrinsic muscles of the hand, including the medial lumbricals, adductor pollicis, flexor digitorum profundus/flexor digiti minimi, interossei, abductor digiti minimi, and opponens. However, it does not supply the thenar muscles and the first two lumbricals, which are instead innervated by the median nerve.
The ulnar nerve originates from the medial cord of the brachial plexus, specifically from the C8 and T1 nerve roots. It provides motor innervation to various muscles in the hand, including the medial two lumbricals, adductor pollicis, interossei, hypothenar muscles (abductor digiti minimi, flexor digiti minimi), and flexor carpi ulnaris. Sensory innervation is also provided to the medial 1 1/2 fingers on both the palmar and dorsal aspects. The nerve travels through the posteromedial aspect of the upper arm and enters the palm of the hand via Guyon’s canal, which is located superficial to the flexor retinaculum and lateral to the pisiform bone.
The ulnar nerve has several branches that supply different muscles and areas of the hand. The muscular branch provides innervation to the flexor carpi ulnaris and the medial half of the flexor digitorum profundus. The palmar cutaneous branch arises near the middle of the forearm and supplies the skin on the medial part of the palm, while the dorsal cutaneous branch supplies the dorsal surface of the medial part of the hand. The superficial branch provides cutaneous fibers to the anterior surfaces of the medial one and one-half digits, and the deep branch supplies the hypothenar muscles, all the interosseous muscles, the third and fourth lumbricals, the adductor pollicis, and the medial head of the flexor pollicis brevis.
Damage to the ulnar nerve at the wrist can result in a claw hand deformity, where there is hyperextension of the metacarpophalangeal joints and flexion at the distal and proximal interphalangeal joints of the 4th and 5th digits. There may also be wasting and paralysis of intrinsic hand muscles (except for the lateral two lumbricals), hypothenar muscles, and sensory loss to the medial 1 1/2 fingers on both the palmar and dorsal aspects. Damage to the nerve at the elbow can result in similar symptoms, but with the addition of radial deviation of the wrist. It is important to diagnose and treat ulnar nerve damage promptly to prevent long-term complications.
-
This question is part of the following fields:
- Neurological System
-
-
Question 17
Incorrect
-
A middle-aged patient from East Asia is presenting symptoms of distal peripheral polyneuropathy, including paraesthesia and reduced knee jerks, which are caused by a chronic deficiency of a certain vitamin. This vitamin's specific diphosphate form acts as a co-factor for the pyruvate dehydrogenase complex during the conversion of pyruvate into acetyl-CoA.
What is the name of the vitamin that this patient is lacking?Your Answer:
Correct Answer: B1
Explanation:The correct answer is Vitamin B1, which is a cofactor for the pyruvate dehydrogenase complex. The patient is experiencing dry beriberi, which is a chronic deficiency of Vitamin B1 that can cause distal peripheral polyneuropathy. The deficiency can be caused by alcohol dependence, malabsorption, or inadequate intake. Vitamin B1’s phosphate derivative, thiamine pyrophosphate, acts as a coenzyme for multiple carbohydrates and amino-acid complexes, including the pyruvate dehydrogenase complex.
Vitamin A is an incorrect answer as its deficiency does not cause the symptoms experienced by the patient. Vitamin A is essential for the function of the retina and its deficiency can lead to skin and ocular impairment, such as xerophthalmia and night blindness. Inadequate intake, fat malabsorption, or pancreatic, liver, and intestinal disease are common causes of Vitamin A deficiency.
Vitamin B6 is also an incorrect answer as the symptoms listed are not relevant to its deficiency.
The Importance of Vitamin B1 (Thiamine) in the Body
Vitamin B1, also known as thiamine, is a water-soluble vitamin that belongs to the B complex group. It plays a crucial role in the body as one of its phosphate derivatives, thiamine pyrophosphate (TPP), acts as a coenzyme in various enzymatic reactions. These reactions include the catabolism of sugars and amino acids, such as pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, and branched-chain amino acid dehydrogenase complex.
Thiamine deficiency can lead to clinical consequences, particularly in highly aerobic tissues like the brain and heart. The brain can develop Wernicke-Korsakoff syndrome, which presents symptoms such as nystagmus, ophthalmoplegia, and ataxia. Meanwhile, the heart can develop wet beriberi, which causes dilated cardiomyopathy. Other conditions associated with thiamine deficiency include dry beriberi, which leads to peripheral neuropathy, and Korsakoff’s syndrome, which causes amnesia and confabulation.
The primary causes of thiamine deficiency are alcohol excess and malnutrition. Alcoholics are routinely recommended to take thiamine supplements to prevent deficiency. Overall, thiamine is an essential vitamin that plays a vital role in the body’s metabolic processes.
-
This question is part of the following fields:
- General Principles
-
-
Question 18
Incorrect
-
A 58-year-old man comes to the emergency department complaining of severe abdominal pain and profuse diarrhoea. He has been experiencing up to 10 bowel movements per day for the past 48 hours. The patient has a history of prostatitis and has recently finished a course of ciprofloxacin. He denies any recent travel but did consume a takeaway meal earlier in the week.
The following investigations were conducted:
Stool microscopy Gram-positive bacillus
What is the probable organism responsible for the patient's symptoms?Your Answer:
Correct Answer: Clostridium difficile
Explanation:Clostridium difficile is a gram-positive bacillus that is responsible for pseudomembranous colitis, which can occur after the use of broad-spectrum antibiotics. This is the correct answer for this patient’s condition. Ciprofloxacin, which the patient recently took, is a common antibiotic that can cause Clostridium difficile (C. diff) diarrhoea. Other antibiotics that can increase the risk of C. diff infection include clindamycin, co-amoxiclav, and cephalosporins.
Campylobacter jejuni is not the correct answer. This gram-negative bacillus is the most common cause of food poisoning in the UK and is also associated with Guillain-Barre syndrome. However, the patient’s stool culture results do not support a diagnosis of Campylobacter jejuni infection.
Escherichia coli is another possible cause of diarrhoea, but it is a gram-negative bacillus and is typically associated with travellers’ diarrhoea and food poisoning.
Shigella dysenteriae is also a gram-negative bacillus that can cause diarrhoea and dysentery, but it is not the correct answer for this patient’s condition.
Clostridium difficile is a type of bacteria that is commonly found in hospitals. It produces a toxin that can damage the intestines and cause a condition called pseudomembranous colitis. This bacteria usually develops when the normal gut flora is disrupted by broad-spectrum antibiotics, with second and third generation cephalosporins being the leading cause. Other risk factors include the use of proton pump inhibitors. Symptoms of C. difficile infection include diarrhea, abdominal pain, and a raised white blood cell count. The severity of the infection can be determined using the Public Health England severity scale.
To diagnose C. difficile infection, a stool sample is tested for the presence of the C. difficile toxin. Treatment involves reviewing current antibiotic therapy and stopping antibiotics if possible. For a first episode of infection, oral vancomycin is the first-line therapy for 10 days, followed by oral fidaxomicin as second-line therapy and oral vancomycin with or without IV metronidazole as third-line therapy. Recurrent infections may require different treatment options, such as oral fidaxomicin within 12 weeks of symptom resolution or oral vancomycin or fidaxomicin after 12 weeks of symptom resolution. In life-threatening cases, oral vancomycin and IV metronidazole may be used, and surgery may be considered with specialist advice. Other therapies, such as bezlotoxumab and fecal microbiota transplant, may also be considered for preventing recurrences in certain cases.
-
This question is part of the following fields:
- Gastrointestinal System
-
-
Question 19
Incorrect
-
A 53-year-old man visits his doctor complaining of heartburn. It occurs after meals and is not related to physical activity. He is a heavy drinker, consuming around 20 units of alcohol per week, and has been smoking 2 packs of cigarettes per day since he was 20 years old. He denies experiencing weight loss, melaena, haematemesis, or dysphagia.
The doctor prescribes ranitidine as an alternative to omeprazole. What is a true statement about ranitidine?Your Answer:
Correct Answer: Is a competitive antagonist of H2 receptors on gastric parietal cells
Explanation:Ranitidine competes with histamine for binding to H2 receptors on gastric parietal cells, acting as an antagonist. It is not associated with sexual disinhibition, but can cause sexual dysfunction such as decreased libido and impotence. When the stomach pH drops too low, somatostatin secretion is stimulated, which inhibits acid secretion by parietal cells and also suppresses the release of positive regulators like histamine and gastrin. Ranitidine enhances the function of somatostatin rather than inhibiting it. As a result, it suppresses both normal and meal-stimulated acid secretion by parietal cells, making the third and fourth options incorrect.
Histamine-2 Receptor Antagonists and their Withdrawal from the Market
Histamine-2 (H2) receptor antagonists are medications used to treat dyspepsia, which includes conditions such as gastritis and gastro-oesophageal reflux disease. They were previously considered a first-line treatment option, but have since been replaced by more effective proton pump inhibitors. One example of an H2 receptor antagonist is ranitidine.
However, in 2020, ranitidine was withdrawn from the market due to the discovery of small amounts of the carcinogen N-nitrosodimethylamine (NDMA) in products from multiple manufacturers. This led to concerns about the safety of the medication and its potential to cause cancer. As a result, patients who were taking ranitidine were advised to speak with their healthcare provider about alternative treatment options.
-
This question is part of the following fields:
- Gastrointestinal System
-
-
Question 20
Incorrect
-
A 35-year-old woman has been diagnosed with gonorrhoeae and prescribed ceftriaxone. She later presents at the emergency department with severe abdominal pain, elevated white blood cell count, and signs of severe colitis. What is the most probable causative organism for these symptoms?
Your Answer:
Correct Answer: Clostridium difficile
Explanation:The correct answer is C. difficile, as it is the causative organism in pseudomembranous colitis that can occur after recent use of broad-spectrum antibiotics like ceftriaxone. These antibiotics can disrupt the gut flora, allowing C. difficile to thrive. Other antibiotics that can cause C. difficile include PPI, clindamycin, and fluoroquinolones.
Campylobacter, Escherichia coli, and Neisseria gonorrhoeae are incorrect answers. Campylobacter infections are typically caused by undercooked chicken, untreated water, or international travel. E. coli infections are usually caused by contact with infected feces, unwashed foods, or unclean water. Neisseria gonorrhoeae is a sexually transmitted disease that is spread through unprotected sex, not through recent use of broad-spectrum antibiotics. The patient in this case does not have symptoms of gonorrhoeae and there is no indication of unprotected sex after the antibiotic prescription.
Clostridium difficile is a type of bacteria that is commonly found in hospitals. It produces a toxin that can damage the intestines and cause a condition called pseudomembranous colitis. This bacteria usually develops when the normal gut flora is disrupted by broad-spectrum antibiotics, with second and third generation cephalosporins being the leading cause. Other risk factors include the use of proton pump inhibitors. Symptoms of C. difficile infection include diarrhea, abdominal pain, and a raised white blood cell count. The severity of the infection can be determined using the Public Health England severity scale.
To diagnose C. difficile infection, a stool sample is tested for the presence of the C. difficile toxin. Treatment involves reviewing current antibiotic therapy and stopping antibiotics if possible. For a first episode of infection, oral vancomycin is the first-line therapy for 10 days, followed by oral fidaxomicin as second-line therapy and oral vancomycin with or without IV metronidazole as third-line therapy. Recurrent infections may require different treatment options, such as oral fidaxomicin within 12 weeks of symptom resolution or oral vancomycin or fidaxomicin after 12 weeks of symptom resolution. In life-threatening cases, oral vancomycin and IV metronidazole may be used, and surgery may be considered with specialist advice. Other therapies, such as bezlotoxumab and fecal microbiota transplant, may also be considered for preventing recurrences in certain cases.
-
This question is part of the following fields:
- Gastrointestinal System
-
-
Question 21
Incorrect
-
A six-month-old infant is brought to the emergency department due to sudden abdominal pain and distension. The infant has a history of lethargy, growth restriction, and overall weakness. Upon abdominal examination, splenomegaly is noted. Further investigations reveal a diagnosis of sickle cell disease, with the acute presentation believed to be an acute crisis. Based on this information, what is the most probable haemoglobin trait in this patient?
Your Answer:
Correct Answer: HbS HbS
Explanation:Understanding Sickle-Cell Anaemia
Sickle-cell anaemia is a genetic disorder that occurs when an abnormal haemoglobin chain, known as HbS, is synthesized due to an autosomal recessive condition. This condition is more common in people of African descent, as the heterozygous condition offers some protection against malaria. In the UK, around 10% of Afro-Caribbean individuals are carriers of HbS. Symptoms in homozygotes typically do not develop until 4-6 months when the abnormal HbSS molecules take over from fetal haemoglobin.
The pathophysiology of sickle-cell anaemia involves the substitution of the polar amino acid glutamate with the non-polar valine in each of the two beta chains (codon 6) of haemoglobin. This substitution decreases the water solubility of deoxy-Hb, causing HbS molecules to polymerize and sickle in the deoxygenated state. HbAS patients sickle at p02 2.5 – 4 kPa, while HbSS patients sickle at p02 5 – 6 kPa. Sickle cells are fragile and can cause haemolysis, block small blood vessels, and lead to infarction.
To diagnose sickle-cell anaemia, haemoglobin electrophoresis is the definitive test. It is essential to understand the pathophysiology and symptoms of sickle-cell anaemia to provide appropriate care and management for affected individuals.
-
This question is part of the following fields:
- Haematology And Oncology
-
-
Question 22
Incorrect
-
At which of the following anatomical locations does the common peroneal nerve bifurcate into the superficial and deep peroneal nerves?
Your Answer:
Correct Answer: At the lateral aspect of the neck of the fibula
Explanation:The point where the common peroneal nerve is most susceptible to injury is at the neck of the fibula, where it divides into two branches.
The common peroneal nerve originates from the dorsal divisions of the sacral plexus, specifically from L4, L5, S1, and S2. This nerve provides sensation to the skin and fascia of the anterolateral surface of the leg and dorsum of the foot, as well as innervating the muscles of the anterior and peroneal compartments of the leg, extensor digitorum brevis, and the knee, ankle, and foot joints. It is located laterally within the sciatic nerve and passes through the lateral and proximal part of the popliteal fossa, under the cover of biceps femoris and its tendon, to reach the posterior aspect of the fibular head. The common peroneal nerve divides into the deep and superficial peroneal nerves at the point where it winds around the lateral surface of the neck of the fibula in the body of peroneus longus, approximately 2 cm distal to the apex of the head of the fibula. It is palpable posterior to the head of the fibula. The nerve has several branches, including the nerve to the short head of biceps, articular branch (knee), lateral cutaneous nerve of the calf, and superficial and deep peroneal nerves at the neck of the fibula.
-
This question is part of the following fields:
- Neurological System
-
-
Question 23
Incorrect
-
A 26-year-old man is involved in a car crash and develops oliguria with worsening renal function. How can acute tubular necrosis be differentiated from pre-renal azotemia in this case?
Your Answer:
Correct Answer: No response to intravenous fluids
Explanation:Inability to respond to intravenous fluids is observed in acute tubular necrosis due to the damage originating from the renal system itself, rather than being caused by a reduction in volume.
Understanding the Difference between Acute Tubular Necrosis and Prerenal Uraemia
Acute kidney injury can be caused by various factors, including prerenal uraemia and acute tubular necrosis. It is important to differentiate between the two to determine the appropriate treatment. Prerenal uraemia occurs when the kidneys hold on to sodium to preserve volume, leading to decreased blood flow to the kidneys. On the other hand, acute tubular necrosis is caused by damage to the kidney tubules, which can be due to various factors such as toxins, infections, or ischemia.
To differentiate between the two, several factors can be considered. In prerenal uraemia, the urine sodium level is typically less than 20 mmol/L, while in acute tubular necrosis, it is usually greater than 40 mmol/L. The urine osmolality is also higher in prerenal uraemia, typically above 500 mOsm/kg, while in acute tubular necrosis, it is usually below 350 mOsm/kg. The fractional sodium excretion is less than 1% in prerenal uraemia, while it is greater than 1% in acute tubular necrosis. Additionally, the response to fluid challenge is typically good in prerenal uraemia, while it is poor in acute tubular necrosis.
Other factors that can help differentiate between the two include the serum urea:creatinine ratio, fractional urea excretion, urine:plasma osmolality, urine:plasma urea, specific gravity, and urine sediment. By considering these factors, healthcare professionals can accurately diagnose and treat acute kidney injury.
-
This question is part of the following fields:
- Renal System
-
-
Question 24
Incorrect
-
A 20-year-old man is rushed to the emergency department following his ejection from a car during a road accident.
During the examination, the patient responds to simple questions with incomprehensible sounds and opens his eyes in response to pain. There is also an abnormal wrist flexion when a sternal rub is applied, and a positive Battle's sign is observed.
A CT scan of the head is ordered, which reveals a fracture of the petrous temporal bone.
Which nerve is most likely to be affected by the patient's injury?Your Answer:
Correct Answer: Facial nerve
Explanation:The facial nerve passes through the internal acoustic meatus, which is correct. This nerve provides motor innervation to the muscles of facial expression, parasympathetic innervation to salivary and lacrimal glands, and special sensory innervation of taste in the anterior 2/3 of the tongue via the chorda tympani. The patient in question has a Glasgow Coma Score of 7, indicating nonspecific neurotrauma from a recent road traffic accident. It is unlikely that damage to the internal acoustic meatus would affect the glossopharyngeal or hypoglossal nerves, which pass through different structures. Damage to the oculomotor nerve, which passes through the superior orbital fissure, may cause ptosis and a dilated ‘down-and-out’ pupil.
Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.
In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.
-
This question is part of the following fields:
- Neurological System
-
-
Question 25
Incorrect
-
A 32-year-old motorcyclist is admitted to the emergency department following a collision with a car. Upon secondary survey, a deep penetrating injury is discovered in the patient's left lateral thigh. The wound is surgically debrided and the patient is subsequently admitted to the neurological intensive care unit.
After a few days, the patient develops a fever and experiences significant swelling in the affected area. Upon applying pressure, crackling sounds are heard, leading to a suspected diagnosis of gas gangrene.
What is the mechanism behind the bacterial toxin responsible for the patient's clinical symptoms?Your Answer:
Correct Answer: Degradation of phospholipids
Explanation:The correct answer is degradation of phospholipids. Gas gangrene, which is characterized by deep tissue crepitus surrounding a penetrating wound, is caused by Clostridium perfringens, an organism that releases an alpha-toxin, a lecithinase enzyme that degrades phospholipids.
The mechanisms of diphtheria toxin and pseudomonas exotoxin A involve ADP-ribosylation of elongation factor II, which inhibits protein synthesis in human cells but does not cause gas gangrene.
Protein A, a virulence factor of Staphylococcus aureus, binds the Fc region of IgA, but infection with Staphylococcus aureus is not associated with gas gangrene.
The tetanus toxin inhibits presynaptic GABA release, causing trismus and opisthotonus rather than gas gangrene.
Exotoxins vs Endotoxins: Understanding the Differences
Exotoxins and endotoxins are two types of toxins produced by bacteria. Exotoxins are secreted by bacteria, while endotoxins are only released when the bacterial cell is lysed. Exotoxins are typically produced by Gram-positive bacteria, with some exceptions like Vibrio cholerae and certain strains of E. coli.
Exotoxins can be classified based on their primary effects, which include pyrogenic toxins, enterotoxins, neurotoxins, tissue invasive toxins, and miscellaneous toxins. Pyrogenic toxins stimulate the release of cytokines, resulting in fever and rash. Enterotoxins act on the gastrointestinal tract, causing either diarrheal or vomiting illness. Neurotoxins act on the nerves or neuromuscular junction, causing paralysis. Tissue invasive toxins cause damage to tissues, while miscellaneous toxins have various effects.
On the other hand, endotoxins are lipopolysaccharides that are released from Gram-negative bacteria like Neisseria meningitidis. These toxins can cause fever, sepsis, and shock. Unlike exotoxins, endotoxins are not actively secreted by bacteria but are instead released when the bacterial cell is lysed.
Understanding the differences between exotoxins and endotoxins is important in diagnosing and treating bacterial infections. While exotoxins can be targeted with specific treatments like antitoxins, endotoxins are more difficult to treat and often require supportive care.
-
This question is part of the following fields:
- General Principles
-
-
Question 26
Incorrect
-
A 58-year-old woman diagnosed with squamous cell carcinoma of the anus is preparing for an abdominoperineal resection (APR). This surgical procedure involves the complete removal of the distal colon, rectum, and anal sphincter complex through both anterior abdominal and perineal incisions, resulting in a permanent colostomy. During the process, several arteries are ligated, including the one that supplies the anal canal below the levator ani. Can you identify the name of this artery and its branching point?
Your Answer:
Correct Answer: Inferior rectal artery - a branches of internal pudendal artery
Explanation:The internal pudendal artery gives rise to the inferior rectal artery, which supplies the muscle and skin of the anal and urogenital triangle. The superior rectal artery, on the other hand, supplies the sigmoid mesocolon and not the lower part of the anal canal. The middle rectal artery is a branch of the internal pudendal artery and not the deep external pudendal artery, making the fifth option incorrect.
Anatomy of the Rectum
The rectum is a capacitance organ that measures approximately 12 cm in length. It consists of both intra and extraperitoneal components, with the transition from the sigmoid colon marked by the disappearance of the tenia coli. The extra peritoneal rectum is surrounded by mesorectal fat that contains lymph nodes, which are removed during rectal cancer surgery. The fascial layers that surround the rectum are important clinical landmarks, with the fascia of Denonvilliers located anteriorly and Waldeyers fascia located posteriorly.
In males, the rectum is adjacent to the rectovesical pouch, bladder, prostate, and seminal vesicles, while in females, it is adjacent to the recto-uterine pouch (Douglas), cervix, and vaginal wall. Posteriorly, the rectum is in contact with the sacrum, coccyx, and middle sacral artery, while laterally, it is adjacent to the levator ani and coccygeus muscles.
The superior rectal artery supplies blood to the rectum, while the superior rectal vein drains it. Mesorectal lymph nodes located superior to the dentate line drain into the internal iliac and then para-aortic nodes, while those located inferior to the dentate line drain into the inguinal nodes. Understanding the anatomy of the rectum is crucial for surgical procedures and the diagnosis and treatment of rectal diseases.
-
This question is part of the following fields:
- Gastrointestinal System
-
-
Question 27
Incorrect
-
A 68-year-old male presents with sudden and severe abdominal pain. He has a medical history of ischaemic heart disease and takes nitrates, atenolol and amlodipine for it. Upon examination, his pulse is irregularly irregular and measures 115 bpm, his blood pressure is 104/72 mmHg, and his temperature is 37.4°C. The abdomen is diffusely tender and bowel sounds are absent. What is the probable diagnosis?
Your Answer:
Correct Answer: Mesenteric ischaemia
Explanation:Narrowing Down the Differential Diagnosis for Acute Abdomen
When presented with a patient experiencing an acute abdomen, the differential diagnosis can be extensive. However, by taking note of the key points in the patient’s history and conducting a thorough examination, one can narrow down the potential causes. In the case of a man with absent bowel sounds, atrial fibrillation, and a history of ischemic heart disease, the most likely cause of his presentation is mesenteric ischemia. This is due to the fact that he is not obstructed and has vascular disease. For further information on acute mesenteric ischemia, Medscape provides a helpful resource. By utilizing these tools and resources, healthcare professionals can more accurately diagnose and treat patients with acute abdominal symptoms.
-
This question is part of the following fields:
- Gastrointestinal System
-
-
Question 28
Incorrect
-
A 25-year-old man arrives at the emergency department after experiencing a 3-minute tonic-clonic seizure observed by his friend. He has had 2 similar episodes before. The neurology team evaluates him and starts him on carbamazepine.
What is the mechanism of action of carbamazepine in suppressing seizure activity?Your Answer:
Correct Answer: Inhibition of voltage-gated sodium channels
Explanation:The inhibition of Na channels and suppression of excitation are caused by sodium valproate and carbamazepine.
Treatment Options for Epilepsy
Epilepsy is a neurological disorder that affects millions of people worldwide. Treatment for epilepsy typically involves the use of antiepileptic drugs (AEDs) to control seizures. The decision to start AEDs is usually made after a second seizure, but there are certain circumstances where treatment may be initiated after the first seizure. These include the presence of a neurological deficit, structural abnormalities on brain imaging, unequivocal epileptic activity on EEG, or if the patient or their family considers the risk of having another seizure to be unacceptable.
It is important to note that there are specific drug treatments for different types of seizures. For generalized tonic-clonic seizures, males are typically prescribed sodium valproate, while females may be given lamotrigine or levetiracetam. For focal seizures, first-line treatment options include lamotrigine or levetiracetam, with carbamazepine, oxcarbazepine, or zonisamide used as second-line options. Ethosuximide is the first-line treatment for absence seizures, with sodium valproate or lamotrigine/levetiracetam used as second-line options. For myoclonic seizures, males are usually given sodium valproate, while females may be prescribed levetiracetam. Finally, for tonic or atonic seizures, males are typically given sodium valproate, while females may be prescribed lamotrigine.
It is important to work closely with a healthcare provider to determine the best treatment plan for each individual with epilepsy. Additionally, it is important to be aware of potential risks associated with certain AEDs, such as the use of sodium valproate during pregnancy, which has been linked to neurodevelopmental delays in children.
-
This question is part of the following fields:
- Neurological System
-
-
Question 29
Incorrect
-
A 55-year-old man with a carcinoma of the lower third of the oesophagus is having an oesophagogastrectomy. During the mobilization of the lower part of the oesophagus, where is the thoracic duct most likely to be encountered by the surgeons?
Your Answer:
Correct Answer: Posterior to the oesophagus
Explanation:The thoracic duct is situated at the back of the oesophagus and takes a leftward course at the Angle of Louis. It joins the aorta at T12 as it enters the thorax.
The Thoracic Duct: Anatomy and Clinical Significance
The thoracic duct is a continuation of the cisterna chyli located in the abdomen. It enters the thorax at the level of T12 and runs posterior to the esophagus for most of its intrathoracic course. At T5, it passes to the left side of the body. Lymphatics from the left side of the head and neck join the thoracic duct before it empties into the left brachiocephalic vein. In contrast, lymphatics from the right side of the head and neck drain into the right lymphatic duct, which eventually empties into the right brachiocephalic vein via the mediastinal trunk.
The thoracic duct’s location in the thorax makes it vulnerable to injury during oesophageal surgery. To avoid damaging the duct, some surgeons apply cream to patients before oesophagectomy to help identify the cut ends of the duct. Understanding the anatomy and clinical significance of the thoracic duct is essential for healthcare professionals involved in thoracic surgery and lymphatic drainage disorders.
-
This question is part of the following fields:
- Gastrointestinal System
-
-
Question 30
Incorrect
-
A 17-year-old girl comes to the emergency department complaining of nausea and vomiting. A medical trainee, who has recently started her emergency rotation, prescribes metoclopramide to alleviate her symptoms before ordering some tests.
The nurse cautions the doctor that metoclopramide is not recommended for young female patients and suggests switching to cyclizine.
What is the reason for metoclopramide being unsuitable for this patient?Your Answer:
Correct Answer: Risk of oculogyric crisis
Explanation:Metoclopramide use in children and young adults can lead to oculogyric crisis, which is a dystonic reaction that causes the eyes to involuntarily gaze upwards for an extended period. Opioids can cause respiratory depression, while cyclizine may result in restlessness and urinary retention. Amiodarone use may cause slate-grey skin discoloration. Additionally, metoclopramide can increase urinary frequency.
Understanding the Mechanism and Uses of Metoclopramide
Metoclopramide is a medication primarily used to manage nausea, but it also has other uses such as treating gastro-oesophageal reflux disease and gastroparesis secondary to diabetic neuropathy. It is often combined with analgesics for the treatment of migraines. However, it is important to note that metoclopramide has adverse effects such as extrapyramidal effects, acute dystonia, diarrhoea, hyperprolactinaemia, tardive dyskinesia, and parkinsonism. It should also be avoided in bowel obstruction but may be helpful in paralytic ileus.
The mechanism of action of metoclopramide is quite complicated. It is primarily a D2 receptor antagonist, but it also has mixed 5-HT3 receptor antagonist/5-HT4 receptor agonist activity. Its antiemetic action is due to its antagonist activity at D2 receptors in the chemoreceptor trigger zone, and at higher doses, the 5-HT3 receptor antagonist also has an effect. The gastroprokinetic activity is mediated by D2 receptor antagonist activity and 5-HT4 receptor agonist activity.
In summary, metoclopramide is a medication with multiple uses, but it also has adverse effects that should be considered. Its mechanism of action is complex, involving both D2 receptor antagonist and 5-HT3 receptor antagonist/5-HT4 receptor agonist activity. Understanding the uses and mechanism of action of metoclopramide is important for its safe and effective use.
-
This question is part of the following fields:
- Gastrointestinal System
-
00
Correct
00
Incorrect
00
:
00
:
00
Session Time
00
:
00
Average Question Time (
Secs)