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  • Question 1 - A 55-year-old man visits his GP complaining of worsening acid reflux, despite receiving...

    Incorrect

    • A 55-year-old man visits his GP complaining of worsening acid reflux, despite receiving aggressive treatment. He reports feeling like he has lost weight and has a medical history of duodenal ulcers. During his last endoscopy, Barrett's oesophagus was detected. Which type of cancer is most commonly linked to this condition?

      Your Answer: Oesophageal squamous cell carcinoma

      Correct Answer: Oesophageal adenocarcinoma

      Explanation:

      The most significant risk factor for developing oesophageal adenocarcinoma, one of the two types of oesophageal carcinomas in the UK, is Barrett’s oesophagus. This condition occurs when chronic acid exposure causes a metaplastic change from squamous epithelium to gastric columnar epithelium in the lower end of the oesophagus, increasing the risk of developing adenocarcinoma.

      Duodenal adenocarcinoma, a relatively rare cancer of the gastrointestinal tract, is often caused by genetic conditions such as HNCCP/Lynch syndrome and familial adenomatous polyposis (FAP), as well as Crohn’s disease. Patients with this type of cancer typically experience abdominal pain, reflux, and weight loss due to the malignancy obstructing the flow of digested chyme from the stomach to the jejunum.

      Gastric malignancy, the most common type of which is adenocarcinoma, is not associated with Barrett’s oesophagus. Symptoms of gastric cancer include heartburn, abdominal pain, loss of appetite, and early satiety, and the most significant risk factor is H. pylori infection.

      Oesophageal leiomyoma, a benign tumour, is not linked to Barrett’s oesophagus. Patients may experience reflux if the mass enlarges, but the most common symptoms are retrosternal discomfort and difficulty swallowing.

      Squamous cell carcinoma, the other type of oesophageal malignancy, is associated with smoking and alcohol and tends to occur in the upper oesophagus. Unlike adenocarcinoma, weight loss is usually an early symptom of this type of cancer.

      Barrett’s oesophagus is a condition where the lower oesophageal mucosa is replaced by columnar epithelium, which increases the risk of oesophageal adenocarcinoma by 50-100 fold. It is usually identified during an endoscopy for upper gastrointestinal symptoms such as dyspepsia, as there are no screening programs for it. The length of the affected segment determines the chances of identifying metaplasia, with short (<3 cm) and long (>3 cm) subtypes. The prevalence of Barrett’s oesophagus is estimated to be around 1 in 20, and it is identified in up to 12% of those undergoing endoscopy for reflux.

      The columnar epithelium in Barrett’s oesophagus may resemble that of the cardiac region of the stomach or that of the small intestine, with goblet cells and brush border. The single strongest risk factor for Barrett’s oesophagus is gastro-oesophageal reflux disease (GORD), followed by male gender, smoking, and central obesity. Alcohol is not an independent risk factor for Barrett’s, but it is associated with both GORD and oesophageal cancer. Patients with Barrett’s oesophagus often have coexistent GORD symptoms.

      The management of Barrett’s oesophagus involves high-dose proton pump inhibitor, although the evidence base for its effectiveness in reducing the progression to dysplasia or inducing regression of the lesion is limited. Endoscopic surveillance with biopsies is recommended every 3-5 years for patients with metaplasia but not dysplasia. If dysplasia of any grade is identified, endoscopic intervention is offered, such as radiofrequency ablation, which is the preferred first-line treatment, particularly for low-grade dysplasia, or endoscopic mucosal resection.

    • This question is part of the following fields:

      • Gastrointestinal System
      14.4
      Seconds
  • Question 2 - A 32-year-old female presents to her GP with complaints of chronic fatigue, bloating,...

    Correct

    • A 32-year-old female presents to her GP with complaints of chronic fatigue, bloating, and intermittent diarrhea. She denies any recent changes in her diet, rectal bleeding, or weight loss. Upon physical examination, no abnormalities are detected. Further investigations reveal the following results: Hb 95g/L (Female: 115-160), Platelets 200 * 109/L (150-400), WBC 6.2 * 109/L (4.0-11.0), and raised IgA-tTG serology. What additional test should the GP arrange to confirm the likely diagnosis?

      Your Answer: Endoscopic intestinal biopsy

      Explanation:

      The preferred method for diagnosing coeliac disease is through an endoscopic intestinal biopsy, which is considered the gold standard. This should be performed if there is suspicion of the condition based on serology results. While endomysial antibody testing can be useful, it is more expensive and not as preferred as the biopsy. A stomach biopsy would not be helpful in diagnosing coeliac disease, as the condition affects the cells in the intestine. A skin biopsy would only be necessary if there were skin lesions indicative of dermatitis herpetiformis. Repeating the IgA-tTG serology test is not recommended for diagnosis.

      Investigating Coeliac Disease

      Coeliac disease is a condition caused by sensitivity to gluten, which leads to villous atrophy and malabsorption. It is often associated with other conditions such as dermatitis herpetiformis and autoimmune disorders. Diagnosis is made through a combination of serology and endoscopic intestinal biopsy, with villous atrophy and immunology typically reversing on a gluten-free diet.

      To investigate coeliac disease, NICE guidelines recommend using tissue transglutaminase (TTG) antibodies (IgA) as the first-choice serology test, along with endomyseal antibody (IgA) and testing for selective IgA deficiency. Anti-gliadin antibody (IgA or IgG) tests are not recommended. The ‘gold standard’ for diagnosis is an endoscopic intestinal biopsy, which should be performed in all suspected cases to confirm or exclude the diagnosis. Findings supportive of coeliac disease include villous atrophy, crypt hyperplasia, increase in intraepithelial lymphocytes, and lamina propria infiltration with lymphocytes. Rectal gluten challenge is a less commonly used method.

      In summary, investigating coeliac disease involves a combination of serology and endoscopic intestinal biopsy, with NICE guidelines recommending specific tests and the ‘gold standard’ being an intestinal biopsy. Findings supportive of coeliac disease include villous atrophy, crypt hyperplasia, and lymphocyte infiltration.

    • This question is part of the following fields:

      • Gastrointestinal System
      4.3
      Seconds
  • Question 3 - A 65-year-old man is scheduled for a splenectomy. What is the most posteriorly...

    Incorrect

    • A 65-year-old man is scheduled for a splenectomy. What is the most posteriorly located structure of the spleen?

      Your Answer: Splenic artery

      Correct Answer: Lienorenal ligament

      Explanation:

      The phrenicocolic ligament provides the antero-lateral connection, while the gastro splenic ligament is located anteriorly to the lienorenal ligament. These ligaments converge around the vessels at the splenic hilum, with the lienorenal ligament being the most posterior.

      Understanding the Anatomy of the Spleen

      The spleen is a vital organ in the human body, serving as the largest lymphoid organ. It is located below the 9th-12th ribs and has a clenched fist shape. The spleen is an intraperitoneal organ, and its peritoneal attachments condense at the hilum, where the vessels enter the spleen. The blood supply of the spleen is from the splenic artery, which is derived from the coeliac axis, and the splenic vein, which is joined by the IMV and unites with the SMV.

      The spleen is derived from mesenchymal tissue during embryology. It weighs between 75-150g and has several relations with other organs. The diaphragm is superior to the spleen, while the gastric impression is anterior, the kidney is posterior, and the colon is inferior. The hilum of the spleen is formed by the tail of the pancreas and splenic vessels. The spleen also forms the apex of the lesser sac, which contains short gastric vessels.

      In conclusion, understanding the anatomy of the spleen is crucial in comprehending its functions and the role it plays in the human body. The spleen’s location, weight, and relations with other organs are essential in diagnosing and treating spleen-related conditions.

    • This question is part of the following fields:

      • Gastrointestinal System
      16.4
      Seconds
  • Question 4 - Sophie, a 19-year-old girl with type 1 diabetes mellitus, arrives at the emergency...

    Correct

    • Sophie, a 19-year-old girl with type 1 diabetes mellitus, arrives at the emergency department with confusion, vomiting, and abdominal pain. Upon examination, she displays tachycardia and tachypnea. The medical team orders various tests, including an arterial blood gas.

      The results are as follows:
      pH 7.29 mmol/l
      K+ 6.0 mmol/l
      Glucose 15mmol/l

      The doctors initiate treatment for diabetic ketoacidosis.

      What ECG abnormality can be observed in relation to Sophie's potassium level?

      Your Answer: Tall tented T waves and flattened P waves

      Explanation:

      When a person has hyperkalaemia, their blood has an excess of potassium which can lead to cardiac arrhythmias. One of the common ECG abnormalities seen in hyperkalaemia is tall tented T waves. Other possible ECG changes include wide QRS complexes and flattened P waves. In contrast, hypokalaemia can cause T wave depression, U waves, and tall P waves on an ECG. Delta waves are typically seen in patients with Wolfe-Parkinson-White syndrome.

      ECG Findings in Hyperkalaemia

      Hyperkalaemia is a condition characterized by high levels of potassium in the blood. This condition can have serious consequences on the heart, leading to abnormal ECG findings. The ECG findings in hyperkalaemia include peaked or ‘tall-tented’ T waves, loss of P waves, broad QRS complexes, sinusoidal wave pattern, and ventricular fibrillation.

      The first ECG finding in hyperkalaemia is the appearance of peaked or ‘tall-tented’ T waves. This is followed by the loss of P waves, which are the small waves that represent atrial depolarization. The QRS complexes, which represent ventricular depolarization, become broad and prolonged. The sinusoidal wave pattern is a characteristic finding in severe hyperkalaemia, where the ECG tracing appears as a series of undulating waves. Finally, ventricular fibrillation, a life-threatening arrhythmia, can occur in severe hyperkalaemia.

      In summary, hyperkalaemia can have serious consequences on the heart, leading to abnormal ECG findings. These findings include peaked or ‘tall-tented’ T waves, loss of P waves, broad QRS complexes, sinusoidal wave pattern, and ventricular fibrillation. It is important to recognize these ECG findings in hyperkalaemia as they can guide appropriate management and prevent life-threatening complications.

    • This question is part of the following fields:

      • Gastrointestinal System
      15.5
      Seconds
  • Question 5 - A patient is evaluated in the Emergency Department after a paracetamol overdose. Why...

    Correct

    • A patient is evaluated in the Emergency Department after a paracetamol overdose. Why was prothrombin time chosen to evaluate liver function instead of albumin?

      Your Answer: Because prothrombin has a shorter half life

      Explanation:

      Prothrombin is a more suitable indicator of acute liver failure than albumin due to its shorter half-life. In cases of acute liver failure caused by paracetamol overdose, the liver is unable to replace prothrombin, leading to a decrease in its levels. On the other hand, albumin levels remain unchanged as its half-life is relatively long. Although albumin levels may decrease with acute inflammation, this does not provide information about the patient’s liver function. Therefore, prothrombin time/INR remains the preferred diagnostic test for acute liver failure. It is important to note that prothrombin does not bind to paracetamol in the blood, and while albumin does affect oncotic pressure, this does not explain its usefulness in detecting acute liver failure.

      Understanding Acute Liver Failure

      Acute liver failure is a condition characterized by the sudden onset of liver dysfunction, which can lead to various complications in the body. The causes of acute liver failure include paracetamol overdose, alcohol, viral hepatitis (usually A or B), and acute fatty liver of pregnancy. The symptoms of acute liver failure include jaundice, raised prothrombin time, hypoalbuminaemia, hepatic encephalopathy, and hepatorenal syndrome. It is important to note that liver function tests may not always accurately reflect the synthetic function of the liver, and it is best to assess the prothrombin time and albumin level to determine the severity of the condition. Understanding acute liver failure is crucial in managing and treating this potentially life-threatening condition.

    • This question is part of the following fields:

      • Gastrointestinal System
      3.3
      Seconds
  • Question 6 - A 28-year-old woman presents to her GP with a complaint of diarrhoea lasting...

    Correct

    • A 28-year-old woman presents to her GP with a complaint of diarrhoea lasting for 5 months. She reports the presence of blood in her stool and feeling excessively fatigued.

      During abdominal examination, tenderness is noted in the lower left quadrant.

      The patient is referred for a colonoscopy and biopsy.

      What characteristic would you anticipate finding based on the probable diagnosis?

      Your Answer: Inflammation from rectum extending proximally

      Explanation:

      Ulcerative colitis is a form of inflammatory bowel disease that usually manifests with symptoms like fatigue, left lower quadrant pain, and bloody diarrhoea. The inflammation associated with ulcerative colitis starts at the rectum and extends proximally, but it does not spread beyond the ileocaecal valve.

      Unlike Crohn’s disease, ulcerative colitis does not typically present with a cobblestone appearance during colonoscopy.

      While diverticula can cause rectal bleeding and abdominal pain, they are more common in older patients and would not be expected in a patient of this age.

      In Crohn’s disease, skip lesions are present, whereas in ulcerative colitis, the inflammation is continuous.

      Inflammatory bowel disease (IBD) is a condition that includes two main types: Crohn’s disease and ulcerative colitis. Although they share many similarities in terms of symptoms, diagnosis, and treatment, there are some key differences between the two. Crohn’s disease is characterized by non-bloody diarrhea, weight loss, upper gastrointestinal symptoms, mouth ulcers, perianal disease, and a palpable abdominal mass in the right iliac fossa. On the other hand, ulcerative colitis is characterized by bloody diarrhea, abdominal pain in the left lower quadrant, tenesmus, gallstones, and primary sclerosing cholangitis. Complications of Crohn’s disease include obstruction, fistula, and colorectal cancer, while ulcerative colitis has a higher risk of colorectal cancer than Crohn’s disease. Pathologically, Crohn’s disease lesions can be seen anywhere from the mouth to anus, while ulcerative colitis inflammation always starts at the rectum and never spreads beyond the ileocaecal valve. Endoscopy and radiology can help diagnose and differentiate between the two types of IBD.

    • This question is part of the following fields:

      • Gastrointestinal System
      26.4
      Seconds
  • Question 7 - What is the nerve root value of the external urethral sphincter? ...

    Incorrect

    • What is the nerve root value of the external urethral sphincter?

      Your Answer: L5, S1, S2

      Correct Answer: S2, S3, S4

      Explanation:

      The pudendal nerve branches provide innervation to the external urethral sphincter, indicating that the root values are S2, S3, S4.

      Urethral Anatomy: Differences Between Male and Female

      The anatomy of the urethra differs between males and females. In females, the urethra is shorter and more angled than in males. It is located outside of the peritoneum and is surrounded by the endopelvic fascia. The neck of the bladder is subject to intra-abdominal pressure, and any weakness in this area can lead to stress urinary incontinence. The female urethra is surrounded by the external urethral sphincter, which is innervated by the pudendal nerve. It is located in front of the vaginal opening.

      In males, the urethra is much longer and is divided into four parts. The pre-prostatic urethra is very short and lies between the bladder and prostate gland. The prostatic urethra is wider than the membranous urethra and contains several openings for the transmission of semen. The membranous urethra is the narrowest part of the urethra and is surrounded by the external sphincter. The penile urethra travels through the corpus spongiosum on the underside of the penis and is the longest segment of the urethra. The bulbo-urethral glands open into the spongiose section of the urethra.

      The urothelium, which lines the inside of the urethra, is transitional near the bladder and becomes squamous further down the urethra. Understanding the differences in urethral anatomy between males and females is important for diagnosing and treating urological conditions.

    • This question is part of the following fields:

      • Gastrointestinal System
      11.6
      Seconds
  • Question 8 - A 58-year-old woman has a sigmoid colon resection in the Hartmans style, with...

    Correct

    • A 58-year-old woman has a sigmoid colon resection in the Hartmans style, with ligation of vessels near the colon. Which vessel will be responsible for directly supplying the rectal stump?

      Your Answer: Superior rectal artery

      Explanation:

      The blood supply to the rectum is provided by the superior rectal artery, which may be affected if the IMA is ligated too high. However, in the case of the Hartmans procedure, the vessels were ligated near the bowel, indicating that the superior rectal artery was not compromised.

      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
      5.2
      Seconds
  • Question 9 - An 80-year-old male with Parkinson's disease (PD) arrives at the emergency department with...

    Correct

    • An 80-year-old male with Parkinson's disease (PD) arrives at the emergency department with sudden chest pain, indicating a possible heart attack. What treatment should be avoided in the management of this patient?

      Your Answer: Metoclopramide

      Explanation:

      Metoclopramide should not be given to patients with Parkinsonism due to its dopamine antagonist properties which can worsen the symptoms of the disease. However, it can be prescribed as an antiemetic when administering morphine to ACS patients who are not contraindicated. Oxygen is safe for PD patients, while clopidogrel is used for its antiplatelet effects.

      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
      10.6
      Seconds
  • Question 10 - A 47-year-old man has a nasogastric tube inserted. The nurse takes a small...

    Correct

    • A 47-year-old man has a nasogastric tube inserted. The nurse takes a small aspirate of the fluid from the stomach and tests the pH of the aspirate. What is the typical intragastric pH?

      Your Answer: 2

      Explanation:

      Typically, the pH level in the stomach is 2, but the use of proton pump inhibitors can effectively eliminate acidity.

      Understanding Gastric Secretions for Surgical Procedures

      A basic understanding of gastric secretions is crucial for surgeons, especially when dealing with patients who have undergone acid-lowering procedures or are prescribed anti-secretory drugs. Gastric acid, produced by the parietal cells in the stomach, has a pH of around 2 and is maintained by the H+/K+ ATPase pump. Sodium and chloride ions are actively secreted from the parietal cell into the canaliculus, creating a negative potential across the membrane. Carbonic anhydrase forms carbonic acid, which dissociates, and the hydrogen ions formed by dissociation leave the cell via the H+/K+ antiporter pump. This leaves hydrogen and chloride ions in the canaliculus, which mix and are secreted into the lumen of the oxyntic gland.

      There are three phases of gastric secretion: the cephalic phase, gastric phase, and intestinal phase. The cephalic phase is stimulated by the smell or taste of food and causes 30% of acid production. The gastric phase, which is caused by stomach distension, low H+, or peptides, causes 60% of acid production. The intestinal phase, which is caused by high acidity, distension, or hypertonic solutions in the duodenum, inhibits gastric acid secretion via enterogastrones and neural reflexes.

      The regulation of gastric acid production involves various factors that increase or decrease production. Factors that increase production include vagal nerve stimulation, gastrin release, and histamine release. Factors that decrease production include somatostatin, cholecystokinin, and secretin. Understanding these factors and their associated pharmacology is essential for surgeons.

      In summary, a working knowledge of gastric secretions is crucial for surgical procedures, especially when dealing with patients who have undergone acid-lowering procedures or are prescribed anti-secretory drugs. Understanding the phases of gastric secretion and the regulation of gastric acid production is essential for successful surgical outcomes.

    • This question is part of the following fields:

      • Gastrointestinal System
      5
      Seconds
  • Question 11 - A 68-year-old man is having his left kidney and ureter removed. During the...

    Incorrect

    • A 68-year-old man is having his left kidney and ureter removed. During the surgery, the surgeons remove the ureter. What provides the blood supply to the upper part of the ureter?

      Your Answer: Direct branches from the aorta

      Correct Answer: Branches of the renal artery

      Explanation:

      The renal artery provides branches that supply the proximal ureter, while other feeding vessels are described in the following.

      Anatomy of the Ureter

      The ureter is a muscular tube that measures 25-35 cm in length and is lined by transitional epithelium. It is surrounded by a thick muscular coat that becomes three muscular layers as it crosses the bony pelvis. This retroperitoneal structure overlies the transverse processes L2-L5 and lies anterior to the bifurcation of iliac vessels. The blood supply to the ureter is segmental and includes the renal artery, aortic branches, gonadal branches, common iliac, and internal iliac. It is important to note that the ureter lies beneath the uterine artery.

      In summary, the ureter is a vital structure in the urinary system that plays a crucial role in transporting urine from the kidneys to the bladder. Its unique anatomy and blood supply make it a complex structure that requires careful consideration in any surgical or medical intervention.

    • This question is part of the following fields:

      • Gastrointestinal System
      15.3
      Seconds
  • Question 12 - In a patient with a carcinoma of the proximal sigmoid colon, what is...

    Correct

    • In a patient with a carcinoma of the proximal sigmoid colon, what is the most probable origin of its vascular supply?

      Your Answer: Inferior mesenteric artery

      Explanation:

      When performing a high anterior resection for these types of tumors, it is necessary to ligate the inferior mesenteric artery. However, it is important to note that the internal iliac artery’s branches, particularly the middle rectal branch, play a crucial role in preserving blood flow to the rectal stump and ensuring the anastomoses’ integrity.

      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
      10.2
      Seconds
  • Question 13 - A 32-year-old woman undergoes a colonoscopy and a biopsy reveals a malignant tumour...

    Correct

    • A 32-year-old woman undergoes a colonoscopy and a biopsy reveals a malignant tumour in her sigmoid colon. Her grandmother died of colorectal cancer at 30-years-old and her father developed endometrial cancer at 40-years-old. Which gene is suspected to be responsible for this condition?

      Your Answer: Mismatch repair genes

      Explanation:

      The patient’s familial background indicates the possibility of Lynch syndrome, given that several of his close relatives developed cancer at a young age. This is supported by the fact that his family has a history of both colorectal cancer, which may indicate a defect in the APC gene, and endometrial cancer, which is also linked to Lynch syndrome. Lynch syndrome is associated with mutations in mismatch repair genes such as MSH2, MLH1, PMS2, and GTBP, which are responsible for identifying and repairing errors that occur during DNA replication, such as insertions and deletions of bases. Mutations in these genes can increase the risk of developing cancers such as colorectal, endometrial, and renal cancer.

      Colorectal cancer can be classified into three types: sporadic, hereditary non-polyposis colorectal carcinoma (HNPCC), and familial adenomatous polyposis (FAP). Sporadic colon cancer is believed to be caused by a series of genetic mutations, including allelic loss of the APC gene, activation of the K-ras oncogene, and deletion of p53 and DCC tumor suppressor genes. HNPCC, which is an autosomal dominant condition, is the most common form of inherited colon cancer. It is caused by mutations in genes involved in DNA mismatch repair, leading to microsatellite instability. The most common genes affected are MSH2 and MLH1. Patients with HNPCC are also at a higher risk of other cancers, such as endometrial cancer. The Amsterdam criteria are sometimes used to aid diagnosis of HNPCC. FAP is a rare autosomal dominant condition that leads to the formation of hundreds of polyps by the age of 30-40 years. It is caused by a mutation in the APC gene. Patients with FAP are also at risk of duodenal tumors. A variant of FAP called Gardner’s syndrome can also feature osteomas of the skull and mandible, retinal pigmentation, thyroid carcinoma, and epidermoid cysts on the skin. Genetic testing can be done to diagnose HNPCC and FAP, and patients with FAP generally have a total colectomy with ileo-anal pouch formation in their twenties.

    • This question is part of the following fields:

      • Gastrointestinal System
      4
      Seconds
  • Question 14 - A 14-year-old boy is brought to the hospital due to severe nausea and...

    Correct

    • A 14-year-old boy is brought to the hospital due to severe nausea and vomiting. He has been unable to eat or drink for the past 48 hours and has not urinated in the last 24 hours. The doctor prescribes an antiemetic, but which antiemetic should be avoided in this situation?

      Your Answer: Metoclopramide

      Explanation:

      The effectiveness of antiemetics depends on their ability to interact with different receptors. Therefore, the selection of an appropriate antiemetic will depend on the patient and the underlying cause of nausea.

      Metoclopramide is a dopamine antagonist that also has peripheral 5HT3 agonist and muscarinic antagonist effects, which help to promote gastric emptying. However, it is not recommended for use in children and young adults due to the potential risk of oculogyric crisis.

      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
      7.4
      Seconds
  • Question 15 - A 73-year-old man is undergoing an open abdominal aortic aneurysm repair. The aneurysm...

    Incorrect

    • A 73-year-old man is undergoing an open abdominal aortic aneurysm repair. The aneurysm is located in a juxtarenal location and surgical access to the neck of aneurysm is difficult. Which one of the following structures may be divided to improve access?

      Your Answer: Coeliac axis

      Correct Answer: Left renal vein

      Explanation:

      During juxtarenal aortic surgery, the neck of the aneurysm can cause stretching of the left renal vein, which may lead to its division. This can worsen the nephrotoxic effects of the surgery, especially when a suprarenal clamp is also used. However, intentionally dividing the Cisterna Chyli will not enhance access and can result in chyle leakage. Similarly, dividing the transverse colon is not beneficial and can increase the risk of graft infection. Lastly, dividing the SMA is unnecessary for a juxtarenal procedure.

      The abdominal aorta is a major blood vessel that originates from the 12th thoracic vertebrae and terminates at the fourth lumbar vertebrae. It is located in the abdomen and is surrounded by various organs and structures. The posterior relations of the abdominal aorta include the vertebral bodies of the first to fourth lumbar vertebrae. The anterior relations include the lesser omentum, liver, left renal vein, inferior mesenteric vein, third part of the duodenum, pancreas, parietal peritoneum, and peritoneal cavity. The right lateral relations include the right crus of the diaphragm, cisterna chyli, azygos vein, and inferior vena cava (which becomes posterior distally). The left lateral relations include the fourth part of the duodenum, duodenal-jejunal flexure, and left sympathetic trunk. Overall, the abdominal aorta is an important blood vessel that supplies oxygenated blood to various organs in the abdomen.

    • This question is part of the following fields:

      • Gastrointestinal System
      34.2
      Seconds
  • Question 16 - A 50-year-old obese woman presents with right upper quadrant abdominal pain, nausea and...

    Correct

    • A 50-year-old obese woman presents with right upper quadrant abdominal pain, nausea and vomiting. She has a family history of gallstone disease. Upon physical examination, a positive Murphy's sign is observed. An abdominal ultrasound reveals gallstones in the thickened gallbladder. The surgeon opts for a laparoscopic cholecystectomy to remove the gallbladder. During the procedure, the surgeon identifies and dissects the hepatobiliary triangle to safely ligate and divide two structures.

      What are the two structures being referred to in the above scenario?

      Your Answer: Cystic duct and cystic artery

      Explanation:

      During laparoscopic cholecystectomy, the hepatobiliary triangle plays a crucial role in ensuring the safe ligation and division of the cystic duct and cystic artery. Surgeons must carefully dissect this area to identify these structures and avoid any potential biliary complications.

      The hepatobiliary triangle is bordered by the common hepatic duct, which is formed by the union of the common bile duct and cystic duct. The cystic artery branches off from the right hepatic artery, while Lund’s node serves as the sentinel lymph node of the gallbladder.

      The accessory duct is considered auxiliary to the biliary tree, and the left and right hepatic ducts merge into the common hepatic duct. The gastroduodenal artery arises from the common hepatic artery, and the cystic vein helps distinguish between the cystic and common hepatic ducts during surgery, but is not ligated.

      The gallbladder is a sac made of fibromuscular tissue that can hold up to 50 ml of fluid. Its lining is made up of columnar epithelium. The gallbladder is located in close proximity to various organs, including the liver, transverse colon, and the first part of the duodenum. It is covered by peritoneum and is situated between the right lobe and quadrate lobe of the liver. The gallbladder receives its arterial supply from the cystic artery, which is a branch of the right hepatic artery. Its venous drainage is directly to the liver, and its lymphatic drainage is through Lund’s node. The gallbladder is innervated by both sympathetic and parasympathetic nerves. The common bile duct originates from the confluence of the cystic and common hepatic ducts and is located in the hepatobiliary triangle, which is bordered by the common hepatic duct, cystic duct, and the inferior edge of the liver. The cystic artery is also found within this triangle.

    • This question is part of the following fields:

      • Gastrointestinal System
      15.3
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  • Question 17 - A 49-year-old woman experiences jaundice and undergoes an ERCP. After 36 hours, she...

    Correct

    • A 49-year-old woman experiences jaundice and undergoes an ERCP. After 36 hours, she develops a fever and rigors. What organism is most likely to be cultured from her blood sample?

      Your Answer: Escherichia coli

      Explanation:

      A surgical emergency is indicated when Charcot’s triad is present. Patients require biliary decompression and administration of broad-spectrum antibiotics. The most frequently identified organism in cholangitis infections is E. coli, with enterobacter being a less common finding.

      Ascending Cholangitis: A Bacterial Infection of the Biliary Tree

      Ascending cholangitis is a bacterial infection that affects the biliary tree, with E. coli being the most common culprit. The primary risk factor for this condition is gallstones. Patients with ascending cholangitis may experience Charcot’s triad, which includes fever, jaundice, and right upper quadrant pain. However, this triad is only present in 20-50% of cases. Fever is the most common symptom, occurring in 90% of patients, followed by RUQ pain (70%) and jaundice (60%). In some cases, patients may also experience hypotension and confusion, which, when combined with the other three symptoms, makeup Reynolds’ pentad.

      In addition to the above symptoms, patients with ascending cholangitis may also have raised inflammatory markers. Ultrasound is typically the first-line investigation used to diagnose this condition. It is used to look for bile duct dilation and stones.

      The management of ascending cholangitis involves intravenous antibiotics and endoscopic retrograde cholangiopancreatography (ERCP) after 24-48 hours to relieve any obstruction. By understanding the symptoms and risk factors associated with ascending cholangitis, healthcare providers can diagnose and treat this condition promptly, reducing the risk of complications.

    • This question is part of the following fields:

      • Gastrointestinal System
      4.9
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  • Question 18 - Which of the following characteristics is atypical for Crohn's disease? ...

    Incorrect

    • Which of the following characteristics is atypical for Crohn's disease?

      Your Answer: 'Rose thorn ulcers' on barium studies

      Correct Answer: Pseudopolyps on colonoscopy

      Explanation:

      Pseudopolyps manifest in ulcerative colitis as a result of extensive mucosal ulceration. The remaining patches of mucosa can resemble individual polyps.

      Understanding Crohn’s Disease

      Crohn’s disease is a type of inflammatory bowel disease that can affect any part of the digestive tract, from the mouth to the anus. The exact cause of Crohn’s disease is unknown, but there is a strong genetic component. Inflammation occurs in all layers of the affected area, which can lead to complications such as strictures, fistulas, and adhesions.

      Symptoms of Crohn’s disease typically appear in late adolescence or early adulthood and can include non-specific symptoms such as weight loss and lethargy, as well as more specific symptoms like diarrhea, abdominal pain, and perianal disease. Extra-intestinal features, such as arthritis, erythema nodosum, and osteoporosis, are also common in patients with Crohn’s disease.

      To diagnose Crohn’s disease, doctors may look for raised inflammatory markers, increased faecal calprotectin, anemia, and low levels of vitamin B12 and vitamin D. It’s important to note that Crohn’s disease shares some features with ulcerative colitis, another type of inflammatory bowel disease, but there are also important differences between the two conditions. Understanding the symptoms and diagnostic criteria for Crohn’s disease can help patients and healthcare providers manage this chronic condition more effectively.

    • This question is part of the following fields:

      • Gastrointestinal System
      19.1
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  • Question 19 - A 65-year-old man who is a heavy smoker complains of dyspepsia. Upon testing,...

    Correct

    • A 65-year-old man who is a heavy smoker complains of dyspepsia. Upon testing, he is diagnosed with helicobacter pylori infection. Later, he experiences an episode of haematemesis and faints. Which blood vessel is most likely responsible for this?

      Your Answer: Gastroduodenal artery

      Explanation:

      It is probable that he has a duodenal ulcer located at the back. Such ulcers can penetrate the gastroduodenal artery and result in significant bleeding. While gastric ulcers can also invade vessels, they are not typically associated with major bleeding of this type.

      The Gastroduodenal Artery: Supply and Path

      The gastroduodenal artery is responsible for supplying blood to the pylorus, proximal part of the duodenum, and indirectly to the pancreatic head through the anterior and posterior superior pancreaticoduodenal arteries. It commonly arises from the common hepatic artery of the coeliac trunk and terminates by bifurcating into the right gastroepiploic artery and the superior pancreaticoduodenal artery.

      To better understand the relationship of the gastroduodenal artery to the first part of the duodenum, the stomach is reflected superiorly in an image sourced from Wikipedia. This artery plays a crucial role in providing oxygenated blood to the digestive system, ensuring proper functioning and health.

    • This question is part of the following fields:

      • Gastrointestinal System
      14.3
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  • Question 20 - Which of the following is not an extraintestinal manifestation of Crohn's disease? ...

    Incorrect

    • Which of the following is not an extraintestinal manifestation of Crohn's disease?

      Your Answer: Pyoderma gangrenosum

      Correct Answer: Erythema multiforme

      Explanation:

      Understanding Crohn’s Disease

      Crohn’s disease is a type of inflammatory bowel disease that can affect any part of the digestive tract, from the mouth to the anus. The exact cause of Crohn’s disease is unknown, but there is a strong genetic component. Inflammation occurs in all layers of the affected area, which can lead to complications such as strictures, fistulas, and adhesions.

      Symptoms of Crohn’s disease typically appear in late adolescence or early adulthood and can include non-specific symptoms such as weight loss and lethargy, as well as more specific symptoms like diarrhea, abdominal pain, and perianal disease. Extra-intestinal features, such as arthritis, erythema nodosum, and osteoporosis, are also common in patients with Crohn’s disease.

      To diagnose Crohn’s disease, doctors may look for raised inflammatory markers, increased faecal calprotectin, anemia, and low levels of vitamin B12 and vitamin D. It’s important to note that Crohn’s disease shares some features with ulcerative colitis, another type of inflammatory bowel disease, but there are also important differences between the two conditions. Understanding the symptoms and diagnostic criteria for Crohn’s disease can help patients and healthcare providers manage this chronic condition more effectively.

    • This question is part of the following fields:

      • Gastrointestinal System
      8.1
      Seconds
  • Question 21 - A 25-year-old male has been referred to the clinic due to a family...

    Correct

    • A 25-year-old male has been referred to the clinic due to a family history of colorectal cancer. Genetic testing revealed a mutation of the APC gene, and a colonoscopy is recommended. What is the probable outcome of the procedure?

      Your Answer: Multiple colonic adenomas

      Explanation:

      Familial adenomatous polyposis coli is characterized by the presence of multiple colonic adenomas, which are caused by mutations in the APC gene.

      Polyposis syndromes are a group of genetic disorders that cause the development of multiple polyps in the colon and other parts of the gastrointestinal tract. These polyps can increase the risk of developing cancer, and therefore, early detection and management are crucial. There are several types of polyposis syndromes, each with its own genetic defect, features, and associated disorders.

      Familial adenomatous polyposis (FAP) is caused by a mutation in the APC gene and is characterized by the development of over 100 colonic adenomas, with a 100% risk of cancer. Screening and management involve regular colonoscopies and resectional surgery if polyps are found. FAP is also associated with gastric and duodenal polyps and abdominal desmoid tumors.

      MYH-associated polyposis is caused by a biallelic mutation of the MYH gene and is associated with multiple colonic polyps and an increased risk of right-sided cancers. Attenuated phenotype can be managed with regular colonoscopies, while resection and ileoanal pouch reconstruction are recommended for those with multiple polyps.

      Peutz-Jeghers syndrome is caused by a mutation in the STK11 gene and is characterized by multiple benign intestinal hamartomas, episodic obstruction, and an increased risk of GI cancers. Screening involves annual examinations and pan-intestinal endoscopy every 2-3 years.

      Cowden disease is caused by a mutation in the PTEN gene and is characterized by macrocephaly, multiple intestinal hamartomas, and an increased risk of cancer at any site. Targeted individualized screening is recommended, with extra surveillance for breast, thyroid, and uterine cancers.

      HNPCC (Lynch syndrome) is caused by germline mutations of DNA mismatch repair genes and is associated with an increased risk of colorectal, endometrial, and gastric cancers. Colonoscopies every 1-2 years from age 25 and consideration of prophylactic surgery are recommended, along with extra colonic surveillance.

    • This question is part of the following fields:

      • Gastrointestinal System
      59.9
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  • Question 22 - A 67-year-old man presents to the emergency department with vomiting blood. The medical...

    Correct

    • A 67-year-old man presents to the emergency department with vomiting blood. The medical team suspects bleeding oesophageal varices and prescribes terlipressin. The patient has a history of alcohol abuse and examination reveals ascites.

      Why was terlipressin prescribed in this case?

      Your Answer: Vasoconstriction of splanchnic vessels

      Explanation:

      Terlipressin works by constricting the splanchnic vessels, which increases systemic vascular resistance and promotes renal fluid reabsorption. This leads to an increase in arterial pressure and helps to treat hypovolaemic hypotension. Terlipressin also has a sympathetic stimulating effect and is an analogue of vasopressin.

      Variceal haemorrhage is a serious condition that requires prompt and effective management. The initial treatment involves resuscitation of the patient, correction of clotting abnormalities, and administration of vasoactive agents such as terlipressin or octreotide. Prophylactic IV antibiotics are also recommended to reduce mortality in patients with liver cirrhosis. Endoscopic variceal band ligation is the preferred method for controlling bleeding, and the use of a Sengstaken-Blakemore tube or Transjugular Intrahepatic Portosystemic Shunt (TIPSS) may be necessary if bleeding cannot be controlled. However, TIPSS can lead to exacerbation of hepatic encephalopathy, which is a common complication.

      To prevent variceal haemorrhage, prophylactic measures such as propranolol and endoscopic variceal band ligation (EVL) are recommended. Propranolol has been shown to reduce rebleeding and mortality compared to placebo. EVL is superior to endoscopic sclerotherapy and should be performed at two-weekly intervals until all varices have been eradicated. Proton pump inhibitor cover is given to prevent EVL-induced ulceration. NICE guidelines recommend offering endoscopic variceal band ligation for the primary prevention of bleeding for people with cirrhosis who have medium to large oesophageal varices.

    • This question is part of the following fields:

      • Gastrointestinal System
      17.8
      Seconds
  • Question 23 - A 35-year-old man has arrived at the emergency department following a car crash....

    Incorrect

    • A 35-year-old man has arrived at the emergency department following a car crash. He is experiencing tachycardia and his blood pressure is rapidly decreasing from 90/60mmHg. He is feeling dizzy and disoriented, and is experiencing pain in his left upper quadrant and left shoulder. Which organ is most likely to have sustained damage?

      Your Answer: Pancreas

      Correct Answer: Spleen

      Explanation:

      The patient’s tachycardia and low blood pressure indicate internal bleeding due to trauma. Although he experiences pain in his upper left abdominal quadrant, it does not rule out the possibility of internal bleeding. However, it makes heart and lung injuries less likely as he would have also complained of chest pain. The pain in his left shoulder suggests that the left phrenic nerve has been affected, which indicates damage to the spleen rather than the liver, as it would have been on the right side. The spleen is commonly damaged in trauma and could explain the rapid drop in blood pressure.

      Understanding the Anatomy of the Spleen

      The spleen is a vital organ in the human body, serving as the largest lymphoid organ. It is located below the 9th-12th ribs and has a clenched fist shape. The spleen is an intraperitoneal organ, and its peritoneal attachments condense at the hilum, where the vessels enter the spleen. The blood supply of the spleen is from the splenic artery, which is derived from the coeliac axis, and the splenic vein, which is joined by the IMV and unites with the SMV.

      The spleen is derived from mesenchymal tissue during embryology. It weighs between 75-150g and has several relations with other organs. The diaphragm is superior to the spleen, while the gastric impression is anterior, the kidney is posterior, and the colon is inferior. The hilum of the spleen is formed by the tail of the pancreas and splenic vessels. The spleen also forms the apex of the lesser sac, which contains short gastric vessels.

      In conclusion, understanding the anatomy of the spleen is crucial in comprehending its functions and the role it plays in the human body. The spleen’s location, weight, and relations with other organs are essential in diagnosing and treating spleen-related conditions.

    • This question is part of the following fields:

      • Gastrointestinal System
      35.2
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  • Question 24 - A 36-year-old female patient presents with persistent dyspepsia of 6 months duration. She...

    Incorrect

    • A 36-year-old female patient presents with persistent dyspepsia of 6 months duration. She failed multiple trials of conservative treatment by her GP, therefore, she was referred for the gastroenterologist for further review.

      Investigations were done and her urea breath test was negative for Helicobacter pylori. Gastroscopy revealed multiple gastroduodenal ulcers. What type of cells are affected by the high levels of fasting gastrin detected?

      Your Answer: G cells

      Correct Answer: Gastric parietal cells

      Explanation:

      The secretion of gastrin hormone from G cells in the antrum of the stomach is responsible for increasing the secretion of H+ by gastric parietal cells. Additionally, chief cells secrete pepsin, which is a proteolytic enzyme, while D cells in the pancreas and stomach secrete somatostatin hormone. Gastrin hormone is released in response to distension of the stomach and vagal stimulation.

      Overview of Gastrointestinal Hormones

      Gastrointestinal hormones play a crucial role in the digestion and absorption of food. These hormones are secreted by various cells in the stomach and small intestine in response to different stimuli such as the presence of food, pH changes, and neural signals.

      One of the major hormones involved in food digestion is gastrin, which is secreted by G cells in the antrum of the stomach. Gastrin increases acid secretion by gastric parietal cells, stimulates the secretion of pepsinogen and intrinsic factor, and increases gastric motility. Another hormone, cholecystokinin (CCK), is secreted by I cells in the upper small intestine in response to partially digested proteins and triglycerides. CCK increases the secretion of enzyme-rich fluid from the pancreas, contraction of the gallbladder, and relaxation of the sphincter of Oddi. It also decreases gastric emptying and induces satiety.

      Secretin is another hormone secreted by S cells in the upper small intestine in response to acidic chyme and fatty acids. Secretin increases the secretion of bicarbonate-rich fluid from the pancreas and hepatic duct cells, decreases gastric acid secretion, and has a trophic effect on pancreatic acinar cells. Vasoactive intestinal peptide (VIP) is a neural hormone that stimulates secretion by the pancreas and intestines and inhibits acid secretion.

      Finally, somatostatin is secreted by D cells in the pancreas and stomach in response to fat, bile salts, and glucose in the intestinal lumen. Somatostatin decreases acid and pepsin secretion, decreases gastrin secretion, decreases pancreatic enzyme secretion, and decreases insulin and glucagon secretion. It also inhibits the trophic effects of gastrin and stimulates gastric mucous production.

      In summary, gastrointestinal hormones play a crucial role in regulating the digestive process and maintaining homeostasis in the gastrointestinal tract.

    • This question is part of the following fields:

      • Gastrointestinal System
      17.6
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  • Question 25 - A 63-year-old man with a history of alcohol abuse presents with recurrent epigastric...

    Correct

    • A 63-year-old man with a history of alcohol abuse presents with recurrent epigastric pain. An OGD reveals the presence of varices in the lower esophagus. To prevent variceal bleeding, which medication would be the most suitable prophylactic option?

      Your Answer: Propranolol

      Explanation:

      A non-cardioselective β blocker (NSBB) is the appropriate medication for prophylaxis against oesophageal bleeding in patients with varices. NSBBs work by causing splanchnic vasoconstriction, which reduces portal blood flow. Omeprazole, warfarin, and unfractionated heparin are not suitable options for this purpose.

      Variceal haemorrhage is a serious condition that requires prompt and effective management. The initial treatment involves resuscitation of the patient, correction of clotting abnormalities, and administration of vasoactive agents such as terlipressin or octreotide. Prophylactic IV antibiotics are also recommended to reduce mortality in patients with liver cirrhosis. Endoscopic variceal band ligation is the preferred method for controlling bleeding, and the use of a Sengstaken-Blakemore tube or Transjugular Intrahepatic Portosystemic Shunt (TIPSS) may be necessary if bleeding cannot be controlled. However, TIPSS can lead to exacerbation of hepatic encephalopathy, which is a common complication.

      To prevent variceal haemorrhage, prophylactic measures such as propranolol and endoscopic variceal band ligation (EVL) are recommended. Propranolol has been shown to reduce rebleeding and mortality compared to placebo. EVL is superior to endoscopic sclerotherapy and should be performed at two-weekly intervals until all varices have been eradicated. Proton pump inhibitor cover is given to prevent EVL-induced ulceration. NICE guidelines recommend offering endoscopic variceal band ligation for the primary prevention of bleeding for people with cirrhosis who have medium to large oesophageal varices.

    • This question is part of the following fields:

      • Gastrointestinal System
      50.7
      Seconds
  • Question 26 - A 36-year-old woman is found to have an aggressive caecal adenocarcinoma. Her sister...

    Correct

    • A 36-year-old woman is found to have an aggressive caecal adenocarcinoma. Her sister passed away from the same disease at 39 years of age. Her mother died from endometrial cancer at the age of 42. What genetic abnormality is the most probable cause of this family's cancer history?

      Your Answer: Mutation of mismatch repair genes

      Explanation:

      Microsatellite instability of DNA repair genes causes Lynch syndrome, which is identified by the presence of aggressive colon cancer on the right side and endometrial cancer.

      Colorectal cancer can be classified into three types: sporadic, hereditary non-polyposis colorectal carcinoma (HNPCC), and familial adenomatous polyposis (FAP). Sporadic colon cancer is believed to be caused by a series of genetic mutations, including allelic loss of the APC gene, activation of the K-ras oncogene, and deletion of p53 and DCC tumor suppressor genes. HNPCC, which is an autosomal dominant condition, is the most common form of inherited colon cancer. It is caused by mutations in genes involved in DNA mismatch repair, leading to microsatellite instability. The most common genes affected are MSH2 and MLH1. Patients with HNPCC are also at a higher risk of other cancers, such as endometrial cancer. The Amsterdam criteria are sometimes used to aid diagnosis of HNPCC. FAP is a rare autosomal dominant condition that leads to the formation of hundreds of polyps by the age of 30-40 years. It is caused by a mutation in the APC gene. Patients with FAP are also at risk of duodenal tumors. A variant of FAP called Gardner’s syndrome can also feature osteomas of the skull and mandible, retinal pigmentation, thyroid carcinoma, and epidermoid cysts on the skin. Genetic testing can be done to diagnose HNPCC and FAP, and patients with FAP generally have a total colectomy with ileo-anal pouch formation in their twenties.

    • This question is part of the following fields:

      • Gastrointestinal System
      11.4
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  • Question 27 - A gynaecologist is performing a laparoscopic hysterectomy on a 45-year-old patient. He is...

    Incorrect

    • A gynaecologist is performing a laparoscopic hysterectomy on a 45-year-old patient. He is being careful to avoid damaging a structure that runs close to the vaginal fornices.

      What is the structure that the gynaecologist is most likely being cautious of?

      Your Answer: Ilioinguinal nerve

      Correct Answer: Ureter

      Explanation:

      The correct statements are:

      – The ureter enters the bladder trigone after passing only 1 cm away from the vaginal fornices, which is closer than other structures.
      – The ilioinguinal nerve originates from the first lumbar nerve (L1).
      – The femoral artery is a continuation of the external iliac artery.
      – The descending colon starts at the splenic flexure and ends at the beginning of the sigmoid colon.
      – The obturator nerve arises from the ventral divisions of the second, third, and fourth lumbar nerves.

      Anatomy of the Ureter

      The ureter is a muscular tube that measures 25-35 cm in length and is lined by transitional epithelium. It is surrounded by a thick muscular coat that becomes three muscular layers as it crosses the bony pelvis. This retroperitoneal structure overlies the transverse processes L2-L5 and lies anterior to the bifurcation of iliac vessels. The blood supply to the ureter is segmental and includes the renal artery, aortic branches, gonadal branches, common iliac, and internal iliac. It is important to note that the ureter lies beneath the uterine artery.

      In summary, the ureter is a vital structure in the urinary system that plays a crucial role in transporting urine from the kidneys to the bladder. Its unique anatomy and blood supply make it a complex structure that requires careful consideration in any surgical or medical intervention.

    • This question is part of the following fields:

      • Gastrointestinal System
      8
      Seconds
  • Question 28 - During liver mobilisation for a pediatric liver transplant, the hepatic ligaments will need...

    Incorrect

    • During liver mobilisation for a pediatric liver transplant, the hepatic ligaments will need to be mobilized. Which of the following statements regarding these structures is false?

      Your Answer: Lesser omentum arises from the porta hepatis and passes the lesser curvature of the stomach

      Correct Answer: The right triangular ligament is an early branch of the left triangular ligament

      Explanation:

      The coronary ligament continues as the right triangular ligament.

      Structure and Relations of the Liver

      The liver is divided into four lobes: the right lobe, left lobe, quadrate lobe, and caudate lobe. The right lobe is supplied by the right hepatic artery and contains Couinaud segments V to VIII, while the left lobe is supplied by the left hepatic artery and contains Couinaud segments II to IV. The quadrate lobe is part of the right lobe anatomically but functionally is part of the left, and the caudate lobe is supplied by both right and left hepatic arteries and lies behind the plane of the porta hepatis. The liver lobules are separated by portal canals that contain the portal triad: the hepatic artery, portal vein, and tributary of bile duct.

      The liver has various relations with other organs in the body. Anteriorly, it is related to the diaphragm, esophagus, xiphoid process, stomach, duodenum, hepatic flexure of colon, right kidney, gallbladder, and inferior vena cava. The porta hepatis is located on the postero-inferior surface of the liver and transmits the common hepatic duct, hepatic artery, portal vein, sympathetic and parasympathetic nerve fibers, and lymphatic drainage of the liver and nodes.

      The liver is supported by ligaments, including the falciform ligament, which is a two-layer fold of peritoneum from the umbilicus to the anterior liver surface and contains the ligamentum teres (remnant of the umbilical vein). The ligamentum venosum is a remnant of the ductus venosus. The liver is supplied by the hepatic artery and drained by the hepatic veins and portal vein. Its nervous supply comes from the sympathetic and parasympathetic trunks of the coeliac plexus.

    • This question is part of the following fields:

      • Gastrointestinal System
      22.2
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  • Question 29 - A 25-year-old female has received a pan proctocolectomy and ileoanal pouch due to...

    Correct

    • A 25-year-old female has received a pan proctocolectomy and ileoanal pouch due to familial adenomatous polyposis coli. What is the most frequent non-colonic manifestation of this condition?

      Your Answer: Duodenal polyps

      Explanation:

      Polyposis syndromes are a group of genetic disorders that cause the development of multiple polyps in the colon and other parts of the gastrointestinal tract. These polyps can increase the risk of developing cancer, and therefore, early detection and management are crucial. There are several types of polyposis syndromes, each with its own genetic defect, features, and associated disorders.

      Familial adenomatous polyposis (FAP) is caused by a mutation in the APC gene and is characterized by the development of over 100 colonic adenomas, with a 100% risk of cancer. Screening and management involve regular colonoscopies and resectional surgery if polyps are found. FAP is also associated with gastric and duodenal polyps and abdominal desmoid tumors.

      MYH-associated polyposis is caused by a biallelic mutation of the MYH gene and is associated with multiple colonic polyps and an increased risk of right-sided cancers. Attenuated phenotype can be managed with regular colonoscopies, while resection and ileoanal pouch reconstruction are recommended for those with multiple polyps.

      Peutz-Jeghers syndrome is caused by a mutation in the STK11 gene and is characterized by multiple benign intestinal hamartomas, episodic obstruction, and an increased risk of GI cancers. Screening involves annual examinations and pan-intestinal endoscopy every 2-3 years.

      Cowden disease is caused by a mutation in the PTEN gene and is characterized by macrocephaly, multiple intestinal hamartomas, and an increased risk of cancer at any site. Targeted individualized screening is recommended, with extra surveillance for breast, thyroid, and uterine cancers.

      HNPCC (Lynch syndrome) is caused by germline mutations of DNA mismatch repair genes and is associated with an increased risk of colorectal, endometrial, and gastric cancers. Colonoscopies every 1-2 years from age 25 and consideration of prophylactic surgery are recommended, along with extra colonic surveillance.

    • This question is part of the following fields:

      • Gastrointestinal System
      6.8
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  • Question 30 - A 56-year-old woman presents with profuse diarrhoea one week after undergoing a cholecystectomy....

    Incorrect

    • A 56-year-old woman presents with profuse diarrhoea one week after undergoing a cholecystectomy. The surgery was uncomplicated, except for a minor bile spillage during gallbladder removal. What is the probable diagnosis?

      Your Answer:

      Correct Answer: Clostridium difficile infection

      Explanation:

      Broad spectrum antibiotics are only given during a cholecystectomy if there is intraoperative bile spillage. It is not standard practice to administer antibiotics for an uncomplicated procedure. Surgeons typically address any bile spills during the operation, which greatly reduces the risk of delayed pelvic abscesses. As a result, such abscesses are very uncommon.

      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
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