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Question 1
Incorrect
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In individuals with an annular pancreas, what is the most probable location of blockage?
Your Answer: The first part of the duodenum
Correct Answer: The second part of the duodenum
Explanation:The pancreas is formed from two outgrowths of the foregut, namely the ventral and dorsal buds. As the rotation process takes place, the ventral bud merges with the gallbladder and bile duct, which are located nearby. However, if the pancreas fails to rotate properly, it may exert pressure on the duodenum, leading to obstruction. This condition is often caused by an abnormality in the development of the duodenum, and the most commonly affected area is the second part of the duodenum.
Anatomy of the Pancreas
The pancreas is located behind the stomach and is a retroperitoneal organ. It can be accessed surgically by dividing the peritoneal reflection that connects the greater omentum to the transverse colon. The pancreatic head is situated in the curvature of the duodenum, while its tail is close to the hilum of the spleen. The pancreas has various relations with other organs, such as the inferior vena cava, common bile duct, renal veins, superior mesenteric vein and artery, crus of diaphragm, psoas muscle, adrenal gland, kidney, aorta, pylorus, gastroduodenal artery, and splenic hilum.
The arterial supply of the pancreas is through the pancreaticoduodenal artery for the head and the splenic artery for the rest of the organ. The venous drainage for the head is through the superior mesenteric vein, while the body and tail are drained by the splenic vein. The ampulla of Vater is an important landmark that marks the transition from foregut to midgut and is located halfway along the second part of the duodenum. Overall, understanding the anatomy of the pancreas is crucial for surgical procedures and diagnosing pancreatic diseases.
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This question is part of the following fields:
- Gastrointestinal System
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Question 2
Incorrect
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A patient with a history of diverticular disease presents to the surgical assessment unit with abdominal pain and a fever. Her white blood cell count is elevated, but she is otherwise stable. The diagnosis is diverticulitis. What is the best course of action for managing this condition?
Your Answer: Analgesia and antibiotics
Correct Answer: Antibiotics, a liquid diet and analgesia
Explanation:The initial management approach for mild diverticulitis typically involves a combination of oral antibiotics, a liquid diet, and analgesia.
Understanding Diverticulitis
Diverticulitis is a condition where an out-pouching of the intestinal mucosa becomes infected. This out-pouching is called a diverticulum and the presence of these pouches is known as diverticulosis. Diverticula are common and are thought to be caused by increased pressure in the colon. They usually occur in the sigmoid colon and are more prevalent in Westerners over the age of 60. While only a quarter of people with diverticulosis experience symptoms, 75% of those who do will have an episode of diverticulitis.
Risk factors for diverticulitis include age, lack of dietary fiber, obesity (especially in younger patients), and a sedentary lifestyle. Patients with diverticular disease may experience intermittent abdominal pain, bloating, and changes in bowel habits. Those with acute diverticulitis may experience severe abdominal pain, nausea and vomiting, changes in bowel habits, and urinary symptoms. Complications may include colovesical or colovaginal fistulas.
Signs of diverticulitis include low-grade fever, tachycardia, tender lower left quadrant of the abdomen, and possibly a palpable mass. Imaging tests such as an erect chest X-ray, abdominal X-ray, and CT scan may be used to diagnose diverticulitis. Treatment may involve oral antibiotics, a liquid diet, and analgesia for mild cases. More severe cases may require hospitalization for intravenous antibiotics. Colonoscopy should be avoided initially due to the risk of perforation.
In summary, diverticulitis is a common condition that can cause significant discomfort and complications. Understanding the risk factors, symptoms, and signs of diverticulitis can help with early diagnosis and treatment.
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This question is part of the following fields:
- Gastrointestinal System
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Question 3
Incorrect
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A 67-year-old man comes to the emergency department complaining of abrupt abdominal pain. He reports the pain as cramping, with a severity of 6/10, and spread throughout his abdomen. The patient has a medical history of hypertension and type 2 diabetes mellitus. He used to smoke and has a smoking history of 40 pack years.
What is the most probable part of the colon affected in this patient?Your Answer: Transverse colon
Correct Answer: Splenic flexure
Explanation:Ischaemic colitis frequently affects the splenic flexure, which is a vulnerable area due to its location at the border of regions supplied by different arteries. Symptoms such as cramping and generalised abdominal pain, along with a history of smoking and hypertension, suggest a diagnosis of ischaemic colitis. While the rectosigmoid junction is also a watershed area, it is less commonly affected than the splenic flexure. Other regions of the large bowel are less susceptible to ischaemic colitis.
Understanding Ischaemic Colitis
Ischaemic colitis is a condition that occurs when there is a temporary reduction in blood flow to the large bowel. This can cause inflammation, ulcers, and bleeding. The condition is more likely to occur in areas of the bowel that are located at the borders of the territory supplied by the superior and inferior mesenteric arteries, such as the splenic flexure.
When investigating ischaemic colitis, doctors may look for a sign called thumbprinting on an abdominal x-ray. This occurs due to mucosal edema and hemorrhage. It is important to diagnose and treat ischaemic colitis promptly to prevent complications and ensure a full recovery.
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This question is part of the following fields:
- Gastrointestinal System
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Question 4
Incorrect
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As a fourth year medical student, you are observing a morning colonoscopy list at the hospital. You come across patients who have been referred for imaging due to specific symptoms like rectal bleeding, as well as those who are undergoing routine annual colonoscopies. You are aware that most cases of colorectal cancer are sporadic, with no known genetic predisposition in patients. However, there are also certain genetic mutations that require patients to undergo colonoscopy screening for the development of colorectal cancer.
Can you provide examples of such genetic mutations?Your Answer: CEA, HNPCC and BRCA 1
Correct Answer: FAP and HNPCC
Explanation: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.
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This question is part of the following fields:
- Gastrointestinal System
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Question 5
Incorrect
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A 20-year-old male is having surgery to remove his appendix due to appendicitis. Where is the appendix typically located in the body?
Your Answer: Pelvic
Correct Answer: Retrocaecal
Explanation:The majority of appendixes are located in the retrocaecal position. In cases where removal of a retrocaecal appendix proves challenging, mobilizing the right colon can greatly enhance accessibility.
Appendix Anatomy and Location
The appendix is a small, finger-like projection located at the base of the caecum. It can be up to 10cm long and is mainly composed of lymphoid tissue, which can sometimes lead to confusion with mesenteric adenitis. The caecal taenia coli converge at the base of the appendix, forming a longitudinal muscle cover over it. This convergence can aid in identifying the appendix during surgery, especially if it is retrocaecal and difficult to locate. The arterial supply to the appendix comes from the appendicular artery, which is a branch of the ileocolic artery. It is important to note that the appendix is intra-peritoneal.
McBurney’s Point and Appendix Positions
McBurney’s point is a landmark used to locate the appendix during physical examination. It is located one-third of the way along a line drawn from the Anterior Superior Iliac Spine to the Umbilicus. The appendix can be found in six different positions, with the retrocaecal position being the most common at 74%. Other positions include pelvic, postileal, subcaecal, paracaecal, and preileal. It is important to be aware of these positions as they can affect the presentation of symptoms and the difficulty of locating the appendix during surgery.
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This question is part of the following fields:
- Gastrointestinal System
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Question 6
Incorrect
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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: Familial adenopolypomatosis coli
Correct 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.
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This question is part of the following fields:
- Gastrointestinal System
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Question 7
Incorrect
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A 50-year-old man presents with a sudden exacerbation of arthralgia affecting his hands and wrists. He also complains of feeling excessively fatigued lately. The patient has a medical history of hypertension and type 2 diabetes mellitus. Upon examination, his BMI is found to be 35 kg/m2. Laboratory tests reveal:
- Na+ 140 mmol/l
- K+ 4.2 mmol/l
- Urea 3.8 mmol/l
- Creatinine 100 µmol/l
- Plasma glucose 11.8 mmol/l
- ALT 150 u/l
- Serum ferritin 2000 ng/ml
What is the most probable diagnosis?Your Answer: Non alcoholic fatty liver disease
Correct Answer: Haemochromatosis
Explanation:Hereditary haemochromatosis is a genetic disorder that affects how the body processes iron. It is inherited in an autosomal recessive pattern. The symptoms in the early stages can be vague and non-specific, such as feeling tired and experiencing joint pain. As the condition progresses, it can lead to chronic liver disease and a condition known as bronze diabetes, which is characterized by iron buildup in the pancreas causing diabetes, and a bronze or grey pigmentation of the skin. Based on the patient’s symptoms of joint pain, elevated ALT levels, and significantly high ferritin levels, it is highly likely that they have haemochromatosis.
Understanding Haemochromatosis: Symptoms and Complications
Haemochromatosis is a genetic disorder that affects iron absorption and metabolism, leading to iron accumulation in the body. It is caused by mutations in the HFE gene on both copies of chromosome 6. This disorder is prevalent in people of European descent, with 1 in 10 carrying a mutation in the genes affecting iron metabolism. Early symptoms of haemochromatosis are often non-specific, such as lethargy and arthralgia, and may go unnoticed. However, as the disease progresses, patients may experience fatigue, erectile dysfunction, and skin pigmentation.
Other complications of haemochromatosis include diabetes mellitus, liver disease, cardiac failure, hypogonadism, and arthritis. While some symptoms are reversible with treatment, such as cardiomyopathy, skin pigmentation, diabetes mellitus, hypogonadotrophic hypogonadism, and arthropathy, liver cirrhosis is irreversible.
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This question is part of the following fields:
- Gastrointestinal System
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Question 8
Incorrect
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A 58-year-old man with a history of multiple emergency department admissions for alcohol-related injuries and admissions under the general medical team for alcohol withdrawal is admitted after a twelve-day drinking binge. He presents with confusion, icterus, and hepatomegaly, with stigmata of chronic liver disease. Upon admission, his blood work shows thrombocytopenia, transaminitis with hyperbilirubinemia, and a severe coagulopathy. The diagnosis is severe acute alcoholic hepatitis. In liver disease-associated coagulopathy, which clotting factor is typically increased?
Your Answer: Factor IX
Correct Answer: Factor VIII
Explanation:Coagulopathy in Liver Disease: Paradoxical Supra-normal Factor VIII and Increased Thrombosis Risk
In liver failure, the levels of all clotting factors decrease except for factor VIII, which paradoxically increases. This is because factor VIII is synthesized in endothelial cells throughout the body, unlike other clotting factors that are synthesized only in hepatic endothelial cells. Additionally, good hepatic function is required for the rapid clearance of activated factor VIII from the bloodstream, leading to further increases in circulating factor VIII. Despite conventional coagulation studies suggesting an increased risk of bleeding, patients with chronic liver disease are paradoxically at an increased risk of thrombosis formation. This is due to several factors, including reduced synthesis of natural anticoagulants such as protein C, protein S, and antithrombin, which are all decreased in chronic liver disease.
Reference:
Tripodi et al. An imbalance of pro- vs anticoagulation factors in plasma from patients with cirrhosis. Gastroenterology. 2009 Dec;137(6):2105-11. -
This question is part of the following fields:
- Gastrointestinal System
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Question 9
Incorrect
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At which of the subsequent spinal levels does the esophagus pass through the diaphragm and enter the abdominal cavity?
Your Answer: L2
Correct Answer: T10
Explanation:The point at which the oesophagus enters the abdomen is located at T10.
Anatomy of the Oesophagus
The oesophagus is a muscular tube that is approximately 25 cm long and starts at the C6 vertebrae, pierces the diaphragm at T10, and ends at T11. It is lined with non-keratinized stratified squamous epithelium and has constrictions at various distances from the incisors, including the cricoid cartilage at 15cm, the arch of the aorta at 22.5cm, the left principal bronchus at 27cm, and the diaphragmatic hiatus at 40cm.
The oesophagus is surrounded by various structures, including the trachea to T4, the recurrent laryngeal nerve, the left bronchus and left atrium, and the diaphragm anteriorly. Posteriorly, it is related to the thoracic duct to the left at T5, the hemiazygos to the left at T8, the descending aorta, and the first two intercostal branches of the aorta. The arterial, venous, and lymphatic drainage of the oesophagus varies depending on the location, with the upper third being supplied by the inferior thyroid artery and drained by the deep cervical lymphatics, the mid-third being supplied by aortic branches and drained by azygos branches and mediastinal lymphatics, and the lower third being supplied by the left gastric artery and drained by posterior mediastinal and coeliac veins and gastric lymphatics.
The nerve supply of the oesophagus also varies, with the upper half being supplied by the recurrent laryngeal nerve and the lower half being supplied by the oesophageal plexus of the vagus nerve. The muscularis externa of the oesophagus is composed of both smooth and striated muscle, with the composition varying depending on the location.
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This question is part of the following fields:
- Gastrointestinal System
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Question 10
Correct
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A 65-year-old obese male presents with recurrent episodes of colicky pain and bloating in the left iliac fossa. The patient has no significant medical history but has been a smoker for 25 years and does not consume alcohol. He works at a fast-food restaurant and usually eats his meals there.
Upon examination, the patient's vital signs are stable with a temperature of 37ºC, respiratory rate of 14 breaths per minute, oxygen saturations of 99% on air, heart rate of 60 beats per minute, and blood pressure of 125/70 mmHg. Abdominal and digital rectal examination reveal no significant findings. A colonoscopy was subsequently performed, which revealed multiple diverticula along the sigmoid colon.
What is the most appropriate course of management for this patient?Your Answer: Encourage high-fibre diet
Explanation:The development of intestinal diverticula is strongly linked to a low fibre diet, making it a major risk factor. To manage mild symptoms, patients are advised to modify their diet by gradually increasing fibre intake over several weeks and staying hydrated.
IV antibiotics and fluids are not necessary for diverticular disease, as it is not the same as diverticulitis.
Surgery is not recommended for uncomplicated diverticular disease.
While encouraging smoking cessation is important, dietary modification is the most suitable option for this patient.
Diverticulosis is a common condition where multiple outpouchings occur in the bowel wall, typically in the sigmoid colon. It is more accurate to use the term diverticulosis when referring to the presence of diverticula, while diverticular disease is reserved for symptomatic patients. Risk factors for this condition include a low-fibre diet and increasing age. Symptoms of diverticulosis can include altered bowel habits and colicky left-sided abdominal pain. A high-fibre diet is often recommended to alleviate these symptoms.
Diverticulitis is a complication of diverticulosis where one of the diverticula becomes infected. The typical presentation includes left iliac fossa pain and tenderness, anorexia, nausea, vomiting, diarrhea, and signs of infection such as pyrexia, raised WBC, and CRP. Mild attacks can be treated with oral antibiotics, while more severe episodes require hospitalization. Treatment involves nil by mouth, intravenous fluids, and intravenous antibiotics such as a cephalosporin and metronidazole. Complications of diverticulitis include abscess formation, peritonitis, obstruction, and perforation.
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This question is part of the following fields:
- Gastrointestinal System
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Question 11
Incorrect
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A 40-year-old male visits a private vascular clinic for his long-standing varicose veins. He had been referred by his family physician and is concerned about the appearance of his legs. He experiences heaviness and aching in his legs. As a professional athlete, he often wears shorts during games and is worried that his condition might affect his performance.
After being informed of the risks associated with varicose vein surgery, he decides to proceed with the operation. However, during his follow-up appointment, he reports a loss of sensation over the lateral foot and posterolateral leg.
Which nerve is most likely to have been damaged during the surgery?Your Answer: Femoral nerve
Correct Answer: Sural nerve
Explanation:During varicose vein surgery, there is a potential for damage to the sural nerve, which innervates the posterolateral leg and lateral foot. Additionally, the saphenous nerve, responsible for sensation in the medial aspect of the leg and foot, and the lateral femoral cutaneous nerve, which innervates the lateral thigh, may also be at risk.
During surgical procedures, there is a risk of nerve injury caused by the surgery itself. This is not only important for the patient’s well-being but also from a legal perspective. There are various operations that carry the risk of nerve damage, such as posterior triangle lymph node biopsy, Lloyd Davies stirrups, thyroidectomy, anterior resection of rectum, axillary node clearance, inguinal hernia surgery, varicose vein surgery, posterior approach to the hip, and carotid endarterectomy. Surgeons must have a good understanding of the anatomy of the area they are operating on to minimize the incidence of nerve lesions. Blind placement of haemostats is not recommended as it can also cause nerve damage.
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This question is part of the following fields:
- Gastrointestinal System
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Question 12
Correct
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A 25-year-old male with Gilbert's syndrome (GS) visits his doctor worried about a recent change in skin tone. During the examination, his skin appears to be normal, but he insists that it was yellow earlier today.
What is true about Gilbert's syndrome?Your Answer: Transient jaundice after physiological stress such as exercise and fasting is seen in Gilbert’s syndrome
Explanation:Gilbert’s syndrome is a harmless liver condition that is characterized by increased levels of bilirubin in the blood. While some individuals may not experience any symptoms, others may develop temporary jaundice following physical stressors such as fasting or exercise. Treatment and regular monitoring are not necessary for this condition. It is important to reassure patients that Gilbert’s syndrome does not progress to chronic liver disease. The condition is caused by a mutation in the UGT1A1 gene, which leads to reduced activity of the UGT1A1 enzyme. Gilbert’s syndrome is more prevalent in males.
Gilbert’s syndrome is a genetic disorder that affects the way bilirubin is processed in the body. It is caused by a deficiency of UDP glucuronosyltransferase, which leads to unconjugated hyperbilirubinemia. This means that bilirubin is not properly broken down and eliminated from the body, resulting in jaundice. However, jaundice may only be visible during certain conditions such as fasting, exercise, or illness. The prevalence of Gilbert’s syndrome is around 1-2% in the general population.
To diagnose Gilbert’s syndrome, doctors may look for a rise in bilirubin levels after prolonged fasting or the administration of IV nicotinic acid. However, treatment is not necessary for this condition. While the exact mode of inheritance is still debated, it is known to be an autosomal recessive disorder.
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This question is part of the following fields:
- Gastrointestinal System
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Question 13
Incorrect
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A 67-year-old male with long standing chronic obstructive pulmonary disease (COPD) presents to the emergency department (ED) with shortness of breath over the last 2 hours and wheezing. On examination, he is cyanosed, has a third heart sound present and has widespread wheeze on auscultation. The emergency doctor also notices hepatomegaly which was not present 10 days ago when he was in the ED for a moderative exacerbation of COPD.
What is the likely cause of the newly developed hepatomegaly in this 67-year-old male with chronic obstructive pulmonary disease?Your Answer: Ascites
Correct Answer: Cor pulmonale
Explanation:The cause of the patient’s hepatomegaly is likely subacute onset cor pulmonale, which is right sided heart failure secondary to COPD. This is supported by the presence of shortness of breath, cyanosis, and a third heart sound. Left sided heart failure is unlikely to be the cause of his symptoms and hepatomegaly. While ascites can be a complication of right sided heart failure and portal hypertension, it does not cause hepatomegaly. Cirrhosis and liver cancer are also unlikely causes given the patient’s presentation, which is more consistent with a cardiorespiratory issue.
Understanding Hepatomegaly and Its Common Causes
Hepatomegaly refers to an enlarged liver, which can be caused by various factors. One of the most common causes is cirrhosis, which can lead to a decrease in liver size in later stages. In this case, the liver is non-tender and firm. Malignancy, such as metastatic spread or primary hepatoma, can also cause hepatomegaly. In this case, the liver edge is hard and irregular. Right heart failure can also lead to an enlarged liver, which is firm, smooth, and tender. It may even be pulsatile.
Aside from these common causes, hepatomegaly can also be caused by viral hepatitis, glandular fever, malaria, abscess (pyogenic or amoebic), hydatid disease, haematological malignancies, haemochromatosis, primary biliary cirrhosis, sarcoidosis, and amyloidosis.
Understanding the causes of hepatomegaly is important in diagnosing and treating the underlying condition. Proper diagnosis and treatment can help prevent further complications and improve overall health.
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This question is part of the following fields:
- Gastrointestinal System
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Question 14
Incorrect
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A 55-year-old man comes to the emergency department complaining of sudden abdominal pain in the epigastric region. He has a history of heavy alcohol consumption, but this is his first visit to the department. Upon examination, he is sweating profusely and has a fever. His heart rate is 130 beats per minute, and his blood pressure is 90/60 mmHg. You diagnose him with acute pancreatitis and are concerned about potential complications.
What symptom is most likely to be present in this patient?Your Answer: Abdominal distention with shifting dullness
Correct Answer: Blue discolouration of the flank regions
Explanation:The patient is experiencing acute pancreatitis, possibly due to excessive alcohol consumption. As this is his first visit to the emergency department, it is unlikely to be a sudden attack on top of chronic pancreatitis. The presence of tachycardia and hypotension suggests that he is also experiencing blood loss. The correct answer should identify an acute condition associated with blood loss.
a. Bulky, greasy stools are a long-term complication of chronic pancreatitis, indicating that the pancreas has lost its exocrine function and is unable to properly digest food.
b. Grey Turner’s sign is a sign of blood pooling in the retroperitoneal space, which can occur due to inflammation of the retroperitoneal pancreas.
c. This is a complication of long-term diabetes or chronic pancreatitis.
d. Ascites is not typically associated with an acute first-time presentation of pancreatitis, although it can have many causes.
e. This description is typical of an abdominal obstruction, which may cause nausea and vomiting.
The retroperitoneal structures are those that are located behind the peritoneum, which is the membrane that lines the abdominal cavity. These structures include the duodenum (2nd, 3rd, and 4th parts), ascending and descending colon, kidneys, ureters, aorta, and inferior vena cava. They are situated in the back of the abdominal cavity, close to the spine. In contrast, intraperitoneal structures are those that are located within the peritoneal cavity, such as the stomach, duodenum (1st part), jejunum, ileum, transverse colon, and sigmoid colon. It is important to note that the retroperitoneal structures are not well demonstrated in the diagram as the posterior aspect has been removed, but they are still significant in terms of their location and function.
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This question is part of the following fields:
- Gastrointestinal System
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Question 15
Incorrect
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Which of the following suppresses the production of stomach acid?
Your Answer: Histamine
Correct Answer: Nausea
Explanation:Gastric secretion is suppressed by nausea through the involvement of higher cerebral activity and sympathetic innervation.
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.
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This question is part of the following fields:
- Gastrointestinal System
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Question 16
Incorrect
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A 50-year-old male has been diagnosed with carcinoma of the head of the pancreas. He has reported that his stool is sticking to the toilet bowl and not flushing away. Which enzyme deficiency is most likely causing this issue?
Your Answer: Elastase
Correct Answer: Lipase
Explanation:Steatorrhoea, characterized by pale and malodorous stools that are hard to flush, is primarily caused by a deficiency in lipase.
Pancreatic cancer is a type of cancer that is often diagnosed late due to its non-specific symptoms. The majority of pancreatic tumors are adenocarcinomas and are typically found in the head of the pancreas. Risk factors for pancreatic cancer include increasing age, smoking, diabetes, chronic pancreatitis, hereditary non-polyposis colorectal carcinoma, and mutations in the BRCA2 and KRAS genes.
Symptoms of pancreatic cancer can include painless jaundice, pale stools, dark urine, and pruritus. Courvoisier’s law states that a palpable gallbladder is unlikely to be due to gallstones in the presence of painless obstructive jaundice. However, patients often present with non-specific symptoms such as anorexia, weight loss, and epigastric pain. Loss of exocrine and endocrine function can also occur, leading to steatorrhea and diabetes mellitus. Atypical back pain and migratory thrombophlebitis (Trousseau sign) are also common.
Ultrasound has a sensitivity of around 60-90% for detecting pancreatic cancer, but high-resolution CT scanning is the preferred diagnostic tool. The ‘double duct’ sign, which is the simultaneous dilatation of the common bile and pancreatic ducts, may be seen on imaging.
Less than 20% of patients with pancreatic cancer are suitable for surgery at the time of diagnosis. A Whipple’s resection (pancreaticoduodenectomy) may be performed for resectable lesions in the head of the pancreas, but side-effects such as dumping syndrome and peptic ulcer disease can occur. Adjuvant chemotherapy is typically given following surgery, and ERCP with stenting may be used for palliation.
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This question is part of the following fields:
- Gastrointestinal System
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Question 17
Incorrect
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A 72-year-old man is receiving an angiogram to investigate gastrointestinal bleeding. During the procedure, the radiologist inserts the catheter into the coeliac axis. What is the usual spinal level where this vessel originates from the aorta?
Your Answer: L3
Correct Answer: T12
Explanation:The coeliac axis is positioned at T12 and branches off the aorta at an almost horizontal angle. It comprises three significant branches.
Branches of the Abdominal Aorta
The abdominal aorta is a major blood vessel that supplies oxygenated blood to the abdominal organs and lower extremities. It gives rise to several branches that supply blood to various organs and tissues. These branches can be classified into two types: parietal and visceral.
The parietal branches supply blood to the walls of the abdominal cavity, while the visceral branches supply blood to the abdominal organs. The branches of the abdominal aorta include the inferior phrenic, coeliac, superior mesenteric, middle suprarenal, renal, gonadal, lumbar, inferior mesenteric, median sacral, and common iliac arteries.
The inferior phrenic artery arises from the upper border of the abdominal aorta and supplies blood to the diaphragm. The coeliac artery supplies blood to the liver, stomach, spleen, and pancreas. The superior mesenteric artery supplies blood to the small intestine, cecum, and ascending colon. The middle suprarenal artery supplies blood to the adrenal gland. The renal arteries supply blood to the kidneys. The gonadal arteries supply blood to the testes or ovaries. The lumbar arteries supply blood to the muscles and skin of the back. The inferior mesenteric artery supplies blood to the descending colon, sigmoid colon, and rectum. The median sacral artery supplies blood to the sacrum and coccyx. The common iliac arteries are the terminal branches of the abdominal aorta and supply blood to the pelvis and lower extremities.
Understanding the branches of the abdominal aorta is important for diagnosing and treating various medical conditions that affect the abdominal organs and lower extremities.
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This question is part of the following fields:
- Gastrointestinal System
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Question 18
Incorrect
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A 16-year-old boy is diagnosed with Meckel's diverticulum. What embryological structure does it originate from?
Your Answer: Foregut
Correct Answer: Vitello-intestinal duct
Explanation:The Meckel’s diverticulum is a condition where the vitello-intestinal duct persists, and it is characterized by being 2 inches (5cm) long, located 2 feet (60 cm) from the ileocaecal valve, 2 times more common in men, and involving 2 tissue types.
Meckel’s diverticulum is a congenital diverticulum of the small intestine that is a remnant of the omphalomesenteric duct. It occurs in 2% of the population, is 2 feet from the ileocaecal valve, and is 2 inches long. It is usually asymptomatic but can present with abdominal pain, rectal bleeding, or intestinal obstruction. Investigation includes a Meckel’s scan or mesenteric arteriography. Management involves removal if narrow neck or symptomatic, with options between wedge excision or formal small bowel resection and anastomosis. Meckel’s diverticulum is typically lined by ileal mucosa but ectopic gastric, pancreatic, and jejunal mucosa can also occur.
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This question is part of the following fields:
- Gastrointestinal System
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Question 19
Correct
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During a radical gastrectomy, the surgeons detach the omentum and ligate the right gastro-epiploic artery. What vessel does it originate from?
Your Answer: Gastroduodenal artery
Explanation:The gastroduodenal artery originates from the upper portion of the duodenum and travels downwards behind it until it reaches the lower border. At this point, it splits into two branches: the right gastro-epiploic artery and the superior pancreaticoduodenal artery. The right gastro-epiploic artery moves towards the left and passes through the layers of the greater omentum to connect with the left gastro-epiploic artery.
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.
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This question is part of the following fields:
- Gastrointestinal System
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Question 20
Incorrect
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A 25-year-old man presents to the hepatology clinic after his general practitioner detected abnormal liver function on routine blood tests. He has been experiencing intermittent pain in the right upper quadrant for the past 3 months. He denies any history of intravenous drug use or recent travel. He has a medical history of depression and takes citalopram daily.
During the examination, the patient exhibits tenderness in the right upper quadrant. There is no visible jaundice, but he has dark rings around his iris.
What investigation finding is associated with the probable diagnosis?Your Answer: Raised transferrin saturation
Correct Answer: Raised free serum copper
Explanation:Autoimmune hepatitis is a condition characterized by inflammation of the liver, which can present as acute hepatitis with symptoms such as abdominal pain, fever, and jaundice. Unlike other conditions such as Wilson’s disease, neuropsychiatric and eye signs are not typically observed in autoimmune hepatitis.
Haemochromatosis, on the other hand, is an autosomal recessive disorder that results in the accumulation and deposition of iron. A raised transferrin saturation is a sign of this condition, which can cause hepatitis, liver cirrhosis, fatigue, arthralgia, and bronze-colored skin pigmentation. If psychiatric symptoms are present, Wilson’s disease may be more likely.
α1-antitrypsin deficiency is an inherited disorder that occurs when the liver does not produce enough of the protease enzyme A1AT. This condition is primarily associated with emphysema, although liver cirrhosis may also occur. However, if there are no respiratory symptoms, α1-antitrypsin deficiency is unlikely to be the cause.
Understanding Wilson’s Disease
Wilson’s disease is a genetic disorder that causes excessive copper accumulation in the tissues due to metabolic abnormalities. It is an autosomal recessive disorder caused by a defect in the ATP7B gene located on chromosome 13. Symptoms usually appear between the ages of 10 to 25 years, with children presenting with liver disease and young adults with neurological disease.
The disease is characterised by excessive copper deposition in the tissues, particularly in the brain, liver, and cornea. This can lead to a range of symptoms, including hepatitis, cirrhosis, basal ganglia degeneration, speech and behavioural problems, asterixis, chorea, dementia, parkinsonism, Kayser-Fleischer rings, renal tubular acidosis, haemolysis, and blue nails.
To diagnose Wilson’s disease, doctors may perform a slit lamp examination for Kayser-Fleischer rings, measure serum ceruloplasmin and total serum copper (which is often reduced), and check for increased 24-hour urinary copper excretion. Genetic analysis of the ATP7B gene can confirm the diagnosis.
Treatment for Wilson’s disease typically involves chelating agents such as penicillamine or trientine hydrochloride, which help to remove excess copper from the body. Tetrathiomolybdate is a newer agent that is currently under investigation. With proper management, individuals with Wilson’s disease can lead normal lives.
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This question is part of the following fields:
- Gastrointestinal System
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