Podcast Beta
Questions and Answers
What is not a reason for diverticulectomy in a case where Meckel's diverticulum is found?
Which malignant tumour is most commonly associated with Meckel's diverticulum?
What condition is associated with excessive colonization of bacteria in the intestine?
Which symptom is commonly associated with small bowel neoplasms?
Signup and view all the answers
What happens to the small bowel mucosa and submucosal vessels in radiation enteritis?
Signup and view all the answers
What is the most effective method to diagnose small bowel tumours?
Signup and view all the answers
What can large benign tumours in the small intestine lead to?
Signup and view all the answers
Which of the following is NOT a symptom associated with small bowel neoplasms?
Signup and view all the answers
What is the most common benign tumor of the small intestine?
Signup and view all the answers
Which type of adenoma is a premalignant lesion that must be removed?
Signup and view all the answers
In which part of the gastrointestinal tract are Brunner's gland adenomas most commonly found?
Signup and view all the answers
Hemangiomas may occur sporadically or as part of which syndrome?
Signup and view all the answers
Which type of intestinal cancer has a poorer prognosis when developing in the background of Crohn's disease?
Signup and view all the answers
What symptom is commonly associated with malignant tumors of the small intestine?
Signup and view all the answers
What is the most common sarcoma of the small intestine?
Signup and view all the answers
Which patient demographic is most commonly diagnosed with adenocarcinoma of the small intestine?
Signup and view all the answers
What is the most common true-congenital diverticulum of the small intestine?
Signup and view all the answers
Which statement about Meckel's diverticulum is true according to the Rule of Twos?
Signup and view all the answers
What complication is most frequently associated with Meckel's diverticulum in adults?
Signup and view all the answers
What is the most common symptom of Meckel's diverticulum in children under 2 years of age?
Signup and view all the answers
Which of the following may develop as a result of non-closure of the omphalomesenteric duct?
Signup and view all the answers
Which of these is NOT a possible complication associated with Meckel's diverticulum?
Signup and view all the answers
What is the significance of ectopic mucosa in Meckel's diverticulum?
Signup and view all the answers
Which of the following is a potential cause of intestinal obstruction related to Meckel's diverticulum?
Signup and view all the answers
Which of the following locations is NOT commonly associated with carcinoid tumors?
Signup and view all the answers
What is the average age at which carcinoid tumors are localized in the appendix?
Signup and view all the answers
What percentage of carcinoid tumors are 1-2 cm in size?
Signup and view all the answers
What is the most common site for carcinoid tumor metastasis?
Signup and view all the answers
Which tumor marker is identified in carcinoid tumors?
Signup and view all the answers
What condition is NOT typically associated with carcinoid tumors?
Signup and view all the answers
What is the primary secretion from carcinoid tumors originating in the middle intestine, such as the appendix and ileum?
Signup and view all the answers
Which statement about carcinoid tumors is true?
Signup and view all the answers
What is primarily responsible for the severe diarrhoea following ileal resection?
Signup and view all the answers
Which phase after surgery represents the highest level of fluid losses?
Signup and view all the answers
Which nutritional disorder is commonly observed in patients after extensive intestinal resection?
Signup and view all the answers
What physiological change occurs with resection of more than 1 m of the ileum?
Signup and view all the answers
What characterizes Phase 2 of the postoperative period?
Signup and view all the answers
What complication increases threefold in patients with short bowel syndrome?
Signup and view all the answers
Which of the following is NOT a consequence of gastric acid hypersecretion following small bowel resection?
Signup and view all the answers
What occurs in Phase 3 of the postoperative period after extensive intestinal resection?
Signup and view all the answers
What is the primary cause of severe diarrhoea after ileal resection?
Signup and view all the answers
Which clinical phase after surgery is associated with intestinal adaptation occurring?
Signup and view all the answers
What complication of short bowel syndrome significantly affects bile salt circulation?
Signup and view all the answers
What physiological change occurs following the resection of more than 1 m of the ileum?
Signup and view all the answers
What is the average length of the ileum in the small intestine?
Signup and view all the answers
Which layer is responsible for peristalsis in the small intestine?
Signup and view all the answers
What type of diverticula in the small intestine are characterized as true diverticula?
Signup and view all the answers
What is the function of Meissner's plexus in the small intestine?
Signup and view all the answers
Which part of the small intestine receives blood supply directly from the SMA except for the proximal duodenum?
Signup and view all the answers
What ligament fixes the ascending duodenum to the diaphragm?
Signup and view all the answers
What component primarily comprises the wall structure of the duodenum?
Signup and view all the answers
Which section of the duodenum is retroperitoneal?
Signup and view all the answers
Which condition is most commonly associated with lipomas in the gastrointestinal tract?
Signup and view all the answers
What is the primary treatment indication for true adenomas in the small intestine?
Signup and view all the answers
What is the most common location for hemangiomas in the gastrointestinal system?
Signup and view all the answers
Which type of tumor is characterized by a poor prognosis when associated with Crohn's disease?
Signup and view all the answers
In which age group is adenocarcinoma of the small intestine most commonly diagnosed?
Signup and view all the answers
Which symptom is NOT commonly associated with malignant tumors of the small intestine?
Signup and view all the answers
Which statement is true regarding leiomyomas in the small intestine?
Signup and view all the answers
What is the most likely diagnosis for a patient with multiple hamartomatous polyps?
Signup and view all the answers
What is the recommended course of action for symptomatic lipomas in the small intestine?
Signup and view all the answers
Which type of adenoma may appear as Brunner's gland adenomas?
Signup and view all the answers
What complication is the most common in adults with Meckel's diverticulum?
Signup and view all the answers
How many types of ectopic tissue can be found in Meckel's diverticulum?
Signup and view all the answers
Which demographic is more likely to have Meckel's diverticulum?
Signup and view all the answers
What is the typical length of Meckel's diverticulum?
Signup and view all the answers
What percentage of the population is affected by Meckel's diverticulum?
Signup and view all the answers
What is the primary reason for rectal bleeding in infants with Meckel's diverticulum?
Signup and view all the answers
Which complication can occur as a result of non-closure of the omphalomesenteric duct?
Signup and view all the answers
What is a common symptom of Meckel's diverticulitis in adults?
Signup and view all the answers
At what average distance from the ileocecal valve is Meckel's diverticulum generally found?
Signup and view all the answers
What condition may develop due to inflammation of Meckel's diverticulum?
Signup and view all the answers
What percentage of carcinoid tumors larger than 2 cm are likely to metastasize?
Signup and view all the answers
Which location is associated with the highest density of carcinoid tumors?
Signup and view all the answers
Which tumor marker is identified in carcinoid tumors?
Signup and view all the answers
What is the average age range for the occurrence of carcinoid tumors in the small intestine?
Signup and view all the answers
Which organ is the most common site for carcinoid tumor metastasis?
Signup and view all the answers
Which of the following statements about carcinoid tumors is true?
Signup and view all the answers
What is the average size of most carcinoid tumors?
Signup and view all the answers
Which region has the highest occurrence of carcinoid tumors based on the locations mentioned?
Signup and view all the answers
What is the risk of metastasis for carcinoid tumors that are between 1-2 cm in size?
Signup and view all the answers
Which symptom is commonly associated with carcinoid tumors?
Signup and view all the answers
Study Notes
Meckel's Diverticulum
- Most common congenital anomaly of the digestive tract (2%)
- Occurs due to non-closure of the omphalomezenteric duct which connected the middle intestine with the yolk sac during fetal development
- May be associated with other congenital malformations such as esophageal atresia, anorectal atresia, SSS, and cardiovascular malformations
- Rule of Twos: found in 2% of the population, located 2 feet (60 cm) from the ileocecal valve, 2 inches (5 cm) long, 2 times more common in men, and contains 2 types of ectopic tissue (stomach, pancreas)
- Complication symptoms in children: rectal bleeding
- Complication symptoms in adults: intestinal obstruction, haemorrhage, and inflammation
- Most common cause of severe lower GI bleeding in children under 2 years of age
- Most common complication in adults: intestinal obstruction
- Causes of intestinal obstruction include: vitelloumbilical band or volvulus around the sinus, intussusception, incarceration of the hernia sac (Littre hernia), structure formation, ectopic tissue in the diverticulum, internal herniation in the mesodiverticular band, and adhesions due to previous inflammation.
- Inflammation (diverticulitis) clinically resembles acute appendicitis; a localised abscess or generalised peritonitis may develop
- Perforation: deeping of peptic ulcer, progression of inflammation, or erosion by a foreign object may perforate the diverticulum
- Neoplasm: rare but small bowel tumors are more likely to occur in Meckel's diverticulum; carcinoid tumours, leimoyosarcoma, and adenocarcinoma are most common
- Blind loop syndrome: excessive colonisation of bacteria in the intestine due to slow passage, causing diarrhoea, steatorrhoea, anemia, weight loss, abdominal pain, neurological findings, and vitamin B12 deficiency
Small Bowel Neoplasms
- Extremely rare, accounting for 3-6% of all GI tumours
- Only 1% of malignant tumours of the small intestine are localized
- Symptoms include macroscopic occult haemorrhage or anaemia, pain, nausia, vomitting, weight loss, and constipation
- Benign tumors: leiomyoma, fibroleiomyoma, adenoma, lipoma
- Malignant tumors: adenocarcinoma, carcinoid tumor, leiomyosarcoma, lymphoma
- Polyps are more common in the small intestine
- Malignant tumors are most commonly located in the ileum
- Enteroclysis is the most effective method for diagnosis (90%)
Benign Tumors
- Small benign tumors are asymptomatic
- Large benign tumors can cause obstruction (partial or intermittent), haemorrhage, intussusception, or volvulus
Benign Stromal Cell Tumors
- Originate from stromal cells
- Leiomyoma is the most common and causes the most symptoms
- Usually located in the jejunum and multiple
- Removal is recommended if symptomatic
Benign Epithelial Tumors
- Adenoma: includes true adenoma, villous adenoma, and Brunner's gland adenomas
- Brunner's gland adenomas result from proliferation of glands with ducts and stromal elements
- Most commonly seen at the junction of the 1st and 2nd parts of the duodenum
- Malignant transformation is not seen
- True adenomas are seen in the ileum 50% of the time
- They are premalignant and must be removed
Hamartomatous Polyps
- Usually present as a component of Peutz-Jeghers syndrome
- Not premalignant but carcinomatous changes have rarely been reported
Other Benign Tumors
- Lipomas are more common in the ileum
- Excision is not required unless symptomatic
- GI involvement is seen in 25% of patients with neurofibromatosis
- The most common sites are the jejunum and stomach
- Malignant transformation can be detected in 15% of the lesions
- Hemangiomas may occur sporadically or as a component of Osler-Weber-Rendau syndrome
- Commonly localised in the jejunum
- Angiography is the most reliable method for diagnosis
Malignant Tumors of the Small Intestine
- Common symptoms: pain, obstruction, palpable mass, diarrhoea with mucus with tenesmus
- Periampullary region tumors may cause intermittent jaundice, occult blood in the stool, and treatment involves wide resection including the lymph nodes
- Adenocarcinoma: common between the ages of 50-60; prognosis depends on lymph node involvement; radiotherapy and chemotherapy are not effective
- Sarcomas: leiomyosarcoma is the most common; incidence is equal in men and women; equally seen in the jejunum and ileum
- Neuroendocrine carcinoma: includes gastric, duodenal, pancreatic, small intestinal, appendix, colorectal, neuroendocrine carcinomas, mixed adenocarcinomas and neuroendocrine carcinomas, and neuroendocrine KC metastases
Carcinoid Tumors
- Low grade tumours originating from all endocrine cell systems except C cells of the pancreas and thyroid
- Highest density in the duodenum, terminal ileum, and appendix
- 60-70% of carcinoids are located in the appendix and ileum
- Tumors originating from the middle intestine (appendix and ileum) secrete serotonin
- Average age at appendix localisation: 20-40 years
- Average age of occurrence in the small intestine: 60 years
- Clinical presentation: primary tumor, metastasis, hormonal secretion, clinical symptoms
- Clinical symptoms: abdominal pain, bowel obstruction due to tumor or desmoplastic reaction in the mesentery, cramp-like, paroxysmal, or intermittent pain, mesenteric ischemia, tumor or desmoplastic reaction in the mesentery
Carcinoid Tumor Prognosis
- Varies according to location, local intramural penetration depth, and tumor diameter
- Metastasis is most common in the mesenteric lymph nodes, liver, lung, and periosteum
Carcinoid Tumor Markers
- Cytokeratin, S-100 protein, prealbumin
- 75% of tumors are smaller than 1 cm and 2% of those smaller than 1 cm metastasize
- 20% of tumors are between 1-2 cm and 50% of these metastasize
- 5% of tumors are larger than 2 cm and 80-90% metastasize
Carcinoid Tumor Metastasis
- Most frequent in the colon (60%), ileal (35%), and appendix (3%)
- Most common sites for metastasis: regional lymph nodes and liver
- Other causes of mesenteric vascular occlusion: Crohn's disease, strangulated hernias, mesenteric vessel injuries, small bowel volvulus, small intestine tumors, and radiation enteritis
Short Bowel Syndrome
- The jejunum and ileum absorb fluids and electrolytes
- After jejunum resection, the ileum and colon absorb increased fluids and electrolytes to minimize diarrhoea
- After ileal resection, isotonic content of the jejunum and unabsorbed bile salts pass into the colon causing severe diarrhoea
- Bile salts destroy the membrane structure of colonic mucosa cells and prevent active Na transport
- Removal of more than 1 m of the ileum impairs the absorption of bile salts
- Absorption of fats is also impaired leading to steatorrhoea
- Gastric acid hypersecretion occurs with small bowel resection
- This is probably due to inhibition or elimination of a factor secreted from the small intestine that inhibits gastric acid secretion
- Gastric hypersecretion is transient
- Increased gastric secretions exacerbate diarrhoea by increasing the fluid-electrolyte load of the intestine
- In short bowel syndrome, gallstone formation increases 3-fold due to impaired enterohepatic circulation of bile salts
Clinical Stages of Short Bowel Syndrome
- Phase 1: Immediately after the operation; fluid loses are at the highest level; fluid electrolyte balance disorders are the most important cause of mortality; lasts an average of 3 weeks.
- Phase 2: Diarrhoea regresses; the patient is comfortable as long as there is no oral fluid and food intake; diarrhoea occurs with meals; intestinal adaptation occurs in this phase and lasts an average of 3-6 months.
- Phase 3: Numerous nutritional and metabolic disorders occur in direct proportion to the length of intestine removed; anaemia is common; osteomalacia is present in 30% of patients; hyperoxaluria, hypomagnesaemia, gallbladder and urinary system stones may be seen.
Small Intestine Anatomy
- The small intestine is divided into three parts: the duodenum, jejunum, and ileum.
- The duodenum is approximately 25 cm long and is retroperitoneal.
- The jejunum is approximately 100-110 cm long.
- The ileum is approximately 150-160 cm long.
- The small intestine is approximately 5-6 meters long when stretched out.
Duodenum Anatomy
- The duodenum has four parts: the superior duodenum (bulbus), descending duodenum, inferior transverse duodenum (pars horizontalis), and ascending duodenum.
- The superior duodenum starts at the pylorus and ends at the neck of the gallbladder.
- The descending duodenum extends from the neck of the gallbladder to the lower edge of the 3rd lumbar vertebra.
- The inferior transverse duodenum extends from the lower edge of the lumbar vertebrae to the abdominal aorta.
- The ascending duodenum forms the duodenojejunal junction and is fixed to the diaphragm by the duodenojejunal flexure suspensory ligament (Trietz ligament).
Small Intestine Histology
- The small intestine wall consists of the serosa, muscular layer, submucosa, and mucosa.
- The mucosa contains circular plicae (Kerckring plicae), villi, lymph follicles, and glands.
Small Intestine Blood Supply and Innervation
- The small intestine receives blood supply from the superior mesenteric artery (SMA), except for the proximal duodenum.
- The ileum has a rich lymphatic network.
- The small intestine is innervated by the vagus nerve (parasympathetic) and splanchnic nerves (sympathetic).
- The small intestine contains two nerve plexuses: the myenteric plexus (Auerbach plexus) responsible for peristalsis and the submucosal plexus (Meissner's plexus) responsible for secretion control.
Small Intestinal Diverticula
- Small intestinal diverticula can be congenital (true diverticula) or acquired.
- Acquired diverticula of the small intestine are most commonly seen in the duodenum.
Meckel's Diverticulum
- Meckel's diverticulum is the most common true congenital diverticulum of the small intestine.
- It occurs in 2% of the population and develops due to a failure of the omphalomezenteric duct to close during fetal development.
- Meckel's diverticulum is typically located 60 cm from the ileocecal valve and is 5 cm long.
- It is more common in males and often contains ectopic gastric or pancreatic tissue.
Meckel's Diverticulum Complications
- The most common complications of Meckel's diverticulum include bleeding, intestinal obstruction, inflammation (diverticulitis), perforation, fibrous hernia, and neoplasm development.
Benign Small Intestine Tumors
- Leiomyoma is the most common benign tumor of the small intestine.
- Adenomas are premalignant lesions and should be removed.
- Hamartomatous polyps are often associated with Peutz-Jeghers syndrome.
- Lipomas are more common in the ileum and do not need to be removed unless symptomatic.
Malignant Small Intestine Tumors
- Adenocarcinoma is the most common malignant tumor of the small intestine.
- Sarcomas are also common, with leiomyosarcoma being the most common type.
- Neuroendocrine carcinomas (carcinoids) are another type of malignant tumor.
Carcinoid Tumors
- Carcinoid tumors are low-grade malignant tumors that originate from endocrine cells.
- They are most commonly found in the duodenum, terminal ileum, and appendix.
- Carcinoids in the middle intestine (appendix and ileum) secrete serotonin.
- Carcinoid tumors can metastasize to mesenteric lymph nodes, liver, lung, and periosteum.
- Carcinoids have variable prognoses depending on location, depth of penetration, and diameter.
Small Bowel Resection Consequences
- Resection of the jejunum leads to increased fluid and electrolyte absorption in the ileum and colon to minimize diarrhea.
- Resection of the ileum leads to severe diarrhea due to unabsorbed bile salts in the colon.
- Removal of > 1 meter of the ileum impairs bile salt absorption and fat absorption, leading to steatorrhea.
- Small bowel resection can cause gastric acid hypersecretion, contributing to diarrhea.
- Gallstone formation increases in short bowel syndrome due to impaired bile salt circulation.
Small Bowel Resection Clinical Stages
- Phase 1: Immediate post-operative period with high fluid losses and electrolyte disturbances.
- Phase 2: Diarrhea regression with comfort in the absence of oral intake; diarrhea returns with meals.
- Phase 3: Long-term complications including anemia, osteomalacia, hyperoxaluria, hypomagnesaemia, and gallstones.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the essentials of Meckel's diverticulum, the most common congenital anomaly of the digestive tract. Explore its characteristics, associated complications in children and adults, and the clinical significance of the Rule of Twos. Test your knowledge on this important pediatric condition.
