What do you call a malformation where there is a narrowing or absence of a portion of the intestine?
Atresia can occur anywhere in the small or large intestine, but where is it most common? Is is strongly associated with what condition?
What is the most common cause of non-duodenal atresia?
Vascular malformation in utero that leads to decreased intestinal perfusion and ischemia of the respective segment of bowel.
A disorder of the gut which is caused by the failure of the neural crest cells to migrate completely during fetal development of the intestine. What is it also known as?
Hirschsprung’s disease; congenital aganglionic megacolon
What is the primary problem in Hirschsprung’s disease and what causes it?
The absence of ganglion cells results in a persistent over-stimulation of nerves in the affected region of the colon, resulting in persistent muscular contraction (failure to relax) causing constipation and eventual obstruction of the bowel.
When do you diagnose a baby with Hirschsprung’s disease?
If the baby fails to pass meconium within 48 hours of delivery. Also consider if there is green or brown vomitus, swelling of the abdomen, gas and bloody diarrhea. Definitive Dx is by biopsy of the distally narrowed segment.
What is a complete twisting of a loop of intestine around its mesenteric attachment site?
What is a general term used when the process of rotation and fixation of the mid-gut fails to normally occur?
What do you call a part of the intestine migrating into another section of intestine, similar to the way the parts of a collapsible telescope may slide into one another?
What are the triad of symptoms associated with intussusception?
Colicky abdominal pain
Red currant jelly stool
On x-ray what is the sign that suggests intussusception? What sign is seen with a barium study?
Crescent sign - lucency usually in the LUQ
What is an out pouching from the intestine located in the distal ileum, usually within 60-100 cm of the ileocecal valve?
What is a vestigial remnant of the vitelline duct (yolk sac) and is the most frequent malformation of the GI tract, present in 2% of the population?
What is the difference between ‘true’ and ‘false’ diverticula?
‘True’ involve all layers of the structure including muscularis propria and adventitia.
‘False’ involve only the submucosa and mucosa and do not involve muscular layers or adventitia.
What is the condition of having outpocketings of the colonic mucosa and submucosa that occur due to weakness of muscle layers in the colon wall?
Where are diverticula more common?
Sigmoid colon, which is a common place for increased pressure.
What is the classic triad of diverticulitis?
How is diverticulitis different from diverticulosis?
-osis may develop -itis. One or more diverticula becomes inflamed and may become infected, develop abscesses and perforate.
What is intestinal obstruction? Where does it happen? How important is it?
A mechanical or functional obstruction preventing the normal transit of the products of digestion.
Any level Distal to the duodenum.
With Celiac disease, what enzyme modifies gliadin causing the immune system to cross react with the small bowel tissue, causing an inflammatory reaction?
What histologic changes are happening in celiac disease and what does it cause?
Shortening of the villi lining the small intestine (villous atrophy).
It interferes with the normal absorption of nutrients, minerals (i.e. iron) and fat-soluble vitamins.
What are the two major types of idiopathic inflammatory bowel disease (IBD)? How are those two different?
Crohn’s disease and Ulcerative colitis.
Location and nature of the inflammatory changes.
What part of the GI tract does Crohn’s effect? Which area is most common? What layers?
Any part (mouth to anus).
Whole bowel wall (transmural lesions)
What part of the GI tract does ulcerative colitis effect? What layers?
The colon and rectum
What is a congenital condition in which the esophagus ends in a blind-ended pouch rather than connecting normally to the stomach?
What is a condition of thin membranes located within the lumen of the esophagus, that can be congenital or acquired? Where do they usually occur?
Congenital: middle and inferior 1/3
Acquired: cervical area
What is the most common cause of odynophagia?
What are the three characteristics of Achalasia?
Increased tone and pressure at the LES
Diminished to absent peristalsis in the distal portion of the esophagus
Lack of a coordinated LES relaxation in response to swallowing
Muscularis externa (aka muscularis propria) varies in different parts of the esophagus to correspond with the conscious control over swallowing in the upper portions and the autonomic control in the lower portions. WHAT MUSCLE TYPES PREDOMINATE IN EACH OF THE UPPER, MIDDLE AND INFERIOR 3RDS OF THE ESOPHAGUS?
Upper third: striated
Middle third: smooth and striated
Inferior third: smooth
Following ingestion of barium, the classic finding of bird’s beak deformity of the distal esophagus is characteristic of what condition?
Though the exact etiology underlying achalasia has not been determined, what is likely the underlying pathophysiology that results in achalasia?
Lymphocytic infiltration of Auerbach’s plexus and destruction of ganglion cells. (mb auto immune or response to toxic/infectious agent)
What are the two types of esophageal spasm and what characterizes each?
Diffuse (corkscrew) - contractions are uncoordinated and several segments of the esophagus contract simultaneously.
Nutcracker - contractions proceed in a coordinated manner but the amplitude is excessive.
What is Mallory Weiss syndrome? where does it happen? What layers are involved? What usually causes it?
Bleeding from tears
Mucosa at the junction of the stomach and esophagus
Mucosa and submucosa but no the muscular layer
Usually caused by sever coughing, retching or vomiting
How is Boerhaave’s Syndrome different from Mallory Weiss? What are some additional causes?
It’s a full thickness tear or rupture of the esophageal wall.
Perforation of esophageal ulcers, sequelae of caustic ingestion such as lye poisoning
What is the most common cause of esophagitis? In this case what is it also called?
What is an opportunistic infection of the esophagus that occurs most frequently in the immunocompromised?
Esophageal candidiasis (candida albicans)
What condition is characterized by mucosal damage to the esophageal lining due to stomach acid reaching the esophagus?
Gastroesophageal reflux disease (GERD)
What causes GERD?
Changes in the barrier between the stomach and the esophagus including abnormal relaxation of the LES, hiatal hernia or any condition which increases intra-abdominal pressure
What is a hiatal hernia?
Protrusion of the upper part of the stomach into the thorax through a tear or weakness in the diaphragm.
What are the two major types of hiatal hernia? Which is more common? How are they different?
Sliding (MC: 95%) - gastroesophageal junction moves above the diaphragm together with some of the stomach.
Para-esophageal (rolling) - part of the stomach herniates through the diaphragm and lies beside the esophagus without movement of the GE junction
What do you call a narrowing of the lower part of the esophagus that can cause difficulty swallowing?
What condition is characterized by metaplasia of the cells at the lower end of the esophagus from normal squamous epithelium to columnar epithelium, likely caused by damage from chronic acid exposure due gastroesophageal reflux?
What is a patient with Barrett’s esophagus at an increased risk of developing?
What are esophageal varices?
Dilated sub-mucosal veins in the lower third of the esophagus
Esophageal varices develop most commonly in patients with what condition? What are these patients at significant risk for developing?
Cirrhosis as a consequence of portal hypertension.
Severe and life threatening hemorrhage.
What is the appearance of distended and engorged peri-umbilical veins, which are seen radiating from the umbilicus across the abdomen to join systemic veins?
What is the most common benign esophageal tumor?
What benign tumor of the esophagus can develop anywhere in the body and are of neural origin, arising from Schwann cells?
Granular cell tumor
The two main forms of esophageal cancer are squamous cell carcinoma and adenocarcinoma. Where do each of them typically arise? What are they associated with?
Squamous: cells that line the upper part of the esophagus. Head and neck cancer in appearance; tobacco and alcohol consumption.
Adenocarcinoma: glandular cells that are present at the junction of the esophagus and stomach. Hx of GERD and Barrett’s.
What is a congenital diaphragmatic hernia? which side does it usually happen on? Although they may be asymptomatic what severe and life threatening condition can they cause?
Defect in the diaphragm, usually on the left, with herniating abdominal contents into the thorax.
Respiratory distress by compressing one or both lungs.
What condition is characterized by thickening of the wall and decreased lumen size of the pylorus, gastric peristalsis is increased, causing gastric pressure to rise and backflow into the esophagus and mouth. It often presents 2-3 weeks after birth with vomiting (non-bilious, may be projectile)and regurgitation of food?
Congenital hypertrophic pyloric stenosis
Histologically, what does one commonly find with acute gastritis?
Gastric mucosa with infiltration by neutrophils
What shape is Helicobacter pylori? Where is it found? What condition is it almost always present with?
Small curved to spiral rod shaped bacterium.
Surface epithelial mucus.
How do you differentiate between benign and malignant peptic ulcers?
Benign: smooth, regular, rounded edges with a flat, smooth base and radiating mucosal folds.
Malignant: irregular, heaped or overhanging margins that may be ulcerated which protrude into the lumen of the stomach.
What are four notable complications of PUD?
Scarring and swelling leading to gastric outlet obstruction
Ulcer transformation into cancer
Zollinger-Ellison syndrome is a triad of what conditions?
Gastric acid hypersecretion
Severe peptic ulceration
Non-beta islet tumor of pancrease
In Zollinger-Ellison syndrome, what causes the stomach to produce excess hydrochloric acid?
The non-beta islet cell tumor (gastrinoma) of the pancreas secretes gastrin which causes excessive HCl production and secretion.
What disorder, also called hyperplastic hypersecretory gastropathy, consists of gastric mucosal fold (rugae) being markedly enlarged?
In Menetrier’s disease, how is the gastric mucosa altered and what does this cause?
It is markedly enlarged. It then produces increased amounts of mucus while the glands in the stomach atrophy, causing decreased acid secretion and loss of protein(albumin) which often results in decreased plasma protein levels.
What distinguishes the childhood and adult forms of Menetrier’s disease?
Childhood: after a viral illness, i.e. CMV, or bacterial infection caused by H. pylori.
Adult: Patients who over-express TGF-alpha (much more common in men)
What is the process of chronic inflammation of the stomach mucosa, leading to the loss of gastric glandular cells and their eventual replacement by intestinal and fibrous tissues, resulting in the stomach’s secretion of hydrochloric acid, pepsin, and intrinsic factor being significantly impaired?
What are the two conditions that usually cause atrophic gastritis? Which of these two are more likely to develop achlorhydria and gastric carcinoma?
Persistent H. pylori and autoimmune destruction of the gastric lining.
The autoimmune version.
The impaired secretion of HCl, pepsin, and IF, seen in atrophic gastritis can lead to what conditions related to nutrition?
B12 deficiency, pernicious anemia and malabsorption of several nutrients that require an acidic environment for breakdown and absorption.
What is often revealed about the gastric mucosa of patients with atrophic gastritis?
Metaplasia in which intestinal-type epithelium replaces the gastric mucosa and there is notable loss in the number of gastric glands.
What is an inherited form of atrophic gastritis characterized by an immune response directed toward parietal cells and IF?
Autoimmune metaplastic atrophic gastritis (AMAG)
In AMAG, hypochlorhydria induces G cell (gastrin producing) hyperplasia, which leads to what?
In AMAG, gastrin exerts a trophic effect on what type of cells and is hypothesized to be one mechanism to explain the malignant transformation of these cells into carcinoid tumors in AMAG?
ECL - enterochromaffin-like cells which are responsible for histamine secretion
In gastric adenocarcinoma, describe a signet ring cell pattern seen histologically.
The cells are filled with mucin vacuoles that push the nucleus to one side.
What is a rare type of gastric cancer that originates in the glandular tissue lining the stomach walls, also known as Brinton’s disease or leather bottle stomach?
In linitis plastica, what happens to the stomach walls over time?
They are turned into leather-like scar tissue that cannot swell or contract as it should, resulting in disrupted digestion and inadequate metabolism of vital nutrients
What is a rare and stubborn to treat form of stomach cancer of mucosa-associated lymphoid tissue (MALT)
Gastric lymphoma or malignant lymphomas of MALT
When are the exams going to end?
Never. They never end. This is your life now.
Carcinoid tumors are a class of neuro-endocrine neoplasms that arise from what kind of cells?