GASTRO: BOARDS AND BEYOND Flashcards
What condition is characterized by endometrial cancer, colon cancer, and a family history of endometrial and ovarian cancer?
Lynch syndrome (hereditary nonpolyposis colorectal cancer).
What is the “3-2-1 Rule” in relation to Lynch syndrome?
Requires 3 or more Lynch-associated cancers (2 of whom are first-degree relatives) over 2 or more generations, with at least 1 person affected by age 50.
What type of genetic inheritance pattern does Lynch syndrome follow?
Autosomal dominant.
What is the underlying cause of Lynch syndrome?
A DNA mismatch repair gene defect leading to microsatellite instability.
How does Lynch syndrome affect the development of cancer?
It causes dysplasia in multiple organs that becomes malignant faster than typical lesions.
At what age do patients with Lynch syndrome typically develop cancers compared to the general population?
Patients develop cancers at a much younger age than would typically occur.
What role do genetic counseling and screening play in managing Lynch syndrome?
They are crucial for early detection and prevention strategies in affected individuals and families.
What gene mutation is associated with familial adenomatous polyposis (FAP)
Mutations in the APC gene.
What is the primary cancer risk associated with familial adenomatous polyposis?
Increased risk of colorectal cancer.
Why is “polyposis” included in the name familial adenomatous polyposis?
Because the APC gene leads to the development of multiple colonic polyps.
Does familial adenomatous polyposis increase the risk of breast or ovarian cancers?
No, it does not increase the risk of breast or ovarian cancers
How many colon polyps do patients with familial adenomatous polyposis typically develop?
Patients can develop hundreds to thousands of colon polyps.
At what age do patients with familial adenomatous polyposis typically start developing polyps?
Often by adolescence.
What is Gardner’s syndrome?
An autosomal dominant condition characterized by adenomatous polyposis and soft-tissue tumors.
Which gene mutation is responsible for Gardner’s syndrome?
APC gene mutation on chromosome 5.
How many colonic polyps do patients with Gardner’s syndrome typically develop?
Hundreds of colonic polyps.
What is the malignancy potential of the colonic polyps in Gardner’s syndrome?
Although benign, they have a strong malignancy potential.
What is the risk of developing colorectal cancer for patients with Gardner’s syndrome or familial adenomatous polyposis (FAP) by age 50?
100% chance if the colon is not removed.
What are some extra-colonic features associated with Gardner’s syndrome?
Osteomas, congenital hypertrophy of retinal pigment epithelium (CHRPE), and epidermoid cysts.
Where do osteomas commonly develop in patients with Gardner’s syndrome?
In the mandible.
Where do epidermoid cysts typically occur in Gardner’s syndrome?
In locations such as the face, scalp, and extremities.
How does classic familial adenomatous polyposis (FAP) differ from Gardner’s syndrome?
FAP is restricted to the colon and does not involve the development of epidermoid cysts, fibromas, or osteomas.
What common genetic mutation is found in both Gardner’s syndrome and familial adenomatous polyposis (FAP)?
APC gene mutation.
Why are the terms Gardner’s syndrome and FAP sometimes used interchangeably?
Because some FAP patients have limited extra-colonic features similar to those in Gardner’s syndrome.
In a patient with osteomas and cysts, which syndrome is the more accurate diagnosis: Gardner’s syndrome or classic FAP?
Gardner’s syndrome is the better answer.
Is a variant of Lynch syndrome (hereditary non-polyposis colorectal cancer) with sebaceous skin tumors.
Muir-Torre syndrome
Is a variant of familial adenomatous polyposis with malignant central nervous system tumors.
Turcot’s syndrome
What is juvenile polyposis syndrome (JPS)?
An autosomal dominant condition involving numerous hamartomatous polyps in the GI tract, primarily in the colon and rectum.
What types of polyps are most commonly found in JPS?
Hyperplastic, adenomatous, and hamartomatous polyps.
At what age can polyps in JPS begin to develop?
As early as the first decade of life.
What does the term “juvenile” refer to in juvenile polyposis syndrome?
It refers to the histological characterization of the polyps, not the age of the patient.
What is the most common clinical manifestation of JPS?
Rectal bleeding
What are some other symptoms that can occur in JPS?
Prolapsing polyps, pain, diarrhea, and iron-deficiency anemia
What is the risk of colorectal cancer in patients with JPS by age 35?
About 20%, increasing to 68% by age 60.
What is the lifetime risk of gastric cancer in patients with JPS?
20% to 30%
What is required for a clinical diagnosis of JPS?
At least one of the following:
- Five or more juvenile polyps in the colorectum
- Multiple juvenile polyps throughout the GI tract
- Any number of juvenile polyps in someone with a known family history of the disease.
How is JPS managed?
Routine screening for colorectal cancer with colonoscopy and gastric cancer with upper endoscopy.
Is an autosomal dominant syndrome associated with hamartomatous polyps of the GI tract, mucosal hyperpigmentation, and increased risk of cancer. Although this patient has hamartomatous lesions of the GI tract, he does not have the pigmented macules seen in more than 95% of PJS.
Peutz-Jeghers syndrome (PJS)
What is a common site for distant metastases of colon cancer?
The liver.
Why does colon cancer commonly metastasize to the liver?
Because of the portal venous drainage from the intestinal tract to the liver.
Besides the liver, what are other potential sites of metastasis for colon cancer?
The lungs and peritoneum.
How do most carcinomas, including colonic adenocarcinoma, primarily spread?
Via lymphatics.
What are the alternative routes of metastasis for colon cancer?
Through the bloodstream (hematogenous spread via the portal system), direct extension of the tumor, and seeding of peritoneal fluid.
What are the most common sites of metastasis for colon cancer?
Regional lymph nodes, the liver, lungs, and the peritoneum.
Intraperitoneal seeding refers to the spread of tumors via intraperitoneal fluid. Ovarian tumors in women often spread through this mechanism. Colon cancer can spread via intraperitoneal seeding. When it does, lesions appear on the outside of the liver, since this is the area in contact with intraperitoneal fluid. In addition to the exterior of the liver, seeding from colon cancer often leads to abdominal lesions in specific areas with stasis of peritoneal fluid (normally this fluid moves with position and bearing down). These include
The pouch of Douglas, the right lower quadrant mesentery, and the peritoneum of the sigmoid colon.
Develops in the setting of cirrhosis and chronic infection by hepatitis B or C.
A primary liver cancer or hepatocellular carcinoma
Occurs in immunocompromised patients (e.g., recipients of solid organ transplants, allogeneic hematopoietic cell transplants, etc.).
Systemic or invasive aspergillosis
What is the progression of mutations in colon cancer called?
The adenoma-carcinoma sequence (chromosomal instability pathway).
Which gene is the first to mutate in the adenoma-carcinoma sequence?
The APC gene (a tumor suppressor gene).
What is the significance of a mutation in the KRAS gene?
It is a proto-oncogene mutation found in the majority of hyperplastic colon polyps and is essential for neoplastic progression.
What is the third mutation that cells acquire to become malignant in colon cancer?
A mutation in the p53 gene (another tumor suppressor gene).
What does the presence of all three mutations (APC, KRAS, p53) indicate?
The cells are malignant.
How does familial adenomatous polyposis (FAP) affect the adenoma-carcinoma sequence?
n FAP, germline mutations in the APC gene are inherited, leading to numerous polyps due to the mutation being present from the start.
What characterizes a sporadic polyp in colon cancer?
A negative family history for colon cancer and no inherited gene mutations.
What deficiency is this woman experiencing in the context of carcinoid syndrome?
Niacin deficiency
What symptoms are associated with elevated serotonin levels in carcinoid syndrome?
Flushing, palpitations, abdominal pain, and diarrhea
What is the precursor molecule to serotonin?
Tryptophan
How much of tryptophan is normally utilized for serotonin production?
About 1%
In carcinoid syndrome, what percentage of tryptophan may be used for serotonin synthesis?
Up to 70%
What deficiency can result from the increased use of tryptophan for serotonin synthesis?
Tryptophan deficiency
How is niacin (vitamin B3) produced in the body?
From tryptophan
What are the primary symptoms of Sjögren’s syndrome?
Dry mouth (xerostomia) and dry eyes (xerophthalmia).
How does diminished saliva production affect oral health in Sjögren’s syndrome?
It frequently leads to an increased risk of dental caries (cavities).
What is the mechanism of action of pilocarpine in treating Sjögren’s syndrome?
Pilocarpine stimulates muscarinic receptors (M1, M2, M3) to increase oral and ophthalmic secretions.
Why is pilocarpine often intolerable for many patients?
Its nonselective action on muscarinic receptors causes cholinergic side effects.
What are some common cholinergic side effects of pilocarpine?
Sweating, urinary frequency, diarrhea, bradycardia, nausea, weakness, flushing, and hypotension.
What eye effect is caused by pilocarpine?
Miosis (pupillary constriction).
Anticholinergic drugs include atropine and scopolamine. Some side effects include:
Hypertension, constipation, urinary retention and mydriasis.
What is the most common type of salivary gland tumor?
Pleomorphic adenomas.
Where are pleomorphic adenomas typically located?
In the superficial lobes of the parotid glands.
Are pleomorphic adenomas benign or malignant?
They are usually benign, but they can undergo malignant transformation.
What is a potential complication of pleomorphic adenomas regarding facial anatomy?
They can invade the facial nerve.
Why are pleomorphic adenomas described as “biphasic”?
They contain glandular epithelial cells surrounded by supportive stroma.
What types of supportive tissue can be found in pleomorphic adenomas?
Cartilage, hyaline, or bone.
What term is sometimes used to describe the composition of pleomorphic adenomas?
“Chondromyxoid,” due to the presence of cartilage (chondroid tissue) and mucous cells (myxoid tissue).
What is a common issue associated with the surgical removal of pleomorphic adenomas?
Local recurrence.
What are Type I branchial cleft cysts, and where do they form?
They are cavities near the parotid gland caused by incomplete regression of ectodermal structures in the embryo.
What is the most common malignant salivary gland tumor?
Mucoepidermoid carcinoma.
What cell types are found in mucoepidermoid carcinoma?
A mixture of mucin-producing columnar cells and epidermoid cells.
What viral infection is caused by paramyxovirus and characterized by bilateral parotid gland swelling?
Mumps.
What would be seen on biopsy in a case of mumps?
A lymphocytic infiltrate consistent with viral infection.
What type of tumors are Warthin’s tumors, and are they benign or malignant?
Warthin’s tumors are benign salivary gland tumors.
What is the histological characteristic of Warthin’s tumors?
Fluid-filled cysts surrounded by lymphoid infiltrates.
What are Warthin’s tumors also known as?
Papillary cystadenoma lymphomatosum.
What is the second most common type of salivary gland tumor?
Warthin’s tumors.
Where do Warthin’s tumors almost always occur?
In the parotid glands.
Why should both parotid glands be examined in clinical practice?
Because Warthin’s tumors can be multifocal and bilateral.
In which gender do Warthin’s tumors occur more commonly?
Males
How much more likely are smokers to develop Warthin’s tumors?
Smokers are 8 times more likely to develop this tumor.
What are the histological features of Warthin’s tumors?
They are composed of fluid-filled cystic spaces lined with epithelial cells and dense lymphoid infiltrates, sometimes forming germinal centers.
Is the most common salivary gland malignancy in adults. It is composed of a variable mixture of squamous, mucus-secreting, and intermediate cells.The cystic appearance of this man’s tumor is not consistent with mucoepidermoid carcinoma.
Mucoepidermoid carcinoma
Represent 60% of parotid tumors and present as painless, slow-growing, discrete masses. Histologically, pleomorphic adenomas are called “biphasic,” because they contain glandular epithelial cells surrounded by stroma (supportive tissue) with cartilage, hyaline, or bone. The tumor is sometimes described as “chondromyxoid,” because it contains cartilage (chondroid tissue) and mucous cells (myxoid tissue).
Pleomorphic adenomas
Are rare and aggressive salivary tumors that occur in older men and have distant metastases at the time of presentation.
Small-cell carcinomas
Adenoid cystic carcinoma (ACC) is a locally aggressive tumor with three growth patterns: ?. This tumor is more common in the submandibular, sublingual, and minor salivary glands. ACC is not associated with smoking.
Tubular, cribriform, and solid.
What is the most common malignant salivary gland tumor in all age groups?
Mucoepidermoid carcinoma.
What types of cells compose mucoepidermoid carcinoma?
Variable mixtures of squamous, mucus-secreting, and intermediate cells
How do low-grade mucoepidermoid carcinoma lesions typically appear histologically?
They are cystic and have a higher percentage of squamous and mucus-producing cells than intermediate cells.
How do high-grade mucoepidermoid carcinoma lesions differ from low-grade lesions?
High-grade lesions are more solid, have more squamous and intermediate cells, show signs of anaplasia in the squamous component, and contain fewer mucus-producing cells.
What percentage of all salivary gland tumors do mucoepidermoid carcinomas represent?
Approximately 15%.
Where do mucoepidermoid carcinomas typically occur?
In the parotid glands or minor salivary glands.
What are some potential complications of mucoepidermoid carcinoma?
They can invade the facial nerve and present with pain and paralysis.
What is Meckel’s diverticulum a remnant of?
The embryonic vitelline duct (or yolk stalk).
What is a diverticulum?
An outpouching of the intestines.
In which part of the intestine does Meckel’s diverticulum occur?
In the small intestine.
What type of tissue can be found in Meckel’s diverticulum?
Gastric mucosa (or, rarely, pancreatic tissue).
What do the parietal cells in the gastric mucosa of Meckel’s diverticulum produce?
Acid.
How can gastric mucosa in Meckel’s diverticulum lead to complications?
It may cause ulceration in the adjacent small bowel, resulting in bleeding.
What is the “rule of twos” regarding Meckel’s diverticulum?
It occurs in about 2% of the population, is about 2 inches long, found about 2 feet from the ileocecal valve, 2% of patients develop complications, and has a male-to-female ratio of 2:1.
Lymphocytes are found in ? of the intestines. These cells are not responsible for the bleeding in Meckel’s diverticulum.
Peyer’s patches
Chief cells are found in the stomach and produce ? for digestion of proteins.
pepsin
Are glandular cells present in epithelial coatings of the mucous membranes of the respiratory tract and the digestive system. These cells produce mucus to protect the digestive or respiratory tubes.
Goblet cells
Are found in the jejunum and duodenum. They release secretin when stimulated by a fall in pH to 4 or below in the small intestinal lumen. Secretin increases the secretion of bicarbonate (HCO3-) from the pancreas.
S cells
What findings during pregnancy are consistent with Down syndrome (trisomy 21)?
Elevated serum β-HCG concentrations and fetal nuchal translucency detected on ultrasound.
What is duodenal atresia?
A complete obstruction of the duodenum by an atretic (closed) lumen.
What is duodenal stenosis?
A narrowed duodenal lumen that causes partial obstruction, allowing some bile and intestinal contents to flow.
How do duodenal atresia and stenosis commonly present in newborns?
With bilious vomiting due to backup of intestinal contents.
What classic sign is seen on an abdominal X-ray for duodenal atresia?
The “double-bubble” sign, showing a pocket of air before and after the duodenum.
What is the initial treatment for duodenal atresia or stenosis?
Nasogastric decompression and fluids, followed by surgical intervention.
Jejunal atresia involves a failure of the jejunum to canalize. This can be indistinguishable from duodenal atresia with abdominal distension and bilious vomiting. The ? on x-ray is classically associated with jejunal atresia. In addition, duodenal stenosis is more likely in a baby with Down syndrome.
“triple bubble” sign
Is a condition that affects premature infants. The intestinal wall develops necrosis, and symptoms start within 2 weeks of birth including fever, vomiting, and diarrhea with abdominal distension.
Necrotizing enterocolitis
Is characterized by narrowing of the lumen of the pylorus due to smooth muscle hypertrophy. Babies present with nonbilious vomiting after eating, and a palpable mass in the right upper quadrant classically described as “olive-shaped.”
Pyloric stenosis
Result from a failure of the trachea to completely separate from the esophagus, leaving a connection between these structures. This results in aspiration of stomach contents into the lungs when infants attempt to feed.
Tracheoesophageal fistulas
What is duodenal atresia?
A congenital failure of the duodenum in the small intestine to canalize.
What are the clinical features of duodenal atresia?
Distension of the stomach with bilious vomiting.
What does the “double bubble” sign indicate on X-ray?
A blind loop of the duodenum and gastric dilatation associated with duodenal atresia.
How common is duodenal atresia?
It occurs in about 1 in every 5,000 to 10,000 live births.
What percentage of infants with duodenal atresia have Down syndrome?
20% to 40%.
What condition can result from any process that disrupts swallowing in the womb?
Polyhydramnios (excess amniotic fluid).
How can pregnancy be affected by a fetus with duodenal atresia?
It is often complicated by polyhydramnios due to disrupted swallowing.
Is a life-threatening complication of pregnancy. It occurs in the 3rd trimester with abrupt onset of painful vaginal bleeding. Abruption is not associated with duodenal atresia.
Placental abruption
Is a complication of pregnancy that leads to hypertension, proteinuria, edema, and seizures. This is not associated with duodenal atresia.
Eclampsia
In placenta previa, the placenta attaches to the lower uterus over the cervix. ? can be life-threatening in this situation. Placenta previa is not associated with duodenal atresia.
Vaginal delivery
How is amniotic fluid produced and removed?
It is produced by fetal kidneys (fetal urine) and removed by fetal swallowing and intestinal absorption.
What can cause excess amniotic fluid?
Increases in urinary excretion or impaired swallowing/digestion.
What physical changes might a woman with polyhydramnios experience?
A rapidly expanding abdomen.
What is the amniotic fluid index (AFI)?
The sum of the measurement of the maximal depth of the amniotic fluid pocket in all four quadrants of the abdomen.
Which condition is specifically associated with polyhydramnios?
Esophageal atresia.
What occurs in esophageal atresia?
The esophagus ends in a blind pouch, preventing appropriate swallowing of amniotic fluid by the fetus.
Refers to poor growth of a fetus during pregnancy. It can be caused by poor maternal nutrition or lack of adequate oxygen supply to the fetus. It is associated with oligohydramnios (decreased amniotic fluid).
Intrauterine growth restriction
Refers to pulmonary hypoplasia and limb abnormalities that occur in the fetus due to oligohydramnios (decreased amniotic fluid). The amniotic fluid index is low in oligohydramnios.
Potter’s syndrome
Pulmonary agenesis
It is associated with oligohydramnios.
Is the failure of one or both kidneys to form. The absence of normal fetal renal function causes oligohydramnios.
Renal agenesis
What is malrotation?
A condition where the cecum is positioned in the right mid- to upper quadrant instead of the right lower quadrant due to improper rotation of the midgut during development.
What causes volvulus in the context of malrotation?
The twisting of the intestines around the mesentery due to abnormal positioning during peristalsis.
What symptoms may develop in a baby with malrotation and volvulus?
Bilious emesis (vomiting) and abdominal pain.
Is an abdominal X-ray reliable for diagnosing malrotation with volvulus?
No, it is often unreliable and can be normal.
What is the test of choice for diagnosing malrotation with volvulus?
Upper GI contrast study with fluoroscopy.
What is the primary treatment for malrotation with volvulus?
Surgical intervention.
Is characterized by absence or underdevelopment of the bile ducts. This leads to biliary obstruction with jaundice, dark urine, and acholic stools.
Biliary atresia
Why is reflux of stomach contents common in neonates?
The lower esophageal sphincter is not completely developed.
How is regurgitation in neonates typically characterized?
It is effortless and without vomiting, often referred to as “happy spitters.”
When does regurgitation usually occur in neonates?
Typically occurs more than 10 minutes after feeding
Is bilious vomiting common in neonates with reflux?
No, bilious vomiting does not occur in these cases.
In atresia, there is no lumen for intestinal flow. This leads to vomitting shortly after the baby first begins to feed. The fact that this baby was feeding normally during his first week of life makes intestinal obstruction from atresia
Very unlikely.
The pylorus is the opening of the stomach into the duodenum. Pyloric stenosis is characterized by narrowing of the lumen of the pylorus due to smooth muscle hypertrophy. Babies present with ? after eating, and a palpable mass in the right upper quadrant, classically described as “olive-shaped.”
Non-bilious vomiting
What is a hiatal hernia?
A protrusion of the stomach through the diaphragm and into the thoracic cavity.
What causes hiatal hernias?
Progressive disruption of the gastroesophageal junction (GEJ) over time.
Where does the gastroesophageal junction (GEJ) normally reside?
Below the diaphragm.
What happens to the hiatal tunnel in patients with a hiatal hernia?
It widens, allowing the GEJ to slide upward.
What happens to the phrenoesophageal membrane in hiatal hernias?
It becomes lax, failing to tether the esophagus to the diaphragm.
What are the two main types of hiatal hernias?
Sliding (type I) and paraesophageal (type II, III, and IV) hernias.
Which type of hiatal hernia is the most common?
Sliding hernias (90 percent).
Can hiatal hernias be asymptomatic?
Yes, they may be asymptomatic.
What are common clinical features of hiatal hernias?
Symptoms of gastroesophageal reflux disease (GERD) such as pain after eating, regurgitation, and dysphagia.
What can a chest x-ray show in large sliding hiatal hernias?
A retrocardiac mass with an air-fluid level, indicating gastric cardia protrusion into the thoracic cavity.
What is achalasia?
A condition characterized by increased tone of the lower esophageal sphincter (LES), making it difficult to relax.
What causes the increased tone of the LES in achalasia?
Absence of inhibitory innervation to the LES, such as that seen in Chagas disease.
Where is Chagas disease common?
South America.
What are common symptoms of achalasia?
Progressive dysphagia, regurgitation, and aspiration of undigested food.
How might a patient with achalasia present in terms of x-ray findings?
Evidence of a hiatal hernia may be present alongside classic symptoms.
What is gastroparesis?
A condition characterized by delayed emptying of gastric contents.
What is a common cause of gastroparesis?
Many cases are idiopathic, but it can be associated with diabetes.
What are common symptoms of gastroparesis?
Early satiety, nausea, abdominal pain, bloating, and weight loss.
How might a patient with gastroparesis present in relation to hiatal hernia?
They may have classic hiatal hernia symptoms and evidence of a hiatal hernia on x-ray.
What are mediastinal lymphomas?
They are a type of lymphoma that can present as a mediastinal mass.
What is an important consideration in the differential diagnosis of a mediastinal mass?
Mediastinal lymphomas are part of the differential diagnosis.
What findings indicate that a patient does not have a mediastinal mass?
A chest X-ray showing no mediastinal mass.
What systemic symptoms do patients with lymphoma commonly present with?
Fevers, weight loss, and night sweats.
Do symptoms of GERD typically occur in mediastinal lymphoma?
No, symptoms of GERD generally do not occur in mediastinal lymphoma.
Zenker’s diverticulum is an outpouching of the mucosa and submucosa between the cricopharyngeus muscle and lower inferior constrictor muscles. This creates an outpouching in the pharynx. Zencker’s diverticulum is characterized by
Transient dysphagia, pulmonary aspiration, foul breath, and appearance of a neck mass.
What is congenital diaphragmatic hernia (CDH)?
A condition where abdominal contents pass into the thoracic cavity through a hole in the diaphragm.
What characteristic appearance does a baby with CDH often have at birth?
A “scaphoid-shaped” (curved inward) abdomen due to abdominal contents in the chest.
Why does herniation of abdominal contents occur more often on the left side in CDH?
The liver provides relative protection of the diaphragm on the right side.
What complication can result from intestinal structures herniating into the chest cavity?
Pulmonary hypoplasia due to lack of space for normal lung development.
What is believed to cause congenital diaphragmatic hernia?
Defective formation of the pleuroperitoneal membranes, which separate the thoracic and peritoneal cavities.
How is CDH often diagnosed in modern medicine?
By ultrasound during pregnancy.
What findings on a chest X-ray indicate CDH?
Air- or fluid-filled structures in the thorax due to herniation of bowel.
What is the primary treatment for congenital diaphragmatic hernia?
Surgery to reposition the abdominal organs and seal the diaphragm.
What factors influence the prognosis of CDH?
The degree of organ hypoplasia, especially pulmonary hypoplasia.
What are foregut defects?
Congenital abnormalities of the upper GI tract, including various malformations.
Name some congenital abnormalities caused by foregut defects
Esophageal atresia and stenosis, pyloric stenosis, atresia of the gallbladder and bile ducts, liver malformations, and pancreatic malformations.
What results from the persistence of the second pharyngeal cleft or pouch?
A branchial fistula, which is an abnormal tract on the side of the neck and in the pharynx.
What causes tracheoesophageal fistulas?
Incomplete separation of the esophagus and trachea by the tracheoesophageal septum during week 4 of development.
What is esophageal atresia?
A congenital condition where the esophagus ends in a blind pouch and does not connect to the stomach.
What is pyloric stenosis?
A condition where the pylorus (the opening from the stomach to the duodenum) is narrowed, causing obstruction.
What is a femoral hernia?
A herniation of bowel through the femoral ring.
What causes the femoral ring to widen and weaken?
Aging, injury, or frequent exposure to high intra-abdominal pressure (e.g., from constipation).
Where is a femoral hernia typically located?
Under the inguinal ligament, producing a mass or bulge.
How can a femoral hernia be identified during an examination?
By a line drawn between the anterior superior iliac spine and the pubis.
In which population is femoral hernia more common?
In woman’s
What is an indirect inguinal hernia?
A type of hernia where bowel herniates above the inguinal ligament.
In which population do indirect inguinal hernias most commonly occur?
Males
Where does the bowel herniate in an indirect inguinal hernia?
Laterally in relation to the inferior epigastric vessels and into the scrotum.
What causes indirect inguinal hernias?
Patency of the processus vaginalis.
How can indirect inguinal hernias be distinguished from direct inguinal hernias?
Indirect hernias occur lateral to the inferior epigastric vessels, while direct hernias occur medial to them.
What is a direct inguinal hernia?
A type of hernia that passes through the inguinal triangle above the inguinal ligament.
Where is a direct inguinal hernia located in relation to the inferior epigastric vessels?
Medially in relation to the inferior epigastric vessels.
In which population are direct inguinal hernias more common?
Older men
What causes direct inguinal hernias?
Weakness of the inguinal canal floor.
How can direct inguinal hernias be distinguished from indirect inguinal hernias?
Direct hernias occur medial to the inferior epigastric vessels, while indirect hernias occur lateral to them.
Occurs when a portion of the intestines is pushed through the umbilical opening in the abdominal wall. Umbilical hernias may occur from the persistence of the umbilical fibromuscular ring in newborns or as a consequence of increased intra-abdominal pressure due to many different causes in adults (obesity, pregnancy, etc.).
An umbilical hernia
The classic imaging finding of a sliding hiatal hernia is ?. This is indicated by the short white arrow above, which points to the GEJ, located above the diaphragm (long white arrow).
An hourglass sign (also called “collar sign”).
What are esophageal varices?
Dilated veins in the esophagus caused by portal hypertension, leading to gastrointestinal bleeding in patients with cirrhosis.
What complication of cirrhosis leads to the formation of esophageal varices?
Portal hypertension.
What is Boerhaave’s syndrome?
Effort ruptures of the esophagus due to increased intraesophageal pressure relative to intrathoracic pressure.
What are common causes of Boerhaave’s syndrome?
Straining and vomiting.
What are clinical features of Boerhaave’s syndrome?
Retrosternal chest pain, dyspnea, and subcutaneous emphysema.
What is achalasia?
The failure of the lower esophageal sphincter (LES) to relax due to the absence of ganglion cells in the esophagus.
What are clinical features of achalasia?
Dysphagia, regurgitation, food aspiration, and inflammation of the esophageal myenteric plexus.
What is eosinophilic esophagitis (EoE)?
An inflammatory condition of the esophagus causing dysphagia, especially in individuals with allergies or asthma.
What are common clinical features of eosinophilic esophagitis?
Dysphagia, vomiting, abdominal pain, and food impaction.
How is eosinophilic esophagitis diagnosed?
Diagnosis is made via histologic findings, as endoscopic findings are not always present.
What factors are involved in the pathogenesis of eosinophilic esophagitis?
Genetic, environmental, and host immune system factors.
What are common symptoms of GERD?
Heartburn, hoarseness, sore throat, regurgitation, and cough.
What occurs in a sliding hiatal hernia?
The gastroesophageal junction (GEJ) slides to a position above the diaphragm.
What characterizes a paraesophageal hiatal hernia?
The gastric fundus herniates upward into the thorax next to the esophagus, while the GEJ may remain in its usual position.
Through what structure does the gastric fundus herniate in a paraesophageal hiatal hernia?
Through a defect in the phrenoesophageal membrane.
What is the function of the phrenoesophageal membrane?
It is a connective tissue structure that anchors the esophagus to the esophageal hiatus in the diaphragm.
In the sliding or type I hiatal hernia, the gastric cardia protrudes above the diaphragm. In a paraesophogeal hernia,
The cardia (the point where the esophagus enters the stomach) remains below the diaphragm
What characterizes a direct inguinal hernia?
Protrusion of abdominal contents into Hesselbach’s triangle.
What are the borders of Hesselbach’s triangle?
Medially by the rectus abdominis, laterally by the inferior epigastric artery, and inferiorly by the inguinal ligament.
What is the most common type of inguinal hernia?
Indirect inguinal hernias, occurring in both men and women.
How does an indirect inguinal hernia occur in males?
The processus vaginalis fails to close, allowing a loop of bowel to enter the scrotum via the inguinal canal.
What is the processus vaginalis?
An embryonic outpouching of the parietal peritoneum that descends with the testes into the scrotum.
What happens to the processus vaginalis normally after descent of the testes?
It closes, preventing any connection to the abdomen.
What forms the tunica vaginalis in males?
Some tissue from the processus vaginalis that remains surrounding the testes.
Where do indirect inguinal hernias pass in relation to the inferior epigastric vessels?
Laterally to the inferior epigastric vessels and through both the deep and superficial inguinal rings.
What are potential complications of groin hernias?
Trapping of herniated intestine, bowel obstruction, and bowel ischemia.
What does tenderness on exam suggest in a patient with a hernia?
It may indicate a strangulated hernia, which requires immediate surgery.
How is the pathogenesis of an indirect inguinal hernia similar to that of a hydrocele?
Both conditions involve fluid or contents entering the incompletely closed processus vaginalis.
Is a superficial, subcutaneous connective tissue layer of the scrotum. The dartos muscle within the dartos fascia assists with scrotal elevation.
Dartos fascia
Is a connective tissue structure in the midline of the abdomen through which umbilical hernias may protrude.
Linda alba
What is the external spermatic fascia?
The outermost layer of fascia that covers the spermatic cord.
From which muscle is the external spermatic fascia derived?
It is derived from the external oblique muscle and its aponeurosis.
What is the internal spermatic fascia?
The innermost layer of fascia that covers the spermatic cord.
From which fascia is the internal spermatic fascia derived?
It is derived from the transversalis fascia.
What is the significance of the spermatic fascia?
It provides protection and support to the spermatic cord structures, including blood vessels and nerves.
What is Hirschsprung’s disease?
A condition caused by failure of neural crest cell migration to the intestinal wall, leading to aganglionosis.
What does “aganglionosis” mean?
A lack of neurons in the colon wall, specifically in Auerbach’s plexus and Meissner’s plexus.
What plexuses are absent in patients with Hirschsprung’s disease?
Both the myenteric (Auerbach’s) plexus and the submucosal (Meissner’s) plexus.
How does the absence of innervation affect intestinal function in Hirschsprung’s disease?
It causes a “functional” blockage due to lost intestinal motility.
What can be seen on a barium study in patients with Hirschsprung’s disease?
Recto-sigmoid narrowing with proximally distended bowel loops.
How can Hirschsprung’s disease be differentiated from functional constipation?
Presence of a tight anal sphincter and an empty rectum.
What is the typical presentation of Hirschsprung’s disease?
Chronic constipation.
When is Hirschsprung’s disease usually diagnosed?
Most patients are diagnosed in the neonatal period, but milder cases may be diagnosed later in infancy or childhood.
What are the crypts of Lieberkühn?
Glandular structures in the mucosal layer of the small intestine that contain goblet cells.
What are goblet cells responsible for?
They produce mucus, which helps lubricate and protect the intestinal lining.
What can a biopsy showing crypt abscess indicate?
It can be seen in ulcerative colitis but would not explain findings in Hirschsprung’s disease.
What are the components of the mucosa?
The epithelium (including the basement membrane), lamina propria, and muscularis mucosae
What are Peyer’s patches?
Masses of lymphatic tissue found in the lamina propria and submucosa of the ileum.
What is the primary function of Peyer’s patches?
They play a role in the immune response by monitoring intestinal bacteria and preventing the growth of pathogenic bacteria.
What is Hirschsprung’s disease?
A congenital disorder where neural crest cells fail to migrate to the intestinal wall, causing a functional blockage due to lack of innervation.
Chronic constipation and failure to pass meconium.
What two disorders should be considered in a case of failure to pass meconium?
Hirschsprung’s disease and cystic fibrosis.
What is the gold standard for diagnosing Hirschsprung’s disease?
A deep rectal suction biopsy.
What does a biopsy in Hirschsprung’s disease reveal?
Lack of ganglion cells (aganglionosis) in the colon wall.
What is the treatment for Hirschsprung’s disease?
Surgical resection of the aganglionic portions of the colon.
Are commonly associated with Crohn’s disease, which does not present in neonates.
Granulomas and transmural ulcers
What is observed in biopsy specimens from patients with Hirschsprung’s disease?
Absence of ganglion cells and hypertrophy of nerve fibers.
Where do the hypertrophied nerve fibers in Hirschsprung’s disease derive from?
Autonomic and sensory nerves outside the affected area.
Why do nerve fibers show hypertrophy in Hirschsprung’s disease?
As a compensatory response to the absence of ganglion cells, as these nerves attempt to integrate with the aganglionic segment.
Is the classic finding in celiac disease
Numerous lymphocytes with villous atrophy
Is characterized by transmural intestinal ganglioneuromas, a rare benign tumor of neural crest cells.
Multiple endocrine neoplasia type 2B (MEN 2B)
What is achalasia?
A disorder of esophageal motility characterized by an inability to relax the lower esophageal sphincter (LES).
What causes achalasia?
Damage to ganglion cells in the myenteric plexus (Auerbach’s plexus).
Where are the ganglion cells that are affected in achalasia located?
Between the inner circular and outer longitudinal layers of the muscularis propria of the esophagus.
What is the consequence of the loss of esophageal motility in achalasia?
Dysphagia for both solids and liquids due to the requirement of peristalsis for swallowing.
What does the inability to relax the LES lead to in achalasia?
Dilatation of the esophageal wall.
What is the classic radiological finding associated with achalasia on a barium swallow study?
The “bird beak” sign.
What are G cells?
Gastrin-producing cells located in the stomach and duodenum.
In which conditions might gastrin concentrations be elevated?
Zollinger-Ellison syndrome and autoimmune gastritis.
What do parietal cells in the stomach produce?
Hydrochloric acid (HCl) and intrinsic factor.
What can intrinsic factor deficiency lead to?
Pernicious anemia.
What is the underlying issue in achalasia related to the lower esophageal sphincter?
An inability of the smooth muscle to relax, but it is not the muscle cells themselves that are damaged.
What are common clinical findings in cirrhotic liver disease?
Jaundice, abdominal pain, and hematemesis from bleeding varices.
What structures are contained within the hepatoduodenal ligament?
The hepatic artery, the portal vein, and the common bile duct.
Why is lymphadenopathy common in patients with end-stage liver disease?
It usually results from lymphatic hyperplasia.
Where is the hepatic bile duct located?
Inferior to the liver and superior to the gallbladder.
Is the hepatic bile duct contained within the hepatoduodenal ligament?
No, it is not contained within the hepatoduodenal ligament.
Why is the gallbladder less likely to be compressed by lymphadenopathy of the hepatoduodenal ligament?
Because it is not contained within the hepatoduodenal ligament.
What is the remnant of the umbilical vein called?
The ligamentum teres of the liver.
Where is the ligamentum teres located?
At the free end of the falciform ligament, and it is not contained within the hepatoduodenal ligament.
What is Superior Mesenteric Artery (SMA) syndrome?
A condition characterized by compression of the third portion of the duodenum between the aorta and the superior mesenteric artery.
What can lead to the development of SMA syndrome?
Significant weight loss, which causes loss of mesenteric fat.
What are common clinical manifestations of SMA syndrome?
Postprandial epigastric pain, early satiety, and occasionally bowel obstruction.
How does SMA syndrome cause duodenal obstruction?
The compression of the duodenum leads to intermittent obstruction.
Hypertrophy of the gastric pylorus causes ?. This is a congenital anomaly that presents in infants with projectile vomiting.
Pyloric stenosis
Meissner’s plexus is located in the ? of the intestines. It is involved in the pathogenesis of Hirschsprung’s disease, a disorder of the colon that occurs predominantly in young children.
Submucosal layer
What two arteries supply blood to the large colon?
The superior mesenteric artery (SMA) and the inferior mesenteric artery (IMA).
Where is the watershed region located in the colon?
At the splenic flexure.
Why does the watershed area become vulnerable to ischemia during shock?
Because under-perfusion occurs, reducing blood flow through the sparse collateral circulation.
What are the primary clinical features of ischemic colitis?
Severe abdominal pain and the passage of blood and mucus from the rectum.
What radiographic findings may be seen in ischemic colitis?
Thumb-printing and dilation of the bowel proximal to the area of ischemia.
Is predominantly supplied by the superior mesenteric artery and does not lie within the watershed region. Hypotension does not easily cause ischemia in this segment of the colon.
The ascending colon
What arteries supply blood to the rectum?
The internal iliac artery and the inferior mesenteric artery.
Why is the rectum infrequently involved in colonic ischemia?
Due to its dual blood supply from the internal iliac artery and the inferior mesenteric artery.
What symptoms are associated with upper gastrointestinal bleeding?
Hematemesis (vomiting blood) or melena (black, tarry stools), but not bright red blood from the rectum.
What is a classic finding in acute mesenteric ischemia?
Pain that is out of proportion to the physical examination.
What might a patient with acute mesenteric ischemia report about their abdominal pain?
Severe abdominal pain (e.g., “10/10”) despite only mild tenderness on examination.
What is a common finding in patients with bowel ischemia?
Blood in the stool.
What laboratory findings might be present in a patient with acute mesenteric ischemia?
Elevated white blood cell count and elevated lactate.
In patients with atrial fibrillation, what is a likely cause of acute mesenteric ischemia?
Formation of a clot in the left atrium that embolizes to the bowel.
Which vessel is most commonly involved in acute mesenteric ischemia?
The superior mesenteric artery.
What are colonic diverticula?
Outpouchings of the bowel wall that form at natural areas of weakness in the muscular layer.
Are diverticula usually symptomatic?
No, they are generally asymptomatic unless complications develop.
What complications can arise from diverticula?
Inflammation (diverticulitis), perforation, or bleeding.
What is diverticulitis?
Inflammation of the diverticula, which can lead to symptoms such as abdominal pain, fever, and changes in bowel habits.
What is diverticulitis?
A complication of diverticular disease (diverticulosis) characterized by inflammation of the diverticula. Largely asymptomatic, but may become symptomatic due to inflammation or complications.
What complications can arise from diverticulitis?
Abscess, bleeding, obstruction, and perforation.
What are common symptoms of diverticulitis?
Constipation and left lower quadrant pain.
What type of granulomas are associated with Crohn’s disease?
Noncaseating granulomas.
What is Crohn’s disease?
A form of inflammatory bowel disease (IBD) that can affect any part of the gastrointestinal tract.
What is the most common symptom of Crohn’s disease?
Recurrent diarrhea (which may or may not be bloody).
Can Crohn’s disease cause symptoms other than diarrhea?
Yes, it can also cause abdominal pain, weight loss, and fatigue, among others.
Perforation of the colon is characterized by acute abdominal pain and systemic inflammatory response. Abdominal examination shows
Rebound tenderness, guarding, and abdominal distention
What is the Pringle maneuver?
A surgical technique involving the placement of a vascular clamp across the hepatoduodenal ligament.
What does the Pringle maneuver accomplish?
It interrupts blood flow to the liver through the hepatic artery and portal vein.
If bleeding continues after the Pringle maneuver, what are the likely sources of blood loss?
The inferior vena cava or the hepatic vein.
When is the Pringle maneuver typically used?
During liver surgery or trauma to assess the source of bleeding
What condition is suggested by a baby’s anal dimple and inability to pass meconium in the first 24 hours?
Imperforate anus
What should children born with an imperforate anus be evaluated for?
Vertebral and renal abnormalities
What does the VACTERL association stand for?
Vertebral anomalies, Anal atresia, Cardiac defects, Tracheoesophageal fistula/Esophageal atresia, Renal and Radial anomalies, and Limb defects.
What are common cardiac abnormalities associated with the VACTERL association?
Ventricular septal defect, atrial septal defect, and tetralogy of Fallot.
What are other common findings in the VACTERL association besides anal atresia?
Tracheoesophageal fistulas and renal agenesis.
What is holoprosencephaly?
A failure of the brain to divide into two hemispheres.
In what genetic condition is holoprosencephaly most commonly seen?
Trisomy 13 (Patau’s syndrome), occurring in about 50% of cases
What sequence is typically associated with pulmonary hypoplasia?
Potter’s sequence.
What are the key features of Potter’s sequence?
Pulmonary hypoplasia, clubbed feet, and cranial abnormalities.
What are the key features of Potter’s sequence?
Pulmonary hypoplasia, clubbed feet, and cranial abnormalities.
What does the pectinate line mark?
The transition from the rectum to the anus.
What type of epithelium is found above the pectinate line?
Columnar epithelium, similar to that of the digestive tract.
Which arteries supply blood to the tissues above the pectinate line?
The superior and middle rectal arteries.
How are hemorrhoids occurring above the pectinate line classified?
Internal hemorrhoids.
Are internal hemorrhoids usually painful?
No, they are generally not painful but are prone to bleeding.
Where does lymph drainage above the pectinate line flow to?
The internal iliac lymph nodes.
Which lymph nodes receive drainage from below the pectinate line?
The superficial inguinal lymph nodes.
Why is the pectinate line clinically significant in terms of lymphatic drainage?
It marks the division between different lymphatic drainage pathways and associated lymph nodes.
What type of innervation do tissues below the pectinate line have?
Somatic innervation.
What type of innervation do tissues above the pectinate line have?
Visceral innervation.
Are lesions below the pectinate line typically painful?
Yes, pain is common in lesions below the pectinate line.
Are hemorrhoids arising below the pectinate line generally painful or prone to bleeding?
They are generally painful and less prone to bleeding.
What artery supplies blood to tissues below the pectinate line?
The inferior rectal artery.
What artery provides blood supply to tissues above the pectinate line?
The superior rectal artery.
What are hemorrhoids?
Vascular structures that drain blood into the venous system.
What can cause engorgement and bleeding of hemorrhoids?
Any cause of venous hypertension.
How does pregnancy contribute to the development of hemorrhoids?
The growing fetus compresses the inferior vena cava, raising venous pressure.
What type of hemorrhoids are commonly associated with painful rectal bleeding during pregnancy?
External hemorrhoids.
Why are hemorrhoids a common problem among pregnant women?
Due to increased venous pressure from compression of the inferior vena cava.
How can disorders of coagulation affect pregnancy?
They may increase the risk of bleeding during pregnancy and delivery.
Which disorders are examples of coagulation disorders?
Hemophilia and von Willebrand’s disease.
Do coagulation disorders typically present as isolated hemorrhoidal bleeding during pregnancy?
No, they do not commonly present as isolated hemorrhoidal bleeding.
What is a common complication of pregnancy related to hemorrhoids?
Painful rectal bleeding, especially from external hemorrhoids.
What are gallstones, and what symptoms do they typically cause?
Gallstones can produce right upper quadrant pain, especially after fatty meals.
What structures are found in the portal triad of the liver lobule?
Bile duct, portal vein, and hepatic artery.
How does the size of the bile ducts compare to the portal veins and hepatic arteries in the portal triad?
Bile ducts are smaller than portal veins and usually larger than hepatic arterial branches.
What is pancreas divisum?
A developmental anomaly characterized by two pancreatic ducts (a dorsal and a ventral duct) instead of a single duct.
From which embryonic structure does the pancreas develop?
The pancreas derives from the foregut.
Which other structures also develop from the foregut?
Esophagus, stomach, liver, gallbladder, and the upper portion of the duodenum.
What percentage of embryos develop pancreas divisum?
Approximately 10%.
What causes pancreas divisum?
Fusion failure of the dorsal and ventral pancreatic ducts.
Are most individuals with pancreas divisum symptomatic or asymptomatic?
Most individuals are asymptomatic, but some may develop pancreatitis.
The hindgut gives rise to the
Distal one-third of the transverse colon, the descending colon, and the rectum.
The intermediate mesoderm gives rise to the
Kidneys, lower urinary tract, and reproductive system.
The midgut gives rise to the
Distal duodenum, jejunum, ileum, ascending colon, and proximal two-thirds of the transverse colon.
Normally disappears before birth but may persist as an anomaly called Meckel’s diverticulum.
The yolk sac
What is annular pancreas?
A rare congenital anomaly where pancreatic tissue surrounds the duodenum, leading to potential obstruction.
What are common symptoms of annular pancreas in infants?
Nonbilious vomiting and poor weight gain.
What is the estimated prevalence of annular pancreas?
Approximately 5 to 15 per 100,000 births.
How does the pancreas normally develop?
From two outpouchings of the duodenum called the ventral and dorsal buds.
What does the dorsal bud of the pancreas become?
The tail and body of the pancreas.
What does the ventral bud of the pancreas become?
The head and uncinate process of the pancreas.
What typically happens during normal gut rotation regarding the pancreatic buds?
The ventral bud passes behind the duodenum to fuse with the dorsal bud.
What percentage of patients with annular pancreas are asymptomatic?
About two-thirds (or approximately 66%).
What complications can arise from annular pancreas?
Impaired flow through the duodenum due to constriction by pancreatic tissue.
How does the pancreatic duct connect to the digestive system?
The pancreatic duct joins the pancreas to the common bile duct.
What complication can arise from obstruction of the pancreatic duct in patients with annular pancreas?
Obstruction can lead to fibrosis and potentially result in pancreatitis.
Does the obstruction of the pancreatic duct describe the embryological cause of annular pancreas?
No, obstruction of the pancreatic duct is a complication, not the embryological cause of the condition.
What potential impact does fibrosis have in patients with annular pancreas?
Fibrosis can obstruct the pancreatic duct, leading to pancreatitis.
What is Zone 3 of the liver also known as?
The centrilobular zone.
What major function occurs in Zone 3 of the liver?
Drug metabolism, including the metabolism of cytochrome P-450 drugs.
Which drugs are metabolized in Zone 3 of the liver?
Phenytoin, macrolides, rifampin, warfarin, and others.
Why is the oxygen content lower in Zone 3 compared to Zones 1 and 2?
Because Zone 3 is farthest from the hepatic artery.
What is the significance of the lower oxygen content in Zone 3?
It affects the metabolic processes and susceptibility to injury in this area.
What are the five structures included in the portal triad?
The proper hepatic artery, the hepatic portal vein, the bile ductules, lymphatic vessels, and a branch of the vagus nerve.
What is the function of the proper hepatic artery within the portal triad?
It supplies oxygenated blood to the liver.
What role does the hepatic portal vein play in the portal triad?
It carries nutrient-rich blood from the gastrointestinal tract to the liver.
What is the function of the bile ductules in the portal triad?
They collect bile produced by the liver and transport it to larger bile ducts.
What is the role of the vagus nerve branch in the portal triad?
It provides autonomic innervation to the liver, influencing various functions.
What is a gastrinoma?
A gastrin-secreting tumor usually found in the pancreas or duodenum.
What does gastrin do?
It stimulates the release of gastric acid from parietal cells in the stomach.
What are common symptoms of gastrinoma?
Abdominal pain from peptic ulcers, diarrhea (either watery or fatty), and high-volume gastric secretions.
How does gastrin affect pancreatic enzymes?
Gastrin creates a low-pH environment that can inactivate pancreatic enzymes.
In which patients should gastrinoma be suspected?
In patients with multiple peptic ulcers, especially those refractory to standard therapy.
What is the first step in evaluating a suspected gastrinoma?
Measurement of serum gastrin levels.
What are the normal serum gastrin levels?
0 to 100 pg/mL.
What serum gastrin level indicates a gastrinoma?
Levels greater than 1,000 pg/mL.
What is the primary function of cholecystokinin (CCK)?
CCK stimulates contraction of the gallbladder and promotes the release of digestive enzymes from the pancreas.
Would elevated cholecystokinin explain symptoms of gastrinoma?
No, elevated CCK levels would not explain the clinical presentation of a gastrinoma.
What role does secretin play in digestion?
Secretin increases bicarbonate release from the pancreas, neutralizing gastric acid in the duodenum.
How is secretin used in the diagnosis of gastrinomas?
In gastrinomas, secretin injection causes a paradoxical increase in gastrin release, aiding in diagnosis.
What is the function of somatostatin in the gastrointestinal system?
Somatostatin inhibits the release of many gastrointestinal hormones and reduces gastric acid secretion.
What symptoms are associated with VIPomas?
VIPomas cause watery diarrhea, hypokalemia, and achlorhydria.
What is the effect of vasoactive intestinal peptide (VIP)?
VIP stimulates pancreatic bicarbonate and fluid secretion, among other functions.
What condition can lead to elevated levels of gastrin?
Gastrinomas, which are gastrin-secreting tumors.
What is a somatostatinoma?
A rare pancreatic tumor that secretes excess somatostatin, inhibiting the secretion of other gastrointestinal hormones.
Which cells produce somatostatin?
Delta cells (D cells) in the pancreas and intestines.
What are the effects of excess somatostatin in the body?
It inhibits the release of secretin, insulin, cholecystokinin, and gastrin, leading to achlorhydria, gallstones, steatorrhea, and hyperglycemia.
What is achlorhydria?
A condition characterized by a lack of hydrochloric acid in the gastric secretions, resulting in a high gastric pH.
What laboratory findings may be associated with cholestasis in somatostatinoma?
Elevated alkaline phosphatase and bilirubin levels.
What symptoms can arise from a somatostatinoma?
Symptoms include steatorrhea (greasy stools), hyperglycemia, abdominal pain, and weight loss.
How is somatostatinoma diagnosed?
Diagnosis is made by identifying elevated fasting plasma somatostatin levels.
What genetic condition is associated with somatostatinomas?
Multiple endocrine neoplasia type 1 (MEN 1), which is characterized by pituitary adenoma, parathyroid adenoma, and pancreatic tumors.
What are the “3 P’s” of MEN 1?
Pituitary adenoma, parathyroid adenoma, and pancreatic tumors.
Why can recognizing somatostatinoma be challenging?
Its key features, such as steatorrhea and hyperglycemia, overlap with conditions like chronic pancreatitis, requiring careful clinical evaluation.
What condition do gastrinomas cause?
Zollinger-Ellison syndrome, characterized by excessive gastrin production leading to peptic ulcers.
What are the typical symptoms of a gastrinoma?
Abdominal pain and watery diarrhea, often accompanied by multiple or refractory peptic ulcers.
Do gastrinomas cause hyperglycemia?
No, hyperglycemia does not occur with gastrinomas.
What is a glucagonoma?
A tumor of the pancreatic alpha cells that leads to hyperglycemia, necrolytic migratory erythema, and weight loss.
What symptoms are associated with glucagonomas?
Hyperglycemia/diabetes, necrolytic migratory erythema, and weight loss. Steatorrhea does not occur.
What do insulinomas produce?
Excess insulin, leading to hypoglycemia that is relieved by glucose administration.
What is a VIPoma?
A tumor that secretes vasoactive intestinal peptide (VIP), causing WDHA syndrome (watery diarrhea, hypokalemia, achlorhydria)
What are the symptoms of WDHA syndrome caused by VIPomas?
Watery diarrhea, hypokalemia, and achlorhydria; the diarrhea is not steatorrhea.
Does hyperglycemia occur with VIPomas?
No, hyperglycemia does not occur with VIPomas.
What is Zollinger-Ellison syndrome (ZES)?
A disorder characterized by gastrin-producing tumors that lead to increased gastric acid production, resulting in ulcers.
What causes the abdominal pain in ZES?
Abdominal pain is caused by peptic ulcers due to excessive gastric acid.
What types of diarrhea are associated with ZES?
Diarrhea may be watery (from high-volume gastric secretions) or fatty (from steatorrhea due to inactivated pancreatic enzymes).
Where are gastrin-secreting tumors typically located in ZES?
Tumors may be found in the duodenum or pancreas.
How is Zollinger-Ellison syndrome treated?
It is treated with proton pump inhibitors (PPIs) like omeprazole, which decrease gastric acid secretion.
What is the mechanism of action of proton pump inhibitors?
PPIs inhibit the H+/K+ ATPase on the luminal surface of parietal cells, reducing gastric acid secretion.
Acinar cells in the pancreas produce enzymes that enter the duodenum to assist in the digestion of food.
Ductal cells of the pancreas line the pancreatic ducts. They produce bicarbonate-rich pancreatic juice in response to secretin.
? of the duodenum and jejunum produce cholecystokinin. This hormone increases pancreatic secretions and causes gallbladder contraction.
I cells
Are found in the duodenum. They produce the hormone secretin, which increases pancreatic bicarbonate secretion and decreases gastric acid secretion.
S cells
What is pernicious anemia?
An autoimmune disorder caused by the destruction of gastric parietal cells, leading to vitamin B12 deficiency.
What do parietal cells produce that is essential for vitamin B12 absorption?
Intrinsic factor.
What are the typical laboratory findings in B12 deficiency due to pernicious anemia?
Macrocytic anemia (low hemoglobin and hematocrit, high MCV).
What are common symptoms of pernicious anemia?
Fatigue, neurologic dysfunction, and difficulty walking due to loss of proprioception.
How does pernicious anemia affect gastric acid production?
Parietal cell atrophy leads to decreased gastric acid production.
What happens to serum gastrin levels in pernicious anemia?
Serum gastrin levels rise (hypergastrinemia) due to decreased acid production.
What histological finding might be seen on gastric biopsy in pernicious anemia?
Hyperplasia of G cells
What is a VIPoma?
A rare tumor of the non-beta islet cells of the pancreas that produces vasoactive intestinal peptide (VIP).
What are the primary symptoms of VIPoma?
Profuse watery diarrhea (10 or more times per day) resembling cholera, non-anion gap acidosis, and hypokalemia.
How does VIP contribute to diarrhea in VIPoma patients?
VIP stimulates pancreatic bicarbonate secretion, leading to watery diarrhea
What electrolyte imbalances are commonly seen in VIPoma?
Hypokalemia due to loss of potassium in the stool and acidosis due to loss of bicarbonate.
What clinical signs might indicate volume depletion in a VIPoma patient?
Tachycardia and dry mucous membranes.
What type of acidosis is typically associated with VIPoma?
Non-anion gap metabolic acidosis.
Typically presents with weight loss, hyperglycemia, and necrolytic migratory erythema, a papular rash of the face, perineum, and extremities.
Glucagonoma
Common clinical features of an ? include hypoglycemia, leading to confusion, altered mental status, palpitations, sweating, and tremulousness. About one-fifth of patients will experience weight gain.
Insulinoma
What LFT patterns are typically seen in acute hepatitis C infection?
Elevated AST and ALT levels, with AST typically being less than or equal to ALT, and Alk Phos levels often normal.
What are the common liver function tests (LFTs) mentioned?
AST (aspartate aminotransferase), ALT (alanine aminotransferase), Alk Phos (alkaline phosphatase).
In chronic hepatitis C, what are the expected LFT findings?
Mild to moderate elevations in AST and ALT, with Alk Phos usually normal.
What is a common mode of transmission for hepatitis C virus (HCV)
Exposure often occurs through dirty needles among IV drug users and at tattoo parlors.
What percentage of initial hepatitis C infections progress to chronic liver disease?
Greater than 90%.
What are the potential outcomes of chronic hepatitis C infection?
Scarring of the liver (fibrosis) and cirrhosis.
In chronic HCV, how do the levels of AST and ALT compare to alkaline phosphatase?
AST and ALT are elevated relative to alkaline phosphatase.
In all forms of viral hepatitis, which enzyme is typically elevated more, AST or ALT?
ALT is usually elevated to a greater degree than AST.
How does the AST
ratio differ in alcoholic hepatitis compared to viral hepatitis?
In alcoholic hepatitis, AST is usually greater than ALT (AST ratio > 1.5), whereas in viral hepatitis, ALT is typically greater than AST.
What are the expected serum levels of AST and ALT in chronic hepatitis C?
Usually less than 500 U/L.
What are alkaline phosphatase levels typically like in chronic hepatitis C?
Alkaline phosphatase levels are often within normal limits.
What is intrahepatic cholestasis of pregnancy (ICP) also known as?
Pruritus gravidarum.
During which trimester does ICP typically occur?
In the second or third trimester of pregnancy.
What causes ICP?
High levels of estrogen and progesterone during pregnancy, which decrease bile flow in the liver.
What is the hallmark symptom of ICP?
Pruritus (itching) of the skin.
What leads to the pruritus experienced in ICP?
Elevated bile acids in the bloodstream.
Can jaundice occur in cases of ICP?
Yes, jaundice may rarely develop in cases of severe cholestasis.
Is ICP a permanent or reversible condition?
It is a reversible form of cholestasis.
What is the effect of ICP on bile flow?
It leads to a lack of bile flow (cholestasis) in the liver.
In a patient with itching in absence of a rash, think of ?. This is seen in pruritus gravidarum as well as other biliary disorders, such as primary biliary cholangitis.
Cholestasis
What does the absence of urine urobilinogen suggest?
It indicates that bile (including bilirubin) is not reaching the intestines due to hepatic or biliary obstruction.
Conjugated hyperbilirubinemia: How elevated are the liver enzymes (AST and ALT) in this case?
They are twice the upper limit of normal.
Conjugated hyperbilirubinemia: How does alkaline phosphatase compare to AST and ALT in this patient?
Alkaline phosphatase is elevated to a much greater degree than AST and ALT.
What is the term for the pattern of liver test abnormalities characterized by greater alkaline phosphatase elevation?
Cholestatic pattern.
In which conditions is the cholestatic pattern typically seen?
It is seen in cases of biliary obstruction.
What are the typical liver enzyme levels (AST, ALT, alkaline phosphatase) in a patient with cholestatic liver disease?
AST and ALT are moderately elevated, while alkaline phosphatase is significantly elevated.
What type of bilirubin is released in extravascular hemolysis?
Unconjugated bilirubin.
