GI

Question 1

What is considered the foregut, midgut and hindgut?

Answer 1

• the foregut is the pharynx to the duodenum, including the liver, gallbladder, pancreas, and spleen
• the midgut is the duodenum to the proximal ⅔ of the transverse colon
• the hindgut is the ⅔ of the transverse colon to the pectinate line

Question 2

Describe midgut development in utero.

Answer 2

• around week 6, the midgut herniates through the umbilical ring
• around week 10, it returns to the abdominal cavity while rotating around the SMA

Question 3

What is gastroschisis?

Answer 3

this is a ventral wall defect that arises from failure of the abdominal folds to properly close, leaving the abdominal contents exposed

Question 4

What is an omphalocele?

Answer 4

• this is a ventral wall defect that arises from persistent herniation of the abdominal contents into the umbilical cord
• the result is that the abdominal contents remain outside the body but are covered by the peritoneum and amnion of the umbilical cord

Question 5

How does a gastroschisis differ from an omphalocele?

Answer 5

gastroschisis leaves the abdominal contents in the abdomen and exposed while omphalocele leaves them herniated and covered by the peritoneum

Question 6

What is the most common tracheoesophageal anomaly?

Answer 6

esophageal atresia with distal tracheoesophageal fistula

Question 7

How does a pure esophageal atresia/stenosis differ from an EA with distal TEF?

Answer 7

• in those with a TEF, air is able to enter the stomach

- in those with no TEF and atresia alone, this doesn’t occur and there is a gasless abdomen

Question 8

Esophageal Atresia with Distal Tracheoesophageal Fistula

Answer 8

• the most common TE anomaly
• presents with polyhydramnios in utero
• neonates drool, choke, and vomit at the time of their first feeding
• the TEF allows air to enter the stomach and duodenum; this helps differentiate it from esophageal atresia alone
• cyanosis can occur secondary to laryngospasm, which occurs to avoid reflux-related aspiration

Question 9

Duodenal Atresia

Answer 9

• failure of the duodenum to canalize
• presents with polyhydramnios in utero plus bilious vomiting and abdominal distention within the first 1-2 days of life
• dilation of the stomach and proximal duodenum occurs and has a “double bubble” appearance on x-ray
• strongly associated with Down syndrome

Question 10

Jejunal/Ileal Atresia

Answer 10

• failure of parts of the jejunum or ileum to develop due to distruption of the SMA
• leads to ischemic necrosis and segmental resorption of the affected segment
• affected segment takes on a spiraled, “apple peel” appearance

Question 11

Hypertrophic Pyloric Stenosis

Answer 11

• congenital hypertrophy of pyloric smooth muscle
• the most common cause of gastric outlet obstruction in infants; more common in males
• presents with non-bilious, projective vomiting at 2-6 weeks old (begins developing at time of birth), which contributes to a hypokalemic, hypochloremic metabolic alkalosis
• can be palpated as an “olive” like mass in the epigastric region and you can visualize peristalsis
• more common in first born males and associated with exposure to macrolides
• treatment is surgical

Question 12

Describe development of the pancreas.

Answer 12

• it is derived from the foregut, which gives rise to two pancreatic buds
• the ventral bud contributes to the uncinate process and main pancreatic duct
• the dorsal bud becomes the body, tail, isthmus, and accessory pancreatic duct
• both buds contribute to the head

Question 13

What is the Ampulla of Vater?

Answer 13

• the dilated portion of the main pancreatic duct where the gall bladder drains into
• terminates in the sphincter of Odi within the duodenal wall

Question 14

Annular Pancreas

Answer 14

• a ventral pancreatic bud abnormality
• arises as the ventral bud encircles the 2nd part of the duodenum
• presents with non bilious vomiting and abdominal dissension, much like duodenal atresia

Question 15

Pancreas Divisum

Answer 15

• failure of the ventral and dorsal pancreatic buds to fuse
• relatively common and most often asymptomatic
• may cause chronic abdominal pain and/or pancreatitis

Question 16

Which abdominal structures are retroperitoneal?

Answer 16

SAD PUCKER

• suprarenal glands
• aorta and IVC
• duodenum (2nd-4th parts)
• pancreas (except tail)
• ureters
• colon (descending and ascending)
• kidneys
• esophagus (thoracic portion)
• rectum (in part)

Question 17

Where is the falciform ligament? What runs within it?

Answer 17

• it is the ligament that connects the liver to the anterior abdominal wall
• contains the ligament teres hepatic derived from the fetal umbilical vein

Question 18

What is contained within the hepatoduodenal ligament?

Answer 18

the portal triad (proper hepatic artery, portal vein, and common bile duct)

Question 19

What is the Pringle maneuver?

Answer 19

a maneuver that consists of compressing the hepatoduodenal ligament, and the portal triad within, by placing your thumb and index fingers within the omental foramen to control bleeding

Question 20

What runs in the gastrohepatic ligament?

Answer 20

gastric arteries

Question 21

Where is the gastrocolic ligament and what runs within it?

Answer 21

• it connects the greater curvature of the stomach with the transverse colon as part of the greater omentum
• it contains gastroepiploic arteries

Question 22

What two ligaments separate the greater and lesser peritoneal sacs?

Answer 22

• gastrohepatic

- gastrosplenic

Question 23

What runs within the gastrosplenic ligament?

Answer 23

• short gastric arteries

- left gastroepiploic vessels

Question 24

What does the splenorenal ligament contain?

Answer 24

• the splenic artery and vein

- the tail of the pancreas

Question 25

What are the layers of the gut tube?

Answer 25

- mucosa (epithelium, BM, lamina propria) - submucosa ( + Meissner plexus) - muscularis externa (inner circular, Auerbach plexus, outer longitudinal) - serosa/adventitia (intraperitoneal/retroperitoneal)

Question 26

What is the basal rate of slow waves in the stomach, duodenum, and ileum?

Answer 26

- stomach: 3 per minute - duodenum: 12 per minute - ileum: 8-9 per minute

Question 27

What epithelium lines the esophagus?

Answer 27

a non-keratinized stratified squamous epithelium

Question 28

What are Brunner glands?

Answer 28

glands found in the submucosa of the duodenum, which secrete bicarbonate and serve to protect the duodenum from gastric acid

Question 29

At what vertebral level do the celiac trunk, SMA, and IMA branch off of the abdominal aorta?

Answer 29

- celiac: T12 - SMA: L1 - IMA: L3

Question 30

Superior Mesenteric Artery SYndrome

Answer 30

- a syndrome of intermittent intestinal obstruction - associated with diminished mesenteric fat (e.g. low body weight or malnutrition) - the transverse duodenum is compressed between the SMA and aorta - primary symptom is post-prandial pain

Question 31

Where do the foregut, midgut, and hindgut receive their blood supply and parasympathetic innervation?

Answer 31

- foregut: celiac trunk, vagus nerve - midgut: SMA, vagus nerve - hindgut: IMA, pelvic nerve

Question 32

Describe the vasculature that arises from the celiac trunk.

Answer 32

- the trunk gives rise to the common hepatic, splenic, and left gastric arteries: - the common hepatic then gives rise to the proper hepatic (which ascends before giving off the right gastric) and the gastroduodenal artery, which divides into the right gastroepiploic artery and pancreaticoduodenal arteries - the left gastric gives off an ascending esophageal branch before running along the lesser curvature and forming a strong anastomosis with the right gastric - the splenic artery supplies the renal artery but also gives rise to the short gastric arteries that supply the fundus and the left gastroepiploic artery

Question 33

Between what vessels do varices form as a result of portal hypertension? What is the clinical manifestation of each?

Answer 33

- esophageal varices: left gastric anastomoses with the azygos - caput medusae: paraumbilical veins with the small epigastric veins of the anterior abdominal wall - anorectal varices: superior rectal with the middle and inferior rectal veins

Question 34

What is a transjugular intrahepatic portosystemic shunt?

Answer 34

a shunt placed between the portal vein and hepatic vein to relieve portal hypertension

Question 35

What is the pectinate line?

Answer 35

a line formed by the meeting of the endoderm and ectoderm in the anal canal

Question 36

How does the region of the anal canal above the pectinate line differ from that below it in blood supply, venous drainage, lymphatic drainage, possible pathologies, and innervation?

Answer 36

- above: risk of internal hemorrhoids (painless) and adenocarcinoma; supplied by the superior rectal artery from the IMA; and drained into the portal system via the superior rectal vein and IMV; drains to the internal iliac nodes - below: risk of external hemorrhoids (painful), anal fissures, and squamous cell carcinoma; supplied by the inferior rectal artery from the internal pudendal artery; and drained into the internal iliac and IVC directly via the inferior rectal and internal pudendal veins; drains to the superficial inguinal nodes

Question 37

Anal Fissure

Answer 37

- a tear in the anal mucosa below the pectinate line - most often posteriorly because that is the most poorly perfused area - associated with low-fiber diets and constipation - presents with pain while pooping and blood on toilet paper

Question 38

Where are Kupffer cells located? What is their role?

Answer 38

- they are specialized macrophages found in the liver | - they line the sinusoids

Question 39

Where are stellate cells found? What is their role?

Answer 39

- also known as ito cells, they are found in the space of disse, the perisinusoidal space of the liver - they store vitamin A when quiescent and are responsible for liver fibrosis when activated

Question 40

Describe the direction of blood and bile flow through the liver?

Answer 40

- blood flows from zone I to III from the portal vein/hepatic artery to the central vein - bile flows in the opposite direction

Question 41

What is unique about zone I of the liver?

Answer 41

- the area surrounding branches of the portal vein and hepatic artery - the first zone affected by viral hepatitis and ingested toxins

Question 42

What is unique about zone II of the liver?

Answer 42

it is the most affected by yellow fever

Question 43

What is unique about zone III of the liver?

Answer 43

- the area surrounding the central vein - the first affected by ischemia - contains the P450 system - most sensitive to metabolic toxins - the site of alcoholic hepatitis

Question 44

What structures are found within the femoral region and in what order are they situated?

Answer 44

- from lateral to medial (toward the navel) you will find the nerve, artery, vein, and then lymphatics (NAVeL)

Question 45

What structures form the femoral triangle?

Answer 45

- the inguinal ligament superiorly - the sartorius muscle laterally - the adductor longs muscle medially

Question 46

What structures are contained within the femoral sheath?

Answer 46

the vein, artery, and canal (containing the deep inguinal lymph nodes)

Question 47

What structures normally passes through the inguinal canal in males and females?

Answer 47

the spermatic cord in males and the round ligament of the uterus in females

Question 48

What are the two primary complications of hernias?

Answer 48

- incarceration (not reducible) | - strangulation (ischemia and necrosis)

Question 49

On which side are diaphragmatic hernias more common?

Answer 49

the left because the right is relatively protected by the liver

Question 50

What is the most common kind of diaphragmatic hernia?

Answer 50

a hiatal hernia in which the stomach herniates upward through the esophageal hiatus

Question 51

What is a sliding hiatal hernia?

Answer 51

- the most common diaphragmatic hernia | - it results when the gastroesophageal junction is displaced upward, forming a "hourglass stomach"

Question 52

What is a paraesophageal hernia?

Answer 52

a type of herniation of the stomach through the esophageal hiatus in which the gastroesophageal junction is in it's normal location but the fundus of the stomach protrudes into the thorax next to the esophagus

Question 53

Indirect Inguinal Hernia

Answer 53

- a hernia that begins with tissue entering the internal inguinal ring lateral to the inferior epigastric vessels - goes through the internal inguinal ring, through the external inguinal ring, and into the scrotum - follows the path of descent of the testes and is covered by all three layers of the spermatic fascia (internal, cremasteric, external) - occurs in infants due to failure of the processes vaginalis to close, particularly in males

Question 54

Direct Inguinal Hernia

Answer 54

- a hernia that bulges directly through the abdominal wall, through the inguinal triangle (medial to the inferior epigastric vessels, lateral to the rectus abdominis, superior to the inguinal ligament) - it passes through the external inguinal ring only and protrudes through the inguinal triangle - it is covered only by the external spermatic fascia - it is more prevalent in older men

Question 55

What kind of abdominal hernia is most common in infants, older men, and older women?

Answer 55

- infants: indirect inguinal hernia - men: direct inguinal hernia - women: femoral hernia

Question 56

Where are indirect inguinal, direct inguinal, and femoral hernias located?

Answer 56

- indirect: above the inguinal ligament, lateral to the inferior epigastric vessels - direct: above the inguinal ligament in the inguinal triangle medial to the inferior epigastric vessels - femoral: below the inguinal line, lateral to the pubic tubercle

Question 57

Describe the source, action, and regulation of gastrin.

Answer 57

- secreted by G cells in the antrum of the stomach and duodenum - in response to stomach distention or alkalization, amino acids, vagal stimulation via gastrin-releasing peptide - promotes gastric acid secretion, growth of gastric mucosa, and gastric motility

Question 58

Gastrin levels will rise if what medication is used chronically?

Answer 58

PPI

Question 59

How do gastrin levels change in chronic atrophic gastritis?

Answer 59

they increase

Question 60

Describe the source, action, and regulation of somatostatin.

Answer 60

- secreted by D cells in the pancreatic islets and GI mucosa - in response to an increase in acid or decrease in vagal stimulation - serves to decrease gastric acid and pepsinogen secretion, pancreatic and small intestine fluid secretion, gall bladder contraction, and insulin and glucagon release

Question 61

What is octreotide? What are it's primary uses and adverse effects?

Answer 61

- a somatostatin analog used to treat acromegaly, carcinoid syndrome, and variceal bleeding - may cause nausea, cramps, steatorrhea, or cholelithiasis

Question 62

Describe the source, action, and regulation of CCK.

Answer 62

- secreted by I cells in the duodenum and jejunum - in response to an increase in fatty acids or amino acids - increases pancreatic secretion and gallbladder contraction, slows gastric emptying, and relaxes the sphincter of Odi

Question 63

Describe the source, action, and regulation of secretin.

Answer 63

- secreted by S cells in the duodenum - in response to an increase in acid or fatty acids in the lumen of the duodenum - increases bicarb secretion from the pancreas, lowers gastric acid secretion, and increases bile secretion

Question 64

Give two reasons bicarb secreted by the pancreas is important.

Answer 64

- it helps neutralize gastric acids, protecting the small intestine - it neutralizes the gastric acid, which is necessary for pancreatic enzymes to function

Question 65

Describe the source, action, and regulation of glucose-dependent insulinotropic peptide.

Answer 65

- also known as GIP, it is secreted by K cells in the duodenum and jejunum - in response to fatty acids, amino acids, or oral glucose - stimulates insulin release and reduces gastric acid secretion

Question 66

Why does oral glucose lead to a greater release of insulin than a the equivalent dose of glucose IV?

Answer 66

because oral glucose triggers release of GIP (glucose-dependent insulinotropic peptide/gastric inhibitory peptide), which stimulates additional insulin release

Question 67

Describe the source, action, and regulation of motilin.

Answer 67

- secreted within the small intestine - in response to a fasting state - produces migratory motor complexes

Question 68

What is the clinical use of motilin agonists?

Answer 68

they are used to stimulate intestinal peristalsis

Question 69

Describe the source, action, and regulation of vasoactive intestinal polypeptide.

Answer 69

- secreted by parasympathetic ganglia in sphincters, gallbladder, and small intestine - in response to distention, vagal stimulation, and reduced adrenergic input - serves to increase intestinal water and electrolyte secretion (i.e. VIPomas cause a watery diarrhea) as well as relaxation of intestinal smooth muscle and sphincters

Question 70

What are the symptoms of a VIPoma?

Answer 70

symptoms are derived from it's action of increasing water and electrolyte secretion in the small intestine and relaxing sphincters - watery diarrhea - hypokalemia - achlorhydia

Question 71

Describe the source, action, and regulation of gherlin.

Answer 71

- secreted by cells in the stomach - in response to fasting - stimulates appetite

Question 72

What molecule is responsible for mediating smooth muscle relaxation within the GI tract and of the LES?

Answer 72

nitric oxide

Question 73

Describe the source, action, and regulation of intrinsic factor.

Answer 73

- produced by parietal cells in the stomach | - binds VitB12 and required for VitB12 absorption in the terminal ileum

Question 74

Describe the source and regulation of gastric acid secretion.

Answer 74

- secreted by parietal cells in the stomach - promoted by histamine, ACh, and gastrin - inhibited by somatostatin, GIP, prostaglandin, and secretin

Question 75

Describe the source, action, and regulation of pepsin.

Answer 75

- secreted by chief cells in the stomach as pepsinogen, which is activated by gastric acid - in response to vagal stimulation and local acid - aids in protein digestion

Question 76

Describe the source, action, and regulation of bicarb secretion within the GI tract.

Answer 76

- secreted by mucosal cells in the stomach, duodenum, salivary glands, and pancreas as well as from Brunner glands in the duodenum - largely basal secretion, but increased release from pancreas and gall bladder in response to secretin - to neutralize acid

Question 77

How does gastrin induce gastric acid release?

Answer 77

it has some direct effect on parietal cells in the stomach, but primarily it acts on enterochromaffin-like cells, which then secrete histamine onto parietal cells

Question 78

What three vitamin/mineral deficiencies are of concern in those with small bowel disease or who have had a resection?

Answer 78

- iron - folate - B12

Question 79

Where and in what form is iron absorbed in the GI tract?

Answer 79

absorbed as Fe 2+ from the duodenum

Question 80

Where is folate absorbed along the GI tract?

Answer 80

the small intestine

Question 81

Where is B12 absorbed along the GI tract?

Answer 81

the terminal ileum

Question 82

Where in the GI tract are bile salts re-absorbed?

Answer 82

the terminal ileum

Question 83

What is intrinsic factor necessary for?

Answer 83

the absorption of vitamin B12 in the terminal ileum

Question 84

List the three groups of pancreatic enzymes that are secreted.

Answer 84

- a-amylase - lipases - proteases

Question 85

How does an increase or decrease in the flow of pancreatic secretions change the content of the solutions?

Answer 85

- low flow secretions have a high chloride ion content | - high flow secretions have a high bicarb content

Question 86

What is unique about alpha-amylase secreted by the pancreas?

Answer 86

it is the only enzymes that is secreted active form

Question 87

Describe pancreatic enzyme activation.

Answer 87

- alpha-amylase is secreted in the active form - enterokinase/enteropeptidases in the brush-border of the duodenum and jejunum activate trypsin, which then activates the rest of the pancreatic proenzymes

Question 88

What is the first pancreatic protease activated? How is it activated?

Answer 88

trypsin is the first activated and it is activated by enterokinases and enteropeptidases in the brush-bord of teh duodenum and jejunum

Question 89

Enterocytes are capable of absorbing what carbohydrates?

Answer 89

only monosaccharides (e.g. glucose, galactose, and fructose)

Question 90

Describe how glucose gets from the lumen of the small intestine into the blood.

Answer 90

- via the Na-dependent SGLT1 from the lumen into enterocytes | - then into the blood by GLUT-2

Question 91

Describe how galactose gets from the lumen of the small intestine into the blood.

Answer 91

- via the same Na-dependent SGLT1 as glucose into enterocytes - then into the blood by GLUT-2

Question 92

Describe how fructose gets from the lumen of the small intestine into the blood.

Answer 92

- into enterocytes via facilitated diffuse mediated by GLUT-5 - then into the blood by GLUT-2

Question 93

What is the D-xylose absorption test?

Answer 93

- a test used to distinguish GI mucosal damage from other causes of malabsorption - it is a monosaccharide and passively absorbed thus only requires an intact mucosa for absorption - in those with a mucosal defect or bacterial overgrowth blood and urine levels remain low; but in those with pancreatic insufficency, blood and urine levels rise normally

Question 94

Describe the location, structure, and primary cell types of Peyer's patches.

Answer 94

- they are unencapsulated lymphoid tissue aggregates found in the lamina porpria and submucosa of the ileum - M cells sample the lumen and present antigens to B cells, which differentiate into IgA-secreting plasma cells

Question 95

What is bile composed of?

Answer 95

- bile salts (acids conjugated to glycine or taurine) - phospholipids - cholesterol - bilirubin - water and ions

Question 96

What enzyme catalyzes the rate-limiting step of bile acid synthesis?

Answer 96

cholesterol 7a-hydroxylase

Question 97

List three functions of bile.

Answer 97

- promote digestion and absorption of lipids and fat-soluble vitamins - cholesterol excretion - antimicrobial activity via membrane disruption

Question 98

What is the body's only means of eliminating cholesterol?

Answer 98

bile formation

Question 99

Describe bilirubin metabolism.

Answer 99

- protoporphyrin is reduced to unconjugated bilirubin - water-insoluble UCB is transported to the liver via albumin where it is conjugated with glucuronate by uridine glucuronyl transferase (UGT) in hepatocytes - CB is water soluble and excreted in bile - in the bile gut bacteria metabolize CB to urobilinogen - most urobilinogen is oxidized and excreted in the feces as stercobilin, giving stool it's brown color - some urobilinogen enters enterohepatic circulation and is reabsorbed - the rest is excreted in urine as urobilin, giving it a yellow color

Question 100

Cleft lips and palates result from failure of what process?

Answer 100

failure of the facial prominences to grow and fuse together

Question 101

How many facial prominences are there?

Answer 101

five: 1 superior, 2 lateral, 2 inferior

Question 102

Aphthous Ulcer

Answer 102

- a painful, superficial ulceration of the oral mucosa - typically arises during periods of stress and will resolve spontaneously - characterized by a grayish base (granulation tissue) surrounded by erythema

Question 103

Behcet Syndrome

Answer 103

an immune complex-mediated small-vessel vasculitis that leads to a syndrome of recurrent aphthous ulcers, genital ulcers, and uveitis

Question 104

Oral Herpes

Answer 104

- vesicles involving the oral mucosa that rupture, resulting in shallow, painful, red ulcers - most cases are due to HSV-1 infection - primary infection occurs in childhood but virus remains dormant in the ganglia of the trigeminal nerve - often reactivated by stress or sunlight

Question 105

Squamous Cell Carcinoma of the Mouth

Answer 105

- a malignant neoplasms of squamous cells lining the oral mucosa - most often arisen in the floor of the mouth - risk factors include tobacco and alcohol - oral leukoplakia and erythroplakia (vascularized leukoplakia) can be precursor lesions, but erythroplakia is more suggestive of dysplasia than leukoplakia

Question 106

What is luekoplakia? What can it be confused with?

Answer 106

- it is an oral lesion described as a white plaque that cannot be scraped away - often represents squamous cell dysplasia and in those cases it is a precursor lesion to squamous cell carcinoma of the oral mucosa - may be confused with oral candidiasis or hairy leukoplakia; however, oral candidiasis is usually easily scraped away and hairy leukoplakia (a form of hyperplasia induced by EBV) arises mostly on the lateral tongue with a shaggy appearance

Question 107

Hairy Leukoplakia

Answer 107

- hyperplasia of the oral mucosa caused by EBV in immunocompromised patients - takes the form of a white, shaggy lesion on the lateral tongue - not to be confused with leukoplakia or oral candidiasis

Question 108

Oral Candidiasis v. Leukoplakia v. Hairy Leukoplakia

Answer 108

- oral candidiasis is a fungal infection of the mouth seen in those who are immunocompromised, and it takes the from of easily scraped away white lesions - leukoplakia is a white lesion that cannot be scraped away, and it often represents dysplasia in which case it is a precursor lesion to squamous cell carcinoma of the oral mucosa - hairy leukoplakia is an EBV-induced hyperplasia that takes the form of a shaggy white lesion on the lateral tongue in immunocompromised individuals

Question 109

Which is more suggestive of squamous cell carcinoma of the oral mucosa, leukoplakia or erythroplakia?

Answer 109

erythroplakia is vascularized leukoplakia and thus more likely to be malignant

Question 110

What are the three major salivary glands?

Answer 110

- parotid - submandibular - sublingual

Question 111

Mumps

Answer 111

- an infection with mumps virus - results in bilateral inflammation of the parotid salivary glands - complications include orchitis, pancreatitis, and aseptic meningitis - orchitis carries a risk of sterility but is only likely in those over the age of 10 who contract mumps - serum amylase is increased due to salivary or pancreatic involvement

Question 112

Sialadenitis

Answer 112

- inflammation of the salivary gland | - most commonly caused by an obstructing stone, leading to a unilateral S. aureus infection

Question 113

What is the most common tumor and the most common malignancy of the salivary gland?

Answer 113

- tumor: pleomorphic adenoma | - malignancy: mucoepidermoid carcinoma

Question 114

Pleomorphic Adenoma

Answer 114

- the most common benign tumor of the salivary gland - it is composed of stromal tissue and epithelial tissue (i.e. pleomorphic) - it most often affects the parotid and presents as a mobile, painless, circumscribed mass at the angle of the jaw - has a high rate of recurrence due to it's irregular borders and often incomplete resection - rarely, may transform into carcinoma, which often presents with signs of facial nerve damage after many recurrences of the benign tumor

Question 115

A patient presents with recurrent pleomorphic adenoma that has begun to cause facial nerve problems. What has likely occurred?

Answer 115

- recurrent pleomorphic adenoma has become malignant | - as such it has become invasive and has affected the facial nerve running through the parotid

Question 116

What nerve runs through the parotid gland?

Answer 116

the facial nerve

Question 117

Warthin Tumor

Answer 117

- a benign cystic tumor of the salivary gland - with abundant lymphocytes and germinal centers (i.e. cystic tumor with lymph node tissue) - almost always affects the parotid

Question 118

Which salivary gland is most affected by pathology?

Answer 118

the parotid

Question 119

Mucoepidermoid Carcinoma

Answer 119

- the most common malignancy of the salivary gland - composed of mutinous and squamous cells - usually affects the parotid and commonly involves the facial nerve

Question 120

Esophageal Web

Answer 120

- a thin protrusion of the esophageal mucosa into the lumen, most often seen in the upper esophagus - presents with dysphagia for poorly chewed food - increases the risk for esophageal squamous cell carcinoma - a feature of Plummer-Vinson syndrome (iron deficiency anemia, esophageal web, and beefy-red tongue due to atrophic glossitis)

Question 121

What are the features of Plummer-Vinson syndrome?

Answer 121

- iron deficiency anemia - esophageal web - beefy-red tongue due to atrophic glossitis

Question 122

Mallory-Weiss Syndrome

Answer 122

- a longitudinal laceration of the mucosa at the gastroesophageal junction caused by severe vomiting - most often seen in alcoholics and bulimics - presents with painful hematemsis - risk of Boerhaave syndrome with rupture of esophagus leading to air in the mediastinum and subcutaneous emphysema

Question 123

Wha tis Boerhaave syndrome?

Answer 123

rupture of the esophagus, which leads to air in the mediastinum and in subcutaneous tissue, which can be heard as crackling when pressing down on the skin

Question 124

Esophageal Varices

Answer 124

- dilated submucosal veins in the lower esophagus - arises secondary to portal hypertension because blood can no longer flow into the left gastric vein and then the portal vein - typically asymptomatic but may present with a painless hematemesis - risk of rupture, which is the most common cause of death in those with cirrhosis

Question 125

Where along the length of the esophagus are varices most likely?

Answer 125

in the lower third

Question 126

What is the most common cause of death in those with cirrhosis?

Answer 126

rupture of esophageal varices

Question 127

Achalasia

Answer 127

- disordered esophageal motility with an inability to relax the LES - caused by damage to ganglion cells in the myenteric plexus, which are important for motility - presents with dysphagia for both solids and liquids, putrid breath, high LES pressure, and "bird beak" sign due to dilation of the esophagus - have an increased risk for esophageal squamous cell carcinoma

Question 128

GERD

Answer 128

- reflux of acid from the stomach due to reduced LES tone - risk factors include alcohol, tobacco, obesity, fat-rich diet, caffeine, and hiatal hernia - presents with heartburn, adult-onset asthma and cough, damage to enamel of teeth, and ulceration with stricture (ulcer heals by fibrosis, which constricts) - risk of Barrett esophagus as a late complication

Question 129

Barrett Esophagus

Answer 129

- a metaplasia of the lower esophageal mucosa from stratified squamous to conciliated columnar with goblet cells - may progress to dysplasia and adenocarcinoma

Question 130

Esophageal Carcinoma

Answer 130

- either adenocarcinoma (more common in the West) or squamous cell carcinoma (more common worldwide) - adenocarcinoma refers to a proliferation of glands, and arises from pre-existing Barrett esophagus in the lower third of the esophagus - squamous cell carcinoma arises in the upper and middle thirds of the esophagus in response to irritation; risk factors include alcohol, tobacco, very hot tea, achalasia, esophageal web, and esophageal injury - both present late and thus have a poor prognosis - symptoms include progressive dysphagia (solids then liquids), weight loss, pain, and hematemesis - squamous cell often presents with hoarse voice and cough as well due to involvement of the recurrent laryngeal nerve and trachea, respectively - spreads to the cervical, mediastinal and tracheobronchial, or celiac and gastric lymph nodes depending on if it is in the upper, middle, or lower portion of the esophagus

Question 131

Where does esophageal carcinoma spread?

Answer 131

- upper ⅓: cervical nodes - middle ⅓: mediastinal or tracheobronchial nodes - lower ⅓: celiac or gastric nodes

Question 132

Acute Gastritis

Answer 132

- acidic damage to the stomach mucosa due to an imbalance between acidity and mucosal defenses - risk factors include: severe burn (hypovolemia leads to decreased blood supply), NSAIDs (reduced prostaglandin production), heavy alcohol consumption, chemotherapy, increased intracranial pressure (stimulates vagus leading to acid production), and shock (reduced blood flow) - the result is superficial inflammation, erosion, or ulcer

Question 133

What defenses protect the gastric mucosa from gastric acid?

Answer 133

- a mucin layer produced by foveolar cells - bicarbonate secreted by surface epithelium - normal blood supply, which provides necessary nutrients and carries away any acid that does happen to get through the other defenses - prostaglandins, which inhibit acid production and stimulate mucin/bicarbonate secretion plus blood flow

Question 134

What is a Curling ulcer?

Answer 134

a stomach ulcer that results after a severe burn, because burn injuries lead to hypovolemia and adequate blood supply is an important defense for the gastric mucosa against gastric acid

Question 135

What is a Cushing ulcer?

Answer 135

a stomach ulcer that results from increased ICP, which stimulates the vagus nerve and promotes increased gastric acid production

Question 136

Why are NSAIDs likely to cause ulcers?

Answer 136

because they reduce prostaglandin formation and PGs are needed to maintain blood flow to the gastric mucosa in addition to promoting bicarbonate and mucin secretion

Question 137

What is the difference between a gastric erosion and gastric ulcer?

Answer 137

an erosion is a loss of superficial epithelium while an ulcer is a loss of the mucosal layer

Question 138

Chronic Gastritis

Answer 138

- chronic inflammation of the stomach mucas - classified as either chronic autoimmune gastritis or chronic H. pylori gastritis (more common) - chronic autoimmune gastritis targets gastric parietal cells located in the body and fundus while H. pylori preferentially affects the antrum

Question 139

Chronic Autoimmune Gastritis

Answer 139

- a form of chronic gastritis due to autoimmune destruction of gastric parietal cells in the stomach body and fundus - antibodies against parietal cells and/or intrinsic factor are diagnostic but pathogenesis is mediated by T cells - presents with atrophy of the mucosa with intestinal metaplasia (lots of goblet cells), achlorhydria with increased gastrin levels and antral G-cell hyperplasia, and pernicious anemia - increased risk for intestinal type gastric adenocarcinoma

Question 140

Chronic H. pylori Gastritis

Answer 140

- a form of chronic gastritis due to H. pylori induced inflammation - more common than chronic autoimmune gastritis - H. pylori ureases and proteases weaken mucosal defenses, particularly in the antrum, and contribute to mucosal inflammation - presents with epigastric abdominal pain - increases risk for ulceration, intestinal type gastric adenocarcinoma, and MALT lymphoma - treat with triply therapy (PPI, amoxicillin/metronidazole, and clarithromycin) - confirm eradiaction with negative urea breath test and lack of stool antigen - treatment resolves ulcers and reverses intestinal metaplasia

Question 141

Duodenal Ulcer

Answer 141

- a solitary mucosal ulcer - more common than a gastric ulcer - most cases are due to H. pylori but a few are due to a gastrinoma (ZE syndrome) - presents with epigastric pain that improves with meals since the duodenum preps for the meal by increasing protective measures - diagnose using endoscopic biopsy, which shows hypertrophy of Brunner glands - anterior wall is more commonly affected but in the posterior duodenal, rupture is more likely - rupture leads to hemorrhage of the gastroduodenal artery or acute pancreatitis and you may see free air under the diaphragm with referred pain to the shoulder via the phrenic nerve - almost never malignant (in contrast to gastric ulcers)

Question 142

Rupture of a duodenal ulcer is most likely when it is located where? What are the likely complications?

Answer 142

- rupture most likely in the posterior wall of the proximal duodenum - complications include hemorrhage of the gastroduodenal artery or acute pancreatitis

Question 143

Gastric Ulcer

Answer 143

- a solitary mucosal ulcer, most often in the lesser curvature of the antrum - less common than a duodenal ulcer - usually due to H. pylori but may also be caused by use of NSAIDs or bile reflux - presents with epigastric pain that worsens with meals because acid production increases - rupture carries a risk of bleeding from the left gastric artery - can be caused by intestinal type gastric carcinoma, in which was they tend to be larger and irregular with heaped up margins

Question 144

How does a duodenal ulcer compare to a gastric ulcer?

Answer 144

- duodenal are more common - duodenal are more often caused by H. pylori - both present with epigastric pain but that associated with duodenal ulcers gets better with meals and that associated with gastric ulcers get worse with meals - rupture of a duodenal ulcer is likely to cause bleeding of the gastroduodenal artery while rupture of a gastric ulcer is likely to cause bleeding of the left gastric artery - duodenal ulcers are almost never malignant but gastric ulcers can be caused by intestinal type gastric carcinoma

Question 145

How can a malignant gastric ulcer be differentiated from a benign one during endoscopy?

Answer 145

- benign ones tend to be smaller (< 3 cm) and sharply demarcated - malignant ones tend to be larger, irregular, and surrounded by heaped up margins

Question 146

What are the two types of gastric carcinoma?

Answer 146

intestinal and diffuse

Question 147

Intestinal Type Gastric Carcinoma

Answer 147

- an adenocarcinoma - presents as a large, irregular ulcer with heaped up margins, most often in the lesser curvature of the antrum - risk factors include intestinal metaplasia (with goblet cells) due to chronic gastritis, nitrosamines in smoked foods, and type A blood group - symptoms arise late with weight loss, abdominal pain, anemia, and early satiety - may present with acanthosis nigricans or Leser-Trelat sign - spread is to the left supraclavicular node known as Virchow's node - most likely to metastasize to the liver but may metastasize to the periumbilical region, known as a Sister Mary Joseph nodule

Question 148

Diffuse Type Gastric Carcinoma

Answer 148

- an adenocarcinoma - characterized by signet ring cells that diffusely infiltrate the gastric wall along with desmoplasia that results in thickening of the stomach wall known as linitis plastica - not associated with H. pylori, intestinal metaplasia, or nitrosamines - symptoms arise late and include weight loss, abdominal pain, anemia, and early satiety - may present with acanthosis nigricans or Leser-Trelat sign - spread is to the left supraclavicular node known as Virchow's node - most likely to metastasize to the liver but may metastasize to the ovaries bilaterally, which is known as a Krukenburg tumor

Question 149

What are signet cells indicative of?

Answer 149

diffuse gastric carcinoma, which may have spread to the liver or bilaterally to the ovaries where it is known as a Krukenburg tumor

Question 150

What is Virchow's node?

Answer 150

the left supraclavicular node where gastric carcinoma is most likely to spread to

Question 151

What is Leser-Trelat sign?

Answer 151

the outbreak of many seborrheic keratoses on the skin, often indicating internal malignancy

Question 152

Meckel Diverticulum

Answer 152

- the most common congenital anomaly of the GI tract - a true diverticulum (outpouching of all three layers of the bowel wall) - arising from failure fate vitelline duct to fully involute - follows the "rule of 2s": seen in 2% of the population, 2 inches long, located in the small bowel with 2 feet of the ileocecal valve, presenting in the fist 2 years of life with bleeding, volvulus, intussusception, or obstruction (mimics appendicitis), 2 times as likely in males, possibility for 2 types of epithelia (gastric/pancreatic) - bleeding is due to heterotopic gastric mucosa - however, most often asymptomatic - diagnosed via a pertechnetate study for uptake by ectopic gastric mucosa

Question 153

If an adult presents with new-onset asthma, what should you consider as a possible cause?

Answer 153

GERD

Question 154

If the vitelline duct fails to involute at all, what is the most obvious sign after birth?

Answer 154

passing of meconium by the umbilicus

Question 155

Volvulus

Answer 155

- a twisting of the bowel along it's mesentery - resulting in obstruction of the bowel and disruption of the blood supply with infarction - most common in the sigmoid colon of the elderly or the cecum if the patient is a younger adult since these are areas with superfluous mesentery - presents with abdominal pain and red "currant jelly" stool

Question 156

Intussusception

Answer 156

- a telescoping of the proximal segment of bowel forward into the distal segment caused by peristalsis pulling a "leading edge" forward - leading edge refers to the focus of traction and in children this is most often lymphoid hyperplasia arising in the terminal ileum with intussusception into the cecum or a Meckel diverticulum - in adults, the leading edge is more commonly formed by a tumor - the deformation results in obstruction and disruption of the blood supply with infarction - can be seen as a "bull's eye appearance on ultrasound - presents with abdominal pain and "currant jelly" stools

Question 157

Why is the small bowel so susceptible to infarction?

Answer 157

because it requires lots of ATP, and therefore oxygen, for absorption of nutrients

Question 158

Small Bowel Infarction

Answer 158

- common because of the high energy needs of the small bowel - simple hypotension is likely to cause a mucosal infarction while transmural infarction occurs with thrombosis of the SMA or mesenteric vein - presents with abdominal pain, bloody diarrhea, and decreased bowel sounds

Question 159

Where is lactase?

Answer 159

it is found in the brush border of enterocytes

Question 160

Lactase catalyzes what reaction?

Answer 160

lactose to glucose and galactose

Question 161

What can cause lactose intolerance?

Answer 161

- may be congenital due to an AR disorder - acquired, developing in late childhood - or transient after a small bowel infection since lactase is highly susceptible to injury

Question 162

Celiac Disease

Answer 162

- an immune mediated damage of the small bowel villi due to gluten exposure, and in particular the component gliadin - strongly associated with HLA-DQ2 and HLA-DQ8 - damage is mediated by CD4 cells - presents in children with abdominal distention, diarrhea, and failure to thrive or in adults with chronic diarrhea and bloating - small, herpes-like vesicles may arise on the skin, known as dermatitis herpetiformis, due to IgA deposition at the tips of dermal papillae - associated with IgA deficiency but labs find IgA or IgG against endomysium, tTG, or gliadin - biopsy reveals flattened villi, hyperplasia of crypts, and increased intraepithelial lymphocytes in the duodenum - small bowel carcinoma and T-cell lymphoma are late complications that often presents as refractory disease despite good dietary control

Question 163

Describe gluten metabolism as it relates to Celiac disease.

Answer 163

- gluten is absorbed - gliadin is deaminated by tissue transflutaminase (tTG) - this is presented via MHC-II and activates helper T cells

Question 164

Patients with Celiac disease who appear to have excellent dietary control but continue to experience symptoms likely have what occurring?

Answer 164

they likely have either a small bowel carcinoma or T-cell lymphoma

Question 165

Tropical Sprue

Answer 165

- damage to small bowel villi due to an unknown organism found in tropical regions, causing malabsorption - arises after infectious diarrhea and responds to antibiotics - damage is most prominent in the jejunum and ileum

Question 166

Describe dietary fat digestion and absorption.

Answer 166

- broken down by pancreatic lipases - bile helps emulsify the metabolites into small droplets, called micelles - micelles diffuse into enterocytes and are repackaged into chylomicrons - chylomicrons are too big to enter the blood stream directly, so they are exported into the lamina propria - there they are absorbed into lymphatic spaces called lacteals, which transport them eventually into the blood

Question 167

Whipple Disease

Answer 167

- systemic tissue damaged characterized by macrophages loaded with partially destroyed Tropheryma whippelii in lysosomes - most often affects the small bowel propria in which case macrophages compress lacteals, preventing the absorption of chylomicrons and contributing to fat malabsorption and steatorrhea - may also affect the synovium of joints, cardiac valves, lymph nodes, or CNS - organism is intracellular gram positive and stains PAS positive in foamy macrophages

Question 168

Abetalipoproteinemia

Answer 168

- an autosomal recessive deficiency of B-48 or B-100 - B-48 deficiency causes malabsorption as it is required for chylomicron formation - B-100 causes an absence of plasma VLDL and LDL as it is required for their formation

Question 169

Carcinoid Tumor

Answer 169

- a malignant proliferation of neuroendocrine cells, which often secrete serotonin - can arise anywhere along the gut but the small bowel is most common where they grow as submucosal polyp-like nodules - secreted serotonin is metabolized by liver MAO into 5-HIAA, so they are asymptomatic until they metastasize to the liver - once metastasized they produce carcinoid syndrome and carcinoid heart disease - contain neurosecretory granules and are thus chromogranin positive; 5-HIAA levels are elevated in urine

Question 170

What are the features of carcinoid syndrome?

Answer 170

- bronchospasm, diarrhea, and flushing of the skin | - often precipitated by alcohol or emotional stress, which stimulate serotonin release from the tumor

Question 171

What are the features of carcinoid heart disease?

Answer 171

- right-sided valvular fibrosis leading to tricupsid regurgitation and pulmonary valve stenosis - left-sided valvular lesions not seen due to MOA in the lung, which metabolizes the serotonin that causes carcinoid heart disease

Question 172

Acute Appendicitis

Answer 172

- the most common cause of acute abdomen - caused by obstruction of the appendix, most commonly by lymphoid hyperplasia in children or a fecalith in adults - presents with periumbilical pain that migrates and eventually localizes to the right lower quadrant over McBurney's point - rupture will result in peritonitis with guarding and rebound tenderness - may be complicated by a periappendiceal abscess

Question 173

Inflammatory Bowel Disease

Answer 173

- a chronic, relapsing inflammation of the bowel - thought to be mediated by an abnormal immune response to enteric flora - most common in young women - subclassified as either ulcerative colitis or Crohn disease

Question 174

Ulcerative Colitis

Answer 174

- a form of inflammatory bowel disease mediated by Th2 cells - affects the mucosal and submucosa only, forming ulcers - begins in the rectum and extends proximally in a continuous manner, limited to the colon - presents with left lower quadrant pain and blood diarrhea - grossly, there are pseudopolyps and a loss of haustra, known as the "lead pipe" sign - histology reveals crypt abscesses with neutrophils - complications include toxic megacolon and carcinoma; importantly the risk of carcinoma is based on extent of colon involved and duration of disease (rarely before 10 years) - may present with primary sclerosing cholangitis or the presence of p-ANCA - smoking is protective - treated with 5-aminosalicylic preparations, 6-MP, infliximab, or colectomy

Question 175

Crohn Disease

Answer 175

- a form of inflammatory bowel disease mediated by Th1 - affects the full thickness of the wall, forming knife-like fissures - can affect anywhere in the GI tract with skip lesions, but the terminal ileum is most common and colon is least - presents with right lower quadrant pain and non-blood diarrhea in contrast to UC - grossly, there is cobblestoning of the mucosa, creeping fat, and stricture as healing involves myofibroblasts - histology reveals granulomas and lymphoid aggregates - complications include malabsorption, calcium oxalate nephrolithiasis, fistula formation, strictures/obstruction, and carcinoma if the colon is involved - may present with arthritis, uveitis, or erythema nodosum - smoking is not protective - treated with corticosteroids, azathioprine, antibiotics, infliximab, or adalimumab

Question 176

Hirschsprung Disease

Answer 176

- defective relaxation and peristalsis of the rectum and distal sigmoid colon - due to a congenital failure of ganglion cells (neural crest derived) to descend into the myenteric and submucosal plexuses - strongly associated with Down syndrome and RET mutations - clinical features are based on obstruction and include failure to pass meconium, an empty rectal vault of digital exam, megacolon, and bilious emesis - requires a rectal SUCTION biopsy to sample the two plexuses, which aren't biopsied normally - treatment involves resection of the involved bowel

Question 177

What is the function of the myenteric and submucosal plexuses of the GI tract?

Answer 177

- the myenteric is located between the inner circular and outer longitudinal muscle layers of the muscularis propria and regulates motility - the submucosal plexus is located in the submucosa and regulates blood flow, secretions, and absorption

Question 178

Colonic Diverticula

Answer 178

- an out pouching of mucosa and submucosa only through the muscularis propria (false diverticulum) - risk factors are those that are related to wall stress: constipation, straining, low-fiber diet, and age - they arise where the vase recta transverse the muscularis propria because this is a weak point in the wall - the sigmoid colon is most often affected - usually asymptomatic but may cause hematochozia, diverticulitis, or fistula

Question 179

Diverticulitis

Answer 179

- a diverticulosis with inflamed micro perforations - classically presenting with LLQ pain, fever, and leukocytosis, mimicking appendicitis but on the left - complications include abscess, fistula, obstruction, or perforation - treat with antibiotics and complications with percutaneous drainage or surgery

Question 180

How does colovesicular fistula present?

Answer 180

- presents with air or stool in the urine | - often due to rupture of a diverticula

Question 181

Angiodysplasia

Answer 181

- an acquired malformation of mucosal and submucosal capillary beds - usually arises in the cecum and right colon due to high wall tension - classically presents as hematochezia in older adults

Question 182

How are colonic diverticula and angiodysplasia related?

Answer 182

- both are due to wall stress and present most often in the elderly with hematochezia - however, diverticula typically occur on the left side in the sigmoid colon and angiodysplasia occur on the right side in the cecum and ascending colon

Question 183

Hereditary Hemorrhagic Telangiectasia

Answer 183

- an autosomal dominant disorder that results in thin-walled blood vessels, particularly in the mouth and GI tract - rupture presents as bleeding/petechiae

Question 184

Ischemic Colitis

Answer 184

- ischemic damage to the colon, most often at the splenic flexure, which is a watershed area of the SMA - most often due to atherosclerosis of the SMA - presents with post-prandial pain (because that is when energy requirement is the highest) and weight loss - if it progresses to infarction, it presents with pain and bloody diarrhea

Question 185

Irritable Bowel Syndrome

Answer 185

- a relapsing abdominal pain with bloating, flatulence, and change in bowel habits that improves with defecation - most often seen in middle-aged females - related to disturbed intestinal motility but there are no identifiable pathologic changes - increased fiber may improve symptoms

Question 186

What are the two most common types of colonic polyps?

Answer 186

hyperplastic and adenomatous

Question 187

Hyperplastic Colonic Polyps

Answer 187

- the most common type of colonic polyp - they form due to hyperplasia of glands - have a "serrated" appearance on microscopy - they have no malignant potential

Question 188

Adenomatous Colonic Polyps

Answer 188

- a neoplastic proliferation of glands - benign but premalignant and may progress to adenocarcinoma via the adenoma-carcinoma sequence - most likely to progress to carcinoma are those more than 2 cm in size, with sessile growth (not pedunculate), and villous histology - goal of a colonoscopy is to remove all adenomatous polyps

Question 189

What is the adenoma-carcinoma sequence?

Answer 189

- a molecular sequence by which normal colonic mucosa forms adenomatous polyps and then carcinoma - begins with a double KO of the tumor suppressor gene APC, which increases the risk for polyp formation - a K-ras mutation then induces polyp formation - p53 mutation and increased expression of COX then allows for progression to carinoma

Question 190

What OTC medication impedes the adenoma-carcinoma sequence? How?

Answer 190

aspirin impedes progression because it limits COX expression, which is an important last step between adenomatous polyp and carcinoma

Question 191

How do we screen for colon cancer?

Answer 191

- colonoscopy | - testing for fecal occult blood

Question 192

What is the goal of colonoscopy?

Answer 192

to remove adenomatous polyps before they progress

Question 193

Which polyps are removed on a colonoscopy?

Answer 193

all polyps are removed because hyper plastic and adenomatous polyps look identical on colonoscopy

Question 194

Which adenomatous polyps have the greatest risk for progression to carcinoma?

Answer 194

those more than 2 cm, with sessile growth (not pedunculate), or villous histology

Question 195

Familial Adenomatous Polyposis

Answer 195

- an autosomal dominant disorder characterized by 100s or 1000s of adenomatous colonic polyps - due to an inherited APC mutation on chromosome 5 (a tumor suppressor gene involve in the adenoma-carcinoma sequence) - colon and rectum are removed prophylactically; otherwise, almost all patients develop carcinoma by age 40 - associated with CRC on the left-side of the colon - Gardner syndrome is a subpopulation of FAP with fibrzomatosis and osteomas - Turcot syndrome is a subpopulation of FAP with CNs tumors

Question 196

Turcot Syndrome

Answer 196

a syndrome of familial adenomatous polyposis (APC mutation) and CNS tumors like medulloblastoma and glial tumors

Question 197

Gardner Syndrome

Answer 197

a syndrome including familial adenomatous polyposis (APC mutation), fibromatosis, and osteoma - fibromatosis is a non-neoplastic proliferation of fibroblasts in the retroperitoneum, which destroys local tissue - additional findings include congenital hypertrophy of teh retinal pigment epithelium and impacted/supernumeray teeth

Question 198

Juvenile Polyp

Answer 198

- a sporadic, hamartomatous, benign polyp that arises in children - tends to prolapse and bleed - juvenile polyposis is characterized by multiple in the stomach and colon - tend to increase the risk for carcinoma

Question 199

Peutz-Jeghers Syndrome

Answer 199

- an autosomal dominant syndrome of multiple hamartomatous, benign polyps throughout the GI tract with hyperpigmentation of the lips, oral mucosa, and genital skin - increases the risk for colorectal, breast, and gynecologic cancer

Question 200

Colorectal Carcinoma

Answer 200

- the third most common site of cancer and third most common cause of cancer-related death - adenoma-carcinoma sequence tends to be at work in cancer on the left and microsatellite instability on the right - left-sided carcinoma tends to grow as a napkin-ring lesion with decreased stool caliber, blood-streaked stools, and left lower quadrant pain - right-sided usually grow as a raised lesion with iron-deficiency anemia and vague pain - increases the risk for S. bovis endocarditis - CEA is an important tumor marker, useful for assessing treatment response and detecting recurrence but not for screening - typically don't spread until they've invaded more than the mucosa because the mucosa lacks lymphatics - most commonly spreads to the liver

Question 201

When does screening for colorectal carcinoma begin?

Answer 201

age fifty

Question 202

What is microsatellite instability?

Answer 202

- a molecular pathway for colorectal cancer - micro satellites are repeating sequences of noncoding DNA that tend to remain unchanged during cell division - instability is indicative of a defective DNA copy mechanism, which contributes to the formation of cancer - most often associated with right-sided colorectal cancer

Question 203

Hereditary Nonpolyposis Colorectal Carcinoma

Answer 203

- aka Lynch syndrome, the typical example of microsatellite instability - an inherited mutation in a DNA mismatch repair enzyme increases the risk for colorectal, ovarian, and endometrial carcinoma - in such cases, colorectal carcinoma tends to arise de novo rather than from an adenomatous polyp and at a relatively early age on the right-side

Question 204

Acute Pancreatitis

Answer 204

- inflammation and hemorrhage of the pancreas due to premature activation of trypsin and autodigestion - results in liquefactive hemorrhagic necrosis of the pancreas and fat necrosis of the surrounding peripancreatic fat - most commonly due to ("I GET SMASH"): idiopathic, gallstones, ethanol, trauma, scorpion stings, mumps/malignancy, autoimmune, steroids, hyperlipidemia/hypercalcemia or rupture of a posterior duodenal ulcer - presents with n/v and epigastric pain radiating to the back - serum lipase and amylase are both elevated, but lipase is more specific - hypocalcemia results from saponification in fat necrosis - complications include shock, pancreatic pseudocyst, pancreatic abscess formation, or DIC/ARDS (enzymes enter blood)

Question 205

Pancreatitis results in what sort of necrosis?

Answer 205

- liquefactive hemorrhagic necrosis of the parenchyma | - fat necrosis of the surrounding peripancreatic fat

Question 206

What is a pancreatic pseudocyst?

Answer 206

- a complication of acute pancreatitis - fibrous tissue surrounding liquefactive necrosis and pancreatic enzymes - presents with an abdominal mass and persistently elevated serum amylase even after pancreatitis has been dealt with - rupture is associated with enzyme release and hemorrhage

Question 207

What are two reasons amylase may remain elevated after treating someone with pancreatitis?

Answer 207

- a pancreatic pseudocyst | - a pancreatic abscess

Question 208

Chronic Pancreatitis

Answer 208

- fibrosis of the pancreatic parenchyma secondary to recurrent acute pancreatitis - most often seen in alcoholics and those with cystic fibrosis - presents with epigastric abdominal pain that radiates to the back, pancreatic insufficiency resulting in malabsorption with steatorrhea and fat-soluble vitamin deficiencies, and secondary diabetes mellitus - dystrophic calcification can be seen on imaging - poses a risk for pancreatic carcinoma

Question 209

Epigastric pain that radiates to the back indicates what?

Answer 209

pancreatitis

Question 210

Pancreatic Adenocarcinoma

Answer 210

- an adenocarcinoma arising from the pancreatic ducts rather than the acini - risk factors include smoking and chronic pancreatitis - presents with epigastric abdominal pain, weight loss, obstructive jaundice with pale stools and palpable gall bladder (when arising in the head of the pancreas), secondary diabetes mellitus (when arising in the body or tail), pancreatitis and migratory thrombophlebitis - serum marker is CA19-9 - treatment is a Whipple procedure but the prognosis is very poor

Question 211

What serum marker is indicative of pancreatic carcinoma?

Answer 211

CA 19-9

Question 212

What happens in a Whipple procedure?

Answer 212

the head and neck of the pancreas, proximal duodenum, and gallbladder are removed

Question 213

How does pancreatic carcinoma in the head/neck differ from that arising in the body/tail?

Answer 213

- in the head, you're more likely to have obstructive jaundice with pale stools and a palpable gallbladder - in the tail, you're more likely to have very late secondary diabetes without obesity

Question 214

A 70-year old, thin women presents with new-onset secondary diabetes. What might you consider as a diagnosis?

Answer 214

pancreatic carcinoma in the tail/body of the pancreas

Question 215

What is migratory thrombophlebitis?

Answer 215

swelling, erythema, and tenderness in the extremities, sometimes seen in those with pancreatic carcinoma

Question 216

Biliary Atresia

Answer 216

- failure to form or early destruction of the extra hepatic biliary tree - leads to biliary obstruction within the first two months of life, which presents with jaundice and progresses to cirrhosis

Question 217

What are the two major kinds of gall stones? Which is more common?

Answer 217

cholesterol stones are more common than bilirubin ones

Question 218

What three changes with lead to precipitation of cholesterol or bilirubin and formation of a cholelithiasis?

Answer 218

- supersaturation - decreased phospholipids or bile acids which normally serve to increase solubility - stasis, which allows for growth of bacteria which deconjugate bile

Question 219

What is a common drug that induces cholelithiasis?

Answer 219

cholestyramine because it binds bile and inhibits reabsorption, reducing the bile content of the gallbladder, reducing solubility of cholesterol and bilirubin

Question 220

Why does stasis contribute to the formation of a cholelithiasis?

Answer 220

- the normal flow of bile clears the biliary tree of bacteria - during times of stasis, bacteria are able to ascend grow - they are capable of deconjugating bilirubin, which makes it insoluble

Question 221

Cholesterol Stones

Answer 221

- the most common type of gallstone - usually radiolucent and yellow on gross exam - risk factors include age, greater exposure to estrogen, clofibrate, Native American ethnicity, Crohn disease, and cirrhosis - usually asymptomatic but may lead to biliary colic, acute or chronic cholecystitis, ascending cholangitis, gallstone ileum, or gallbladder cancer

Question 222

Why is estrogen a risk factor for cholesterol gallstones?

Answer 222

because it increases the activity of HMG-CoA reductase, promoting cholesterol synthesis while also increasing lipoprotein receptor expression by hepatocytes, increasing their cholesterol uptake

Question 223

Why does Crohn disease contribute to the formation of gallstones?

Answer 223

because it can damage the ileum and impair recycling of bile salts and acids, reducing the solubility of cholesterol in the gall bladder

Question 224

Bilirubin Cholelithiasis

Answer 224

- a radiopaque, pigmented gallstone - risk factors include extravascular hemolysis, which increases bilirubin content in the bile and biliary tract infection (E. coli, A. lumbricoides, or Clonorchis sinensis) - usually asymptomatic but may lead to biliary colic, acute or chronic cholecystitis, ascending cholangitis, gallstone ileum, or gallbladder cancer

Question 225

Ascaris lumbricoides

Answer 225

- a common roundworm - common in areas with poor sanitation because it utilizes fecal-oral transmission - infects the biliary tract and increases the risk for gallstones

Question 226

Clonorchis sinensis

Answer 226

- a liver fluke endemic to China, Korea, and Vietnam | - infects the biliary tract and increases the risk for gallstones, cholangitis, and cholangiocarcinoma

Question 227

Biliary Colic

Answer 227

- a waxing and waning right upper quadrant pain due to gallbladder contracting against a stone lodged in the duct - relieved by passaged of the stone - may cause acute pancreatitis or obstructive jaundice if it is lodged in the common bile duct

Question 228

Acute Cholecystitis

Answer 228

- acute inflammation of the gallbladder wall - often due to an impacted stone in the cystic duct which causes dilatation with pressure ischemia, bacterial overgrowth (commonly E. coli), and inflammation - presents with right upper quadrant pain radiating to the scapula, a high WBC count, n/v, and elevated serum alkaline phosphatase - Murphy sign is likely positive (respiratory arrest on palpation) - risk of rupture if untreated

Question 229

What causes right upper quadrant pain that radiates to the scapula?

Answer 229

acute cholecystitis

Question 230

Chronic Cholecystitis

Answer 230

- chronic inflammation of the gallbladder - most often due to chemical irritation from longstanding cholelithiasis - characterized by herniation of the gallbladder mucosa into the muscular wall, forming a Rokitansky-Aschoff sinus - presents with vague right upper quadrant pain, especially after eating - porcelain gallbladder is a late complication described as a shrunken, hard gallbladder due to chronic inflammation, fibrosis, and dystrophic calcification, which increases the risk for carcinoma - treat with cholecystectomy

Question 231

What is porcelain gallbladder?

Answer 231

a late complication of chronic cholecystitis described as a shrunken, hard gallbladder due to chronic inflammation, fibrosis, and dystrophic calcification, which increases the risk for carcinoma

Question 232

Ascending Cholangitis

Answer 232

- a bacterial infection of the bile ducts - most often due to an ascending infection with enteric gram-negative bacteria - presents as sepsis with jaundice and abdominal pain - increased incidence with choledocholithiasis (presence of a stone in the duct), which reduces bile flow

Question 233

Gallstone Ileus

Answer 233

a phenomenon whereby gallstones enter and obstruct the small bowel by way of a fistula formed during a bout of cholecystitis with rupture

Question 234

Gallbladder Carcinoma

Answer 234

- an adenocarcinoma arising from the wall - major risk factor is gallstones, especially when complicated by porcelain gallbladder - classically presents as cholecystitis in an elderly woman

Question 235

What is jaundice due to?

Answer 235

an elevated serum bilirubin caused by a disturbance in normal bilirubin metabolism

Question 236

How does extravascular hemolysis cause jaundice? How does this manifest compared to other causes of jaundice?

Answer 236

- it results in high levels of UCB, which overwhelm the conjugating ability to the liver - as a result there is increased UCB in the blood - the conjugating ability is maxed out, so there is also more CB in the bile than usual; this manifests as dark urine and a risk for bilirubin gallstones

Question 237

Physiologic Jaundice of the Newborn

Answer 237

- jaundice that arises because the newborn liver has transiently low UGT activity - the result is an increase in UCB within the blood - UCB is fat soluble so it can be deposited in the basal ganglia, a phenomenon known as kernicterus, which leads to neurologic deficits and death - treatment is phototherapy, which makes UCB water soluble and it is excreted in the urine - however, it usually resolves without treatment in 1-2 weeks

Question 238

What is kernicterus?

Answer 238

a complication sometimes seen in newborns because unconjugated bilirubin builds up in the blood and is fat soluble so it is deposited in the basal ganglia leading to neurologic deficits and death

Question 239

Gilbert Syndrome

Answer 239

- an autosomal recessive condition characterized by mildly diminished UGT activity - results in a mild elevation of UCB during times of stress - not normally significant clinically - the mild version of Crigler-Najjar syndrome

Question 240

Crigler-Najjar Syndrome, Type I

Answer 240

- the absence of UGT, which leads to extremely high levels of unconjugated bilirubin in the blood - often leads to Kernicterus in the early days of life - treatment involves plasmapheresis and phototherapy, but is usually fatal

Question 241

Dubin-Johnson syndrome

Answer 241

- a deficiency of the bilirubin canalicular transport protein required for hepatocytes to move CB into the canaliculi - results in elevated conjugated bilirubin in the blood - the liver becomes pitch black but otherwise this is not clinically significant; it is often an incidental finding during surgery - Rotor syndrome is similar but lacks liver discoloration

Question 242

What would cause conjugated bilirubin levels in the blood to rise as well as an elevation of alkaline phosphatase?

Answer 242

biliary tract obstruction (aka obstructive jaundice), which will cause CB to leak into the blood rather than moving into the GI tract and which damages the wall and causes the release of alkaline phosphatase

Question 243

Obstructive Jaundice

Answer 243

- biliary tract obstruction due to gallstones, carcinoma, parasites, or liver fluke leading to jaundice - the obstruction prevents conjugated bilirubin from entering the GI tract, so it leaks into the blood instead - urine will be dark with bilirubin rather than urobilinogen and urine urobilinogen will be low and stools pale - there is pruritus due to an increase in plasma bile acids, hypercholesterolemia with xanthomas, and steatorrhea with malabsorption of fat-soluble vitamins - labs show elevated direct (CB) bilirubin, reduced urine urobilinogen, and an increase in alkaline phosphatase

Question 244

Describe how the jaundice caused by viral hepatitis compares to other causes of jaundice.

Answer 244

- arises because inflammation disrupts hepatocytes and small bile ductules - contributes to an increase in both conjugated bilirubin and unconjugated bilirubin because less bilirubin is conjugated and that which is doesn't leave via the GI tract, instead it leaks into the blood - urine is dark due to an increase in urine bilirubin, but urine urobilinogen is normal or decreased

Question 245

Viral Hepatitis

Answer 245

- an inflammation of liver parenchyma, most often due to hepatitis virus, but occasionally to EBV or CMV - the acute phase lasts less than six months and presents as jaundice (elevated UCB and CB) with dark urine, fever, malaise, nausea, and elevated liver enzymes (ALT > AST) - inflammation during the acute phase involves the lobules of the liver and portal tracts and triggers CD8 mediated apoptosis of hepatocytes - the chronic phase is that which lasts more than six months - during the chronic phase, inflammation predominantly involves the portal tract - chronic hepatitis increases the risk for cirrhosis

Question 246

How does the inflammation during acute hepatitis differ from that seen in chronic hepatitis?

Answer 246

in the acute phase, the inflammation involves lobules of the liver and portal tracts, but during the chronic phase, it predominantly involves the portal tracts

Question 247

Hepatitis A

Answer 247

- an infection spread by fecal-oral transmission, most commonly acquired during travel outside the US - causes only acute hepatitis without a risk for chronic hepatitis - anti-virus IgM marks an active infection while anti-virus IgG is protective and indicates prior infection or immunization, which is available for HAV

Question 248

Hepatitis E

Answer 248

- an infection spread by fecal-oral transmission and is commonly acquired from contaminated water or undercooked seafood - poses no risk for chronic hepatitis - anti-virus IgM marks an active infection while anti-virus IgG is protective and indicates prior infection - there is no vaccination available - importantly, in a pregnant woman, HEV is associated with fulminant hepatitis

Question 249

What is fulminant hepatitis?

Answer 249

a complication of HEV infection in a pregnant women characterized by liver failure with massive liver necrosis

Question 250

Hepatitis C

Answer 250

- an infection spread via parenteral transmission | - results in an acute hepatitis that only occasionally progresses to chronic disease

Question 251

Hepatitis B

Answer 251

- an infection spread via parenteral transmission - results in acute hepatitis and chronic hepatitis in most cases - HCV-RNA test confirms infection and decreased RNA levels indicate recovery

Question 252

What is unique about Hepatitis D?

Answer 252

infection with HDV is dependent on a simultaneous or pre-existing infection with HBV

Question 253

Which is worse, hepatitis B/D superinfection or co-infection?

Answer 253

superinfection (B and then D) is more severe

Question 254

Describe the antigen and antibody profile of someone with an acute HBV infection.

Answer 254

- HBsAG is the first marker to rise - HBeAG and HBV DNA are also positive, and indicate infection - IgM to HBc is present

Question 255

Describe the antigen and antibody profile of someone with an chronic HBV infection.

Answer 255

- HBsAG is present - HBeAG may or may not be present - IgG to HBc is present and antibody to HBs is absent

Question 256

What does the presence of HBsAg in an individual indicate?

Answer 256

it is the first serologic marker to rise in those with an HBV infection and it is indicative of present infection, either acute or chronic

Question 257

What does the presence of HBeAg or HBV DNA in an individual indicate?

Answer 257

- it is a marker of infectiousness, so it is positive during the acute phase and can be positive or negative during the chronic phase - it is absent in all other phases

Question 258

What do IgM and IgG against HBc indicate in an individual being assessed for hepatitis?

Answer 258

- IgM is seen only in the acute and window stages early in infection - IgG is seen in the later phases (chronic infection or resolution) - importantly no such antibodies are seen in individuals who have only been immunized and not exposed to HBV

Question 259

What does the presence of antibodies to HBs indicate in an individual being assessed for hepatitis?

Answer 259

it is protective and as such, is seen in those with resolved past infection and who have been immunized

Question 260

Those who have been immunized against HBV have what antibodies?

Answer 260

IgG against HBs

Question 261

Cirrhosis

Answer 261

- end-stage liver damaged characterized by disruption of the normal hepatic parenchyma by bands of fibrosis and regenerative nodules of hepatocytes - mediated by TGF-B from stellate cells that line the sinusoids - presents with portal hypertension, which manifests as ascites, congestive splenomegaly, and portosystemic shunts - presents with decreased detoxification which manifests as mental status change, asterisks, and eventual coma due to elevated serum ammonia; gynecomastia, spider angiomata, and palmar erythema due to hyperestrinism; and jaundice - presence with decreased protein synthesis manifesting as hypoalbuminemia with edema and a coagulopathy

Question 262

Alcohol-Related Liver Disease

Answer 262

- damage to the liver parenchyma due to alcohol consumption - can produce three patterns of injury: fatty liver, alcoholic hepatitis, or cirrhosis - fatty liver is the accumulation of fat in hepatocytes and grossly the liver becomes heavy and greasy; this resolves with abstinence - alcoholic hepatitis results from chemical injury to hepatocytes and is generally seen with binge drinking; the primary mediator of this is the ethanol metabolite acetaldehyde; hepatocytes swell and Mallory bodies (damaged cytokeratin filaments) form; notably AST > ALT - cirrhosis is a complication of long-term chronic alcohol-induced liver damage

Question 263

What does liver failure in the context of an AST more elevated than an ALT indicate?

Answer 263

it is indicative of alcoholic hepatitis because AST is found in the mitochondria and alcohol is a mitochondrial poison

Question 264

What are Mallory bodies?

Answer 264

aggregates of damaged cytokeratin filaments found in hepatocytes indicating alcoholic hepatitis

Question 265

Nonalcholic Fatty Liver Disease

Answer 265

- fatty change, hepatitis, or cirrhosis that develop without exposure to alcohol or other known insult - associated with obesity - a diagnosis of exclusion - ALT more elevated than AST

Question 266

Hemochromatosis

Answer 266

- organ damage due to excess iron in the body - usually due to an autosomal recessive C282Y mutation of the HFE gene on chromosome 6, which leads to abnormal iron sensing and increased intestinal absorption - secondary hemochromatosis may arise from chronic transfusion therapy - iron accumulates in the liver, pancreas, skin, heart, pituitary, and joints and can be identified on MRI or with a Prussian blue stain - presents after age 40 with a triad of cirrhosis, diabetes, and skin pigmentation ("bronze diabetes") as well as restrictive cardiomyopathy, hypogonadism, arthropathy due to deposition of calcium pyrophosphate in the MCPs - HCC is a common cause of death - treat with phlebotomy and chelation

Question 267

What is the difference between hemosiderosis and hemochromatosis?

Answer 267

- hemosiderosis is just the state of having elevated iron | - hemochromatosis is the organ damage that results

Question 268

What distinguishes iron deposits from lipofuscin?

Answer 268

iron deposits will stain using Prussian blue

Question 269

Wilson Disease

Answer 269

- an autosomal recessive mutation in the hepatocyte copper-transporting ATPase gene ATP7B on chromosome 13 - this defect prevents incorporation of copper into apoceruloplasmin for transport in the blood and into bile for excretion - instead, copper accumulates in the liver, brain, cornea, and kidneys - it presents before age 40 with cirrhosis, neurologic changes (including Parkinsonian symptoms from deposition in the basal ganglia), Kayser-Fleisher rings (deposits in the Descemet membrane of the cornea), hemolytic anemia, and Fanconi syndrome - labs show elevated urine copper and low serum ceruloplasmin - increases the risk for hepatocellulr carcinoma - treat with penicillamine or trientine and oral zinc

Question 270

Primary Biliary Cirrhosis

Answer 270

- autoimmune granulomatous destruction of intrahepatic bile ducts - antimitochondrial antibodies are present but do not mediate the disease - presents with obstructive jaundice and cirrhosis later in the disease course

Question 271

Primary Sclerosing Cholangitis

Answer 271

- inflammation and fibrosis of intrahepatic and extra hepatic bile ducts - histology reveals an onion-skin appearance of the periductal fibrosis and a beaded appearance on contrast imaging because uninvolved segments dilate - associated with ulcerative colitis and p-ANCA is often positive but the etiology is unknown - presents with obstructive jaundice and cirrhosis is a late complication - patients are at increased risk for cholangiocarcinoma

Question 272

Reye Syndrome

Answer 272

- fulminant liver failure and encephalopathy in children with a viral illness who take aspirin - likely due to mitochondrial damage within hepatocytes; aspirin metabolites reduce beta-oxidation by reversible inhibition of mitochondrial enzymes - presents with hypoglycemia, fatty liver, n/v, hepatomegaly, and coma - Reye of sunSHINE: steatosis of liver, hypoglycemia/hepatomegaly, infection, not away (coma), encephalopathy

Question 273

Why are children with a viral illness never given aspirin? What disease complicates this general rule?

Answer 273

- because it may induce Reye syndrome of fulminant liver failure and encephalopathy - this is complicated by Kawasaki disease with looks viral but is not and is treated with aspirin

Question 274

Hepatic Adenoma

Answer 274

- a benign tumor of hepatocytes - associated with oral contraceptive use grows during pregnancy because it responds to estrogen - they are sub capsular but risk rupture and intraperitoneal bleeding during pregnancy for this reason

Question 275

Hepatocellular Carcinoma

Answer 275

- a malignant tumor of hepatocytes - risk factors include chronic hepatitis, cirrhosis (secondary to alcohol, nonalcoholic fatty liver disease, hemochromatosis, Wilson disease, A1AT deficiency), and aflatoxins - tumors are often detected late because the symptoms are masked by cirrhosis - symptoms include jaundice, tender hepatomegaly, ascites, polycythemia, and anorexia - primarily complication is Budd-Chiari syndrome (liver infarction secondary to hepatic vein obstruction) - primary serum marker is alpha fetoprotein

Question 276

What are aflatoxins and why are they clinically important?

Answer 276

they are derived from Aspergillus which grows in stored grains and the toxin induces p53 mutations, increasing the risk for hepatocellulr carcinoma

Question 277

What serum marker is useful in diagnosing HCC?

Answer 277

alpha-fetoprotein

Question 278

What is Budd-Chiari syndrome?

Answer 278

- liver infarction secondary to hepatic vein obstruction - presents with painful hepatomegaly and ascites - often complicates hepatocellulr carcinoma when the tumor invades the hepatic vein

Question 279

What are the most common sources of metastasis to the liver?

Answer 279

colon, pancreas, lung, and breast

Question 280

How do metastases to the liver often compare to primary cancers in gross appearance?

Answer 280

metastases result in multiple nodules in the liver whereas a primary tumor is more likely to arise as one lesion

Question 281

How can metastasis to the liver present on physical exam?

Answer 281

may be able to palpate the hepatomegaly as a nodular free edge of the liver (due to multiple nodules of tumor)

Question 282

Eosinophilic Esaphagitis

Answer 282

- an infiltration of the esophagus by eosinophils, most often in patients with atopy - presents with dysphagia and food impaction for food allergens - can see esophageal rings and linear furrows on endoscopy - doesn't respond to GERD therapy

Question 283

Esophagitis

Answer 283

- an infection of the esophagus - commonly associated with reflux, immunocompromised hosts, caustic ingestion, or medications - Candida will presents as white pseudomembranes, HSV-1 as punched out ulcers, and CMV as linear ulcers

Question 284

Sclerodermal Esophageal Dysmotility

Answer 284

- smooth muscle atrophy of the esophagus - results in reduced LES pressure and dysmotility, which contribute to acid reflux and dysphagia - complications include stricture, Barrett esophagus, and aspiration - a feature of CREST syndrome

Question 285

Menetrier Disease

Answer 285

- hyperplasia of the foveolar cells of the gastric mucosa mediated by excess TGF-a - results in hypertrophied rugae, which take on the appearance of brain gyro on imaging, excess mucus production with resultant protein loss, and parietal cell atrophy with low acid production - considered precancerous

Question 286

What is a sister mary joseph nodule?

Answer 286

a subcutaneous periumbilical metastasis (often from diffuse or intestinal gastric carcinoma)

Question 287

How do we detect fecal fat in those with a malabsorption syndrome?

Answer 287

a Sudan stain

Question 288

Lactose Intolerance

Answer 288

- a deficiency in lactase, which normally breaks lactose down into glucose and galactose - can be congenital via an AR mutation, acquired most often in late childhood, or transient following infection of the small bowel - villi appear normal unless it is secondary to injury to the tips of the villi as in viral enteritis - lactose remains in the lumen and causes an osmotic diarrhea with low stool pH since it is fermented by colonic bacteria - diagnosed via a lactose hydrogen breath test which is positive for malabsorption if post lactose breath hydrogen rises more than 20 ppm above base

Question 289

What is the lactose hydrogen breath test?

Answer 289

- a test used to diagnose lactose intolerance - works on the basis that lactose that isn't broken down and absorbed is formed in the colon by bacteria, increasing [H+] - positive if breath hydrogen rises more than 20 ppm after lactose is administered orally

Question 290

Pancreatic Insufficiency

Answer 290

- a deficiency of pancreatic secretions - dueto chronic pancreatitis, CF, or obstructing cancer - results in a malabsorption of fat and fat-soluble vitamins as well as B12 - low duodenal pH and fecal elastase are indicative signs

Question 291

The differential for appendicitis should include what else?

Answer 291

- diverticulitis if elderly | - ectopic pregnancy if a young woman

Question 292

What is the most common congenital anomaly of the GI tract?

Answer 292

Meckle diverticulum

Question 293

What is an omphalomesenteric cyst?

Answer 293

a cystic dilation of the vitelline duct, related to Meckel diverticulum

Question 294

What is a pertechnetate study?

Answer 294

a diagnostic study for Meckel diverticulum that relies on uptake by ectopic gastric mucosa

Question 295

Zenker Diverticulum

Answer 295

- a false pharyngoesophageal diverticulum - caused by dysmotility, which results in herniation of mucosal tissue at the Killian triangle between the tyropharyngeal and cricopharyngeal parts of the inferior pharyngeal constrictor - results in dysphagia, obstruction, gurgling, aspiration, foul breath, and a neck mass - most often seen in elderly males

Question 296

What are Ladd bands?

Answer 296

fibrous bands that form due to improper positioning of the bowel, which can lead to volvulus or duodenal obstruction

Question 297

What is the most common cause of small bowel obstruction?

Answer 297

adhesion

Question 298

Ileus

Answer 298

- intestinal hypo motility in the absence of obstruction - presents with a distended/tympanic abdomen with diminished bowel sounds - often after abdominal surgeries, opiates, hypokalemia, or sepsis - treat with bowel rest, electrolyte correction, or a cholinergic drug

Question 299

Meconium Ileus

Answer 299

a feature of cystic fibrosis in which a meconium plug obstructs the small intestine, preventing stool passage at birth

Question 300

Necrotizing Enterocolitis

Answer 300

- necrosis of the intestinal mucosa, most often the colon - seen in premature, formula-fed infants with immature immune systems - complicated by possible perforation, which can lead to pneumatosis intestinal, free air in abdomen, or portal venous gas

Question 301

What happens to albumin, prothrombin time, and platelets in those with liver disease?

Answer 301

- albumin is decreased - there is a coagulopathy from reduced production of clotting factors, so prothrombin time increases - platelets are decreased in liver disease due to low thrombopoietin and liver sequestration and in portal hypertension due to splenic sequestration

Question 302

What causes platelets to decrease in those with liver disease?

Answer 302

- liver disease results in low thrombopoietin production and liver sequestration of platelets - portal hypertension leads to splenomegaly and splenic sequestration

Question 303

Hepatic Encephalopathy

Answer 303

- encephalopathy that results from cirrhosis, which diminishes ammonia metabolism - presentation can range from disorientation with asterisks to severe coma - may be triggered by increased ammonia production and absorption (dietary protein, GI bleed, constipation, or infection) or reduced ammonia removal (renal failure, diuretics, TIPS) - treat with lactulose which increases ammonium production or with rifaximin or neomycin which decrease ammonia-producing gut bacteria

Question 304

Cavernous Hemangioma

Answer 304

- a common, benign tumor of the liver - typically occurring between the ages of 30-50 - biopsy is contraindicated by the risk of hemorrhage

Question 305

How do Crigler-Najjar syndrome type I and II differ?

Answer 305

- type II is less severe | - because of this it responds to phenobarbital, which increases liver enzyme synthesis

Question 306

Secondary Biliary Cirrhosis

Answer 306

- extrahepatic biliary obstruction, which increases pressure in the intrahepatic ducts and leads to injury, fibrosis, and bile stasis - primarily arises in those with known obstructive lesions such as gallstones, biliary strictures, or pancreatic carcinoma - may be complicated by ascending cholangitis

Question 307

What are the risk factors for gallstones?

Answer 307

the 4 F's - female - fat - fertile (pregnant) - forty

Question 308

What is the difference between a black and a brown gallstone?

Answer 308

- black are radiolucent and formed from calcium, bilirubinate, and hemolysis - brown are radiopaque and indicative of infection

Question 309

What is the Charcot triad of cholangitis?

Answer 309

jaundice, fever, and RUQ pain

Question 310

What is a positive Murphy sign?

Answer 310

inspiratory arrest on RUQ palpating due to pain, indicating cholecystitis

Question 311

What are the causes of acute pancreatitis?

Answer 311

I GET SMASHED - Idiopathic - Gallstones - Ethanol - Trauma - Steroids - Mumps - Autoimmune disease - Scorpion sting - Hypercalcemia/Hypertriglyceridemia - ERCP - Drugs (sulfa, NRTIs, protease inhibitors)

Question 312

What is Trousseau syndrome?

Answer 312

a migratory thrombophlebitis presenting with redness and tenderness on palpitation of extremities, indicative of malignancy

Question 313

What are the mechanisms, uses, and adverse effects of aluminum hydroxide?

Answer 313

- it is an antacid - used to treat gastric acid diseases - can cause hypokalemia, constipation, hypophosphatemia, proximal muscle weakness, osteodystrophy, and seizures

Question 314

What are the mechanisms, uses, and adverse effects of calcium carbonate?

Answer 314

- it is an antacid - used to treat gastric acid diseases - can cause hypokalemia, hypercalcemia, and rebound acid secretion

Question 315

What are the mechanisms, uses, and adverse effects of magnesium hydroxide?

Answer 315

- it is an antacid - used to treat gastric acid diseases - can cause hypokalemia, diarrhea, hyporeflexia, hypotension, and cardiac arrest

Question 316

What are the mechanisms and uses of bismuth and sucralfate?

Answer 316

- they bind to the base of an ulcer and provide physical protection while bicarb secretion re-establishes the pH gradient in the mucous layer - used to treat ulcers and travelers' diarrhea

Question 317

What are the mechanisms, uses, and adverse effects of misooprostol?

Answer 317

- it is a PGE1 analog, which increase production and secretion of the gastric mucous barrier while limiting acid production - it is used to prevent NSAID-induced peptic ulcers, maintenance of a PDA, and induction of labor/as an abortifacient - may cause diarrhea or abortion

Question 318

What are the mechanisms, uses, and adverse effects of osmotic laxatives? List four examples.

Answer 318

- magnesium hydroxide, magnesium citrate, polyethylene glycol, lactulose - provide an osmotic load to draw water into the GI lumen - used to treat constipation - may cause diarrhea or dehydration and may be abused by bulimics

Question 319

What are the mechanisms, uses, and adverse effects of sulfasalazine?

Answer 319

- it is a combination of sulfapyridine and 5-aminosalicylic acid (anti-bacterial and anti-inflammatory), which is activated by colonic bacteria - used to treat UC and Crohn disease (if it affects the colon) - may cause malaise, nausea, sulfa toxicity, and a reversible oligospermia

Question 320

What are the mechanisms, uses, and adverse effects of Loperamide?

Answer 320

- it is an agonist at mu receptors with very little CNS penetration - used to treat diarrhea - may cause constipation or nausea

Question 321

What are the mechanisms, uses, and adverse effects of orilstat?

Answer 321

- a weight loss medication that functions by inhibiting gastric and pancreatic lipase, reducing the breakdown and absorption of dietary fats - may cause steatorrhea and a fat-soluble vitamin deficiency

Question 322

What are the mechanisms, uses, and adverse effects of ursodiol?

Answer 322

- it is a nontoxic bile acid that improves bile secretion and reduces cholesterol secretion and reabsorption - used to treat primary biliary cirrhosis as well as to prevent or dissolve gallstones