Chapter 10 - GI

Question 1

Which vitamins are fat soluble?

Answer 1

A, D, E, and K

Question 2

How does vitamin A deficiency present?

Answer 2

with night blindness and xerophthalmia (dry conjunctiva and cornea)

Question 3

How does vitamin E deficiency present?

Answer 3

with anemia or hemolysis, neurologic deficits, and altered prostaglandin synthesis

Question 4

How does vitamin B1 deficiency present?

Answer 4

as beriberi, consisting of cardiac failure, peripheral neuropathy, hoarseness or aphonia, and Wernicke’s encephalopathy

Question 5

How does vitamin C deficiency present?

Answer 5

as scurvy with hematologic abnormalities, edema, spongy swelling of the gums, poor wound healing, corkscrew hairs, and impaired collagen synthesis

Question 6

How does niacin deficiency present?

Answer 6

as pellagra with diarrhea, dermatitis, and dementia and with glossitis or stomatitis

Question 7

How does zinc deficiency present?

Answer 7

with skin lesions, poor wound healing, immune dysfunction, diarrhea, and growth failure

Question 8

What is the difference between marasmus and kwashiorkor?

Answer 8

• marasmus is a total calorie deficiency, yielding a very thin individual
• kwashiorkor is a protein deficiency, presenting as generalized edema, abdominal distention, changes in skin pigmentation, and thin sparse hair

Question 9

What is the difference between digestion and absorption?

Answer 9

• digestion is an intraluminal event requiring digestive enzymes and bile acids for micelle formation
• absorption requires an intact intestinal mucosal surface and villous brush border with intact transport mechanisms

Question 10

Carbohydrate Malabsorption

Answer 10

• may be caused by an isolated congenital enzyme deficiency like a lactase deficiency or by mucosal atrophy
• undigested sugars are osmotically active, causing increased stool volume and thus peristaltic activity, which subsequently decreases transit time; furthermore, unabsorbed carbohydrates are fermented by colonic bacteria producing gas and acid
• the result is watery, acidic stools which test positive for reducing substances

Question 11

Protein Malabsorption

Answer 11

• may be caused by congenital enterokinase deficiency, a protein-losing enteropathy with transudation of protein from inflamed mucosa, or an inflammatory disorder of the intestinal mucosa such as IBD
• presents with hypoproteinemia, edema, and growth impairment
• fecal alpha-antitrypsin levels may be used to identify enteric protein losses

Question 12

Lipid Malaborptions

Answer 12

• causes include exocrine pancreatic insufficiency, intestinal mucosal atrophy, bile acid deficiency, or abetalipoproteinemia
• results in steatorrhea and decreased absorption of fat-soluble vitamins

Question 13

What stool findings are consistent with carbohydrate, protein, and lipid malabsorption?

Answer 13

• carbohydrate: watery, acidic stools positive for reducing substances
• protein: elevated a1-antritrypsin
• lipid: steatorrhea

Question 14

Protein Intolerance

Answer 14

• a syndrome of diarrhea, vomiting, and colicky abdominal pain after exposure to dietary protein
• most often after an exposure to cow’s milk, but eggs and soy products can also trigger episodes
• presents with diarrhea, vomiting, and abdominal pain; chronic blood loss may lead to anemia and protein loss may lead to edema and failure to thrive
• diagnosis is made by withdrawal of symptoms following avoidance of suspected antigen
• most cases are transient and resolve by 1-2 years of age

Question 15

Celiac Disease

Answer 15

• an autoimmune disease mediated by CD4 cells, which damage the small bowel villi following exposure to gliadin, a component of gluten
• strongly associated with HLA-DQ2 and HLA-DQ8
• presents in children, usually 6-24 months old, with abdominal pain and distention, diarrhea, vomiting, irritability, failure to thrive, and large, foul-smelling stools
• 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 is the gold standard for diagnosis and 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 16

Short Bowel Syndrome

Answer 16

• a malabsorption resulting from congenital gut lesions that require surgical resection, surgery for necrotizing enterocolitis, Crohn’s disease, tumors, or radiation enteritis
• presents with diarrhea, malabsorption, and failure to thrive
• carbohydrate and fat malabsorption with steatorrhea are common; dehydration, hyponatremia, and hypokalemia may occur; B12 and bile acid deficiencies may result if the terminal ileum is affected
• managed with TPN and early enteral feedings to ensure adaptive growth of remaining bowel, proper GI functioning, and proper oral motor development
• may be complicated by TPN cholestasis, intestinal bacterial overgrowth, nutritional deficiency, poor bone mineralization, renal stones, and secretory diarrhea

Question 17

What is the difference between gastroesophageal reflex and GERD?

Answer 17

• reflux is the normal physiologic state

- GERD is a pathologic state associated with GI or pulmonary symptoms and sequelae

Question 18

Physiologic Gastroesophageal Reflux

Answer 18

• reflux is the normal physiologic state whereas GERD is a pathologic state associated with GI or pulmonary sequelae
• important to remember that reflux and emesis itself is benign
• manage with parental education and reassurance; typically resolves by 6-12 months of age

Question 19

GERD

Answer 19

• reflux is the normal physiologic state whereas GERD is a pathologic state associated with GI or pulmonary sequelae
• during childhood, the most common cause of GERD is inappropriate, transient, lower esophageal sphincter relaxation, but delayed gastric emptying may contribute
• infants typically present with emesis, potentially leading to poor calorie retention and FTT; sandier syndrome, torticollis with arching of the back caused by painful esophagitis; and feeding refusal with irritability or constant hunger
• older children presents with symptoms of esophagitis, including midepigastric pain relieved with food or antacids and worsened by fatty foods, caffeine, and the supine position; in addition to nausea, hoarseness, halitosis, and wheezing
• may eventually lead to upper and lower airway disease because it induces bronchopulmonary constriction and may lead to aspiration; may also see esophageal strictures or Barrett’s esophagus
• increases the risk for esophageal adenocarcinoma
• diagnosed involves a barium upper GI study to examine the anatomy, but this is a poor test for diagnosing GERD; scomtography provides information on the rate of gastric emptying; pH probe measurement of the esophagus correlated with clinical symptoms over at least 18 hours is the gold standard for diagnosis; endoscopy can be used when uncertain
• treat with upright positioning, thickening feeds, use of acid inhibitors, motility agents to increase LES tone or gastric emptying speed, and Nissen fundoplication to reduce TLESR if severe enough to warrant surgery

Question 20

Hypertrophic Pyloric Stenosis

Answer 20

• congenital hypertrophy of pyloric smooth muscle
• more common in first born males and individuals exposed to macrolides
• 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
• diagnosis is made by ultrasound and treatment is surgical

Question 21

Midgut Malrotation

Answer 21

• an instance in which the midgut is twisted around the superior mesenteric vessels, causing obstruction and infarction
• occurs when normal bowel rotation in utero is disrupted: lack of fixation results in peritoneal bands that can compress the duodenum or the narrow pedicle which suspends the bowel can easily twist
• presents with sudden onset abdominal pain and bilious vomiting with anorexia, abdominal distention, and blood-tinged stools
• diagnosed using an upper intestinal contrast imaging, which shows abnormal position of the ligament of Treitz to the right of midline, partial or complete duodenal obstruction, and the jejunum to the right of midline
• considered a surgical emergency; fluid resuscitation, nasogastric suctioning, and broad-spectrum parenteral antibiotics should be given

Question 22

Volvulus

Answer 22

• 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 cecum if the patient is younger since that is an area with superfluous mesentery
• presents with acute onset abdominal pain and red “currant jelly” stool

Question 23

Describe mid-gut rotation in utero.

Answer 23

the intestines normally return to the abdomen through the umbilical cord during the tenth week of gestation and undergo a counterclockwise rotation about the SMA

Question 24

Duodenal Atresia/Stenosis

Answer 24

• a failure of the lumen to fully recanalize at 8-10 weeks
• commonly associated with Down syndrome
• presents with gastric dilation and polyhydramnios on prenatal US; epigastric distention, feeding intolerance, and bilious vomiting if atresia; emesis, weight loss, and FTT if stenosis
• x-ray shows the double bubble sign and intestinal contrast studies are also very effective for diagnosis
• treat with hydration, correction of electrolyte abnormalities, and surgical correction
• often associated with other abnormalities, so exploration for malrotation and other obstructions are often needed

Question 25

Jejunal Atresia

Answer 25

• caused by mesenteric vascular accident during fetal life
• not usually associated with other anomalies, in contrast to duodenal atresia
• presents with bilious emesis and abdominal distension
• diagnose with abdominal radiograph demonstrating the “triple bubble” sign, finding air-fluid levels, and contrast studies
• treat with fluid resuscitation then surgical correction

Question 26

Intussusception

Answer 26

• 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 is most often lymphoid hyperplasia arising in the terminal ileum with intussusception into the cecum or a Meckel diverticulum
• typically occurs before one year of age at the ileocecal junction and presents with sudden onset, intermittent colicky abdominal pain, vomiting, lethargy, and “currant jelly” stools
• diagnosed and treated with air or contrast enema with hydrostatic pressure; this should be supplemented with fluid resuscitation
• surgery is indicated only if the enema fails to reduce the intussusception or there are signs of peritonitis or pneumoperitoneum

Question 27

What is an acute abdomen?

Answer 27

sudden onset of abdominal pain that requires urgent evaluation

Question 28

Appendicitis

Answer 28

• caused by obstruction of the appendix, usually by either a fecalith or lymphoid tissue; this causes distention and ischemia, which can lead to perforation after 36-48 hours
• presentation begins with periumbilical pain followed by vomiting, then the pain localizes to McBurney’s point; patients often experience fever and anorexia; exam shows guarding and rebound tenderness
• management requires fluid resuscitation, preoperative antibiotics, and appendectomy
• if there is perforation, irrigation of the peritoneal cavity and parenteral antibiotics are indicated

Question 29

Acute Pancreatitis

Answer 29

• 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 blunt trauma or infection; drugs, toxins, congenital anomalies, and obstruction are also possible causes; generally uncommon in pediatrics
• presents with periumbilical pain that radiates to the back; fever, anorexia, n/v; decreased bowel sounds; bluish discoloration of the flanks known as Gray-Turner sign; and blue discoloration of the periumbilical area known as Cullen sign; hypotension, tachycardia, and hypoxia
• may be complicated by respiratory insufficiency, ARDS, renal failure, shock, and GI bleeding
• serum amylase rises early but serum lipase is more specific and remains elevated longer; may also have hyperglycemia, hypocalcemia, and elevated transaminases
• abdominal US is the most common method for diagnosis and management but CT may be needed for diagnosing complications such as pseudocyst
• treat with supportive care minimizing oral feedings, possible TPN, and antibiotics

Question 30

Cholecystitis

Answer 30

• 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
• sickle cells disease, cystic fibrosis, and prolonged TPN are all risk factors
• presents with diffuse abdominal pain that eventually localizes to the right upper quadrant and radiates to the scapula; positive Murphy sign with inspiration
• fever, anorexia, n/v, elevated WBC, and elevated serum alkaline phosphatase are often present
• diagnosis confirmed by ultrasound
• begin fluid resuscitation, parenteral antibiotics, and analgesia

Question 31

Functional Abdominal Pain

Answer 31

• a non-organic cause of chronic abdominal pain, defined as occurring each month for at least three consecutive months
• classified according to clinical features: periumbilical pain is classic and confers secondary gain without interfering with pleasurable activities or sleep; epigastric pain associated with belching, bloating, n/v, and early satiety; or infra umbilical pain associated with cramping, bloating, and alterations in stool similar to IBS
• it is a diagnosis of exclusion and the healthier the child appears, the more likely the pain is functional
• when ruling out other causes, keep in mind that may children are asymptomatic carriers of H. pylori
• treated with family and individual counseling but the long-term prognosis is poor and many have symptoms that persist into adulthood

Question 32

Define constipation.

Answer 32

a reduction in defecation that causes adverse symptoms

Question 33

Define encopresis.

Answer 33

a developmentally inappropriate release of stools, primarily referring to leakage of liquid stool around a hard, retained stool mass that is involuntary released through the distended anorectal canal

Question 34

How should the stooling pattern of infants change as they age?

Answer 34

• 4 per day during the first week of life
• 2 per day by the first year of life
• 1 per day by four years of age

Question 35

Compare and contrast the features of functional and organic constipation.

Answer 35

• can be either functional, due to inappropriate constriction of the external anal sphincter, or organic
• functional is more common and is the more likely cause if it arises after toilet training, a sentinel event can be identified, or there is normal growth and development
• functional usually is behavioral and usually follows a traumatic event like a hard stool, diaper rash, or physical abuse, leading to a cycle of increased fecal mass and distress
• organic is more likely in those who haven’t yet toilet trained, have a history of pelvic surgery, or have delayed meconium passage
• organic causes include Hirschsprung’s, neuroenteric dyscuntiong, low-fiber diet, anatomic abnormalities, or systemic disease (e.g. dehydration, hypothyroidism, celiac’s)

Question 36

How should constipation be managed?

Answer 36

• mild, episodic constipation can usually be addressed with changes in the diet, including increased soluble fiber, more water, and less cow’s milk
• FFR requires cleaning out the fecal mass, softening the stool, and educating the patient and family so they can correct triggers, create a toilet routine, and remove negative reinforcements

Question 37

Ulcerative Colitis

Answer 37

• 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; colectomy can be curative but is reserved for intractable colitis

Question 38

Crohn’s Disease

Answer 38

• 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 39

Define hematemesis, hematochezia, and melena.

Answer 39

• hematemesis is vomiting of fresh or old blood, which often has a coffee ground appearance
• hematochezia is bright red blood passed via the rectum, typically with a lower GI source
• melena are dark, tarry stools, often indicating upper GI bleed proximal to the ligament of Treitz

Question 40

How should upper GI bleeding be evaluated and managed?

Answer 40

• get a history and physical, paying attention to hemodynamic status
• assess for ongoing bleeding and look for sources of bleeding with upper intestinal endoscopy if suspected
• stabilize their hemodynamic state and use endoscopic therapy for active bleeding or if rebleeding is very likely

Question 41

Name two conditions that may mimic upper GI bleeding but are not actual upper GI bleeding.

Answer 41

• newborns may swallow maternal blood and have hematemesis without upper GI bleeding
• older children may swallow blood during an epistaxis and can present with hematemesis without an upper GI bleed

Question 42

Juvenile Polyps

Answer 42

• a sporadic, hamartomatous, benign polyp
• it is the most common cause of significant lower GI bleeding after infancy
• tends to prolapse and cause bleeding that is painless, intermittent, and often streaky
• juvenile polyposis is characterized by multiple in the stomach and colon
• treat with colonoscopy and polypectomy

Question 43

Peutz-Jeghers Syndrome

Answer 43

• 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 44

List three markers for hepatocellular injury.

Answer 44

AST, ALT, and LDH

Question 45

Name three markers for biliary injury.

Answer 45

alkaline phosphatase, gamma glutamic transpeptidase, and 5’-nucleotidase

Question 46

Inspissated Bile Syndrome

Answer 46

• a form of infant jaundice caused by the biliary system becoming overwhelmed
• associated with hemolysis or a very large hematoma
• UCB predominates early but conjugated becomes elevated eventually as hepatocellulr function increases to meet demand

Question 47

What is the difference between Gilbert’s syndrome, Crigler-Najjar type I, and Crigler-Najjar type II?

Answer 47

• Gilbert: 50% of UDPGT function remains and jaundice is only during times of stress
• CN Type I: an autosomal recessive condition in which all UDPGT function is absent, leading to kernicterus
• CN Type II: an autosomal dominant condition in which 90% of UDPGT function is absent, leading to variable bilirubin levels and rates of kernicterus

Question 48

Cholestatic Diseases of Infancy

Answer 48

• a group of disorders characterized by retention of bile within the liver causing prolonged direct hyperbilirubinemia
• may be caused by infection, metabolic derangement, extra hepatic or intrahepatic obstruction, or TPN-associated disease
• presents with jaundice, acholic stools, dark urine, hepatomegaly, bleeding, and failure to thrive

Question 49

Neonatal Hepatitis

Answer 49

• an idiopathic hepatitis and the most common cause of cholestasis in the newborn
• jaundice and hepatomegaly typically present in the first week of life with failure to thrive and potentially liver failure coming later
• it is a diagnosis of exclusion
• management involves nutritional support, possibly requiring TPN, and ursodeoxycholic acid (a bile acid which reduce bile viscosity and enhances flow) after biliary obstruction has been ruled out

Question 50

Biliary Atresia

Answer 50

• failure to form or early fibrosclerotic destruction of the extrahepatic biliary tree
• typically presents in the first two months of life with jaundice, dark urine, and acholic stools; bilirubin levels are moderately elevated
• progresses quickly with cirrhosis occurring by four months of age, indicated by hepatosplenomegaly, ascites, peripheral edema, etc.
• diagnosed with ultrasound, radio nucleotide imaging, and liver biopsy to rule out other causes; then an intraoperative cholangiogram with laparotomy confirms the diagnosis
• treated with Kasai portoenterostomy to establish bile flow, but the success is dependent on the timing and is highest if performed in the first two months of life

Question 51

Alagille Syndrome

Answer 51

• an autosomal dominant disorder with a paucity of intrahepatic bile ducts and multi organ involvement
• presents with cholestatic liver disease, debilitating pruritus, unusual facial characteristics, cardiac disease and pulmonary outflow obstruction in particular, renal disease, eye anomalies, growth failure and short stature, pancreatic insufficiency, and hypercholesterolemia
• treatment is supportive

Question 52

Most cases of pediatric viral hepatitis are caused by which viruses?

Answer 52

Hep A and B

Question 53

What is the most common finding in pediatric patients with viral hepatitis?

Answer 53

most cases are asymptomatic

Question 54

Hepatitis A

Answer 54

• an infection spread by fecal-oral transmission, most commonly acquired during travel outside the US or from eating contaminated shellfish brought from elsewhere
• children are usually asymptomatic in the acute phase but there may be malaise, anorexia, vomiting, fever, abdominal pain, etc.
• jaundice occurs very rarely and chronic infection does not occur
• anti-HAV IgM marks an active infection while anti-virus IgG is protective and indicates prior infection or immunization

Question 55

Hepatitis B

Answer 55

• a DNA virus transmitted via vertical exposure in the perinatal period, the parenteral route, or by exposure to infected body secretions
• children are usually asymptomatic in the acute phase but there may be malaise, anorexia, vomiting, fever, abdominal pain, etc.
• chronic HBV infection is likely, especially in those who acquire it via vertical transmission, and results in severe liver disease, increasing the risk for HCC
• management is supportive during the acute phase; consider interferon-a and antivirals for chronic infection

Question 56

Describe Hepatitis B serology.

Answer 56

• HBsAg is indicative of active disease
• HBsAb is protective and can result from either vaccination or prior infection
• HBcAb results only from prior infection and does not convey immunity
• HBeAg and HBV DNA indicate infectiousness

Question 57

Hepatitis C

Answer 57

• an RNA virus of the flavivirus family
• transmitted perinatally via the vertical route and by parenteral exposure
• children are usually asymptomatic in the acute phase but there may be malaise, anorexia, vomiting, fever, abdominal pain, etc.
• less likely to progress to the chronic phase than HepB, but it is still a possibility
• diagnosis is by serology demonstrating the HCV antibody and HCV PCR

Question 58

What is unique about hepatitis D?

Answer 58

infection with HDV is dependent on a simultaneous or pre-existing infection with HBV because it requires the HBsAg

Question 59

Hepatitis E

Answer 59

• an RNA virus spread by fecal-oral transmission
• poses no risk for chronic hepatitis but carries a high mortality rate in pregnant women
• there is no vaccination available

Question 60

Autoimmune Hepatitis

Answer 60

• a progressive liver disease characterized by elevated serum transaminases, hypergammaglobulinemia, and circulating autoantibodies
• type I is more common and is defined by the presence of ANA or anti-smooth muscle antibody
• type II is defined by anti-liver kidney microsome antibody or anti-liver cytosol type I antibody
• presents in females before puberty, typically with acute hepatitis, mimicking viral hepatitis with the addition of non hepatic signs like fatigue, anorexia, arthritis, rash, nephritis, and vasculitis
• half of patients go on to have chronic liver disease
• diagnosed based on elevated serum transaminases, hypergammaglobulinemia, and circulating autoantibodies and a liver biopsy
• treated with supportive care, corticosteroids, immunosuppression, and liver transplantation depending on severity