First Aid: Gastrointestinal

Question 1

What is gastroschisis?

Answer 1

Extrusion of abdominal contents through abdominal folds (intestines are exposed and NOT covered by peritoneum)

Question 2

What is an Omphalocele?

Answer 2

Persistence of herniation of abdominal contents into umbilical cord. Failure of intestines to RETURN to body cavity. Contents ARE COVERED by peritoneum and amnion.

Question 3

After feeding her newborn for the first time, a mother notices the baby is drooling, choking and vomiting. You notice abdominal distension. What sign could the child have presented during the pregnancy that would help identify the disease? What test would you do next?

Answer 3

Esophageal Atresia with distal Tracheoesophageal Fistula (TEF)

Polyhydramnios because fetus couldn’t swallow amniotic fluid.

Try to pass nasogastric tube into stomach to confirm

Question 4

A baby boy presents two weeks after birth. You notice nonbilious projectile vomiting and an olive-like mass in the epigastric region. Peristalsis is visible through the abdominal wall. What should be done next?

Answer 4

Pyloric stenosis from congenital hypertrophy of smooth muscle of the pyloric sphincter.

Image the child to confirm and do a myotomy to surgically repaire

Question 5

What is an annular pancreas?

What is pancreas divisum?

Answer 5

Annular pancreas is when ventral pancreatic bud abnormally encircles the 2nd part of duodenum forming a ring of pancreatic tissue. May cause narrowing of small bowel.

Pancreas divisum is when ventral and dorsal parts fail to fuse at 8 weeks.

Question 6

What are the structures in the retroperitoneal space?

Answer 6

SAD PUCKER

Suprarenal (adrenal) glands
Aorta and IVC
Duodenum (2nd-4th parts)
Pancreas (except tail)
Ureters
Colon (ascending and descending)
Kidneys
Esophagus (lower 2/3)
Rectum (partially)

Question 7

You are doing a cholesystectomy procedure when you notice excessive bleeding occurring in the surgical site, possibly from the liver. What surgical maneuver, taking advantage of anatomical structures, would help control the bleeding?

Answer 7

Pringle maneuver - compressing hepatoduodenal ligament (which contains proper hepatic hartery, common bile duct, and portal vein) between thumb and index finger placed in omental foramen (also could use a soft hemostat).

Question 8

What ligament may be cut during surgery to access the lesser peritoneal sac?

Answer 8

Gastrohepatic (connects liver to lesser curvature of stomach) and contains gastric arteries. Separates greater and lesser sacs on the right.

Question 9

What are the four layers of the digestive tract, and what do they contain/function?

Answer 9

MSMS - inside out

Mucosa - epithelium (absorption), lamina propria (support), muscularis mucosa (motility)

Submucosa - submucosal nerve plexus (meissner)

Muscularis externa - includes myenteric nerve plexus (Auerbach’s), inner longitudinal and outer circular muscle layers

Serosa (when intraperitoneal)/Adventitia when retroperitoneal.

Question 10

What layers of the GI tract will ulcers affect? How about erosions?

Answer 10

Erosions affect only the mucosa

Ulcers can extend into submucosa, inner or outer muscle layers.

Question 11

In cases when an artery is blocked or damaged, anastomeses can be very helpful in keeping an organ perfused. Which arteries branching off of the celiac trunk have strong anastomeses, and which have poor?

Answer 11

Strong anastamoses between:

• Left and right gastroepiploics
• Left and right gastrics

Short gastrics provide poor anastamoses to spleen if the splenic artery is cut.

Question 12

What clinical signs are commonly seen with portal hypertension?

Answer 12

Varices of GUT, BUTT, and CAPUT (medusae):

Gut = EsophaGUS (from left gastric –> esophageal)
Butt = Rectum (from IMV –> superior rectal vein)
Caput medusae =Umbilicus (from paraumbilical vein)

Question 13

What treatment can be used to relieve portal hypertension?

Answer 13

transjugular intrahepatic portosystemic shunt (TIPS) between portal and hepatic veins relieves by shunting portal blood to systemic circulation

Question 14

What is the key symptomatic difference between hemorrhoids above and below the pectinate line?

Answer 14

Above (internal hemorrhoids) is not painful because visceral innervation

Below (external hemorrhoids) is painful because somatic innervation

Also venous and lymphatic drainages are different.

Question 15

What are the key signs and symptoms of an anal fissure?

Answer 15

The P’s:

below the Pectinate line. Pain while Pooping. blood on toilet Paper. located Posteriorly since this area is Poorly Perfused.

Question 16

Which liver zone is most at risk for ischemia? What 3 characteristics are unique about this area?

Answer 16

Zone III: pericentral vein (centrilobular) zone

Contains cytochrome p450 esystem
Most sensitive to metabolic toxins
Site of Alcoholic hepatitis

Question 17

Which structure in the biliary system can cause the most problems if blocked by a stone? What is another pathology that can occur in this area that disrupts biliary function?

Answer 17

Gallstones that reach the common channel at ampulla of Vater can block BOTH bile and pancreatic ducts

Tumors of head of pancreas (near duodenum) can obstruct common bile duct.

Question 18

What is the difference between an indirect and direct inguinal hernia? Through what opening do femoral hernias protrude?

Answer 18

Indirect protrudes through the internal inguinal ring while Direct protrudes through abdominal wall via the weak area of Hesselbach’s (inguinal) triangle.

Femoral hernias protrude through femoral ring which contain the lymphatics (most medial, preceded by Vein, artery and nerve most lateral)

Question 19

Which pathological conditions will increase gastrin levels the most?

Answer 19

Zollinger Ellison syndrome the most

Chronic PPI use

Phenylalanine and tryptophan are potent stimulators.

Question 20

A patient presents with copious Watery Diarrhea, Hypokalemia, and Achlorhydria. What GI regulatory substance is most likely the cause for this presentation?

Answer 20

Vasoactive intestinal polypeptide (VIP) will increase if patient has a “VIPoma”, a non-alpha non-beta islet cell pancreatic tumor that secretes VIP.

WDHA syndrome results in the symptoms described.

Question 21

What regulators will increase and decrease gastric acid levels? What pathology will increase gastrin acid resulting in ulcers that are refractory to medical therapy?

Answer 21

Histamine, ACh and Gastrin are major upregulators of gastric acid.

Somatostatin, GIP, prostaglandins, and secretin are downregulators.

Gastrinoma is a gastrin secreting tumor that will increase gastric acid.

Question 22

Where in the stomach are Chief cells and Parietal cells located? Where does gastrin predominantly act to increase gastric acid levels?

Answer 22

the Body

Gastrin primarily acts on enterochromaffin-like (ECL) cells –> leading to histamine release –> activating parietal cells to increase acid secretion

Question 23

Which enzymes are primarily released in pancreatic secretions?

Answer 23

alpha-amylase for starch digestion
Lipases for fat digestion
Proteases for protein digestion
Trypsinogen which becomes trypsin

Question 24

What are the main clinically useful inhibitory sites in the gastric parietal cell?

Answer 24

Atropine at ACh receptor on basal side

H2 blockers at Histamine receptor on basal side

Prostaglandins which inhibit intracellular cAMP formation

Proton pump inhibitors which block ATPases on luminal surface

Question 25

Where are Peyer patches located and what do they secrete? What pathology can result from these sites?

Answer 25

Lymphoid tissue found in lamina propria and submucosa of ILEUM.

B-cells become –> IgA secreting plasma cells –> Release IgA

Peyer patches can become large and inflamed following viral infection and can get hooked during peristalsis and pushed into cecum resulting in INTUSSUCEPTION