GI tract pathology

acute appendicitis

inflammation of the appendix

what is the most common cause of acute abdominal pain, resulting in surgery?

acute appendicitis

acute appendicitis may results from:

• appendicolith

• fecalith

• lymph node

• tumor

• foreign body

• seeds

• parasite

McBurney sign

rebound tenderness over the McBurney point in the RLQ

Rovsing sign

pain elicited in the RLQ when the LLQ is palpated

complications of acute appendicitis include:

• perforation

• peritonitis

• abscess formation

• death

clinical findings of acute appendicitis:

• initial epigastric or general abdominal pain that, with time, is eventually restricted to the RLQ or over the inflamed appendix

• acute abdominal pain

• rebound tenderness → McBurney sign

• nausea and vomiting

• possible leukocytosis

• high fever → with abscess formation

• Rovsing sign

sonographic findings of acute appendicitis:

• non-compressible, blind-ended tube that measures more than 6 mm in diameter from outer wall to outer wall

• echogenic structure within the lumen of the appendix → appendicolith

• hyperemic flow within the wall of the inflamed appendix

• periappendiceal fluid collection

• possible thyroid in the belly sign → hyperechoic edematous connective tissue that surrounds the inflamed appendix that has similar echogenicity of a normal thyroid

pyloric channel

located at the distal portion of the pylorus, between the stomach and the proximal duodenal bulb

pyloric sphincter

a group of muscles that control gastric emptying and prevents undigested food products, or chyme, from refluxing back into the stomach from the duodenum

hypertrophic pyloric stenosis (HPS)

• a defect in the relaxation of the pyloric sphincter

• leads to the enlargement, or hypertrophy, of the pyloric muscles, causing a persistent closure of the pyloric sphincter and ultimately causes a gastric outlet obstruction

HPS is most common in what population?

• infants between 2-6 weeks old

• first-born, white male infants are more likely to suffer from HPS

olive sign

enlarged pyloric muscle that may be palpable during a physical exam of an infant with pyloric stenosis

how is pylorus stenosis examined in infants?

the infant is placed in the right lateral decubitus position. If the stomach is completely empty, a small amount of glucose solution may be given to the infant to drink to better visualize the pylorus

clinical findings of pyloric stenosis:

• first-born, white, male infant

• nonbilious, projectile vomiting

• weight loss

• constipation

• dehydration

• insatiable appetite

• palpable olive sign

sonographic findings of pyloric stenosis:

• abnormal pylorus appears as a target or doughnut in the short-axis view

• abnormal pylorus appears as a cervix in the long-axis view

• wall of pylorus will measure 3 mm or greater in thickness

• length of pyloric channel will measure 17 mm or greater

how is gastroesophageal reflux imaged?

a transverse section of the gastroesophageal junction can be obtained in most persons posterior to the left lobe of the liver and anterior to the abdominal aorta in the sagittal scan plane of the abdomen. After identifying the gastroesophageal junction, the transducer is manipulated to obtain a longitudinal image of the esophagus.

sonographic appearance of gastroesophageal reflux:

fluid mixed with gas bubbles can be observed traveling retrograde up the esophagus

midgut malrotations with or without volvulus

• the small bowel mesentery rotates around the superior mesenteric artery (SMA)

• pt will likely have bilious vomiting

how is midgut malrotation diagnosed?

• it is confirmed by identifying the relationship of the SMA with the superior mesenteric vein (SMV). The SMA is typically located to the left of the SMV. With malrotation, the position of the two vessels will be reversed.

• with color Doppler, a whirlpool appearance of the vasculature may be noted

intussusception

• the telescoping of one segment of bowel into another

• the intussusceptum, the proximal portion of the bowel, is allowed to invaginate into the next distal segment, the intussuscipiens

• the most common cause of intestinal obstructions in children less than 2 years of age and occurs most often in males

what is the most common type of intussusception?

the ileocolic intussusception, which occurs within the right lower quadrant at the level of the ileocecal valve

intussusception can lead to what other diseases?

ischemia and gangrene of the bowel

clinical findings of intussusception:

• intermittent, severe abdominal pain

• vomiting

• palpable abdominal mass

• red currant jelly stools

• leukocytosis

sonographic findings of intussusception:

• noncompressible, target-shaped or pseudokidney-shaped mass that consists of alternating rings of echogenicity (cinnamon-bun sign)

• the diameter of the intussuscepted bowel will exceed 3 cm

what are the 2 types of intestinal obstructions?

• mechanical

• nonmechanical

mechanical intestinal obstruction

results from the bowel being physically blocked by something, including adhesions, volvulus, herniations, intussusception, tumors, and inflammatory bowel disease

nonmechanical intestinal obstruction/paralytic ileus

when the bowel lacks normal peristalsis

bezoars

masses of various ingested materials that can cause intestinal obstructions

trichobezoars

• more often found in pediatric pts

• consist of ingested hair

lactobezoars

consist of powdered milk that has not been adequately mixed with water

phytobezoars

• more often found in older pts

• consist of vegetable material

sonographic appearance of bezoars:

will appear as complex masses with varying degrees of acoustic enhancement and posterior shadowing, depending on their structure

clinical findings of an intestinal obstruction:

• abdominal distention

• intermittent abdominal pain

• constipation

• nausea and vomiting

sonographic findings of an intestinal obstruction:

• small bowel diameter measure 2.5 cm or greater from outer wall to outer wall

• distended fluid-filled loops of bowel → keyboard sign

• an abrupt termination point of the distended bowel may be identified

• increased peristaltic motion with to-and-fro motion of intraluminal contents → in mechanical obstruction only

• colon diameter will exceed 6 cm

Crohn disease

• autoimmune disorder characterized by periods of inflammation of the gastrointestinal tract

• cause is unknown

what is the most common inflammatory disease of the small intestine?

Crohn disease

what part of the GI tract does Crohn disease usually involve?

the terminal ileum or proximal colon, but it can affect any part of the GI tract

clinical findings of Crohn diease:

• episodes of diarrhea

• abdominal pain

• weight loss

• rectal bleeding

sonographic findings of Crohn diease:

• bowel wall thickening → will measure > 3 mm

• affected bowel will be noncompressible and have a target appearance

• hyperemic wall

diverticulosis

the development of small outpouchings, diverticuli, in the digestive tract, most often the sigmoid colon

diverticulitis

inflammation resulting from infection of the outpouchings

clinical findings of diverticulitis:

• constipation or diarrhea

• fever

• nausea and vomiting

• cramping, LLQ pain

sonographic findings of diverticulitis:

• segmentally thickened bowel with evidence of an inflamed diverticula and inflamed perienteric fat

• affected bowel segment will typically reveal hyperemia

• inflamed diverticula may appear as echogenic projections from the bowel that produce shadowing or ring-sown artifact

colitis

inflammation of the colon

what are the different forms of colitis?

• pseudomembranous

• ulcerative

• ischemic

• infectious

pseudomembranous colitis

• more often associated with watery diarrhea

• can result from the use of antibiotic therapy that destroys the healthy flora of the intestines and leads to the subsequent proliferation of Clostridium difficile

clinical findings of colitis:

• bloody or watery diarrhea

• fever

• abdominal pain

• previous use of antibiotic therapy

sonographic findings of colitis:

• thickened, hypoechoic colon wall

• hyperemia within the colon wall

gastric cancer/stomach cancer

most often in the form of adenocarcinoma

colon cancer

• 3rd leading cause of death in Western countries

• typically found in the rectosigmoid colon

• endorectal sono is more effective than transabdominal for these lesions

adenocarcinoma of the appendix

can lead to rupture with the subsequent development of a gelatinous ascites → pseudomyxoma peritonei

sonographic appearance of pseudomyxoma peritonei:

may appear as a multiseptated cystic mass within the pelvis

what are the most commonly encountered metastatic tumors to the bowel?

• malignant melanoma

• primary tumors of the lungs and breast

clinical findings of gastrointestinal carcinoma:

• weight loss

• abdominal pain

• anorexia

• vomiting

sonographic findings of gastrointestinal carcinoma:

• hypoechoic, irregularly shaped, bulky mass

• could appear as a target or have a pseudokidney appearance

• masses can measure up to 10 cm