GI Tract Flashcards
What are the four layers of the bowel wall?
Mucosa
Submucosa
Muscularis externa
Adventitia or serosa
How thick is the normal intestinal wall?
3-5 mm
How does the bowel wall appear on ultrasound?
“Gut signature” or “target” or “pseudokidney” sign
Hypoechoic external rim corresponding to thickened intestinal wall and a hypoechoic center relating to a residual gut lumen or mucosal ulceration
What is the gastroesophageal junction?
Segment of the esophagus between the diaphragm and the stomach
How is pneumoperitoneum detected on ultrasound?
Free peritoneal air will float anteriorly with the patient in the supine position
A reverberation artifact or total sound reflection will appear after placing the transducer on the anterior abdomen
How do patients present with acute appendicitis?
Periumbilical pain shifting to RLQ
Anorexia
Leukocytosis
Rebound tenderness
What is the typical location for the appendix?
Posterior to the terminal ileum
Anterior to iliac vessels
What is the cause of appendicitis?
Obstruction of the appendiceal lumen by a fecalith or hyperplasia of the submucosa
What technique is used with ultrasound to displace bowel gas and decrease the distance between the transducer and the appendix?
Graded compression
What is sonographic criteria for diagnosing and inflammatory appendix?
Non-compressible appendix
> 6 mm diameter
Appendicolith
What does hypertrophic pyloric stenosis cause?
Functional gastric outlet obstruction and as a result of hypertrophy and hyperplasia of the muscular layers of the pylorus
At what age do patients present with hypertrophic pyloric stenosis?
3 to 8 weeks
What do patients with pyloric stenosis present with?
Vomiting (non-bloody, non-bilious)
Palpable olive shaped pylorus
Visible peristalsis
What is the pylorus size criteria?
Muscle thickness > 3 mm
Channel length > 17 mm
Cross-section diameter > 15 mm
What measurement is considered the most accurate for diagnosing a hypertrophic pylorus?
Muscle wall thickness
What are symptoms of diverticulitis?
Left lower quadrant pain
Fever
Leukocytosis
What are sonographic findings of diverticulitis?
Thickening of the bowel wall (> 4mm)
Abscess formation
Inflamed diverticula - round echogenic structures
What are causes of mechanical small bowel obstruction?
Intraluminal (food bolus)
Bowel wall lesion (tumor, Crohn’s disease)
Extrinsic (adhesions, hernia) - most common
How is ultrasound used to demonstrate small bowel obstruction?
Loops of distended bowel, level of obstruction, and peristalsis
What is the most common cause of intestinal obstruction in the infant – toddler age?
Intussusception
How does intussusception occur?
Peristalsis results in invagination of proximal bowel into lumen of more distal bowel = “telescoping” causing a bowel obstruction
Where does intussusception typically occur?
Ileocolic junction
What is the typical clinical presentation of intussusception?
Bloody diarrhea/currant jelly May be post viral illness Right-sided abdominal mass Vomiting Lethargy and irritability
What is the classic sign of an intussusception?
Sausage-shaped mass in the right hypochondrium
How does intussusception appear sonographically?
“Pseudo-kidney” mass - longitudinal plane
“Target sign” or concentric rings of folded bowel - transverse plane
