GI path cont. and anatomy

Mucocele of appendix

Appendix is obstructed by scarring or fecaliths

Isolated segment continues to produce mucus

Causes the formation of a retrocecal mass

Asymptomatic, 50% have palpable mass in RLQ

Usually benign

USA Mucocele

Elongated appendix filled with mucus

Variable internal echogenicity can calcs

Wall thickness an be normal or thickened

Onion signs - Layers of debris within the appendix appear similar to the layers of an onion

Mucocele of appendix

Epiploic appendagitis

Thick fatty strands that attach to the serosal surface of the colon

Torsion or thrombosis can cause ischemia or infarction of the appendage

Leads to localized inflammation and pain

Epiploic appendagitis USA

Echogenic finger-like projection from colon wall

The surrounding pericolic fat becomes thickened and echogenic

Can simulate appendicitis; must differentiate b/c the treatments are different

Look for wall layers that are seen with appendix

Epiploic appendagitis

Functional bowel obstruction

Paralysis of the muscle in the bowel wall, lack peristalsis

Mechanical bowel obstruction

Physical impediment to progression of the luminal contents

Causes of bowel obstruction

Material in lumen, intrinsic/extrinsic masses, and circulatory compromise

Number 1 cause of bowel obstruction

Adhesions

Bezoars are intraluminal masses of undigested material:

Concretions - Inorganic substances; medications, bubble gum

Trichobezoar - hairball

Phytobezoar - indigestible plant or vegetable materials (cellulose)

Lactobezoar - milk materials, seen in infants

Serious complication of bowel obstruction

Bowel ischemia

Ultrasound eval of bowel obstruction:

Describe location of gut loops

Eval the caliber of the segment and size of obstruction

Describe the contents of the segment; solid, fluid, gas

Assess peristalsis

USA bowel obstruction

Dilation of the GI tract proximal to the obstruction; >2.5cm is abnormal

Luminal contents tend to move to-and-fro within the lumen, instead of progressing forward

Visualization of the plicae circulares

Difficult to diagnose with US, assess GI tract caliber, content, peristalsis, site of liminal obstruction, location of gut loops

Bowel obstruction

Intussusception most commonly occurs at

Ileocecal junction in the RLQ

Most common cause of small bowel obstruction in children 6mo - 4yrs old

Intussusception

Intussusception

Usually the small intestine (ilem) involutes into the large bowel

Lymph nodes, mesentery and blood vessels can be pulled into the cecum

Causes anemia, dehydration, and leukocytosis

Severe pain with peristalsis, vomiting, blooD in rectum

Red currant jelly stool - contains a mixture of blood and mucus

Compression techniques used to eval

USA Intussusception

Non-compressibility of the affected segment

Telescoping segments demonstrate multiple concentric rings of tissue

Also described as a target or doughnut-shaped lesion in the transverse plane

Wall folded over on each other

Thickened walls

Intussusception

Midgut malrotation

Refers to any variation in the normal rotation and fixation of the GI tract during development

Associated with MALPOSITION of SMA and SMV

Varices are usually present

Left gastric vein is most common portosystemic collateral seen with malrotation

Midgut malrotation USA

Document the reversed position of the SMA and SMV

Doppler used to eval flow in the SMA, SMV and collaterals

Flow reversal occurs in the left gastric vein

Color Doppler can be used to assess loss of flow to wall

Midgut malrotation

Adenocarcinoma

Colon cancer is the 3rd leading cause of death from cancer

Increased CEA levels in blood

Gastric tumors usually arise in the pre-pyloric region, antrum, and lesser curvature

Most common location of colon cancer

Rectum

Most common malignant tumor of GI

Adenocarcinoma

USA adenocarcinoma

Solid intraluminal mass of varying echogenicity

Difficult to asses with US, but administering a water enema during the exam may help to visualize an intraluminal tumor or abnormality

Endoscopic sonography

Rotating high frequency transducer (7.5MHz)

Pt placed in LLD position

Used to localize and characterized benign masses

Also used to staging esophageal cancer and differentiation gastric lymphoma from gastric carcinoma

Lymphoma

May be primary or widespread dissemination

Nodular, ulcerative, or infiltrating

Common in AIDS pt

Lymphoma USA

Large hypoechoic ulcerated masses

Found in stomach or small bowel

Gas artifact or small bowel

Gas artifact seen within ulcerations

Mets of GI

Lung, breast, melanoma

Multiple small ulcerated nodules

Difficult to differentiate from primary carcinoma

Hodgkin lymphoma

Esophagus connects to the _______ of the stomach

Cardiac orifice

Valvulae conniventes

Intraluminal extensions/folds that increase surface area for absorption in the jejunum

What vitamin is produced by the colon

K

The wall of a normal distended bowl segment will demonstrate ______ layers and measure ____mm thick

5; <3

Hormones that stimulate the digestive system

Gastrin, secretin, cholecystokinin

Hematocrit can be tested to evaluate suspected ___________, while WBC levels can be tested to eval suspected __________

GI bleed; Infection

Graded compression and deep breathing can be used:

To displace gas out of the field of view

What causes stenosis in the median arcuate ligament syndrome

Compression

Which of the following indicates mesenteric ischemia?

Dilated IMA

Retrograde flow in the hepatic artery

Portal venous gas

All of the above

All of the above

The olive, doughnut and cervix signs are indications of:

Pyloric stenosis

Pts evaluated to pyloric stenosis are typically ________ in age and evaluated with US with the pt in the _______ position

2-10 weeks, Right lateral decubitus

Which of the following measurements should be obtained when evaluating a pt for suspected pyloric stenosis?

Muscle thickness, channel length, cross sectional thickness

What is evaluated on pts with suspected inflammatory bowel disease?

Fecal testing

Creeping fat and pseudokidney sign are findings associated with:

Crohn disease

Acute RLQ pain is commonly associated with_______, while acute LLQ pain is commonly associated with _______

Appendicitis; diverticulitis

Which of the following correctly described ulcerative colitis?

Associated with Marfan syndrome

Usually affects jejunum

Causes portal venous gas

All of the above

Causes portal venous gas

The normal appendix is identified posterior to the ___________ and anterior to the _________

Terminal ileum; iliac vessels

Appendix can be obstructed by:

Fecalith, corprolith, stercolith

Primary purpose for using graded compression during US eval of GI tract

To cause peristalsis

If the appendix is obstructed by a fecalith, a _________ typically forms

Mucocele

Epiploic appengitis is most likely to be mistaken sonographically for________

Appendicitis

How can you differentiate epiploic appendagitis from appendicitis?

Document gut wall signature