Pathoma- Chapter 10: Appendix and IBD
Terms in this set (44)
What is acute appendicitis?
-Acute Inflammation of the appendix
What is the most common cause of an acute abdomen?
What is an acute abdomen?
-When a pt. presents with acute abdominal pain and is often a surgical emergency
What is the most common cause of appendicitis in kids?
-Obstruction of the appendix by lymphoid hyperplasia
-This lymphoid hyperplasia can be seen as the result of a GI infection
What is the most common cause of appendicitis in adults?
-Obstruction of the appendix by a fecalith
How do pts. with acute appendicitis present?
In appendicitis, the pan is initially periumbilical but localizes to where?
-Localizes to the right lower quadrant (McBurney point)
What can rupture of the appendix lead to?
-Peritonitis that presents with guarding and rebound tenderness
What is the formation of an abscess around the appendix?
What is IBD?
-Chronic, relapsing inflammation of the bowel
What is the classical presentation of IBD?
-Young women (teens to 30s) with recurrent bouts of bloody diarrhea and abdominal pain
What demographics are more likely to be affected by IBD?
-Young women (teens to 30s)
-More prevalent in the West, particularly Caucasians and Eastern European Jews
What are the 2 types of inflammatory bowel disease?
Ulcerative colitis (UC)
-Mucosal and submucosal ulcers
-The word 'ulcer' means that you are basically damaging the mucosa along with a bit of the submucosa
-Begins in the rectum and can extend proximally up to the cecum (involvement is continuous- involves the entirety of the colon)
-Remainder of the GI tract is unaffected (high-yield)
Where does it always begin and where can it end?
-In the rectum
-The cecum is its endpoint
-Left lower quadrant pain (rectum) with bloody diarrhea
What is the key histologic hallmark (very high-yield)?
-Crypt abscess with neutrophils (very high-yield)
What is a crypt abscess?
-The normal histology of the colon is rows of crypts
-In UC, the crypts will be filled with neutrophils
-Pseudopolyps- represent these numerous bumps that arise on the surface of the colon as a response to the healing of the ulceration
-There will also be the loss of the haustra
How will the loss of the haustra appear on imaging?
-'lead pipe' sign on imaging
What is toxic megacolon?
-Get massive dilation of the colon- and the patients begin to appear toxic (febrile, etc.)
-This has the risk of rupture
What is the most important complication of UC?
-The feared complication is that they are going to develop dysplasia- after which, they will develop a carcinoma
What is the risk of carcinoma development based on (very high-yield)?
-The extent of colonic involvement- the more of the colon that is involved- the more likely you are to get cancer
-Duration of the disease- generally not a concern until >10 years of the disease
Why must they undergo screening colonoscopies?
-To determine whether or not dysplasia is present
-The presence of dysplasia gets you one step closer to carcinoma
-Primary Sclerosing Cholangitis
What marker can be positive in this disease (very high-yield)?
Which vasculitidies will also have a positive p-ANCA?
What does smoking do to UC?
-Smoking does protect against UC
-Full-thickness inflammation with knife-like fissures
-Anywhere from the mouth to anus with skip lesions
-Terminal ileum is the most common site
-Rectum is the least common
Is the disease continuous in its involvement of the GI tract?
-No, it has skip lesions- hits one area and then skips to another
What is the most common site (high-yield)?
What is the least common site (high-yield)?
-Right lower quadrant pain (due to involvement of the terminal ileum) and non-bloody diarrhea
What is the histological hallmark of the disease (very high-yield)?
-Lymphoid aggregates with granulomas (very high-yield) (40% of cases)
-The appearance of granulomas in Crohn's disease is very high-yield
-Cobblestone mucosa (represents the healing process)
-strictures ('string-sign' on imaging)
What is the string'-sign?
What is the creeping fat that is seen?
-In Crohn Disease, you are getting a full-thickness inflammation through the wall of the GI tract
-Outside, in the serosa, you have the mesentery and adipose tissue is hanging off of the mesentery
-When you get healing of the full-thickness inflammation- it will result in the appearance of granulation tissue because the stem cells have been knocked out- so this will result in fibrosis
-The myofibroblasts within the granulation tissue have contractile function- will cause the wall of the GI tract to contract and become fibrotic- this will narrow the lumen of the tract resulting in a stricture
-As the myofibroblasts contract- it will bring the fat closer into the serosa- which is what they call creeping fat
-Malabsorption with nutritional deficiencies (if there is significant damage to the small bowel)
-Calcium oxalate nephrolithiasis
-Carcinoma- if colonic disease is present
Calcium Oxalate Nephrolithiasis (very high-yield)
-We normally have oxalate in the gut, but we don't absorb very much of it
-If there is inflammation of the bowel- this then increases the ability of the oxalate to come into the blood
-If oxalate comes into the blood- it can eventually bind with calcium- especially in the filtrate of the glomerulus- resulting in kidney stones
Fistulas (very high-yield)
-Fistulas are abnormal connections between 2 tubes or a tube and another surface
What does smoking do to it?
-Increased risk for Crohn Disease in smokers