GI - Malabsorption Syndromes; Inflammatory Bowel Disease Flashcards
What is the term for poor oxygenation to the intestines due to decreased/impeded blood flow?
Mesenteric ischemia
Name a few levels of infarction severity of acute mesenteric ischemia.
Mucosal infarction;
mural infarction;
transmural infarction
Describe the gross morphology of a case of transmural acute mesenteric ischemia.
Bowel:
Submucosa/subserosa:
Wall:
Lumen:
Bowel: dusky red, congested
Submucosa/subserosa: ecchymosis (skin discoloration due to bleeding underneath)
Wall: edematous, thick, hemorrhagic
Lumen: bloody (this is what presents clinically; patients come in with bloody stool)
How does acute mesenteric ischemia present clinically?
Bloody stool
Describe the microscopic morphology of acute mesenteric ischemia.
Mucosal necrosis/hemorrhage
Submucosal edema
Muscle layer is indistinct
Gangrene and perforation due to intestinal bacteria
Fibrin deposition
Chronic mesenteric ischemia is caused by severe compromise of ___+ major arteries by ___________.
Chronic mesenteric ischemia is caused by severe compromise of 2+ major arteries by atherosclerosis.
What are the lesions of chronic mesenteric ischemia situated?
Segmental and patchy
Clinically, chronic mesenteric ischemia mimics what disorder?
Inflammatory bowel disease
Most nutrient absorption occurs in what portion(s) of the intestines?
The duodenum and jejunum
What substances are absorbed in the distal ileum only?
Bile salts;
B12
__________ refers to poor transport/absorption of micronutrients that have already broken up.
__________ refers to incomplete breakdown of particles in the intestinal lumen.
Malabsorption refers to poor transport/absorption of micronutrients that have already broken up.
Maldigestion refers to incomplete breakdown of particles in the intestinal lumen.
What is the most common cause of malabsorption disorders?
Absence of brush border enzymes
(e.g. lactase deficiency, post-viral enzyme deficiency, etc.)
True/False.
Malabsorption has many potental causes, including: enzyme deficiencies, impaired mobility, secretory insufficiency (e.g. gallbladder or pancreatic issue), sprue, fibrosis, short-bowel syndrome.
True.
Malabsorption with diarrhea is usually a result of impaired absorption of what?
Carbohydrates
Malabsorption with steatorrhea is often a result of what?
Pancreatic insufficiency
A mix of what three S/Sy are typically seen in malabsorptive disorders?
Diarrhea;
steatorrhea;
bloating
What is the most important of the diagnostic tests malabsorption syndromes?
What does it differentiate?
The stool fecal fat test (Sudan stain);
osmotic diarrhea vs. true fat absorption issues
What test can be used to check for pancreatic exocrine insufficiency?
The fecal pancreatic elastase test
______ vitamin levels can be checked to assess a patient’s potential malabsorption.
Serum vitamin levels can be checked to assess a patient’s potential malabsorption.
True/False.
Celiac disease is a wheat allergy.
False.
Celiac disease is a multifactorial autoimmune disorder triggered by the proteins in wheat, rye, barley, and sometimes oats.
What genetic haplotype is most associated with Celiac disease?
HLA DQ2 and DQ8
Celiac disease is a _________-mediated disorder that presents most severely in the __________ and _________ of the intestines.
Celiac disease is a T-cell-mediated disorder that presents most severely in the duodenum and jejunum of the intestines.
In Celiac disease, T cells are targeting what?
Tissue transglutaminase
Celiac disease leads to ___________ of the small intestinal villi and loss of the ______________.
Celiac disease leads to flattening of the small intestinal villi and loss of the microvilli brush border.
Normally villous height should be _______ than crypt depth. This is inverted in celiac disease.
Normally villous height should be larger than crypt depth. This is inverted in celiac disease.
Celiac disease is characterized by the presence of _____________ in the lamina propria.
Celiac disease is characterized by the presence of mononuclear cells (plasma cells, lymphocytes, macrophages, eosinophils, and mast cells) in the lamina propria.
What antibodies are associated with Celiac disease?
Anti-TTG, anti-endomysial antibodies, deamidated-gliadin antibodies
Will a patient with Celiac disease still have relevant serum antibodies if they stop eating gluten?
No.
Tropical (post-infectious) sprue can affect what portion(s) of the intestines?
The entire small bowel
True/False.
Tropical (post-infectious) sprue almost always presents as severely flat lesions.
False.
Tropical (post-infectious) sprue is variable and can present normally or as severe flat lesions.
Tropical (post-infectious) sprue typically follows what geographic distribution?
Caribbean or southeast Asia
How is tropical (post-infectious) sprue treated?
Antibiotics
What term refers to a non-infectious over-colonization of the small intestine by normal gut flora?
Small intestine bacterial overgrowth
(SIBO)
Name some potential causes of small intestine bacterial overgrowth (SIBO).
Surgical resection, multiple diverticula, stasis, blind-loop syndrome
Small intestine bacterial overgrowth (SIBO) is characterized by __________ inclusions.
Small intestine bacterial overgrowth (SIBO) is characterized by neutrophilic inclusions.
Whipple’s disease (an extremely rare form of malabsorption syndrome) is of what etiology?
Tropheryma whipplei
(WD is a systemic bacterial infection.)
Name some of the S/Sy associated with Whipple’s disease.
Fever, malabsorption, weight loss, lymphadenopathy
What are the CAN effects associated with Whipple’s disease?
Cardiac effects
Arthralgias
Neurologic effects
Describe the histology of Whipple’s disease.
Organism-laden macrophages building up in the lamina propria;
PAS-positive granules within macrophages
Describe the Gram-stain and shape of Trophyerma whippli.
Gram-positive bacilli
What are the two main forms of irritable bowel disease?
Ulcerative colitis
+
Crohn’s disease
Crohn’s disease is a chronic inflammatory disease of __________ etiology that can affect any part of the GI tract and occasionally other organs, but usually affects the __________ and __________.
Crohn’s disease is a chronic inflammatory disease of idiopathic etiology that can affect any part of the GI tract and occasionally other organs, but usually affects the distal ileum and proximal colon.
How do Crohn’s disease lesions appear?
Transmural, discontinuous (‘skip’) lesions
(with thickening, cobblestoning, fistulas, fibrosis, and non-caseating granulomas)
Ulcerative colitis is a chronic inflammatory disease of __________ etiology affecting primarily the _______ (layer(s)) of the _______ (intestinal section(s)).
Ulcerative colitis is a chronic inflammatory disease of idiopathic etiology affecting primarily the mucosa of the colon.
How do the lesions of ulcerative colitis appear?
Superficial, mucosal lesions that are diffuse & contiguous
(and flattened mucosa stemming from the rectum)
Inflammatory pseudopolyps are sometimes associated with which form of inflammatory bowel disease?
Ulcerative colitis
In ulcerative colitis, the bowel wall is _______ (thickened/thinned).
In Crohn’s disease, the bowel wall is _______ (thickened/thinned).
In ulcerative colitis, the bowel wall is thinned.
In Crohn’s disease, the bowel wall is thickened.
In ulcerative colitis, the inflammation is _______ (mucosal/submucosal/transmural).
In Crohn’s disease, the inflammation is _______ (mucosal/submucosal/transmural).
In ulcerative colitis, the inflammation is mucosal.
In Crohn’s disease, the inflammation is transmural.
In ulcerative colitis, the fibrosis is _______ (mild/marked).
In Crohn’s disease, the fibrosis is _______ (mild/marked).
In ulcerative colitis, the fibrosis is mild.
In Crohn’s disease, the fibrosis is marked.
Which form of inflammatory bowel disease is associated with non-caseating granulomas?
Crohn’s disease (50% of cases)
Which form of inflammatory bowel disease is associated with fistulas and deep, linear ulcers?
Crohn’s disease
Which form of inflammatory bowel disease is most associated with superficial ulcerations only?
Ulcerative colitis
How does Crohn’s disease typically present clinically?
Pain, diarrhea, perianal disease, obstruction, fistulas, strictures
How does ulcerative colitis typically present clinically?
Bloody diarrhea, strictures, toxic colitis
Which inflammatory bowel disease is associated with systemic complications?
Both Crohn’s disease and ulcerative colitis
Which inflammatory bowel disease is associated with strictures, dysplasia, and carcinoma?
Both ulcerative colitis and Crohn’s disease
The longer the _________ of either Crohn’s disease or ulcerative colitis, the higher the incidence of associated malignancy.
The longer the duration of either Crohn’s disease or ulcerative colitis, the higher the incidence of associated malignancy.
Describe the following colorectal malignancies:
Colonic –
Mucinous –
Signet ring –
Describe the following colorectal malignancies:
Colonic – flat ulcers
Mucinous – tumor cells floating in mucus
Signet ring – mucin-filled signet ring cells, but remember these also come up in Lynch syndrome
