First Aid, Chapter 5, Anatomy, Physiology, and Pathology, Gastrointestinal Flashcards
How do Peyer’s patch follicles differ from LN?
Peyer’s patches follicles differ from LN in that there is never a resting appearance due to a constant response to gut flora.
Where are Peyer’s patches located?
Small and large intestine.
What are microfold cells in GALT?
Microfold (M) cells are overlying specialized epithelial cells with microvilli that help in antigen sampling.
Where do follicles exist in GALT? What do they contain?
Follicles located within lamina propria of intestinal mucosa have B lymphocytes.
What do parafollicular areas in GALT contain?
T lymphocytes
Are there afferent lymphatics in GALT?
No afferent lymphatics, lymphocytes reach here via high endothelial venules (HEV) and leave via efferent lymphatics.
What is a diagnostic biopsy characteristic for eosinophilic esophagitis (EoE)?
Greater than 15 eosinophils per high powered field while on a proton pump inhibitor (PPI) for at least 4–8 weeks.
Where are eosinophils located in the GI tract?
Eosinophils are present in all segments of gastrointestinal tract mucosa at baseline EXCEPT for the esophagus.
What type of immune process are eosinophilic associated GI disorders?
Th type 2 lymphocyte mediated process driven by food allergens.
What layers of the gut do eosinophils infiltrate in EGID (eosinophilic associated GI disorders).
Characterized by eosinophilic infiltrates in the mucosal, vascular, and/or serosal layers of the gut (Figure 5-13).
What cytokines are implicated in the pathogenesis of Eoe?
IL-5 and Eotaxin-3
Describe allergic proctocolitis or eosinophilic proctocolitis. What is the cause? Is there an association with atopy or specific IgE? What is the prognosis?
Allergic proctocolitis, or eosinophilic proctocolitis, typically presents with bloody stools in an otherwise well-appearing infant. The condition occurs in infants, is strongly associated with breast-fed infants, and has a benign and limited course. Dietary proteins, most commonly cow’s milk protein, excreted in the mother’s milk are responsible for the majority of cases. There is no association with atopy or specific IgE, and greater than 90% will tolerate an unrestricted diet by 1 year of age.
What is found on endoscopy of eosinophil associated gastrointestinal disorders?
On endoscopy, linear furrows, white papules or plaques, or concentric rings may be found.
Why does total IgA need to be measured when screening for celiac diseased?
Diagnostic screening for celiac disease with antitTG IgA should always be accompanied by a serum IgA level. IgA deficiency is often undiagnosed as it can commonly occur without clinical symptoms. Therefore low Anti-tTG IgA levels can be a false-negative result in the setting of IgA deficiency and warrants screening for total IgA in conjunction with antitTG IgA.
What is celiac disease a sensitivity to? What ages does it occur?
Celiac disease is an autoimmune disorder of the small intestine that presents in genetically predisposed people of all ages, from infancy onward. It occurs due to sensitivity to gliadin, the alcohol-soluble portion of gluten.
