GI Flashcards
Most common cause of Pseudomembranous colitis
C.difficile
Terminal ileum lumpy why?
Correlation?
Peyers patches:- lymphoid follicles/nodules
Crohns ileitis with structure: thicked wall and peyers patches
Define diverticula versus pseudo diverticula
Diverticula:- Mucosa penetrates the muscle layer
Pseudo:- Defective wall
Stomach parts describe with cell tyoes
- Cardia: have the esophagic sphincter
- Fundus and body:- no histologic difference, make acid
- short gastric pits, gland is 2/3 mucosal, parietal and chief cells - Antrum:- No pink mucin (1/2 glands of mucosal)
- Pyloris: more flat, theres are pyloric junction before the duodenum
H and E in stomach and in ulcers
Blue for nuclei which takes H and E for cytoplasm/mucin in cytoplasm
- tortuousity: hyperplasia
- erosion of stomach
- fibrin (pink) and neutrophils:- PUS (due to sloughing)
H.Pylori Sequela
-Incites duodenal and gastric ulcer,
-intestinal metaplasia/dysplasia/then neoplasia
Sequela:
-Gastric Ulcer, Metaplasia, Carcinoma,, Lymphoma
- Gastric ulcer (indent with smooth edges not heaped up, benign)
-Intestinal Metaplasia
- Carcinoma (e.g. signet cell adenocarcinoma or Linitis Plastica- See mucin in center and nuclei pushed into periphery,)
-lymphoma (if switch from polyclonal to monoclonal..proliferative small round blue cells or B cell lymphocytes that efface architecture)..also MALTOMA
-KISSING ULCERS (not pathognomic)
Intestinal metaplasia describe
Goblet cells are INTENSTINAL NOT GASTRIC ORGAN
Paneth cells native to intestines
When you find this in the stomach it is a sign of METAPLASIA
Signet ring cell seen in
Linitis Plastica..THICK FOLDS., leather bottle stomach
Substance P is a capsaicin senstive neuron T or F
Describe sequence
IN RESPONSE TO INJURY
Sub P secreting neuron and CGRP activate NO (hence vasodilation)which activates COX-1 hence PGI2 which inhibits neutrophil activation
Which gender is less prone to duodenal ulcer
Females of child bearing age
CGRP in mucosa greater in females, FGI2 metabolite greater as well. Sex differences in mucosal defense may be partly due to estrogen (CGRP mice with ovaries removed, can be replaced with estrogen, reverses ulcer)
Mucoid cap..Describe how its formed
Bicarb, mucus, exuded plasma and cell debris: gelatinous cap in response to injury.
-Cells from outer epithelium send lamellopodia projections to seal off..allow regeneration of epithelial layer
Acute gastropathy
Chronic Gastropathy
Acute: Little inflammation, some erosion. due to stress gastritis, NSAID gastropathy, alcoholic gastritis (Tend to be hemorrhagic)
Chronic: autoimmune as with Pernicious anemia and inflammation as with H.pylori
Stress gastritis
- Vasoconstriction
- Hypo perfusion
- Cytokines
HPylori Colonization
- Superficial Diffuse Antral Gastritis (CHronic gastritis with neutrophils). Can lead to Increased gastrin and HCl, then Duodenal ulcer (BUT H.P is not in duodenum)
- Multifocal Pangastritis
- Chronic atrophic gastritis with intestinal metaplasia (Similar to pernicious anemia)
- Then lead to gastric carcinoma
- Can lead to gastric ulcer - MALT
- MALToma
Where in which H-Pylori chooses 1, 2 or 3 is very geographically based. Likely strain related
Gastric versus Duodenal Ulcers Trends
-gastric
appetite reduced, older, weight loss, low acid…
-duodenal
appetite ok, younger, normal, increased acid
NB Gastric ulcers tend to be related to atrophic gastritis
Indications for endoscopy..other tests
age>= 55 years…
if less do serology which is very sensitive! C-diff antigen test or breath test
Gastric vs duodenal..clinical assessment
- Assess aspirin status
- if YES, stop, do serology if yes treat and protect..if no, just protect
- if NO, check for H.Pylori, if not do fasting gastrin
IF WITH ENDOSCOPE, ulcer seen? -acid suppresed, mucosal protection NO BIOPSY duodenal ulcer -Send blood for serology, if pos, eradicate, if negative fastin serum gastrin -Re endoscope 8-12 wks
Pharmacology of Ulcers..Side effects etc
-Acid suppresion
1) Buffer (not bicarb but use antaacid..mg
2) Histamine receptor blocker on parietal cell (cimetidine, ranitidine, famotidine/nizavadine). Competes with creatinine for tubulous secretion. hence Cr goes up slightly..Side effect of C is diarrhea, etc gynectomastia, oligospermia..slightly..second generation dont have these side effects
3) Acetylcholine receptors
BTW:- Enterochromaffin cells paracrine secretion of histamine
4) Somatostatin analog subcutaneously. TURNS EVERYTHING OFF, as well as PROSTAGLANDINS..BUT IV! and side effects are like ulcer
5) Mucosal protection:-(sulcrafate)
Forms of Budesonide (an oral glucocorticoid for IBD)
Ileal disease is Crohns (pH 5.2)
Colonic release is ulcerative colitis ( at the ileocecal junction)
Immunosuppresive agents for induction and maintenance of remission in IBD
- are weight based
- Azathioprine/6-MP
- Crohns and UC
- dose dependent liver injury and leukopenia, dose independent infx and pancreatitis
- MTX
- only Crohns
- Teratogenic, hepatic fibrosis, interstitial pneumonitis, transaminitis
Biologics(anti TNF alpha:- fc/IgG1). Name them and side effects
- Chimeric monoclonal antibody: infliximab/remicade (crohns)
- Human monoclonal:- Adalimumab/humira (crohns)
- Human monoclonal:- Golimunab (UC)
- Humanized Fab1 fragment:- Certolizumab pegol
Side effects:- NHL lymphoma, TB infx, infusions rxn, Hepatosplenic T cell lymphoma in young males (HSTCL), skin cancer, autoimmune (SLE, vasculitis, psoriasis), demyelinating diseases and heart failure