Inflammatory Bowel Disease/Carcinoid, Gastrointestinal Stromal Tumor and Lymphoma Flashcards
Inflammatory Bowel Disease
- group of chronic inflammatory conditions of colon and small intestine
- chronic relapsing immune activation and inflammation within the GI tract
- dysregulation of the immune response to GI luminal bacteria
2 major forms of IBD
1) Crohn Disease
2) Ulcerative Colitis
Environmental Risk Factors for IBD
- cigarette smoking (dec. UC, inc. CD)
- appendectomy (dec. UC, inc. CD)
- high-sanitation level in childhood (inc. CD)
- high-intake refined carbs (inc. CD)
“Hygiene Hypothesis”
- -incidence of immune-mediated diseases rising in developed countries (related to modern hygiene or lack of exposure)
- Conflicting data in IBD (protective: exposure to pets), or maybe risk factor
Ulcerative Colitis
- chronic inflammatory disorder of the GI tract affecting the large bowel, relapsing
- begins in rectum and extends proximally continuously,no skin lesions
- rarely pericolonic abscess
- indolent, relapsing disease
- no skip lesions
Ulcerative Colitis: Endoscopically
-hyperemia, edema, granularity with friability, easy bleeding, broad based ulceration, pseudopolyps, tunnels with mucosal bridges, rarely perforation
Ulcerative Colitis: Toxic Megacolon
-shutdown of neuromuscular function secondary to exposure of fecal material to muscularis mucosae and neural plexus
Ulcerative Colitis: Gross Pathology
-edematous, congested and hemorrhagic mucosa with superficial ulceration and loss of normal folding pattern
Ulcerative Colitis: Microscopic Pathology
- edematous congested mucosa with more blue than normal = inflammatory cell nuclei, and with superficial ulceration
- cyrpt “abscesses”
Ulcerative Proctitis
- inflammation is confined to the rectum
- rectal bleeding may be the only sign
- rectal pain, feeling of urgency or an inability to move the bowels in spite of the urge to do so (tenesmus)
- this form of ulcerative colitis tends to be mildest
Proctosigmoiditis
- involves rectum/sigmoid
- bloody diarrhea, abdominal cramps and pain and tenesmus are common
- continuous
Left-sided colitis
- inflammation extends from rectum up the left side through the sigmoid and descending colon
- bloody diarrhea, abdominal cramping and pain on left side, and unintended weight loss
- continuous
Pancolitis
- entire colon
- bouts of bloody diarrhea that may be severe, abdominal cramps and pain, fatigue and significant weight loss
Fulminant Colitis
- uncommon, life-threatening
- entire colon
- severe pain, profuse diarrhea, dehydration and shock, SIRS
- extensive and deep colonic injury
Barium Contrast Studies
- superb instrument to observe fine mucosal detail
- dependent on skill of radiologist
- requires appropriate use of barium, air insufflation, palpation, positioning, compression and use of spot films
Ulcerative Colitis: CT
- increasing use in diagnosis
- most sensitive for evaluation of free air (toxic megacolon with perforation)
- See liver, mesenteric inflammation & lymphadenopathy
- CT dosen’t show mucosal detail well (may miss subtle changes early in disease that can be seen with air contrast BE and endoscopy
Crohn’s Disease
- chronic
- involves any location of GI tract
- propensity for distal small bowel & proximal colon
- can involve mouth to anus: apthoid ulcers in mouth, esophageal ulcers, gastric disease, small bowel
Main location for Crohn’s?
illeum small intestine alone (30%) small intestine + colon (40%) colon alone (40%)
Peak age for Crohn’s?
20-29
Crohn’s Colitis
- asymmetrical disease where there is involvement
- aphthous ulcers
- rectal sparing
- skin lesions
- deep ulcerations
- stricture formation
- fistula
- disease can be limited to right colon
Characteristics of Crohn’s?
- transmural involvement
- noncaseating granuloma (40-60%)
- Fissuring with fistula
- Skip lesions
Crohn’s Disease: Gross Pathology
- transmural
- “cobblestone” mucosa
- “skip lesions” alternating areas of involved and uninvolved bowel
- “creeping fat” on the serosa extending to seal off areas of transmural inflammation
Crohn’s Disease: Microscopic Pathology
- fistula
- edema, inflammation w/neutrophils, lymphocytes, plasma cells, eosinophils & macrophages, forming granulomas (35%)
- rarely necrotizing, not as tightly cohesive as sarcoidosis
Endoscopy in Crohn’s Disease
- ulcerations
- pseudopolyps
Gastric & Duodenal Crohn’s
- gastric ulcers
- crohn disease in distal antrum & duodenal bulb
Crohn’s Disease: Radiology
mucosal hyperenhancement and mesenteric hypervascularity
-fistulas
Erythema Nodosum: microscopic pathology
-type of panniculitis (inflammation of subcutaneous tissue) with lymphocytes, macrophages and multinucleated giant cells, leading to fibroblastic repair response and fibrosis
Pathophysiology of Gastric Carcinoid Tumors
- chronic gastritis or gastric acid suppression
- hypergastrinemia compensatory response
- gastric diffuse neuroendocrine hyperplasia
-comes from neuroendocrine cells
Gastric Neuroendocrine Tumor (Carcinoid) Immunostain
+ for chromogranin
Gastric Neuroendocrine Tumor
- 80% associated with hypergastrinemia, indolent, metastases uncommon (can remove antrum)
- 20% not associated with hypergastrinemia, aggressive, many with metastases at diagnosis, associated with carcinoid syndrome
Zollinger-Ellison Syndrome: diagnosis
- fasting gastrin level >1000 pg/ml with gastric pH below 5
- secretin stimulation test (gastrin levels 0, 2, 5, 10, 15, 20 min after IV secretin)
- increase in gastrin of >200 pg/ml (100% specific)
Treatment of Zollinger-Ellison Syndrome
- surgical resection: solitary, non-metastatic disease
- medical management: high dose PPI, long asting somatostatin analog
- Metastatic disease: streptozocin/doxorubicin or temozolamide
- resection, TACE, RFA, OLT
Intestinal Neuroendocrine Tumor (Carcinoid)
- typically late middle-age
- ileum & appendix = common
- multiple sites
- abdominal pain = most frequent symptom
- intermittent obstruction can occur
- most common neoplasm in appendix (1 in 300 appendectomies)
- rectal tumors small, rarely metastatic
Carcinoid Syndrome
- episodes of flushing (95%), diarrhea, wheezing, colicky abdominal pain
- right heart endocardial fibrosis (50%)
- 10% liver metastases (ileal tumors)
- due to vasoactive polypepptides, serotonin
- high urine 5-hydroxyindole acetic acid (5-HIAA) diagnositc (but limited sen & spec)
Colorectal Neuroendocrine Tumors
Colon: more in right colon, usually large mass
Rectum: found incidentally, carcinoid syndrome is rare, prognosis depends on size
Gastrointestinal Stromal Tumors (GIST)
- uncommon (5,000/yr in US), older adults
- most common in stomach and small intestine
- derive from or differentaited toward interstitial cells of Cajal, GI pacemaker cells that form the interface b/w autonomic innervation & smooth muscle cells of gut
- most have mutation in KIT transmembrane receptor tyrosine kinase, activating it as an oncogene, with positive immunostain for CD117
- all possibly malignant or malignant
GI stromal Tumors (GIST) Presentation
40% with overt GI bleeding
40% with abdominal mass
20% abdominal pain
GIST Detection
CT detects, but endoscopy biopsy can be false - b/c they are in the wall, not mucosa
-Endoscopic ultrasound-guided fine needle aspiration has 82% sen and 100% spec
-
GIST treatment
surgery, if metastatic, can usually be given tyrosine kinase inhibitor imatinib mesylate
Post-Transplant Lymphoproliferative Disorder
- Immunosuppression can allow B cells infected with Epstein-Barr virus to proliferate in an uncontrolled manner
- Blood test for EBV DNA can detect it
- If immunosuppression can be safely decreased, sometimes the proliferation will come under control
Gastrointestinal Lymphoma
-Rare ( most of the rest aggressive diffuse large B-cell lymphomas
GI Lymphoma Presentation
- epigastric pain (93%)
- anorexia (47%)
- weight loss (25%)
- occult bleeding (19%)
- nausea/vomiting (18%)
GI lymphoma diagnosis
endoscopy with biopsy
GI lymphoma treatment
antibiotics for MALToma
radiation/chemo for other types
GI lymphoma prognosis
good for MALToma
bad for other types
