Duodenum
The duodenum is the first part of the small bowel. It is accessible by EGD (esophagogastroduodenoscopy) and frequently biopsied.
The clinical history is often: r/o celiac or r/o giardia.
Getting started
- Celiac
- Loss of villi.
- Intraepithelial lymphocytes.
- Giarrdia
- Like celiac... but giarrdia organisms.
- Adenomas
- Too much blue - similar to colonic adenomas.
- Cancer
- Too much blue and epithelium in the wrong place.
Celiac sprue
Etiology
- Autoimmune.
Serology
- Anti-transglutaminase antibody.
- Alternative test: anti-endomysial antibody.
Epidemiology
- Associated with:
- The skin condition dermatitis herpetiformis.[1]
- Tx: dapsone.
- IgA deficiency - 10-15X more common in celiac disease vs. healthy controls.[2]
- The skin condition dermatitis herpetiformis.[1]
Histology
Features:[3]
- Enteritis.
- Intraepithelial lymphocytes - key feature.
- Plasma cells.
- Macrophages.
- Loss of villi - key feature.
- Normal duodenal biopsy should have 3 good villi.
- Mitosis increased (in the crypts).
Notes:
- If you see acute inflammatory cells consider Giardiasis.
Treatment
- Gluten free diet.
- Mnemonic: BROW = barley, rye, oats, wheat.
DDx
- Giardiasis.
- Have giarrdia organisms.
- Always consider Giardiasis and especially on exams.
- Whipple's disease (very rare).
- Abundant macrophages should make one suspicious.
Giardiasis
Etiology
- Flagellate protozoan Giardia lamblia.
Histology
- Loss of villi.
- Intraepithelial lymphocytes.
- +Other inflammatory cells, especially PMNs, close to the luminal surface.
- Flagellate protozoa -- diagnostic feature.
- Organisms often at site of bad inflammation.
- Pale/translucent on H&E.
- Size: 12-15 micrometers (long axis) x 6-10 micrometers (short axis) -- if seen completely.[4]
- Often look like a crescent moon (image of crescent moon) or semicircular[5] -- as the long axis of the organism is rarely in the plane of the (histologic) section.
Notes:
- Giardiasis can look (histologically) a lot like celiac disease.
Images:
Treatment
- Antibiotics, e.g. metronidazole (Flagyl).
Whipple's disease
Epidemiology
- Very rare.
- Classically middle aged men.
Clinical
- Malabsorption (diarrhea), arthritis + others.
- Symptoms are non-specific.
Etiology
- Infection - caused by Tropheryma whipplei.[6]
Histology
Features:[7]
- Infectious microorganism typically found in macrophages.
- Macrophages usually abundant - key feature that should raise Dx in DDx.
- Organisms periodic acid-Schiff (PAS) positive.
Treatment
- Antibiotics - for months and months.
Micrograph: Whipple's disease - wikipedia.org.
Tumours
Lymphoma
- NHL (non-Hodgkin's lymphoma) - see haematologic malignancies.
Note:
- Hodgkin's lymphoma does not arise in the GI tract.
Adenocarcinoma
- Similar to large bowel adenocarcinomas (see colon article).
- Duodenum - most common site in small bowel.
Risk factors:
Neuroendocrine tumours
General
Microscopic
Features:
- Nests of cells.
- Stippled chromatin - AKA: salt-and-pepper chromatin, coarse chromatin.
- Classically subepithelial/mural.
Images:
- Neuroendocrine tumour - low mag. (WC).
- Neuroendocrine tumour - intermed. mag. (WC).
- Neuroendocrine tumour - high mag. (WC).
Ampullary tumours
- Ampullary carcinoma - has separate staging.
- Intraductal papillary mucinous tumour (IPMT) - a pancreatic tumour, see pancreas article.
See also
References
- ↑ TN 2007 D22
- ↑ Kumar, V.; Jarzabek-Chorzelska, M.; Sulej, J.; Karnewska, K.; Farrell, T.; Jablonska, S. (Nov 2002). "Celiac disease and immunoglobulin a deficiency: how effective are the serological methods of diagnosis?". Clin Diagn Lab Immunol 9 (6): 1295-300. PMID 12414763.
- ↑ PBoD P.843
- ↑ http://www.water-research.net/Giardia.htm
- ↑ http://en.wikipedia.org/wiki/Semicircle
- ↑ Liang Z, La Scola B, Raoult D (January 2002). "Monoclonal antibodies to immunodominant epitope of Tropheryma whipplei". Clin. Diagn. Lab. Immunol. 9 (1): 156?9. PMC 119894. PMID 11777846. http://cvi.asm.org/cgi/pmidlookup?view=long&pmid=11777846.
- ↑ Bai J, Mazure R, Vazquez H, Niveloni S, Smecuol E, Pedreira S, Mauriño E (2004). "Whipple's disease". Clin Gastroenterol Hepatol 2 (10): 849?60. doi:10.1016/S1542-3565(04)00387-8. PMID 15476147.
- ↑ Can J Gastroenterol. 2008 Apr;22(4):357-8. PMID 18414708.
- ↑ Ann N Y Acad Sci. 2004 Apr;1014:13-27. PMID 15153416.
- ↑ Pathologe. 2003 Jul;24(4):287-96. PMID 18414708.