Food Allergy- Flashcards
describe IgE mediated in terms of onset, cell types, common foods, & ssxs
rapid onset (mins to 2 hrs of ingestion) from mediators released from mast cells or basophils
foods: cow’s milk, egg, soy, wheat, tree nuts, peanuts, shellfish
ssxs: vary: dermatologic, ophthalmologic, GI, respiratory, CV, neurologic, n/v, cramping, diarrhea, flushing pruritis, edema, syncope
what is needed to determine a food allergy? what are the two types of responses? what normally blocks a food allergy rxn? driven by what type of allergic rxn? hypothesized cause?
thorough hx to clarify type of rxn & culprit foods
includes: immunological/allergic & non-immunologic rxn
healthy gut immune sys typically blocks intact proteins & other antigens to enter the sys
drive by Th2 skewed response & cytokine release
hypothesized causes: better infant hygiene = less microbial exposure, decreased omega-3 & increased omega-6 fats, processed foods= less antioxidants, change in protein configuration
describe non-IgE mediated food allergy d/os, types onset, & ssxs
subacute/chronic sxs in GI & or skin
often type III or type IV hypersensitivity rxns
delayed onset, hours to days after food is ingested
ssxs: chronic vomiting, diarrhea, reflux, failure to thrive, atopic dermatitis
testing for food allergies?
skin tests (IgE), RAST (IgE), elimination/challenge diet, food diary
what is non-immunologic adverse food rxn in terms of prevalence and examples
very common
anatomic conditions, malabsorption syndromes, GERD, toxic rxn, agents, contaminants, food aversions/phobias
examples of small bowel tumors benign & serious
benign: leiomyoma, lipoma, neuromas, can cause distention, abd pain, bleeding & obstruction
serious: adenocarcinoma (Crohn’s), lymphoma (celiac), carcinoid, kaposi’s sarcoma
what is a polyp of the colon & rectum? what are the 3 types?
small sessile or pedunculated mass of tissue, grows into lumen
- non-neoplastic polyps (benign)
- adenomas (precursor to CA)
- polyposis syndromes: familial inherited (AD) or non-familial
hyperplasticity of non-neoplastic polyps? other types?
hyperplastic usu <.5 cm in diameter, 90% of epithelial polyps
also: hamartomas, pseudopolyps, lipomas
prevalence of adenomas? histological types? risk assoc w/?
precursor to CA
~10% of all colonic polyps
histological types: tubular, tubulovillous or villous adenomas
risk of malignant potential related to size & histological type
2 types of polyposis syndromes? what is each? complications?
- familial adenomatous polyposis: rare, hereditary,
begins in childhood & involves entire colon, many asx, some rectal bleeding 100% HAVE CARCINOMA BY AGE 40, some have extracolonic ssxs such as osteomas of skull or mandible, sebaceous cysts, adenomas in other pars of GI - peutz-jeghers syndrome: AD, hamartomas in stomach, small bowel and colon, self-limiting, mucocutaneous pigmentation
etiology of polyps of colon & rectum?
exposure to cig smoke, chronic EtOH intake, UC increases risk & pts w/ primary relatives with UC have increased risk, pts w/acromegaly have 3x increased risk, pts w/skin tags have 10-77% incidence of colon polyps, pts who have had pelvic radiation have 2-4x increased incidence of colon polyps
Ssxs of polyps of colon or rectum?
2/3 of individuals >65 yo have at least one adenomatous polyp often multiple, occur most commonly in recut & sigmoid colon
asx or bleeding, abd pain dt partial obstruction, change in bowel habits, watery diarrhea w/large villous adenomas
how common is colorectal CA? high where, low here? more common in what genders where? etiology of colorectal CA?
very common CA, #3 after lung, prostate/lung , breast
high in North america, western Europe, Australia, low in japan, south america, Africa
colon CA more common in females, rectum in males
etiology: low fiber, high fat & animal protein, esp beef w/prolonged transit time, intestinal flora produces carcinogens & transformation of adenomatous polyp
9 RFs of colorectal CA?
- > 40 yo
- IBD: UC risk is 30% after 25 yrs, Crohn’s dz (4-10x risk)
- familial polyposis (100% WILL DEVELOP)
- family hx of 1 relative w/colon CA (3x CA risk)
- personal hx of breast & female genital CA
- acromegaly
- hamartoma
- septicemia from strep bovis infxn
- smoking/alcohol
ssxs of colorectal CA? if early? R colon? L colon? rectum? advanced?
early: asx
R colon: ascending & cecum, usu lg before any sxs, fatigue, SOB, angina, vague abd discomfort or palpable mass later, usu fungating, grow large & mb palpable, bleeding usu occult
L colon: descending & sigmoid, tends to encircle colon, diarrhea & constipation or alternating, tenesmus with BM, late pain dt partial obstruction, hematochezia or occult blood loss
rectum: gross blood w/defecation
advanced: wt loss, anorexia, malaise, jaundice, ascites, hepatomegaly, SCLN enlargement
screening for colorectal CA? diagnostic labs? DI?
screening: fecal occult blood, colonoscopy, CT colonography, urinary indican test to measure metabolites of undigested proteins
diagnostic labs: hemoccult blood, CBC, liver enzymes, carcinomebryonic antigen elevated in 70% of CRC but not specific
DI: sigmoidoscopy, double contrast barium enema, colonoscopy
forms of anorectal CA? RFs assoc with?
adenocarcinoma, SCC, BCC, lymphoma
RFs: HPV, fistulas, leukoplakia, lymphogranuloma, venereum, condyloma accuminata, anal intercourse
7 anorectal d/o’s
hemorrhoids anal fissure anoretal abscess/fistula pruritis ani proctalgia fugax proctitis pilonidal dz
what are hemorrhoids? RFs? complicated by what 3 things? prevalence?
clusters of vascular tissue, smooth muscle 7& overlying mucosa
often complicated by inflam, thrombosis & bleeding
~50% of adults, peaks btw 45-65 yo, M+F
RFs: diarrhea, pregnancy, childbirth, increased interabd pressure, heavy lifting, prolonged sitting or standing, valsalva maneuver, anal intercourse, low fiber/high fat diet
sxs of internal hemorrhoids & location to be considered internal?
internal= above dentate line, no sensory innervation
most commonly painless bleeding w/ BM, bleed, prolapse & cause perianal itching & irritation, perianal pain by prolapse & spasm of sphincter complex, acute pain when incarcerated & strangulated, related to sphincter complex spasm
ssxs of external hemorrhoids & definition to be an external hemorrhoid?
external= below dentate line, sensory innervation present
sxs in 2 ways:
1. acute thrombosis of underlying external hemorrhoidal vein, usu dt specific event, acute pain lasts 7014 d & resolves w/resolution of thrombosis
recurrence occurs ~ 40-50% of the time at the same site
- cause trouble w/hygiene w/development of skin tags
PE of hemorrhoids?
visualization if external, skin tags, DE to find internal (non-tender), anoscopy: pink/blue friable swellings of the mucosa
what is an anal fissure?etiology?
acute linear midline tear in anal canal from dentate line to anal verge
mostly b/w 20-60 yo, in a child usu indicates sexual abuse
etiology: hard stool, chronic diarrhea, 10% of chronic are caused by childbirth, habitual use of cathartics, anal intercourse or DRE, hx of syphilis & other STIs, TB, leukemia, Crohn’s, previous anal surgery, HIV
ssxs of an anal fissure?
rectal pain usu burning, cutting or tearing, painful defecation, spasm of anus, bloody stools (bright red), mucoid d/c, pruritis
