L1 endosc tour GIT Flashcards
LO1+2: outl broad funcs var regs GIT.
id comm dis procs aff each part gut and ways they present.
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OGD OESOPH:
- 25cm. lower bord cricoid cartil to card orifice of stom at 7th costal cartil. cricophar sphinct= start. endosc landmarks- indent L main bronchus T5 or L atrium T6/7. main oesophagogastric mucosal junc where pale pink squam to dark red gastric- us 40cm from incisor.
- upper 2/3 blood from infer thyroid art and aortic br’s and drains direc to systemic circ by infer thyr vein and azygos br’s. lower 1/3 blood from L gastric br celiac trunk and L infer phrenic art. so oesoph has mixed ven drain to port sys via L gastric vein and into systemic via azygos=porto systemic anast. oesoph varices can occ if port hypert.
- chronic ac expos= reflux oesophagitis= metaplasia LO squam to gastric col. Barretts.
- diaph us cuffs at/below oesophagogastric muc junc. disturbed in hiatus hernia- weakn in oesoph hitaus allow cardia and funcdus into throax.
OGD STOM:
- endosc through LOS. phys sphinct reduc reflux chyme. aided by- acute angle ent= valve eff. muc folds at oesophagogastric junc act as valve. R crus diaph pinch cock. pos intra abdo press compress walls of intra abdo oesoph.
- cardia, fundus, bod, pyloric antrum. greater and lesser curves. incisura angularis in less curve div bod and antrum. antrum narrs to prod pyloric canal. pyloric sphinct at end canal, musc thicken. stom lining longit ridges rugae- gastric folds var size. gastric ulcerat comm benign, often on lesser curve and angulus. malig susp if ulcer irreg margins but many early CA app like small benign so biop mandat at endosc.
endoscopy
- direc vis exam, biopsy, and therap tx GIT.
- small caliber nasendoscs allow vis naso and oropharynx and throat- pharynx and larynx.
- upper GI endosc- oesoph, stom, duod (OGD).
- endoscopic retrograde cholangiography and pancreatography (ERCP) perf by duodenoscopy, allow cannulat of duod papilla.
- tech adv allow view SI by capsular endosc.
- whole colon by colonosc.
OGD DUOD:
-until duodenojejunal flexure supp by lig of treitz. start L1 to R of midline, curves rnd to R at L2/3 and the duodenojej flexure. starts intraperit becomes retro.
-endoth macrosc diff from stom. (*coeliac dis look up).
-4 divs-
1) super part 5cm. overlapped by liv and gallb. occas gallst= eros to 1st part duod= choledocoduodenal fistula= subseq gallst ileus as gallst trav through SI event obstruc lumen. duod ulcers comm in 1st part. ant ulcer may perfor= peritonitis. post ulcer may erode into gastroduod art=massive heamorr, or into panc= sev lumbar pain.
2) retroperit desc part. 7.5cm. rnd head panc.
maj duod papilla halfway along post aspect. opening of main panc duct. guarded by sphinct or oddi. access panc duct open bit above papill. papill= transit emb foreg to midg. so duod blood supp from celiac access foreg and SMA midg. ulcerat less comm, suggs panc dis or zollinger ellison.
3) horix 10cm. trasnv at L2/3, x aorta below ori of SMA. duod close to aorta may= aorto-duod fistula in dis of either, us presents as upp GI heamorr, rare. duod is btw SMA ant, and aorta post. rap weight loss can= SMA synd where duod obstrub due to ext compress of duod by aorta and SM.
4) asc 2.5cm. retroperit, ascs L of midline to L1 where turns L= DJ flexure. lig of treitz is fib and anchors start of jej and in decelerat inj may= traction inj in jej and subseq perfor.
OGD DUOD:
-until duodenojejunal flexure supp by lig of treitz. start L1 to R of midline, curves rnd to R at L2/3 and the duodenojej flexure. starts intraperit becomes retro.
-endoth macrosc diff from stom. (*coeliac dis look up).
-4 divs-
1) super part 5cm. overlapped by liv and gallb. occas gallst= eros to 1st part duod= choledocoduodenal fistula= subseq gallst ileus as gallst trav through SI event obstruc lumen. duod ulcers comm in 1st part. ant ulcer may perfor= peritonitis. post ulcer may erode into gastroduod art=massive heamorr, or into panc= sev lumbar pain.
2) retroperit desc part. 7.5cm. rnd head panc.
maj duod papilla halfway along post aspect. opening of main panc duct. guarded by sphinct or oddi. access panc duct open bit above papill. papill= transit emb foreg to midg. so duod blood supp from celiac access foreg and SMA midg. ulcerat less comm, suggs panc dis or zollinger ellison.
3) horix 10cm. trasnv at L2/3, x aorta below ori of SMA. duod close to aorta may= aorto-duod fistula in dis of either, us presents as upp GI heamorr, rare. duod is btw SMA ant, and aorta post. rap weight loss can= SMA synd where duod obstrub due to ext compress of duod by aorta and SM.
4) asc 2.5cm. retroperit, ascs L of midline to L1 where turns L= DJ flexure. lig of treitz is fib and anchors start of jej and in decelerat inj may= traction inj in jej and subseq perfor.
ERCP- allow endosc and radiologic exam of bil tree and panc duct, biopsy, and therap proceds for obstruc jaundice.
BILIARY TREE:
exam in retrograde fashion by cannul duod papilla, through sphinct oddi into small widening at distal end comm bile duct- ampulla of vater.
-bil tree start in liv from intrahepat ducts which form L+R hepat ducts. these converge at porta hepatis to form comm hepat duct 4cm. cystic duct from gallbl joins comm hepat= comm bile duct 10cmx7mm. CBD passes beh duod, run in groove in post aspect of panc head or within panc sunbst. opens to duod midway 2nd part.
-block CBD=obstruc bile flow= jaundice and disrup enterohepatic circ of bile salts. dark urine, pale stool, jaund.
painles obstruc jaund comm secondary to tum- most comm carcinoma of panc head obstrucs CBD as passes through or close to head. others incl cholangiocarcinoma of bile duct, adenocarcin of duod or liv tum extrinsic comp.
painful obstruc jaund more likely gallst.
- US scan meas CBD diam for sign obstruc jaund. max diam 7mm. but dilat if prev ECRP and sphincterectomy.
- super to duod CBD runs in free edge of less omentum along with port vein and hepat art. free edge is ant bord of epiploic foramen of winslow- ent to lesser sac. contr hepat heamorr by press to free edge lesser sac occlud port vein and hepat art=pringle manouver used in hepatobiliary surg.
SI endosc
-3-10m. jej 2/5. ileim 3/5. 15cm mesent atts to post wall from DJ flexure to L of L2 passing obliquely R to sacro-iliac jnt.
now capsule endosc.
-jej thicker wall as more lager taller plicae circulares of mucosa. also deeper red as greater BS from few large vasc arcades. wall tall villi deep crypts- in coeliac dis villi and crypts atrophy.
-meckels divertic in distal ileum remn of emb vitelloint duct. 2 ft from ileocecal valve, 2% pop, 2 inches long. may cont gastri mucosa which secs ac= bleed/inflamm-is diff diag with unexpl GI blood loss or acute abdo pain.
paralytic ileus.
-SI has aggregs LT in wall-PP. ileum lot. can enlarge partic in lymphoma= obstruc.
COLON:
- retrograde exam from anus to caecum with colonoscope. L side colon exam in isol with sigmoidoscope. 100-180cm. longer in fems. 3 longit bands musc=taenia coli-converge at base of append. taenia coli often cause int lumen to app triang, esp in transv. lengths of musc shorter than colon so bunch colonic wall= haustrations/sacculations.
- LI= caecum and append. ileocecal junc valve formed by oblique ent and part invag of ileum into caecum=folds. prev backflow dur peristal. obstruc LI can= dilat caecum to pt of necrosis or perfor if valve compet. caecum fisrt part LI in RIF. 20% colonic tums in caecum and R side colon, often present mass, change bowel habit, iron defic anaemia, or pain.
- appendix- blind end struc from postero med aspect of caecum. differential overgrowth of cecal wall= append med/infer displ. append orifice endosc at converg of 3 taenia coli at pole of caecum.
- asc colon 12-20cm. super from caecum to heapt flexure.
- transv colon 45cm, v mobile. start hepat flexure to splenic. diffic endosc. at lev umb, poss hang down- more in fems so colonosc more diffic.
- desc 22-30cm.
- sigm 37cm av. most appendices epiploicae on outer surf- fat fill perit tags not on rectum/caecum. length and loose mesent att= can twist on self=sigm volvulus. symps of large bowel obstruc. tx flexib sigmoidosc. 25% colon CA in sigm. in W world sigm most comm site colonic divertic- out pouchings bowel wall. comm where art pierces musc wall=weakn. 10% pop over 40 have diverticulosis, 60% over 80. may cause divertic dis, diverticulosis, diverticulitis.
RECTUM:
- 12cm. start ant to sacrum at S3 leads to anal canal. hum not straight. curves ant foll sacrum then turns at 90 deg through pelvic diaph. also has 3 lat curves corresp with mucosal folds/valves of houston.
- apps circ desp 3 taenia coli to thick circ musc lay to cope with stool. tubul app broekn by haustral folds. 50% colon CA.
- if mucosa friable and erythematous its inflamed. macrosc app poss norm in infamm bowel symps. need biop. inflamm in colon due to infec, autoimm eg UC and crohns, iatrogenic eg radietherap.
- UC us occ rectum, spread proxim through colon. areas inflamm contin and mucosa v friable.
- crohns us patchy or focal areas inflamm=skip lesions. assoc ulcers us deep and fissuring and prod cobblestone app. full thickn aff.
ANAL CANAL:
-4cm, ends anal orifice. col epith. mid canal is transit btw endod of hindg and ectod or proctadeum invag from skin. marked by valaves of Ball arise from vertic cols of Morgagni which ext from upp rectum = dentate/pectinate line.
-below pectinate line canal cov by stratif squam epith.
is watershed area for vasc and nerve supp and ven and lymphat drain. upper rectum supp by br of IMA via super rectal br and nerve supp from visc pelvic splanchnic nerves from the sympath chain and S2,3,4, so pain is dull and poorly loc. ven drain to port sys via IMV. lymphat drain to mesenteric nodes.
lower rectum supp by infer rectal art br of int iliac art. nerve supp from infer rectal nerve, a somat nerve from the pudendal nerve so pain is sharp and well def. ven drain to systemic circ via int iliac vein. lymph drain to iliac and inguinal nodes.
watershed area is porto systemic anast can=varices in port hypert.
haemorr dilats of super rectal veins. if above dentate painless. below somat innerv means v pain. injec or banding haemorr above dentate painless, below not tol.
tums above dentate adenocarcinoma, below gen sqaum cell carcin.
