胰腺疾病的诊治课件.ppt

1、APPROACH TO THE PATIENT WITH PANCREATIC DISEASE GENERALCONSIDERATIONS Inflammatorydiseaseofpancreas:acute/chronic.acutepancreatitis:frequency:5000/new cases/yr USA mortality rate:10%recurrentacutepancreatitisorchronicpancreatitis:Incidence:8.2 new cases/100,000/year prevalence:26.4 cases/100,000.pre

2、valence of chronic pancreatitis(autopsy):0.04 5%.PANCREATITIS:DEFINITIONAcutepancreatitisAbdominalpainUsuallyassociatedwithelevatedlevelsofpancreaticenzymesinbloodorurineresultingfromaninflammatorypancreaticdiseaseChronicpancreatitisIrreversiblemorphologicchange,sclerosisPainPermanentimpairmentoforg

3、ansfunctionProblemsinDxofPancreaticDisease relativeinaccessibilitytodirectexaminationandnonspecificityoftheabdominalpain usually dependent on elevation of blood amylase.Manypatientswithchronicpancreatitisdonothaveelevatedbloodamylaselevels.subclinicalexocrinedysfunction(90%of pancreas be damaged.sec

4、retin stimulation test(the most sensitive method of assessing pancreatic exocrine function):60%of exocrine function lost.Noninvasive,indirect tests(bentiromide,trypsinogen):in obvious(calcification,steatorrhea,DM)than occult disease.clinicalmanifestations clinicalmanifestations:Protean hypertriglyce

5、ridemia,vit-B12 malabsorption,hypercalcemia,hypocalcemia,hyperglycemia,ascites,pleural effusions,and chronic abdominal pain with normal blood amylase.if considers pancreatitis only classic symptoms(i.e.,severe,constant epigastric pain that radiates through to the back,along with an elevated blood am

6、ylase level):only a minority of patients will be diagnosed correctly.Etiologies:quitevaried.frequently secondary to alcohol abuse and biliary tract disease drugs,trauma,virus,metabolic&connective tissue disorders.Idiopathic pancreatitis:30%(acute),25 40%(chronic)TESTS IN THE DIAGNOSIS OF PANCREATIC

7、DISEASE pancreaticfunctiontestsareperformedifthediagnosisofpancreaticdiseaseremainsapossibilityafternoninvasivetestsUS,CTandinvasivetestsERCPhavegivennormalorinconclusiveresults.testsemployingdirectstimulationofthepancreasarethemostsensitive.PANCREATICENZYMESINBODYFLUIDS serumamylase:ascreeningtestf

8、oracutepancreatitisinacuteabdominalpainorbackpain.65 U/L:raise the question of acute pancreatitis.130 U/L:make the diagnosis more likely,3x:clinch the Dx if gut perforation/infarction is excluded.acutepancreatitis:85%of patients with will have an serum amylase.serum amylase:within 24 h of onset,rema

9、ins 1 3 days.return to normal within 3 5 days unless extensive necrosis,incomplete ductal obstruction,pseudocyst formation.may be normal,if:(1)delay(of 2 5 days)before blood samples are obtained(2)chronic pancreatitis rather than acute pancreatitis (3)hypertriglyceridemia.spuriously low amylase,lipa

10、se.serumamylaseelevatedinotherconditions:the enzyme is found in many organs(salivary glands,liver,small intestine,kidney,fallopian tube)produced by tumors(Ca of lung,esophagus,breast,ovary).Isoenzymesofamylase:pancreas(P isoamylases);nonpancreatic source(S isoamylases).normal serum:35 45%is of pancr

11、eatic origin.The clinical importance in measurement of isoamylases.acute pancreatitis:total serum amylase returns to normal more rapidly than pancreatic isoamylase.postoperative state,acute alcohol intoxication,and DKA:due to an elevation of the S isoamylase.tests to distinguish isoamylase:not relia

12、ble when the total amylase is minimally moderately elevated.assay of trypsinogen:if normal r/o acute pancreatitis.Urinaryamylase,amylase/creatinineclearanceratio:nomoresensitive/specificasciticfluidamylase acutepancreatitis(1)pancreatogenousascites:disruption of the main PD of a leaking pseudocyst(2

13、)otherabdominaldisordersthatsimulatepancreatitis intestinal obstruction,intestinal infarction,PPU Elevationofpleuralfluidamylase acute pancreatitis,chronic pancreatitis,carcinoma of the lung,and esophageal perforation.Lipase:the single best enzyme for the Dx of acute pancreatitis.Improvements in sub

14、strates and technology(turbidometric assay).newer lipase assays:colipase as a cofactor and are fully automated.assayfortrypsinogen(trypsin-likeimmunoreactivity)useful&theoretical advantage over amylase and lipase.Sensitivity,specificity:C/W those of amylase and lipase.trypsinogen is also excreted by

15、 the kidney:in renal failure NosinglebloodtestisreliablefortheDxofacutepancreatitisinrenalfailure.whether a patient with ESRD and abdominal pain has pancreatitis remains a difficult clinical problem.serum amylase in patients with renal dysfunction only when CCr 50 mL/min.level was invariably 3x norm

16、al are highly specific.STUDIES PERTAINING TO PANCREATIC STRUCTURE Radiologic Tests Plain films of abdomen:useful information in 30 50%of acute pancreatitis.(1)localized ileus:usually the jejunum(sentinel loop),(2)generalized ileus+air-fluid levels (3)isolated distention of transverse colon colon cut

17、off sign,(4)duodenal distention with air-fluid levels (5)mass(frequently a pseudocyst).chronic pancreatitis:pancreatic calcification characteristically localized adjacent to and superimposed on the second lumbar vertebra Upper gastrointestinal x-rays displacement of stomach by the retroperitoneal ma

18、ss widening and effacement of the duodenal C loop(also,pancreatic mass,inflammatory,cystic,or neoplastic).Ultrasonography initial investigation for pancreatic disease.Interference:obesity,excess bowel gas,recently performed barium contrast examinations appearances:edema,inflammation,calcification ps

19、eudocyst,mass lesions,and gallstones acute pancreatitis:characteristically enlarged pancreas.Pseudocyst:echo-free,smooth,round fluid collection.Pancreatic carcinoma:distorts the usual landmarks mass lesions 3.0 cm:localized,echo-free solid lesions.thebestimagingstudyforinitialevaluation especially u

20、seful:tumors,fluid-containing lesions(seudocysts,abscesses,calcium deposits)Mostlesionsarecharacterizedby (1)enlargement of the pancreatic outline (2)distortion of the pancreatic contour (3)a fluid filling that has a different attenuation coefficient than normal pancreas.CT occasionallydifficulttodi

21、stinguishbetweeninflammatoryandneoplasticlesions.Oral water-soluble contrast agentspermits more precise delineation of various organs as well as mass lesions.DynamicCT:estimating the degree of pancreatic necrosis and in predicting morbidity and mortality.Spiral(helical)CT:clear images much more rapi

22、dly negates artifact caused by patient movementSelective catheterization celiac&SMA+superselectiveothersarteriesvisualizationofthepancreasanddetectionofneoplasmsandpseudocysts.Pancreatic neoplasms:identified by the sheathing of vessels by a mass lesion Hormone-producing pancreatic tumors:especially

23、increased vascularity and tumor staining.in pancreatic carcinoma,uncommon without pancreatic disease AngiographycomplementsultrasonographyandERCP:if ERCP is unsuccessful or nondiagnostic.magnetic resonance cholangiopancreatography(MRCP):tobeofvalueERCP Pancreaticcarcinoma:stenosis/obstructionofeithe

24、rthePDorCBD;bothductalsystemsareoftenabnormal.chronicpancreatitis:(1)luminal narrowing(2)irregularities in the ductal system with stenosis,dilation,sacculation,and ectasia(3)blockage of the pancreatic duct by calcium deposits.ERCPchangessimilartochronicpancreatitis:the effects of aging on the pancre

25、atic duct Although aging may cause impressive ductal alterations,it does not affect the results of pancreatic function tests(i.e.,the secretin test).the procedure was performed within several weeks of an attack of acute pancreatitis difficult DDx between chronic pancreatitis and carcinoma:ductal ste

26、nosis and irregularity.followingERCP serumand/orurineamylase:2575%clinicalpancreatitis:uncommon.Pancreatitis:5/300 patients following ERCP.more common in patients with a nondilated pancreatic duct.manometry of the sphincter of Oddi:risk of post-ERCP/manometry acute pancreatitis.Pancreatic Biopsy Wit

27、h Radiologic Guidance:(Percutaneousaspirationbiopsy)DDxpancreaticinflammatorymassandneoplasm.TESTSOFEXOCRINEPANCREATICFUNCTION1.Direct stimulation of the pancreas:IV secretin or secretin+CCK collection and measurement of duodenal contents2.Indirect stimulation of the pancreas:using nutrients,AA,FA,a

28、nd synthetic peptides assays of proteolytic,lipolytic,and amylolytic enzymes3.Studyofintraluminal digestion products:undigested meat fibers,stool fat,and fecal nitrogen4.Measurement of fecal pancreatic enzymes:such as chymotrypsin secretintest detectdiffusepancreaticdisease physiologicprinciple:panc

29、reatic secretory response is directly related to the functional mass of pancreatic tissue standardassay:secretin1CU/kgIV Normal:(1)volume output 2.0 mL/kg/hr,(2)HCO3-80 mmol/L,(3)HCO3-output 10 mmol in 1 h.Themostreproducible,highestdiscriminationbetweennormalandchronicpancreatitis maximal bicarbona

30、te concentrationcombined secretin-CCK test measure:pancreaticamylase,lipase,trypsin,chymotrypsin Problemsinfunctionaltest overlap between normal&patients with pancreatitis markedly low enzyme outputs suggest advanced damage and destruction of acinar cells.frank exocrine insufficiency:in both HCO3-an

31、d output of several enzymes.lesser damage:dissociation between HCO3-&enzyme output.dissociation between secretin test&absorptive function tests.chronicpancreatitis often have abnormally low outputs of HCO3-after secretin but have normal fecal fat excretion.secretin test measures the secretory capaci

32、ty of ductular epithelium fecal fat excretion indirectly reflects intraluminal lipolytic activity.Steatorrhea does not occur until intraluminal levels of lipase are markedly reduced abnormalsecretintestresult:suggests chronic pancreatic damage is present not consistently distinguish between chronic

33、pancreatitis and pancreatic carcinoma.tripeptide hydrolysisorbentiromide test measureintraluminalchymotrypsinactivityindirectly POsyntheticpeptide,N-benzoyl-L-tyrosyl-p-aminobenzoicacid(Bz-Ty-PABA)cleaved by chymotrypsin to Bz-Ty+PABA.Normal:the peptide is hydrolyzed in the small intestine by chymot

34、rypsin with the liberation of PABA rapidly absorbed and excreted in the urine.chronic pancreatitis:PABA excretion is significantly lower than control subjects.sensitivity:60%(46 74%)Specificity:90%(if coupled with a D-xylose test).Measurement of blood PABA sensitivity.intraluminal digestion products undigestedmusclefibers,stoolfat,andfecalnitrogen,amountofchymotrypsininstool:pancreaticoutputofthisproteolyticenzyme chronic pancreatitis and cystic fibrosis:chymotrypsin activity in stool.normalvaluesmayoccurinpatientswithpancreaticinsufficiency,false-positive:10%ofnormalindividuals.