GI labs Flashcards
FWhy do we do a GI tract work up
-direct visualization (endoscopy and colonoscopy) can be expensive and invasive
-dyspepsia
-ulcer disease- MC cause h. pylori
-celiac disease
-GI tract bleeding
-colorectal cancer
dyspepsia
-causes- GERD, peptic ulcer, gastritis
-ulcer disease
-H. pylori:
-Bx during endoscopy
-Histology
-Urease enzyme
-PRC
-culture
-Breath test:
-Non-invasive
-Urea labeled with radioactive carbon
-If urease is present the urea will be split into ammonia and radioactive carbon
-Test can also be used to prove eradication
-Stool test:
-H. pylori antigens
celiac disease
-immune mediated disorder
-triggered by gluten
-who to test:
-malabsorption
-first degree relative
-elevated aminotransferase level
-type 1 DM with GI symptoms
-IgA for antibodies- Sen and Spec of 98% -> if you have a very high suspicion you can still bx if neg
-bx for confirmation
-if neg workup consider non-celiac gluten sensitivity
approach to celiac disease disorder
-dont need to know specifics
-basically if neg and still high sus -> bx
-if pos -> still bx
-celiac disease suspected
-order IgA tTG with total IgA
-IgA tTG + and total IgA normal -> small bowel bx
-IgA tTG and total IgA normal -> unlikely dx -> if suspect celiac disease remains do a bx
-IgA deficiency -> order IgG deaminated gliadin peptide -> if + -> small bowel bx
-> if neg and suspect celiac disease remains -> small bowel bx
upper GI bleeding
-Esophageal varices- caput medusa, ascites
-Peptic ulcer disease- NSAIDs
-tell pts to have take enteric baby aspirin
-GERD- beta blocks decrease sphincter tone
-Gastritis
-Duodenitis
-CANCER
lower GI bleeding
-CANCER (colorectal)
-Hemorrhoids
-Anal fissures
-Inflammatory bowel disease- know diff between crohns and ulcerative colitis
-Diverticulitis
GI bleed work up
-endoscopy or colonoscopy-bx
-CBC- anemia
-fecal occult blood test- accurate but maybe pt isnt currently bleeding or maybe the pt is bleeding in mouth or nose
colorectal cancer
-2nd leading cause of death
-colonoscopy- every 10 years
-fecal immunochemical test (FIT) with DNA- sensitivity 79% (20-30% missed with a false negative!) -> test annually
-fecal occult blood test- only 20-50% identified with colon cancer
-CT colonography
-flexible sigmoidoscopy
liver
-1. excretory- excrete bilirubin into bile, bile acid in excreted into the bile
-2. synthesis- protein (proteins LFTs, albumin), coagulation factors, transport proteins, bile acids from cholesterol -> PT INR elevated with liver disease due to decreased coagulation factors
-coomanin ?
-3. detoxification- drugs and toxins
-4. storage- amino acids, carbohydrates (gluconeogenesis), lipids, vitamins, minerals
-5. metabolism- thyroid hormone, steroid hormones
-6. conjunction- bilirubin -> direct vs total bilirubin
total bilirubin
-direct (conjugated) and indirect (unconjugated)
-indirect- bilirubin in the blood -> elevated in hemolytic anemia, genetic disorders,
-direct- hepatocytes done the work and packaged -> elevated in liver disease, obstruction in liver or gal bladder, pancreatitis
-pancreatic cancer- extrahepatic blockage
liver: excretory
-bilirubin comes from broken down RBCs (90-120 days)
-hemolysis
-recycle it in liver
-unconjugated -> conjugated bilirubin -> bile
-store in galbladder
-aid in digestion of lipids
liver function test
-ALT- heptocellular damage -> specific to liver
-AST- hepatocellular damage -> can be elevated with muscle fatigue
-bilirubin- cholestasis, impair conjugation, or biliary obstruction
-alkaline phosphatase (ALP)- cholestasis, infiltrative disease, or biliary obstruction -> also elevated in breakdown of bone or pregnancy
-PT- synthetic function
-albumin- synthetic function
-GGT- cholestasis or biliary obstruction -> confirms alk phos is biliary related
liver enzymes: AST and ALT
-hepatocellular damage- inconsistent - snapshot
-alanine aminotransferase (ALT)- more specific for liver function -> elevated in liver disease
-aspartate aminotransferase (AST):
-decreased AST- liver congestion, high cholesterol
-increased AST: liver disease, EtOH, MI, kidney infection and disease
-AST:ALT ratio- ETOH induced liver disease, AST:ALT- AST value greater than 2x
liver enzymes: lactate dehydrogenase (LDH)
-elevated in cardiac, RBC hemolysis, renal disease
-could be many things
-non specific
Hepatic shock is detected in ill patients, especially those with hemodynamic disorders
-It can be prevented by early treatment of underlying disease.
-There is no definite treatment for hepatic shock and should be managed conservatively
-Hepatic shock in patients can increase the mortality rate
-portal vein
-lack of blood flow to liver -> shock
-can be clot
biliary tract: alkaline phosphatase
-INCREASED:
-pregnancy
-1. Liver diseases:
-Cirrhosis
-Hepatitis
-Biliary obstruction
-2. Bone Diseases:
-Bone Tumors
-Osteoporosis
-Rickets
-Padget’s disease- lytic lesions on all of bones
-Hyperparathyroidism
-Malignancies (leukemias & Lymphomas)
-DECREASED:
-Wilson’s Disease
-Hyperphosphatasia
-Cretinism
-Pernicious Anemia
-Aplastic Anemia
-CML- chronic myeloid leukemia
mc cancers that metastases to bone
-breast
-prostate
biliary tract: gamma-glutamltransferase (GGT)
-increased:
-liver disease
-cancer of prostate, breast or lung
-pancreatitis
-SLE
-used along with elevated alk phos to determine the disease source -> if both elevated indicative of hepatobiliary disease
-decreased:
-hyperthyroidism
-hypothalamic dysfunction
bilirubin
-total: hepatic:
-hepatitis
-cirrhosis
-alcoholic liver disease
-indirect: pre-hepatic:
-hemolysis
-Newborns
-Malaria
-Sickle cell anemia
-Thalassemia
-Hemolytic uremic syndrome
-direct: post-hepatic:
-gallstones
-bile duct strictures
-biliary atresia
-pancreatic cancer
bilirubin chart
-ignore dubin johnson par
-understand chart
synthetic liver function: hypoalbuminemia
-Liver diseases
-Kidney diseases
-Malnutrition
-Burn injury
-if albumin is low you have more fluid shifts -> swelling
-PT INR and albumin can show liver disease
synthetic liver function: transthyretin/prealbumin
-malnutrition
synthetic liver function: high prothrombin time and INR
-due to synthetic factor production (1, 2, 5, 7, 10)
HBsAg, anti-HBc, anti-HBs negative
-susceptible
HBsAg neg, anti-HBc pos, anti-HBs pos
resolved HBV infection
HBsAg neg, anti-HBc neg, anti-HBs pos
vaccinated
HBsAg pos, anti-HBc pos, anti-HBs neg
-active HBV infection (usually chronic)
-if anti-HBc IgM present, may represent acute infection
HBsAg neg, HBcAB pos, HBsAb neg
-distant resolved infection (MC)
-recovering from acute infection
-false pos
-occult hepatitis B
tests used in dx of hepatitis C
-anti-HCV EIA neg / HCV RNA neg- not infected
-anti-HCV EIA pos / HCV RNA neg- resolved HCV infection
-anti-HCV EIA neg / HCV RNA pos- early acute HCV infection or chronic HCV infection in immune compromised person
-anti-HCV EIA pos / HCV RNA pos- acute or chronic HCV infection
acute pancreatitis
-autodigestion by its own enzymes
-epigastric pain, nausea, vomiting, back pain
-severe- fever, hypotension, tachycardia
-causes: biliary tract obstruction, alcohol abuse, idiopathic
-dx by amylase or lipase elevation greater than 3 times normal
-lipase has 95% sensitivity and specificity (more organ specific)
-together with clinical presentation
chronic pancreatitis
-multiple acute events, ETOH consumption, malnutrition, cystic fibrosis in children
-impaired glucose tolerance testing or diabetes
-amylase and lipase*** do not tell the story
-lipase is more organ specific- if amylase is high and lipase is low - may be something else
-cellular destruction leading to scar tissue then causing pancreatic duct obstruction
-can destroy endocrine function- cause diabetes!
-abdominal pain, weight loss, pancreatic calcification and steatorrhea
-endoscopic US
-endoscopic retrograde cholangiopancreatography…however can cause acute event
exocrine pancreatic neoplasms
-CA 19-9 tumor marker for pancreatic cancer
-70-90% sensitivity
-68-92% specificity
-dependent on tumor size
-elevated in other GI cancers
BMP + LFTs
-CMP
