Flashcards in Diagnostics Deck (102):
what virus commonly found in daycare is less common now that there is a vaccine?
your patient has been hospitalized for 5 days, will their sample work for stool cultures?
nope, rejected if hospitalized >3 days
blunt abdominal trauma imaging
focused assessment with sonography for trauma (FAST)
you suspect a mid GI bleed. what imaging could you use to investigate?
HBV DNA in serum is bound to _____. is it typically infectious?
IgG, rarely infectious
imaging modality of choice for pancreatitis?
CT (esp in urgent/emergent)
what can you use to visualize the whole dang small intestine?
push enteroscopy (but still difficult AF due to tortuosity of intestines, balloon-assisted endoscopy facilitates)
what lab test should all pts with HCV infection undergo prior to tx
quantitative NAT with HCV genotyping
which liver enzyme is more specific for hepatocellular injury
ALT (more than AST)
total bilirubin can be elevated due to what 3 things
1. overproduction of bilirubin (hemolysis)
2. impaired uptake, conjugation, or excretion of bilirubin
3. backward leakage from damaged hepatocytes or bile ducts (hepatitis, autoimmune, drugs, obstruction)
what does the presence of IgM anti-HAV indicate?
acute infection - hep a
what is first line colorectal cancer screening test?
what might you see on imaging for diverticulitis?
stranding, wall thickening, wall enhancement
how is hep D diagnosed?
presence of anti-HDV or HDV RNA in serum
what abnormalities might you see on an abdominal xray?
air, fluid, radiopacities (FB or calcifications)
compared to HBeAg, anti-HBe tells you what?
indicates less viral replication and infectivity
describe the antibody/antigen situation in a patient who has a vaccination against Hep B
HBsAg neg, Anti-HBs pos, Anti-HBc IgG neg, HBeAg neg, Anti-HBe neg
imaging of choice for appendicitis?
CT (usually without contrast) imaging
but if chronic, consider contrast
you should only order bacterial culture & sensitivity stool studies if (3)
1. diarrhea >1 week or recurring
2. sxs of dysentery (fever, blood, tenesmus)
3. high-risk host or public health concern
what is the most sensitive liver enzyme for detecting biliary obstruction, cholangitis, and cholecystitis?
can you perform a flex sig on a pt with diverticulitis?
your patient has iron deficiency anemia and you suspect GI bleed. what dx imaging should you use?
hep C Ab indicates
present or resolved infection
what should you do after you place an NG tube?
get an xray! (prior to putting anything through it)
two modes of imaging for cholecystitis?
Murphy's sign (US)
turtle shells on an xray indicate
trapped fluid in dilated loops of bowel -- air fluid levels
do you test for c diff in asymptomatic patients?
what is urea breath test particularly helpful for?
diagnosis and documenting successful treatment of H. pylori
(same for stool antigen)
what is the gold standard for small bowel (tumors, bleeding) visualization?
video capsule endoscopy
hyper-unconjugated bilirubin is defined as
<15-20% of total bilirubin is direct
when do you use a diagnostic peritoneal lavage
trauma, hemorrhage, ruptured intestine
will PT be increased or decreased in a patient with liver disease
increased (once CFs drop to 30-40% normal levels)
first study used for jaundice
what technique combines contrasted radiography with endoscopy to look at bile and pancreatic ducts?
MC cause of ascites
portal hypertension resulting from cirrhosis
decreased plasma protein synthesis by the liver results in decreased colloid osmotic pressure
results in primarily water leaking into the peritoneal space (transudate)
what is SAAG
serum albumin level : ascitic fluid albumin level; tells you if portal hypertension is present
what does ERCP look at?
pancreatic and biliary ducts
apple core sign associated with what?
colon tumor seen on barium enema
when would you want to see the small intestine with enteroscopy
when you suspect mid-GI bleeding
what parallels HBeAg but is more sensitive and precise marker of viral replication and infectivity?
high SAAG >1.1 indicates
which pancreatic enzyme is highly specific to the pancreas?
do you test for cured c diff?
when is paracentesis indicated? (3)
1. eval of new ascites
2. suspected bacterial peritonitis
3. therapeutic large-volume paracentesis
what do you need to tell a patient about their diet before a fecal fat study?
high fat diet for 3 days before and through collection
what parasite should you think of in HIV positive and sporadic water-related outbreaks?
HBeAg is found only in HBsAg positive serum soon after its detection and tells you what
presence indicates viral replication and infectivity
you suspect your patient has swallowed a foreign body. what imaging might you first obtain?
chest and upright abdominal film
describe the antibody/antigen situation in a patient who has recovered from Hep B
HBsAg neg, Anti-HBs pos, anti-HBc IgG pos, HBeAg neg (anti-Hbe can be pos or neg)
can you use flexible sigmoidoscopy in patients with diverticulits?
what appears with anti-HBc IgM but persists?
does albumin drop slowly or quickly with acute problems
prealbumin drops quickly when deprived of protein/calories
what imaging modality can be used as a screening in trauma?
is an elevated amylase or lipase alone wo clinical signs pancreatitis
what 3 types of lesions can be seen on a liver?
3. tumor (primary v metastatic)
what should you think of in travelers to Latin America and HIV positive?
how many negative
EIA toxin tests do you need to rule c diff out?
3 specimens on 3 different days
how is rotavirus detected?
ELISA or latex agglutination
most common c diff testing
EIA testing for toxins A and B (uses antibodies)
what dx imaging are you going to use to evaluate jaundice?
routine stool culture screens for what 3 MC bacterial pathogens implicated in diarrhea?
salmonella, shigella, campylobacter
what is most often used for staging colon ca?
MRI does have increasing sensitivity
hep G is associated with extensive exposure to what?
which liver enzyme is present in high amounts in heart and skeletal muscle?
gold standard for imaging AAA
what imaging can you use to differentiate between acute and chronic cholecystitis?
...but you're not really getting this if the patient is acute
what point can an EGD not visualize beyond?
ligament of Treitz
what types of viral hepatitis are only acute? (never turn chronic)
A and E (acute starts with A, ends with E)
does HBcAg appear in serum
why type of endoscopy would be used for refractory GERD, esophageal varices, or upper GI bleed?
EGD (aka upper endoscopy)
what colitis is associated with antibiotics?
Anti-HBs is what
appears after clearance of HBsAg and after successful vaccination;
signals recovery fro HBV infection, noninfectivity, and immunity
what are two contraindications for ERCP?
acute pancreatitis, esophageal diverticula
(non acute pancreatitis okay)
HBsAg tells you what
first evidence of infection, persists throughout clinical illness; establishes infection and implies infectivity
what imaging tool for biliary tree eval can be both diagnostic and interventional?
ERCP (endoscopic retrograde cholangiopancreatography)
acute pancreatitis requires what features (two of three)
1. abdominal pain typical of acute pancreatitis
2. blood amylase and/or lipase >3x ULN
3. typical finding of pancreatic inflammation on contrast CT or MRI
what can be used to stage rectal, esophageal, and gastric cancer and identify pancreatic tumors?
what is the most sensitive liver enzyme for detecting biliary obstruction, cholangitis, and cholecystitis
invasive test of choice for helicobacter pylori
serology test for h pylori is helpful in what scenario?
to exclude h. pylori (does not distinguish between active and prior infection)
describe 2 major criteria for acceptable specimens for bacterial stool cultures
1. fresh (unpreserved) stool to lab in < 2 hrs
2. preserved specimen in <96 hours
diagnostic criteria for hep C
presence of anti-HCV by ELISA; may need confirmation with HCV RNA and anti HCV RIBA
imaging of choice for diverticulitis? why?
CT w IV contrast
concern for perforation
a disease that affects bilirubin metabolism after conjugation can be detected as
increased bilirubin in urine
(cholestasis, stones, obstructions)
indications for C diff testing
clinically significant diarrhea (>3 loose stools in 24 hrs) plus:
1. abx use in past 3 months
2. hospitalization, nursing home
3. advanced age
hepatitis D requires ?
coinfection with Hep B (specifically, presence of HBsAg)
Anti-HBc IgM appears soon after ____ and before _____
soon after HBsAg, before anti-HBs
how is norovirus detected?
(only performed for epidemologic reasons)
what does presence of IgG anti-HAV indicate?
previous exposure to HAV, non-infectivity, & immunity
a general haziness or cloudy appearance of the abd indicates what?
what could be the etiology?
abnormal water shadows
etiologies: ascites, intra-abdominal bleeding, abscess, formation, etc
when will anti-HCV show up after exposure in acute hep C?
10 wk to 6 mo after exposure
are flexible sigs more or less effective than colonoscopies?
the MC cause of nosocomial diarrhea is
HCV RNA indicates
infection with HCV
when is a video capsule endoscopy used?
small bowel: tumors, obscure bleeding, polyposis syndromes, malabsorption syndromes, uncertain dx of Crohns
CDC recommends hep C screening for what populations?
1 time for adults born 1945-1965; also risk factors IVDU, tranfusion/organ transplant, recognized exposure
hyper-conjugated bilirubin is defined as
increased total bilirubin with >50% conjugated
if you suspect cryptosporidium, cyclospora, or giardia, what do you need to do?
communicate with lab; not tested on routine stool O and P
what is the primary modality for directly visualizing the GI tract?
can you do an EGD if the pt has esophageal diverticula or suspected perforation?
string of pearls on xray indicates
small bowel obstruction