Elimination & Detox 2: Portosystemic Shunts Flashcards
what PSS tends to have a HIGHER FLOW?
INTRAHEPATIC > EXTRAHEPATIC
name the AT-RISK BREEDS & SPECIES FOR…
INTRAHEPATIC PSS?
EXTRAHEPATIC PSS?
INTRAHEPATIC = mostly LARGE-BREED DOGS, very occasionally SMALL BREED (like frenchies)
EXTRAHEPATIC = CATS & SMALL BREED DOGS, also LARGE BREED DOGS
what 3 main CATEGORIES of CLINICAL SIGNS do we expect with PORTOSYSTEMIC SHUNTS?
which one is more common in INTRAHEPATIC shunts?
- NEUROLOGIC
- GI SIGNS –> more common with INTRAHEPATIC shunts
- URINARY
what kinds of CLINICAL SIGNS do we USUALLY NOTICE WITH PSS?
give 3 examples of the clinical signs we can see
what DISEASE do we usually see? why?
+/- possible CBC finding
NEUROLOGIC
3 examples?
1. HEAD-PRESSING
2. BLINDNESS
3. SEIZURES
usually see HEPATIC ENCEPHALOPATHY because AMMONIA IN BLOOD & NOT PROCESSED BY LIVER
+/- HYPOGLYCEMIA
what 2 clinical signs can CATS present with that SUGGEST PSS?
what TYPE of PSS are cats MOST LIKELY to get?
2 clinical signs?
1. COPPER-COLORED EYES
2. PTYALISM
more likely to get EXTRAHEPATIC PSS
four URINARY clinical signs with PSS?
what PORTION of the URINARY TRACT is usually affected?
- PU/PD
- STRANGURIA
- HEMATURIA
- URETHRAL OBSTRUCTION/STONES
usually LOWER URINARY TRACT affected
describe likely dz & clinical sign
EXTRAHEPATIC PSS due to COPPER-COLORED IRISES
what MAINLY causes HEPATIC ENCEPHALOPATHY & how? (3)
- usually from AMMONIA BUILDUP in SYSTEMIC CIRCULATION (not being turned into urea after produced in GI TRACT)
- has an EXCITATORY EFFECT ON NEUROLOGIC SYSTEM
- can also CHANGE BBB to CAUSE EDEMA IN BRAIN
TRUE/FALSE
we can MEASURE the AMMONIA LEVELS to CORRELATE with NEUROLOGIC SYNDROME SEVERITY
FALSE, AMMONIA LEVELS DO NOT CORRELATE TO HOW SEVERE NEUROLOGIC DZ LIKE HEPATIC ENCEPHALOPATHY IS
movement of BILE in HEPATOCYTES in PSS (4)
- CHOLESTEROL is DEGRADED into BILE ACID in HEPATOCYTE
- BILE ACIDS SECRETED into the INTESTINAL TRACT
- MOST of bile acids are RESORBED IN ILEUM, some RESORBED in COLON if DECONJUGATED
- overall, HEPATOCYTES EXTRACT ALL OF THESE BILE ACIDS and PUSH BACK INTO CIRCULATION
3 qualities of the MCHC, MCV, & HCT in PSS?
what 2 findings on URINALYSIS can you expect?
CBC?
1. NON-REGENERATIVE ANEMIA
2. MICROCYTIC
3. NORMOCHROMIC
UA?
1. ISOSTHENURIA
2. AMMONIUM BIURATE UROLITHS/CRYSTALS
what 2 tests are CRUCIAL for DIAGNOSIS OF PSS?
which one is “better” and used MORE often?
SENSITIVITY/SPECIFICITY?
how is it PERFORMED?
- BILE ACIDS = normally resorbed by LIVER, so an INCREASE signals LIVER NOT RESORBING THEM
–> RESTING & 2 HOUR POST-PRANDIAL READING - AMMONIA = normally CONVERTED TO UREA IN LIVER, so if INCREASE then POOR LIVER FUNCTION from PSS
–> used MORE OFTEN
both are SENSITIVE & SPECIFIC for DETECTION OF PSS in DOGS/CATS
4 options for IMAGING DIAGNOSTICS for PSS?
- NUCLEAR SCINTIGRAPHY
- US
- CT
- MRI
NUCLEAR SCINTIGRAPHY…
used to diagnose WHAT?
sensitivity/specificity?
requires patient to be…
con?
used to diagnose PSS
HIGHLY SENSITIVE & SPECIFIC
requires patient to be LIGHTLY ANESTHETIZED/SEDATED
con = CHALLENGING FOR SURGICAL PLANNING because we CANNOT SEE SURROUNDING ANATOMY
COLONIC PORTOGRAM…
what KIND of imaging is this?
what’s it used for?
HOW does it work? (3)
this is NUCLEAR SCINTIGRAPHY
used for DIAGNOSING PSS
HOW does it work?
1. CONTRAST MEDIUM is administered…
–> via CATHETER into DESCENDING COLON
–> via US into SPLEEN
- MEDIUM should ALL DRAIN INTO LIVER
- MEASURE WHAT FRACTION OF MEDIUM IS IN LIVER OR NOT
ULTRASOUND for PSS…
3 pros?
2 cons?
3 pros?
1. gives you SURROUNDING anatomic information
2. evaluate abdomen for SECONDARY CHANGES or CONCURRENT DZ
3. can be HIGHLY SENSITIVE/SPECIFIC
2 cons?
1. OPERATOR-dependent
2. 2D imaging
what 3 ABDOMINAL SECONDARY CHANGES/CONCURRENT DZ should we look for on US with PSS?
- MICROHEPATICA
- RENOMEGALY
- URINARY CALCULI
describe what you SEE on US
what DZ is this likely?
CYSTIC CALCULI
likely EXTRAHEPATIC PSS