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
describe this PATHOLOGY on US
MICROHEPATICA
CT for PSS…
allows for GREAT VISUALIZATION of what 2 things?
3 pros?
2 cons?
GREAT VISUALIZATION of SYSTEMIC & PORTAL veins
3 pros?
1. excellent for SURGICAL PLANNING
2. 2D –> 3D IMAGE RECONSTRUCTION POSSIBLE
3. helps to ID CONCURRENT DZ
2 cons?
1. EXPENSIVE
2. GA
in PSS, WHEN should we PROTEIN-RESTRICT?
only when we see CLINICAL SIGNS OF HEPATIC ENCEPHALOPATHY (ammonia to brain –> EDEMA)
REGARDLESS if a PSS patient gets SURGERY, what treatment do they REQUIRE?
if they DO go to surgery…
require MEDICAL MANAGEMENT!
if they DO GO TO SURGERY, do MEDICAL MANAGEMENT AT LEAST 2 WEEKS BEFORE to make them a BETTER SURGICAL CANDIDATE & HELP WITH RECOVERY
4 options for AT HOME MEDICAL management for PSS?
what does each hope to achieve? give an example of a few
- LACTULOSE
see another card for functions!! –> OVERALL DECREASES AMMONIA
–> give JUST ENOUGH TO TREAT & NOT CAUSE D+ - ANTIBIOTICS to DECREASE BACTERIAL TRANSLOCATION into PORTAL VENOUS SYSTEM
–> AMOXICILLIN COMMON - GI PROTECTANTS like H2-BLOCKERS or PPIs
–> OMEPRAZOLE - DIGESTIBLE diets with HIGH QUALITY PROTEIN
GI protectants are MORE COMMONLY USED to treat WHAT kind of PSS?
INTRAHEPATIC PSS > EXTRAHEPATIC PSS
4 IN-HOSPITAL treatment options for PSS?
which one is MOST IMPORTANT for LITTLE DOGS?
- continue AT-HOME MEDICATIONS
- if HYPOGLYCEMIC, SUPPLEMENT with GLUCOSE; ESPECIALLY FOR LITTLE DOGS!
- consider ANTI-CONVULSANTS during ANESTHESIA
- if COAGULOPATHY from LIVER DYSFUNCTION, can give PLASMA to RESTORE ONCOTIC PRESSURE
3 ACTIONS of LACTULOSE for PSS treatment?
given at home/in-hospital?
- PROMOTES ACIDIFICATION of the COLONIC CONTENTS to TRAP AMMONIA
- DECREASES number of AMMONIA-PRODUCING BACTERIA
- DECREASES GI TRANSIT TIME so LESS TIME to absorb TOXIC METABOLIC SUBSTANCES
given AT HOME!
should you give LEVETIRACETAM (keppra) as a PREVENTATIVE against ____ during SURGERY for PSS? why or why not?
SEIZURES
LACKING STRONG EVIDENCE that Keppra can help PREVENT seizures, so UP TO YOU
SUTURE LIGATION…
used to treat WHAT PSS? (2)
commonality?
how is it basically performed?
what is the MAIN LIMITING FACTOR? & describe WHAT can potentially happen?
used to treat EXTRA- & INTRAHEPATIC PSS
UNCOMMONLY done these days
how is it basically performed? = SHUNT VESSEL is DISSECTED OUT & SUTURE is TIED AROUND IT
LIMITING FACTOR = RISK OF PORTAL HYPERTENSION
what can happen? –> if TOO TIGHT can cause INCREASED PRESSURE UPSTREAM –> GI EDEMA, PANCREATIC HYPERTENSION & lead to ASCITES
COIL EMBOLIZATION is used to treat ____-HEPATIC PSS
INTRA
how do we AVOID PORTAL HYPERTENSION & its subsequent effects in SUTURE LIGATION? (2)
NOWADAYS, what technology have we developed?
- TIE IT TIGHT but NOT TOO TIGHT via MEASURING PORTAL PRESSURES AT THE TIME OF SURGERY WITH A CATHETER IN JEJUNUAL VEIN
- as we TIGHTEN SUTURE DOWN, CHECK PRESSURE to make sure we’re not going too high
NOWADAYS, we’ve developed devices that can MECHANICALLY & GRADUALLY tighten shunt vessel OVER TIME
what is the MOST COMMON FORM of SURGICAL TREATMENT for PSS?
how does it work? (3)
OVERALL, what does this surgery aim to do?
AMEROID CONSTRICTORS (for INTRA & EXTRA)
how does it work?
1. put STAINLESS STEEL RING with CASEIN PROTEIN around SHUNTING VESSEL (not too tightly)
- CASEIN RING will SWELL & DECREASE INTERNAL DIAMETER over 2-5 WEEKS
- eventually, shunt will close via RING CONSTRICTION + FIBROUS REACTION IN VESSEL TO CLOSE OFF SHUNT
OVERALL = DECREASES RISK OF PORTAL HYPERTENSION
what SURGICAL PROCEDURE is this used for?
AMEROID CONSTRICTOR for IHPSS and EHPSS
CELLOPHANE BANDING..
used for WHAT PSS?
procedure? (2)
when compared to AMEROID CONSTRICTORS… 1 pro & 1 con
used for INTRA & EXTRA-HEPATIC PSS
procedure?
1. place a SMALL STRIP OF CELLOPHANE around the SHUNTING VESSEL while measuring PORTAL PRESSURE
- over time, FIBROUS/INFLAMMATORY REACTION occurs and causes OCCLUSION OF VESSEL
when compared to AMEROID CONSTRICTORS, has a HIGHER INCIDENCE OF RESIDUAL FLOW THROUGH THE SHUNT, but CELLOPHANE CAN BE MORE UNIVERSALLY USED (rings only come in some sizes)
HYDRAULIC OCCLUDERS…
process in 3 steps?
commonality?
process?
1. OCCLUDER is PLACED AROUND SHUNTING VESSEL
- TUBE CONNECTS to PORT and SITS BELOW SKIN
- TUBE IS INJECTED WITH SALINE OVER TIME, causing SLOW ATTENUATION OF VESSEL OVER TIME
RARELY USED
PERCUTANEOUS TRANSVENOUS COIL EMBOLIZATION…
what is the GOAL of this procedure?
most commonly used to treat ___HEPATIC SHUNTS
GOAL = allows us to MEASURE SIZE OF THE STENT WE’LL NEED FOR THE SHUNTING VESSEL ATTACHED TO VENA CAVA and HYPERTENSION
most commonly used to treat INTRAHEPATIC SHUNTS
4 main POST-OP concerns with PSS?
- HYPOGLYCEMIA
- PORTAL HYPERTENSION
- LONG-TERM RECURRENCE
- GI ULCERATION
HYPOGLYCEMIA…
commonly seen WHEN in the tx for PSS?
___-PSS MOST LIKELY
what size of dog predisposed?
2 reasons this could occur?
commonly seen as a POST-OP COMPLICATION
EXTRAHEPATIC-PSS MOST LIKELY
SMALL BREEDS PREDISPOSED
2 reasons?
1. FASTED prior to sx
2. has LIVER DYSFUNCTION
PORTAL HYPERTENSION as a POST-OP COMPLICATION…
commonality? & why?
UNCOMMON because we’re NOT DOING SUTURE LIGATION, portal vein SHOULD NOT BE AFFECTED
GI ULCERS are MORE common in ____PSS > ____PSS
what drugs should we NOT administer? in ___PSS
INTRAHEPATIC PSS > EXTRAHEPATIC PSS
DO NOT GIVE NSAIDS IN INTRAHEPATIC PSS
POST-ATTENUATION NEUROLOGIC SIGNS…
= what is it?
commonality in dogs vs. cats?
how is it treated? (2)
= NEUROLOGIC SIGNS such as SEIZURES, ATAXIA, ABNORMAL MENTATION that can occur WITHIN 96 HOURS OF PSS SURGERY
CATS MUCH MORE LIKELY than dogs, but TEND TO SEE NEURO SIGNS RATHER THAN SEIZURES
treated via…
1. ANTI-CONVULSANTS
2. ANTI-SEIZURE MEDICATIONS
if animal experiences a SEIZURE POST-OP, then…
VERY POOR PROGNOSIS
if there’s A LOT OF BLEEDING POST-OP for PSS, what 2 things can we do?
- ADD VITAMIN K
- GIVE FRESH FROZEN PLASMA
PERIOPERATIVE support for PSS? (4)
- ACTIVELY WARM
- IV FLUIDS
- PAIN MEDS (NOT NSAIDS)
- watch the BLOOD SUGAR
what are the 3 ANTIBIOTICS that are commonly used for PSS?
- AMOXICILLIN/AMPICILLIN
- METRONIDAZOLE
- NEOMYCIN
give 4 OVERALL POST-OP MEDS/LIFESTYLE CHANGES for PSS (one is +/-)
what should we do regarding administration of POST-OP medications for PSS?
OVERALL…
1. PROTEIN-RESTRICTED diet
2. LACTULOSE
3. ANTIBIOTIC like AMOXICILLIN or METRONIDAZOLE
4. +/- ANTI-SEIZURE MEDS
we should WEAN OVER 2-3 MONTHS to allow LIVER TO REGENERATE & SHUNT TO CLOSE
