hepatobiliary 4: other cholestatic disorders Flashcards
EHBDO - what is it? what animals does it affect?
- Extrahepatic biliary duct obstruction
- cats and dogs
EHBDO is secondary to what?
Secondary to pancreatitis, choleliths, mass, other
EHBDO can cause what? presentation?
- Can cause acute partial to complete biliary obstruction
- Presentation: Signs of cholestasis, can be painful
EHBDO ultrasound findings
Ultrasound can show biliary dilation (intra and/or extrahepatic)
* Can show cause of obstruction
EHBDO treatment
- Treatment aimed at underlying cause
- Ursodiol often used
- Complete obstruction is uncommon
Gall Bladder Mucocele (GBM) - typically in what species? what is it and what can it cause?
- Typically dogs
- Gall bladder distention by abnormal accumulation of mucoid contents
- Can cause partial to complete biliary obstruction
- Varying degrees of organization
Gall Bladder Mucocele (GBM) cause and risk factors
- Cause not known
- Risk factors:
- Genetic( Shetland Sheepdog predisposed)
- Endocrine disease (hypothyroidism, hyperadrenocorticism, hyperlipidemia)
- Possibly previous biliary inflammation
GBM: what signalment is typical? breeds?
- Middle aged to older dogs, any bred
- Breeds at risk: Sheltie, Cocker Spaniel, Miniature Schnauzer
GBM: Presentation
- clinical findings?
- Clinical findings range in severity:
- Incidental finding on AUS
- Inappetence, lethargy, vomiting, icterus
- Neutrophilia, left shift
- Hyperbilirubinemia, elevated liver enzymes (ALP, GGT)
- GB rupture more likely if fever, tachycardia/tachypnea, left shift
GBM: Diagnosis
- Abdominal radiographs
> Low sensitivity - Abdominal ultrasound
> Presence of semisolid to immobile mucoid material in gall bladder
> Highly variable appearance
> Gall bladder “sludge” might progress to mucocele, can be incidental and non-progressive
GBM: Treatment options
- Surgery (cholecystectomy)
> Referral procedure - Some cases without complete obstruction or GB rupture have resolved with medical management
> Ursodiol
> Low fat diet
> +/- antibiotics
> +/- antioxidants
GBM - how do we decide what treatment options to follow? what has best prognosis?
- Indications are evolving
- Mobile sludge > start medical treatment
- Fixed sludge and no clinical signs > conservative treatment acceptable
- In both cases monitor progression
- If any progression > cholecystectomy
- Surgical removal has better prognosis in a healthy candidate
> GBM can eventually cause obstruction
GBM Treatment: Dogs with Signs - what is the ideal treatment? second option?
- Ideal treatment is surgery
- If owner declines and there is not complete obstruction: Medical management acceptable
GBM in dogs: Prognosis? what can affect prognosis?
- Initial perioperative mortality 20-30%
- If discharge from hospital, good prognosis
- Variable negative prognostic indicators:
> Concurrent pancreatitis
> Complete obstruction
> Gall bladder rupture
> Older animal - May animals with negative indicators have survived > surgery still indicated
- Probably better prognosis if uncomplicated
types of Vacuolar Hepatopathies in Dogs
- Steroid hepatopathy – glycogen
- Idiopathic glycogen deposition
- Hepatocellular steatosis (lipid)
Steroid hepatopathy caused by what? how bad is it?
- Exogenous glucocorticoids, Cushing’s
- Reversible, usually not clinically relevant
- Hepatocellular steatosis is secondary to what?
- Secondary to lipid disorders, diabetes mellitus (reversible)
Vacuolar Hepatopathies in Dogs
- what do we see on biochem profile?
Cholestatic liver pattern on biochemical profile:
* Elevated ALP (moderate, can be marked - dogs); elevated GGT in parallel
* Mild elevation ALT can be found
* Bilirubin normal
hepatic Vascular anomalies - which are there? are they more common in dogs or cats?
- Portosystemic shunt
> Congenital extrahepatic**
> Congenital intrahepatic
> Acquired - Portal vein hypoplasia, microvascular dysplasia
- Dogs»_space; cats
normal hepatic bloodflow and what is carries? what does the liver do?
- Blood from GI tract, other abdominal organs normally drains into portal vein
> Delivers nutrients, toxins, bacteria, other elements to liver
> Oxygenates liver - Liver performs metabolic functions on the blood
> Extract nutrients
> Modify toxins
what is a portosystemic shunt, generally
Abnormal connection between the portal vascular system and systemic circulation
- Anomalous connection between the portal circulation and systemic venous circulation
- Bypass of hepatic sinusoids
- Many anatomic variants
- ”Shunt fraction” varies
CASE:
6-month-old Miniature Poodle
- runt of litter
- one month of intermittent vomiting
- quiet
- walking abnormally and bumping into furniture
- Problem list:
- Acute onset neurological signs (suspect ataxia, blindness)
- Chronic intermittent vomiting
- Quiet demeanour
- Poor growth
Primary differential?
portosystemic shunt
portosystemic shunts are commonly associated with what other condition?
- Commonly associated with hepatic encephalopathy
how does congenital PSS arise?
All mammalian fetuses have a large shunt called the ductus venosus that carries blood quickly through the fetal liver to the heart. A congenital portosystemic shunt develops if:
- The ductus venosus fails to collapse at birth and remains intact and open after the fetus no longer needs it.
- A blood vessel outside the liver develops abnormally and remains open after the ductus venosus closes.
difference between extrahepatic PSS with small vs large shunt fraction?
Small shunt fraction:
* small amount of blood bypassing liver
* most blood still entering portal circulation
* potentially fewer clinical signs
Larger shunt fraction
* large amount of blood bypassing liver
* Small amount of blood entering portal circulation
* Likely more clinical signs
Intrahepatic PSS - how common is this form of congenitcal PSS? in what breeds, mostly?
- Approximately 25-33% of congenital PSS are intrahepatic
- Most occur in larger breed dogs
Intrahepatic PSS - do these generally have a large volume of diverted blood? where is the shunt located?
- IHPSS have largest volume of diverted blood
- Shunt located within the hepatic parenchyma
Acquired PSS develop secondary to what?
Develop secondary to severe liver disease
* E.g., extensive hepatic fibrosis from CH
Acquired PSS effects on blood pressures?
- Increase in portal hypertension
- Creates high pressure environment for portal circulation
> Recanalization of previous portosystemic collateral vessels
> Multiple tortuous anastomotic vessels connecting portal vein & vena cava
> Path of least resistance
Hepatic Encephalopathy - when does this arise? what is the result?
- Caused by >70% liver function lost, or diversion of portal blood flow
- Results in decreased metabolic & detoxifying functions of liver
? Toxins can affect cerebral cortex exposed to toxins and cause neuro signs - Most commonly seen with congenital PSS
- Also seen with:
> Acquired PSS
> Cirrhosis/end stage liver failure in CH, other hepatopathies
> Acute liver failure
> Hepatic lipidosis
Hepatic Encephalopathy: Pathogenesis? toxins and sources?
- Toxins cross blood-brain barrier
- Most important & well known is ammonia
- Sources of ammonia = dietary protein, body protein breakdown, metabolism of bacteria in microflora, cell metabolism
> Not just from dietary protein - Other toxins involved in pathogenesis of HE, not well identified
Hepatic Encephalopathy: Presentation
- Signs and severity are highly variable
- Non-localizing CNS signs:
> Mentation changes: depression, lethargy
> Trembling
> Ataxia
> Circling
> Head pressing
> Cortical blindness
> Seizures - Ptyalism in cats common
Hepatic Encephalopathy: Diagnosis
- Often presumptive based on clinical signs, presence of PSS or other liver disease that causes dysfunction
- Can measure ammonia levels but not widely available
extrahepatic portosystemic Shunt: Presentation: what breeds?
- Small breeds
- E.g., Yorkshire Terriers
intrahepatic portosystemic Shunt: Presentation: what animals?
- Large breeds
- German shepherd dogs
- Irish wolfhound
- Old English sheepdog
- Australian cattle dogs,
Australian shepherds
Portosystemic Shunt: Presentation
- age of animal?
- Often young dogs
- Can present middle-aged to older when shunt fraction is low, clinical signs
are minimal - E.g., present for signs secondary to urate uroliths
Portosystemic Shunt: clinical signs summary?
Clinical signs often relate to effects of decreased liver function:
* Neurologic (HE)
* Gastrointestinal (increased gastrin or other effects)
* Urinary (urate stones)
* Poor growth, “failure to thrive” (decreased nutrient metabolism)
examples of Hepatic encephalopathy / CNS signs from portosystemic shunt? how common are they and when do they arise?
- Star-gazing/staringintospace
- Abnormalbehaviourincludingaggression
- Headpressing
- Intermittentblindness
- Ataxia
- Pacing
- Seizures
- Stupor
- 41-90% of patients (high rate especially in cats)
- Occur shortly after a meal in 30-50% of cases
examples of GI signs from portosystemic shunt? how common are they and when do they arise?
- Vomiting, diarrhea
- GI blood loss (melena) especially in IHPSS
- 30-50% dogs; less common in cats
examples of lower urinary tract signs from portosystemic shunt? how common are they?
(urate uroliths, UTI)
* Stranguria, hematuria
- 25-50% of cases
