Liver Flashcards
How might liver dysfuntion typically present?
What are some labs that are essential to determine the cause and severity?
- typically presents as flu-like symptoms followed by jaundice
- Labs
- bilirubin
- aminotransferases (ALT, AST)
- alkaline phosphatase
- INR
- albumin
- serologic and genetic testing
What is bilirubin?
What is its “pathway?”
- Bilirubin is the pruduct of broken down hemoglobin and myoglobin
- Unconjugated bilirubin is formed in the periphery, it is transported to the liver bound to albumin
- In the liver it is conjugated, making it water soluble so it can be excreted
What increases unconjugated bilirubin?
What increases conjugated bilirubin?
- Unconjugated
- increased bilirubin production
- decreased hepatic uptake
- decreased conjugation
- Conjugated
- decreased canalicular transport of bilirubin
- acute/chronic hepatocellular dysfunction
- obstruction of bile ducts
What is the difference between AST and ALT?
What can the ratio of AST to ALT tell us?
- AST represents Liver AND extrahepatic tissues
- ALT is highly specific to the liver
- Ratio of AST:ALT
- 2:1 is seen in patients with Alcoholic liver disease (ALD)
- <1 is seen in patients with non-alcoholic steatohepatitis (NASH)
What can an elevated alkaline phosphatase tell us?
- Increases in serum Alk phos levels lack specificity because it is found in cell membranes throughout entire body
- In Cholestatic disorders, increased levels may indicate that bile salts are damaging hepatocyte membranes
What can the INR tell us regarding liver disease?
- INR is a good test of the liver’s ability to synthesize things
- if clotting time is prolonged, the liver may not be making adequate clotting factors
- INR depends a lot on factor VII, which is produced in the liver and relies on Vit K
- other vitamin K clotting factors are II, IX, X, proteins C and S
- INR is part of MELD score because it is a reliable independent risk factor for mortality
What is another scoring tool used to determine mortality with ESLD?
Child-Pugh score
How is albumin used to assess liver function?
What else can cause decreased albumin levels?
- Albumin is the most abundant plasma protein and is synthesized exclusively by hepatocytes
- decreased albumin levels also seen in:
- protein malnutrition
- protein-losing disease (nephrotic syndrome)
- severe reduction in synthetic capacity of liver
What lab differences would you see between prehepatic, intrahepatic, and posthepatic dysfunction? (chart)
Bili
AST/ALT
Alk phos
causes of changes
What are the different types of liver disease?
- Biliary disease (acute cholecystitis)
- acute hepatitis
- chronic hepatitis
- cirrhosis
- acute liver failure
- porphyria
What are the functions of the liver?
- Glucose homeostasis
- coagulation
- metabolism of:
- drug/toxin
- heme
- cholesterol/lipid
- protein
- production of thrombopoietin
- **impaired liver function affects nearly every organ system in the body
What is cholecystitis?
Who is at greatest risk?
symptoms
How is it treated?
- gallbladder or biliary tract stone
- Fat, fair, female, forty, fertile
- symptoms:
- N/V
- fever
- abdominal pain
- RUQ tenderness radiating to back
- dark urine
- scleral icterus
- Surgery when condition has stabled
- laparoscopic–>5% convert to open
- ERCP (endoscopic retrograde cholangiopancreatography)
What are some considerations for all laparoscopic procedures?
- insufflation will increase intraabdominal pressure
- risk for inadequate ventilation- decrease TV, increase RR
- decreased venous return leading to decreased CO and increased MAP and SVR
- bradycardia due to peritoneal stretching
- Risk for vascular injury and acute blood loss
- CO2 embolism
General considerations for Liver patients
- Consider volume and electrolyte replacement before procedure
- Consider how pt will be positioned
- trendelenburg- increases venous return and CO
- reverse trendelenberg- aids surgical access and may improve ventilation but decreases venous return and CO
- support HR and BP
- Ventilation-watch PIP and MV
- adjust accordingling: decrease TV, increase RR
- NG/OG tube
- avoid N2O
- careful use of opioids- risk of sphincter of oddi spasm
How do inhaled agents affect blood flow to the liver?
- Halothane: vasoconstriction of hepatic arterial bed, decreased O2 delivery to liver
- also a concern for halothane hepatitis
- NO Halothane, isoflurane, or sevoflurane
- Isoflurane- increased flow velocity in hepatic sinusoids
- Sevoflurane- equal or superior to Isoflurane in maintaining Hepatic artery blood flow (HABF)
What is the Hepatic artery buffer response (HABR)?
- Autoregulatory
- matches a drop in portal bloodflow (PBF) with an increase in hepatic artery blood flow (HABF)
What are the different types of hepatitis?
acute vs chronic?
- Inflammation of the liver parenchyma
- viral
- autoimmune
- drug induced
- Acute- usually self limiting
- most often viral
- can be caused by drugs/toxins
- Chronic- hepatic inflammation >6 months
- cirrhosis, hepatocellular carcinoma or liver failure
- Symptoms can range from minimal (malaise/jaundice) to severe with multiple organ compromise
What is autoimmune hepatitis?
How is it diagnosed?
How is it cured?
Treatment goals?
- cellular immune response against self-antigens in the liver
- diagnosis is confirmed with clinical findings, lab testing, and histologic evaluation
- no curative intervention
- Goal is to induce remission with corticosteroids and immunosuppressive drugs or liver transplantation
