Term
| what is the most severe clinical consequence of liver disease? |
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Definition
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Term
| how does liver failure develop? |
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Definition
| either insidiously (often represents the end stage of progressive chronic damage) or rapidly (as from fulminant hepatic failure) |
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Term
| how much hepatic function must be lost before liver failure? what is the tx if this occurs? |
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Definition
| 80-90%. liver transplant is the only option. |
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Term
| what are the different presentations of liver failure? |
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Definition
| acute/chronic liver failure and hepatic dysfunction |
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Term
| what is the association between jaundice and liver failure? where should you look for this? |
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Definition
| jaundice is a very common finding, but is not pathognomonic for liver disease. its association to liver disease depends on the mechanism such as a mass obstructing the biliary tree or production of bile stasis. since pts have different skin pigmentations, the sclera is the best location to look for jaundice |
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Term
| what characterizes hypoalbuminemia in liver failure? |
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Definition
| b/c pts cannot make as much protein, they get peripheral edema and ascites |
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Term
| what characterizes hyperammonemia in liver failure? |
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Definition
| the urea cycle does not properly run and this *may lead to mental status changes |
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Term
| what characterizes fetor hepaticus in liver failure? |
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Definition
| fetor hepaticus = musty body odor due to the formation of mercaptans by the action of GI bacteria on sulfur-containing AAs w/shunting of splanchnic blood from the portal into systemic circulation. |
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Term
| how can liver failure affect estrogen metabolism? |
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Definition
| liver failure can *impair estrogen metabolism - leading to vasodilation, causing palmar erythema and spider angiomas. in males, hyperestrogenemia can give rise to hypogonadism and gynecomastia |
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Term
| what is caput medusae, as seen in pts w/liver failure? |
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Definition
| very distended abdomen w/markedly distended blood vessels radiating around the umbilicus |
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Term
| what can liver failure lead to? |
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Definition
| encephalopathy, multiorgan failure, respiratory issues, sepsis, coagulopathy, massive GI bleeds, and increased metabolic load on the liver w/intestinal absorbtion |
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Term
| what characterizes acute liver failure? |
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Definition
| generally acute liver failure *occurs in pts w/o previously recognized liver disease, often associated with various toxins, *wilson's disease, reactivation of viral hepatitis, and autoimmune hepatitis. acute liver failure results in the rapid loss of hepatic function, and most pts will require liver transplantation |
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Term
| what is a common cause of acute liver failure in the US? |
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Definition
| drug induced injury, such as w/tylenol in suicide attempts or unintentional overdosing/idiopathic drug interaction |
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Term
| what is a common cause of acute liver failure in the world? |
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Definition
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Term
| how do most pts with acute liver failure present? |
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Definition
| w/multisystem organ failure, often due to sepsis |
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Term
| how can acute liver failure affect pts? |
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Definition
| bleeding disorders can be exacerbated, intracranial hypertension may develop, and *systemic inflammatory response syndrome (SIRS) may result from massive cytokine release from the necrotic liver. |
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Term
| what triggers much of the pathology associated with acute liver failure? |
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Definition
| infections including respiratory and urinary staph and strep infections |
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Term
| what can happen if the lungs are involved in pathology resultant from acute liver failure? |
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Definition
| ARDS (adult respiratory distress syndrome - very difficult to treat). CO2 levels rise, leading to cerebral vasodilation (due to loss of cerebral autoregulation w/an increase in circulating cytokines) and increased intracranial pressure. |
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Term
| what osmotic abnormalities due to acute liver failure can lead to cerebral edema? |
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Definition
| glutamate is converted to glutamine by ammonia, which accumulates in the astrocytes. glutamine is the cause of osmotic stress by the overwhelming ability of the astrocytes to expel organic osmolytes. thus high levels of ammonia increase the risk of cerebral edema. |
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Term
| what are complications of hepatic failure? |
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Definition
| hepatic encephalopathy, hepatorenal syndrome, and hepatopulmonary syndrome |
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Term
| what is hepatic encephalopathy? |
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Definition
| a spectrum of changes in consciousness from coma to death which may occur more rapidly in acute liver failure. signs include rigidity, hyper reflexia, and asterixis |
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Term
| what is hepatorenal syndrome? |
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Definition
| renal failure w/no morphologic or functional causes of renal failure. it is characterized by Na+ retention, impaired free-water excretion, decreased renal perfusion, and decreased glomerular filtration rate. it is due to decreased renal perfusion as a result of systemic vasodilation, activation of the renal sympathetic nervous system w/vasoconstriction of the afferent renal arterioles, and increased synthesis of renal vasoactive mediators |
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Term
| how do pts with hepatorenal syndrome present? |
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Definition
| urine output drops w/a rising BUN and creatinine. hepatorenal syndrome is often associated with a precipitating stressor such as an infection, gastrointestinal hemorrhage or sx. it has a poor prognosis and liver transplant is the tx of choice. |
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Term
| what is the clinical triad associated with hepatopulmonary syndrome? |
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Definition
| hypoxemia, chronic liver disease and intrapulmonary vascular dilations |
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Term
| how does hypoxemia arise in hepatopulmonary syndrome? |
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Definition
| hypoxemia arises from ventilation-perfusion mismatch, marked by inadequate time for O2 exchange at the alveolocapillary junction due to the rapid flow of blood in the dilated vessels, shunting of blood from pulmonary arteries to the pulmonary veins, and an increase in production of NO by the lung. |
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