Chronic liver disease is defined as any sort of hepatic dysfunction which has persisted for longer than 6 months. There are several key differences in the presentation of an acute decompensation of chronic disease, as opposed to the presentation of an acutely sick liver which was previously well.
Question 4 from the first paper of 2018 asked for six reasons for why chronic liver disease might suddently decompensate. Kim et al (2012) give a list which probably varies slightly depending on geographical region:
This had come up in Question 18 from the first paper of 2020, where the college wanted a tabulated answer comparing these conditions on the basis of their "history, examination, biochemical findings, haematological findings, imaging and biopsy".
|Domain||Acute fulminant hepatic failure||Decompensated chronic liver disease|
A few other differences exist between ICU management of acute and acute-on-chronic liver failure.
In brief summary:
Well, they are already having a hyperdynamic circulation, but apart from that, several other differences exist.
One of the reasons for such severe systemic consequences of sepsis is the normal role of the liver in clearing LPS from the gut. Lipopolysaccharide would normally be gobbled up by Kupffer cells, but in cirrhosis they are all dead, and unclean portal blood escapes into the systemic circulation via portasystemic shunts. Systemic exposure to LPS (and to translocated bacteria) seems to be the main reason there is such an extensive activation of nitric oxide synthase, and explains the hyperdynamic circulation of the cirrhosis patient.
On top of all that, there tends to be a "sepsis-like immune paralysis" where numerically normal macrophage and neutrophil populations somehow fail to opsonise and phagocytose the invading enemy. This must be to some extent a consequence of the complement deficiency (as the liver is normally responsible for the syntesis of complement).
Because of massive shunts, there may be whole lumps of tissue bypassed by the circulation entirely, thus generating a falsely elevated SvO2.
Because the liver-diseased patient lacks the major clearance mechanism for lactate, it would be silly to expect their lactate to fall satisfyingly in response to resuscitation. A falsely elevated lactate may exist in a well-resuscitated patient.
Small weirdly-designed studies seem to support the use of albumin as a resuscitation fluid in a septic patient with chronic liver disease. Sure, its better than hetastarch, but then probably toilet water is better than hetastarch. There may also be some benefit in preventing hepatorenal syndrome and renal failure.
This pathology attracted college atttention in Question 4 from the first paper of 2018, and has therefore been given a chapter all of its own. Key features to remember when you draw some ascitic fluid for culture:
This topic is discussed elsewhere. In short summary, it is renal failure without any better reason for renal failure, in the patient with severe liver disease.The management of confirmed hepatorenal syndrome would consist of:
This uncommon syndrome features the dilatation of pulmonary vessels, which leads to an inappropriate increase in perfusion to relatively underventilated regions. Again, nitric oxide synthase is to blame. There are diagnostic criteria:
Diagnostic criteria for hepatopulmonary syndrome:
Apparently this is present in 20% of cirrhosis patients. It does tend to resolve after transplantation, but this may take up to 1 year.
This is pulmonary hypertension with evidence of increased pulmonary resistance (in contrast to the "normal" pulmonary hypertension of the cirrhosis patient, which is associated with increased pulmonary pressure due to increased flow though dilated unresisting arteries).
Diagnostic criteria for portopulmonary hypertension
This is also present in 20% of cirrhosis patients. Management here is different; the goal is to reduce the pulmonary pressure. Bosantan sildenafil and epoprostenol have been used.
The presence of portopulmonary hypertension is a major issue; perioperative mortality due to right heart decompensation is 100% if the MPAP is over 50mmHg. All sorts of advanced hemodynamic monitoring tools should be deployed to keep these patients alive; milrinone and intravenous prostacycline have been used by various authors.
This topic is discussed elsewhere. In the chronic liver disease patient, there are few additional points to remember: