The main features of<unk>  are rapid-onset jaundice, weakness, and eventually, changes in mental status that can begin as mild confusion but progress to coma. Encephalopathy and cerebral edema In<unk> , hepatic encephalopathy leads to cerebral edema, coma, brain herniation, and eventually death. Detection of encephalopathy is central to the diagnosis of<unk> . It may vary from subtle deficit in higher brain function (e.g. mood, concentration in grade I) to deep coma (grade IV). Patients presenting as acute and hyperacute<unk>  failure are at greater risk of developing cerebral edema and grade IV encephalopathy. The pathogenesis remains unclear, but is likely to be a consequence of several phenomena. There is a buildup of toxic substances like ammonia, mercaptan, serotonin and tryptophan in the brain. This affects neurotransmitter level and neuroreceptor activation. Autoregulation of cerebral blood flow is impaired, and is associated with anaerobic glycolysis and oxidative stress. Neuronal cell astrocytes are susceptible to these changes, and they swell up, resulting in increased intracranial pressure. Inflammatory mediators also play important role. Unfortunately, signs of elevated intracranial pressure, such as papilledema and loss of pupillary reflexes, are not reliable, and occur late in the disease process. CT imaging of the brain is also unhelpful in detecting early cerebral oedema, but is often performed to rule out intra-cerebral bleeding. Invasive intracranial pressure monitoring via subdural route is often recommended; however, the risk of complications must be weighed against the possible benefit (1% fatal haemorrhage). The aim is to maintain intracranial pressures below 25 mm Hg, and cerebral perfusion pressures above 50 mm Hg. Coagulopathy Coagulopathy is another cardinal feature of<unk> . The<unk>  has the central role in the synthesis of almost all coagulation factors and some inhibitors of coagulation and fibrinolysis. Hepatocellular necrosis leads to impaired synthesis of many coagulation factors and their inhibitors. The former produces a prolongation in prothrombin time which is widely used to monitor the severity of hepatic injury. There is significant platelet dysfunction (with both quantitative and qualitative platelet defects). Progressive thrombocytopenia with the loss of larger and more active platelets is almost universal. Thrombocytopenia with or without DIC increases risk of intracerebral bleeding. Kidney failure Kidney failure is common, present in more than 50% of<unk>  patients, either due to original insult such as paracetamol resulting in acute tubular necrosis or from hyperdynamic circulation leading to hepatorenal syndrome or functional kidney failure. Because of impaired production of urea, blood urea does not represent the degree of kidney impairment. Inflammation and infection About 60% of all<unk>  patients fulfil the criteria for systemic inflammatory syndrome irrespective of presence or absence of infection. This often contributes towards multi organ failure. Impaired host defence mechanism, due to impaired opsonization, chemotaxis and intracellular killing, substantially increases risk of sepsis. Bacterial sepsis mostly due to gram positive organisms and fungal sepsis are observed in up to 80% and 30% patients, respectively. Metabolic derangements Hyponatraemia is an almost universal finding due to water retention and a shift in intracellular sodium transport from inhibition of Na/K ATPase. Hypoglycaemia (due to depleted hepatic glycogen store and hyperinsulinaemia), hypokalaemia, hypophosphataemia and metabolic alkalosis are often present, independent of renal function. Lactic acidosis occurs predominantly in paracetomol (also known as acetaminophen) overdose. Haemodynamic and cardio-respiratory compromise Hyperdynamic circulation, with peripheral vasodilatation from low systemic vascular resistance, leads to hypotension. There is a compensatory increase in cardiac output. Adrenal insufficiency has been documented in 60% of<unk>  cases, and is likely to contribute in haemodynamic compromise. There is also abnormal oxygen transport and utilization. Although delivery of oxygen to the tissues is adequate, there is a decrease in tissue oxygen uptake, resulting in tissue hypoxia and lactic acidosis. Pulmonary complications occur in up to 50% of patients. Severe lung injury and hypoxemia result in high mortality. Most cases of severe lung injury are due to ARDS, with or without sepsis. Pulmonary haemorrhage, pleural effusions, atelectasis, and intrapulmonary shunts also contribute to respiratory difficulty. Late pregnancy In late pregnancy<unk>  function decreases significantly, which can be easily monitored by blood tests. Early clinical manifestations of<unk>  in late pregnancy include hypodynamia, decrease in appetite, dark amber urine, deep jaundice, nausea, vomiting, and abdominal distention. Among patients whose deaths were attributed to<unk>  in late pregnancy, the majority had experienced vaginal deliveries.
Acute liver failure
Acute kidney injury
Liver failure
Hepatic encephalopathy
Water intoxication
Hepatopulmonary syndrome
Acute decompensated heart failure
Adrenal crisis