Acute Liver Failure

1. Acute Liver Failure

2. Topics • Definitions of failure and classification • Aetiology- Acute versus acute on chronic • Basic diagnostic workup • Liver biopsy in the context • ACLF-Ethical dilemma- HDU admission • Treatment of complication • Hepatic encephalopathy • Renal failure • GI bleed • Infection • Coagulopathy • Aetiology specific treatment • Organ support • Liaison with Transplant centre

3. The mortality rate for acute liver failure ranges between 56% and 80%

4. Abnormal LFT is NOT ALF • Dear Doctor • Patient’s bilirubin is 600 and has liver failure- kindly urgently see • Family was told transplant may be necessary

5. Formal diagnosis of acute liver failure • An increase in PT by 4-6 seconds (INR>1.5) • And the development of hepatic encephalopathy (HE). • In a patient without pre-existing cirrhosis and with an illness of less than six months duration.

6. UK incidence of cirrhosis 17 per 100,000 • Prevalence of cirrhosis is 76 per 100,000 • ALF incidence is 1-6 per million per year

7. aCLF • This entity is quite common- background of cirrhosis. Innocent precipitating event culminates in MOF • Events • Toxins (alcohol!) • Vascular (hypotension- GI bleed, dehydration, Portal vein thrombosis) • Infection (SBP) • HCC

8. ACLF-Ethical dilemma- HDU admission

9. For patients with aCLF • Young age • First presentation • Reversible pathology- sepsis, GI bleeding or severe hepatitis • A trip to ITU is a life changing experience to some ‘alcoholics’

10. Few definitions • Hyperacute- <7days • Acute - >7days <21days • Subacute- >21days <6months • FHF- not used

12. Diagnostics: • Good history- difficult if HE

13. Initial Laboratory Analysis- general • Prothrombin Time/INR • Blood Chemistry Sodium, potassium, chloride, bicarbonate, calcium, magnesium, phosphate, AST, ALT, alkaline phosphatase, GGT, total bilirubin, albumin, Creatinine, urea Glucose • Arterial blood gas • Arterial lactate • Full blood count • Blood type and screen • Ammonia (arterial if possible) • HIV status • Amylase and lipase

14. Diagnostics- specific • Paracetamol (acetaminophen) level • Toxicology screen • Viral hepatitis serologies Anti-HAV IgM, HBSAg, anti-HBc IgM, anti-HEV, anti-HCV CMV EBV VZ/HZ • Ceruloplasmin level • Pregnancy test • Autoimmune markers- ANA, ASMA, Immunoglobulin levels • Doppler US- ischaemic vs thrombosis

15. Liver biopsy • Importance of early biopsy- severity and aetiology • Particularly useful in Hep B, AIH, Alcoholic hepatitis, differentiate between ALF and aCLF • Transjugular route

16. www.gastrotraining.com

17. Urgent OLT is the only life saving therapy • The main role of intensive care therapy is multi-organ support

18. All Liver transplants • CLD – 60% • Malignancy- 10% • ALF- 10% ( Paracetamol) • Cholestasis - 10-20%

21. Paracetamol Overdose • Phase I – 0-24h • Anorexia, nausea and vomiting, malaise • LFT derrangement at 12h • Phase II – 18-72h • RUQ pain • LFT derrangment • Phase III – 72-96h • Centrilobar necrosis • Liver failure • Phase IV – 4d-3wk • Recovery, transplant or death • No chronic state

22. When to pick up the phone • D2- • pH <7.3 • INR>3 • Cr >200 • Hypoglycaemia • D3- • HE • Cr>200 • INR >4.5 • D4- • Any rise in INR • Cr >250 • HE

23. Definition:HRS • ARF in a patient • CLD, severe alcoholic hepatitis or ALF from any cause • End-stage of reduction in renal perfusion induced by increasingly severe hepatic injury.

24. Sinusoidal portal hypertension, in the presence of severe hepatic decompensation • Leads to splanchnic and systemic vasodilatation-role of NO • Decreased effective arterial blood volume • Activation of RAS, and vasopressin aimed at restoring arterial filling pressure. • Renal vasoconstriction increases counterbalanced by the intrarenal prostaglandins. • When this balance is lost renal hemodynamics worsens, and hepatorenal syndrome develops

25. Terlipressin • NSBB

26. HRS • Major criteria • Chronic or acute hepatic disease and liver failure with portal hypertension • Serum creatinine level >133 micromoles/L • Absence of shock, ongoing bacterial infection, recent use of nephrotoxic drugs, excessive fluid or blood loss • No sustained improvement in renal function after volume expansion with 1.5 L isotonic saline solution • No Proteinuria (Protein<500 mg/day) and no ultrasonographic evidence of renal tract or parenchymal disease • Minor criteria • Urine volume <500 mL/day • Urine sodium <10 mEq/L • Urine osmolality greater than plasma osmolality • Urine red blood cell count <50 per high-power field • Serum sodium <130 mEq/L

27. Classification of HRS • Type I is defined by a rise in creatinine level to over 221 micromoles/L in less than 2 weeks • Median survival of 2 weeks • Type II is defined as less severe renal insufficiency; it is principally characterized by ascites that is resistant to diuretics. • Median survival of 3-6 months.

28. Vasoactive Medical treatment • Terlipressin bolus(0.5mg/4h)-increase every 3 days if no response to 1-2mg/4h • Given until creatinine normalizes or for 15 days • Albumin 1g/kg on day1( one bag of HAS contains 20grams) • 20-60g/d thereafter

29. Step by step guide : • Normal renal us • Normal urine dipsix – no RBC cast • No nephrotoxic drugs • Fluid challenge • Spot Na and serum Na • Serum and urine osmolality • Urine output

30. The stages of HE- West Haven criteria: Stage 0. Lack of detectable changes in personality or behaviour. Asterixis absent. Stage 1. Trivial lack of awareness. Shortened attention span. Impaired addition or subtraction. Hypersomnia, insomnia, or inversion of sleep pattern. Euphoria ordepression. Asterixis can be detected. Stage 2. Lethargy or apathy. Disorientation. Inappropriate behaviour. Slurred speech. Obvious asterixis. Stage 3. Gross disorientation. Bizarre behaviour. Semistupor to stupor. Asterixis generally absent. Stage 4. Coma.

31. HE- Four compatible theories • Cerebral vasomotor dysfunction • Oedema secondary to ammonia toxicity • Inflammation due to SIRS • putative benzodiazepine-like molecules

32. The pathophysiology of HE • A large body of work points at ammonia as a key factor in the pathogenesis of HE. • Portal ammonia is derived from both the urease activity of colonic bacteria and the deamidation of glutamine in the small bowel. • The intact liver clears almost all of the portal vein ammonia, converting it into glutamine and preventing entry into the systemic circulation. • Ammonia- astrocyte swelling in brain

33. Patients with grade II HE should be managed in a HDU environment. • Grades III and IV HE requires definitive airway protection and appropriate monitoring. • Grade IV HE is strongly associated with elevated levels of serum ammonia, a high incidence of raised intracranial pressure and the development of uncal herniation.

34. GCS –HE correlation • Grade1- GCS 14-15 • Grade2- GCS 11-13- HDU • Grade3- GCS 8-11 (Stupor or precoma) • Grade4- GCS<8 (Coma)

35. In acute and chronic liver disease, increased arterial levels of ammonia are commonly seen. • However, correlation of blood levels with mental state in cirrhosis is inaccurate.

36. Lactulose is a first-line pharmacological treatment of HE. • Lactulose – reaches colon, where bacteria will metabolize the lactulose to acetic acid and lactic acid. • This lowers the colonic pH • formation of the non-absorbable NH4+ from NH3, • Other effects like catharsis also contribute to the clinical effectiveness of lactulose.

37. Lactulose • For acute encephalopathy, lactulose (ingested or via nasogastric tube), 45 ml p.o., • Is followed by dosing every hour until evacuation occurs. • Target -three soft bowel movements per day • If response to disachharide is poor- add antibiotic (metronidazole or rifaximine after 48Hrs) to reduce enteric bacterial mass.

38. If patient is refusing oral lactulose prescribe phosphate enemas TDS! An excessively sweet taste, flatulence, and abdominal cramping are the most frequent subjective complaints with this drug.

39. The coagulopathy of liver disease • Failure to produce clotting factors II, V, VII and IX • Failure of the diseased liver to clear activated clotting factors. • Degree of hypersplenism and thrombocytopaenia often adds to the coagulopathy, especially if disseminated intravascular coagulation (dic) also co-exists. • The degree of coagulopathy is a measure of severity of liver disease and of patient prognosis. • Routine correction of coaguloapthy is therefore NOT indicated unless active bleeding or planned interventions require it

40. Sepsis • Infection may be the initiating event of liver failure, • Intercurrent sepsis is also a common problem . • Impaired immune function, in part secondary to reduced complement factor production and • Impaired neutrophil, leukocyte and monocyte function, can result in delayed presentation of clinical signs of infection. • The interventions required for diagnosis and management of liver disease also increase patient vulnerability to invasive infection.

41. Role of prophylactic antibiotic • Only patients who have an episode of gastrointestinal bleeding • or an episode of spontaneous bacterial peritonitis (SBP) have been shown to have a significant outcome benefit from prophylactic antibiotics.

42. In presence of sepsis • Choice of antibiotic should be guided by local microbiological surveillance. • The high incidence of mycoses - low threshold for antifungal. • Regular microbiological surveillance

43. Role of NAC • Efficacy of NAC is well established in PCM induced ALF • Non PCM ALF – role of NAC is controversial • 175 patients of non PCM ALF received NAC • Transplant free survival at 3 weeks was 52% in NAC group compared to 30% in placebo arm ( only with coma grade of 1-2) • United States ALF study group- overall was 70% vs 66%

44. Artificial liver??

45. Extracorporeal Liver Assist Device (ELAD) • Hepatocyte bioreactor- hepatoma cells cultivated on the exterior surface of semipermeable hollow fibres • MARS (molecular adsorbent recirculating system)

46. ELAD • Both reduce the level of bilirubin, bile salt ammonia etc • However no of patients dying or requiring liver transplant did not improve Devices remain experimental and large-scale phase two and three trials are awaited

47. Summary • The mortality rate for acute liver failure ranges between 56% and 80% • The main role of intensive care therapy is multi-organ support • The commonest cause of acute liver failure in the western world is paracetamol toxicity • Hepatic encephalopathy is no longer the main cause of death but it’s detection and management requires sophisticated cardiovascular and cerebral monitoring • Hepatorenal failure is due to the complex interplay between splanchnic, renal and systemic circulatory responses to liver failure. Terlipressin has been shown to be of use in its treatment • Novel hepatic replacement therapies are under development but definitive studies as to their efficacy are, as yet, unpublished.