What is the hepatorenal syndrome?  List causes, mechanism, diagnosis and treatment

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College Answer

The hepatorenal syndrome  is defmed as profound oliguria and avid sodium  retention in the setting of severe liver dysfunction.

{a) Causes: 
Can occur in the setting of both acute and acute-on-chronic liver disease of almost any cause 
eg. hepatitis, gestational liver failure, cirrl:tosis. 

(b) Mechanism: 
The  pathogenesis  appears  to be purely  functional  in  that  recovery:of :liver  function  or-· 
transplantation  of  the  failing  kidney  leads  to  recovery  of ·renal ·function.  Mechanisms··· implicated  include: hyperdynamic· circulation  with  lowering  of  renal  perfusion  pressure, activation   of   the  sympathetic   nervous   system   and   a  combination   of   precapillary vasoconstriction and past capillary dilatation  by vasoactive mediators leading to decreased glomerular  ultrafiltration  coefficient.  Hypovolaemia  and  raised  intra abdominal  pressure from ascites may also be factors. 

(c) Diagnosis: 
Is based on history (deteriorating renal function in the presence of severe liver disease) and the  combination   of  avid  sodiwn   retention  (UNa   <30mmolll),  oliguria,   unremarkable urinalysis and  sediment,  absence  of  obstruction and  exclusion  of  intravascular  volume depletion. 

(d) Treatment: 
Classic teaching is that. in the absence of liver function recovery or liver transplantation, 
there  is  no  treatment  other  than renal  replacement  therapy  for  established  hepatorenal 
syndrome. Other measures to be considered or experimental are: 
•  Volume expansion and albumin infusion 
•  Paracentesis 
•  Relief of portal hypertension (TIPS, shunt) 
•  Vasopressin analogs (omipressin), experimental 
•  Prostaglandin analogs -experimental

Discussion

Briefly, what is hepatorenal syndrome

Hepatorenal syndrome is kidney injury as the consequence of gradually reducing renal blood flow, in the context of gradually worsening liver failure.

Mechanism of hepatorenal syndrome

  • Worsening hepatic function leads to worsening peripheral arterial vasodilation
  • Vasodilation leads to increased cardiac output, renin-angiotensin-aldosterone overactivity, and sympathetic overactivity
  • As a result, renal arterial vascular resistance increases in proportion to splanchnic and systemic arterial vasodilation
  • This, there is progressive renal vasoconstriction and thus decreased glomerular filtration.
  • In addition to this, worsening hepatic failure results in increasing ascites pressure (and thus decreasing renal perfusion pressure)

Causes of hepatorenal syndrome

  • Sepsis of any origin
  • Nephrotixic drugs in a patient with cirrhosis, particularly NSAIDs
  • Rapid diuresis
  • GI bleeding

Diagnosis

  • This is a diagnosis of exclusion. The following criteria apply:
    • presence of liver disease and portal hypertension
    • increase in creatinine to over 133micromol/L
    • no other obvious cause of renal failure
    • no microscopic hematuria
    • no reponse to fluid challenge (i.e. no pre-renal failure)

Treatment of hepatorenal syndrome

  • Albumin and fluid resuscitation
  • Terlipressin
  • Noradrenaline
  • Octreotide

if all else fails, TIPS procedure may be appropriate.

References

References

UpToDate has an excellent synopsis of hepatorenal syndrome.

 

However, if you are cheap, you need free articles.

 

Salerno, Francesco, et al. "Diagnosis, prevention and treatment of hepatorenal syndrome in cirrhosis." Postgraduate medical journal 84.998 (2008): 662-670.

 

Solà, Elsa, Mónica Guevara, and Pere Ginès. "Current treatment strategies for hepatorenal syndrome." Clinical Liver Disease 2.3 (2013): 136-139.