Volume 70 - 2007 - Fasc.2 - Symposium
Hepatopulmonary Syndrome and Portopulmonary Hypertension : what's new ?
Hepatopulmonary syndrome (HPS) is found in 4-47% of patients with cirrhosis and is characterized by intrapulmonary vascular dilatations especially in the basal parts of the lung. Liver injury and/or portal hypertension trigger the release of endothe- lin-1, TNF-a, cytokines and mediate vascular shear stress and release of nitric oxide and carbon monoxide, all contributing to intrapulmonary vasodilation.
Severe HPS increases mortality (30%) after liver transplanta- tion, especially if Pa O2 is below 50 mmHg. The diagnosis is made by calculating the alveolar-arterial oxygen gradient and by per- forming a contrast echocardiography. Medical therapy fails and the only long-term treatment available is liver transplantation. More than 85% experience significant improvement or complete resolution in hypoxaemia, but this may take more than 1 year.
Portopulmonary hypertension (PPHT) occurs in 2-8% of the patients with cirrhosis. Imbalance between vasodilating (decreased pulmonary expression of eNOS and prostacyclin I2) and vasoconstrictive agents (increased expression of ET-1 and angiotensin 1) may be responsible for misguided angiogenesis and pulmonary hypertension. The diagnosis is made by performing an echocardiography and a right heart catheterisation when systolic pulmonary artery pressure is higher than 30 mmHg on echocar- diography. Although prostacyclin analogues are efficacious, adverse effects in terms of safety, tolerability and drug delivery occur. Bosentan is probably the therapy of choice for patients with PPHT because it decreases pulmonary but can also diminish por- tal hypertension. Sildenafil, a phosphodiesterase-5 inhibitor is used for idiopathic pulmonary hypertension, however, it should be used cautiously in patients with portal hypertension as it may increase portal hypertension by splanchnic vasodilation. (Acta gastroenterol. belg., 2006, 69, 203-209).
Acute liver failure - practical management
The three most important components of the management of Acute Liver Failure are :-
1) Identification of causes requiring specific treatment includ- ing hepatic lymphoma, the Budd-Chiari syndrome, ischaemic hepatic necrosis, fulminating septicaemia, Wilson's disease and reactivation of HBV in chronic carriers.
2) Institutionofearlymonitoringandoptimalintensivecarefor multi-organ involvement to improve chances of spontaneous recovery or of transplantation. Deteriorating encephalopathy with cerebral oedema is related to a systemic inflammatory response and infections need to be treated aggressively.
3) Assessment of the need for transplantation based on strong positive predictive values provided by the King's or Clichy crite- ria. A significant percentage of those not fulfilling criteria also progress. The MARS liver support device has corrective effects on the disturbed pathophysiology of ALF and may be used to enhance spontaneous recovery or as a bridge to transplant, although the latter is not yet proven by controlled clinical trial. (Acta gastro- enterol. belg., 2006, 69, 210-213).
Hypoxic hepatitis : The point of view of the clinician
Hypoxic hepatitis better known under the terms of ischemic hepatitis or shock liver is the clinical manifestation of an acute liver cell necrosis consecutive to liver hypoxia. The clinical syndrome is defined as a massive but rapidly resolutive increase in serum aminotransferase activities (AT) occurring in a clinical setting of hemodynamic failure. Actually, when confronted to a case of mas- sive increase in serum AT in the setting of cardiac or respiratory failure, the diagnosis of HH may be assumed without liver biopsy if another cause of hepatocyte necrosis such as viral hepatitis or drug induced hepatitis may be excluded. To our opinion, in these patients often aged and in poor general condition, it is particularly important to exclude herpes simplex virus infection and para- cetamol intoxication. In case of doubt, a mere ultrasonography of the liver will be helpful. Indeed the majority of these patients will have a dilation of hepatic veins due to passive congestion of the liver. There is no specific liver therapy and the prognosis is poor depending on the severity of the underlying condition. In this point of view, we report what could be of interest for the hospital clinician. (Acta gastroenterol. belg., 2007, 70, 214-216).
Treatment of cirrhotic ascites
Cirrhosis is the most common cause of ascites and accounts for almost 85% of all cases. It is the most common complication of cir- rhosis, after development of ascites only 50% of patients will sur- vive for 2 to 5 years.
Successful treatment is dependent on accurate diagnosis of the cause of ascites.
Because sodium and water retention is the basic abnormality leading to ascites formation, restriction of sodium intake and enhancing sodium excretion is the mainstay of the treatment of ascites. Patients with cirrhosis and ascites must limit sodium intake to 2 gram per day. Enhancement of sodium excretion can be accomplished by usage of oral diuretics. The recommended initial dose is spironolactone 100-200 mg/d and furosemide 20-40 mg/d. usual maximum doses are 400 mg/d of spironolactone and 160 mg/d of furosemide. The recommended weight loss in patients without peripheral edema is 300 to 500 g/d. There is no limit to the daily weight loss of patients who have edema.
About 90% of patients respond well to medical therapy for ascites. Refractory ascites is defined as fluid overload that is unre- sponsive to sodium restricted diet and high dose diuretic treatment (diuretic resistant) or when there is an inability to reach maximal dose of diuretics because of adverse effects (diuretic-intractable). It has a poor prognosis. Treatment options for patients with refractory ascites are serial therapeutic paracentesis, transjugular intrahepatic stent-shunt (TIPS) or peritoneovenous shunt and liver transplantation. TIPS should be considered in patients who repeatedly fail large-volume paracentesis and have relatively pre- served liver functions. Liver transplantation is the only modality that is associated with improved survival. (Acta gastroenterol. belg., 2006, 69, 217-222).