Volume 71 - 2008 - Fasc.4 - Symposium
Hyponatremia in cirrhosis Pathophysiology, prevalence, prognostic value, treatment
Hypervolemic hyponatremia is common in patients with decom- pensated cirrhosis, resulting from solute-free water retention caused by the stimulation of V2 receptors of the distal nephron by relatively high circulating levels of arginine vasopressin (AVP, a nonapeptide). A nonosmotic secretion of AVP by the hypothalamo- neurohypophysial system is responsible for high plasma AVP con- centrations. This hypersecretion of AVP is triggered by a decrease in effective arterial blood volume and arterial pressure caused by splanchnic/systemic vasodilation. Hyponatremia is an independent predictor of mortality in patients with cirrhosis ; however, it is still unknown if hyponatremia by itself plays a role or if it is a simple marker of the severity of liver disease. Pharmacological treatments of hypervolemic hyponatremia using drugs that antagonize the binding of AVP to V2 receptors are under evaluation in patients with cirrhosis. (Acta gastroenterol. belg., 2008, 71, 379-385).
Hyponatremia : pathophysiology, treatment and prognostic value Summary of the discussion
Hyponatremia in cirrhosis, like in other diseases, has been generally considered as a minor clinical event with- out real repercussion on the physical and mental status of the patient. However, it has been demonstrated that mild hyponatremia (> 125 mEq/L) and even very mild hyponatremia (serum sodium level 127-132 mEq/L) is associated with an increased risk of falls, probably due to impairment of attention, posture and gait mecha- nisms (1). It was noted that in volunteers of similar age, after mild alcohol intake (0.55 g/kg body weight), atten- tion and gait tests were less affected (1). Patients with severe hyponatremia should be advised not to drive. Hyponatremia is also an independent prognosis factor in case of cirrhosis as pointed out by several recent studies and might be added to the MELD score in order to improve organ allocation in patients on the waiting list for liver transplantation.
