Sarcopenia, myosteatosis and frailty in patients with liver cirrhosis

Skeletal muscles are the biggest tissue in healthy people (30–40% of total body mass) and they comprise three quarters of total body proteins. Muscle alterations, especially muscle wasting and loss of muscle function, have an indisputable prognostic value in the outcome of chronic diseases, including chronic liver diseases. Muscle wasting is associated with higher morbidity, mortality and poor quality of life. The terms sarcopenia and myosteatosis are used to describe specific muscle alterations, both forming substantial components of multidimensional construct “frailty syndrome”. Sarcopenia is defined as loss of muscle mass and/or loss of muscle function. It is usually dia­gnosed using the skeletal muscle index from computed tomography (CT) image analysis at the L3 vertebra. Myosteatosis is defined as an excess intramyocelullar and intermyocellular fat deposition. Dia­gnosis of myosteatosis is based on a measurement of skeletal muscle density by CT imaging at the L3 vertebra (skeletal muscle radiation attenuation – SM-RA). Besides muscle alterations and decreased physical performance, frailty syndrome also comprises changes of other organ systems, leading to the loss of functional reserves and higher vulnerability. Different scoring systems, such as Fried Frailty Index (FFI) or modified Liver Frailty Index (LFI) for patients with liver cirrhosis, are used to dia­gnose patients with frail phenotype. The principle of the treatment of patients with muscle alterations is therapy of liver disease (including liver transplant in advanced cirrhosis), improvement of the nutritional status, adequate physical activity and supplementation of vitamin D deficiency, if necessary. In this review, we summarize up-to-date knowledge about pathophysiology, dia­gnostic tools and treatment options of sarcopenia, myosteatosis and frailty syndrome in patients with liver cirrhosis. Key words: sarcopenia – myosteatosis – frailty syndrome – liver cirrhosis