REPLY
Liver Cirrhosis and Circadian Rhythm
Petra Steindl, MD;
Phyllis Zee, MD, PhD; and
Andres T. Blei, MD
15 July 1996 | Volume 125 Issue 2 | Page 154
IN RESPONSE:
Drs. Garfinkel and Zisapel suggest that wrist actigraphy is superior to sleep diaries as a method to monitor sleep in patients with cirrhosis. Our preliminary studies indicate that this tool may be of value for such patients [1], but caution is warranted before this new technology is embraced. Measurement of wrist activity during polysomnography has not yet been validated for cirrhotic patients, and results may differ from those seen in other populations [2]. Furthermore, we would rather not be hasty in dismissing the role of sleep diaries. They reflect a subjective symptom, which is in essence what the physician is attempting to address.
We postulated two explanations for our results, but Garfinkel and Zisapel advocate only one. We find their reasoning to be erroneous. The demonstration of decreased 6-sulphatoxymelatonin levels would confirm what is already known: that the hepatic clearance of melatonin is reduced in patients with cirrhosis [3]. This finding does not, however, indicate whether the elevated melatonin levels observed in the morning hours are phase shifting the endogenous "biological clock." Additional studies are needed to examine other biological rhythms and to assess the ability of other stimuli to produce phase shifts.
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Author and Article Information
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Lakeside Veterans Affairs Medical Center, Chicago, IL 60611
1. Steindl PE, Zee P, Bendok B, Blei AT. Ambulatory monitoring of a diurnal motor rhythm indicates altered day/night activity in cirrhotic patients [Abstract]. Hepatology. 1995; 22:161A.
2. Garfinkel D, Laudon M, Nof D, Zisapel N. Improvement of sleep quality in elderly people by controlled-release melatonin. Lancet. 1995; 346:541-4.
3. Iguchi H, Kato KI, Ibayashi H. Melatonin serum levels and metabolic clearance rate in patients with liver cirrhosis. J Clin Endocrin Metab. 1982; 54:1025-7.
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