Peritoneal inflammation and fatigue experiences following colorectal surgery: a pilot study.

Objective: The effect of post-surgical inflammation, as indicated by peritoneal cytokines and neopterin, was assessed on the duration and characteristics of post-surgical fatigue (PSF) experiences.

Background: During the weeks following major colorectal surgery, many patients report experiencing substantial fatigue but the physiological factors contributing to this are not well understood. Because cytokines, particularly pro-inflammatory cytokines, have been found to be important in fatigue-related experiences in experimental systems, they may well be important mediators of PSF.

Methods: In 27 patients following colorectal surgery, cytokines and neopterin (a relatively stable immune activation marker) were measured in 24-h peritoneal drain fluid and in serum 2, 5 and 14 days post-operatively. Patient fatigue was assessed using the Identity-Consequence Fatigue Scale questionnaire pre-operatively and 2, 5, 14, 30 and 60 days after surgery.

Results: Using linear mixed model analysis controlling for age, gender and ASA score, the trajectory of fatigue experience during the first 2 months of surgical recovery was significantly related to intra-peritoneal concentrations of IL-6, IL-10 and TNF-alpha during the first 24h after surgery, while the trajectory of fatigue impacts was related only to IL-6 and TNF-alpha concentrations. Moreover, correlations between neopterin, and post-operative peritoneal (within 24h of surgery) and serum cytokine concentrations permitted neopterin to be used as a surrogate inflammation marker. Patients with elevated neopterin concentrations during the initial weeks following surgery reported significantly more severe and sustained PSF.

Conclusions: Locally occurring inflammatory responses may influence reports of fatigue following major surgery in a sustained manner, and, as a consequence, reducing inflammation may be effective in reducing PSF.