The above study describes a case report of a patient suffering from medically unexplained fatigue concurrent with dysmenorrhoea membranacea and the sudden resolution of both conditions. Whilst reviewing the above manuscript, we noted some limitations. These are as follows: (1) it is only a one patient case study and (2) there was a significant leucocytosis, with a white cell count (WCC) of 15.7 9 10 L [6]. This is elevated above the healthy clinical range of 4 9 10–11 9 10 L [4], and suggests the presence of a disease causing organic pathogen. Previous research has shown that the resting leukocyte count in CFS patients is indeed within these normal clinical ranges [3]. The patient in the case study had prolonged problems with fatigue, lasting for 12 years. If the aetiology was infectious, it is possible that this infection could have been chronic or reoccurring in its nature, and is unusual that this would resolve following a dysmenorrhic event. However, a chronic endometrial infection may explain the symptoms and haematological findings. In the case study, there does not appear to be a discussion of any investigation into the cause of this immunological anomaly. Owing to the nature of the clinical presentation, and the elevation of WCC, with the concurrent elevation in the pro-inflammatory acute phase protein, C-reactive protein (CRP), we therefore suggest an investigation into possible urinary tract infection, or any other undiagnosed infection should have been conducted, and excluded, to rule out an alternative pathology [2]. There was no mention of such an investigation in the manuscript. Consequently, the discussion presented in this case report should perhaps be viewed with caution. Owing to the leucocytosis and elevated CRP observed in this patient, an investigation into pro-inflammatory cytokines may have proved beneficial. Elevations in CRP are the result of an inflammatory response, such as that which would be mounted either as a consequence of an autoimmune disorder, or against an invading pathogen. Recent work investigating CRP has shown a positive correlation between this inflammatory marker and fatigue [1], hence, this may, at least in part explain the fatigue suffered by the patient. In this case study, there was no discussion of any parameter that may have caused this elevation in CRP, and if this may have contributed to the patient’s symptoms. Various immune markers can cause an increase in the plasma CRP, including elevations in the pleiotrophic cytokine, interleukin-6 (IL-6), which has been linked to fatigue. IL-6 released from immune cells during infection, is transported to the liver, where binding to the hepatocytes induces CRP synthesis and release into the circulation. The elevation of IL-6 has been postulated to cause fatigue in healthy cohorts [5] and is elevated in a variety of clinical disorders characterised by severe fatigue, including rheumatoid arthritis, Sjogren’s syndrome and systemic lupus erythematosus [7]. The authors explain that after vaginal expulsion of a significant sized piece of tissue, the patient’s sensations of fatigued appeared to be completely resolved. This coincided with the resolution of the leucocytosis and CRP. The recovery of these haematological variables, may point to an infectious organism playing a role in the fatigue, which would again rule out a diagnosis of CFS. Therefore, the speculative nature and limitations of this manuscript must be acknowledged if any conclusions are to be drawn. C. Toms (&) P. Robson-Ansley A. St. Clair Gibson Department of Sports Sciences, Northumbria University, Northumberland Building, Newcastle upon Tyne NE1 8ST, UK e-mail: christopher.toms@unn.ac.uk