The name is: Systemic Exertion Intolerance Disease (SEID) (which as one of my very observant Facebook friends pointed out is DIES backwards).
A very quick post to direct you to the public release of the findings from the US Institute of Medicine (IoM) looking at the name and current criteria used to diagnose Chronic Fatigue Syndrome / Myalgic Encephalomyelitis (CFS/ME) (see here). The proposed diagnostic criteria for CFS/ME, sorry SEID can be viewed here.
Some of the background to these findings can be seen here and some of the media about the new IoM recommendations can be seen here and here.
Many with either personal or professional experience of CFS/ME will know all about the issue of diagnosis and CFS/ME, and outside of the struggle to recognise that this is a very real condition which can severely impact on a person's life, how confusing the diagnostic criteria can be. This has also had various implications on both research and practice .
The IoM was charged with looking at the existing ways and means that CFS/ME was defined and "recommend clinical diagnostic criteria for the disorder to address the needs of health providers, patients, and their caregivers" (see here). To that end, their guidance now reflects these efforts although at the current time I'm having some difficulty in locating how they tackled the idea of "distinguish[ing] between disease subgroups" which I think should have represented quite a big leap forward in these days of plural labels and heterogeneity in symptoms and comorbidity (see here). At this point I might refer you to a paper I wrote that touched upon this a few years back . I am however happy to see that pediatric ME/CFS or SEID has been mentioned in their various guidance in light of the growing realisation that the condition can manifest in children and young people too (see here).
Obviously it's going to take time for these findings to find their way from guidance to practice and beyond so I don't think massive changes will be immediately forthcoming. One would hope that alongside the growing interest in the biology/genetics of CFS/ME (acknowledging how the condition can also impact on psychology too) that moves towards the development and testing of biological therapeutics in particular, might be accelerated (see here).
To close: Breaking Bad and Say My Name... 'sorta Greg'.
 Morris G. & Maes M. Case definitions and diagnostic criteria for Myalgic Encephalomyelitis and Chronic fatigue Syndrome: from clinical-consensus to evidence-based case definitions. Neuro Endocrinol Lett. 2013;34(3):185-99.
 Whiteley P. et al. Correlates of Overlapping Fatigue Syndromes. Journal of Nutritional and Environmental Medicine. 2004; 14: 247-259.
Morris G, & Maes M (2013). Case definitions and diagnostic criteria for Myalgic Encephalomyelitis and Chronic fatigue Syndrome: from clinical-consensus to evidence-based case definitions. Neuro endocrinology letters, 34 (3), 185-99 PMID: 23685416