Characteristic Symptoms of ME
Looking at the principal symptom, The prevailing symptom of ME is an overwhelming and incapacitating post-exertional muscle fatiguability with prolonged recovery time: it bears little resemblance to normal "tiredness" or to "sleepiness". Many can walk only very short distances and require a wheelchair. ME patients have an extremely low tolerance for physical activity and a low oxygen consumption, thought to be linked to an abnormal oxidative metabolism. There is firm laboratory evidence which demonstrates delayed muscle recovery after fatiguing exercise; these findings show convincingly that in ME, there is continued loss of post-exertional muscle power (giving an additional loss of power), with delayed recovery for at least 24 hours, whereas sedentary controls recovered full muscle power after 200 minutes.
This muscle fatiguability is usually accompanied by a variable degree of malaise. It is the constant feeling of extreme but invisible "ill-ness" which makes ME so hard to cope with and so easy for the ill-informed to dismiss.
ME is a multi-system disorder which is primarily neurological, affecting not only the central nervous system (CNS) but also the autonomic nervous system (ANS) and the peripheral nervous system (PNS). Sympathetic nervous system dysfunction is integral to ME pathology. Frequency of micturition with nocturia is almost invariably present, together with sweats and hot flushes (resulting from HPA dysfunction) and orthostatic intolerance is very common.
It is a potentially severe, disabling and chronic disorder of not only the nervous system but of the immune system also. There is a considerable clinical overlap of symptoms with multiple sclerosis and like multiple sclerosis, it often follows a relapsing and remitting course but about 25% do not improve and may deteriorate.
Cognitive dysfunction follows a distinctive and unusual pattern, including difficulty with memory sequencing, information processing speed, word searching, spatial organisation and calculation.
Other hallmarks of ME are alcohol intolerance and the presence of environmental sensitivities; patients are unusually sensitive to chemicals, including therapeutic drugs and anaesthetic agents. At the Dublin International Meeting presented under the auspices of The World Federation of Neurology (18-20th May 1994), Professor Charles Poser of the Department of Neurology, Harvard Medical School, said this is virtually pathognomonic of ME.
Pain is often extreme and intractable: the control of pain in certain very sick patients can easily be the most challenging problem in ME management.
In short, ME has features of autoimmune disorders (e.g. lupus); features of allergy and multiple chemical sensitivity (MCS); features of neurological disease (multiple sclerosis); features of infectious disease and features of tempero-limbic encephalopathies. As in most severe, chronic illness, there are accompanying psychological features, including emotional lability.
The chronicity and severity of this condition, together with the degree of disablement, loss of employment (with consequent financial loss), the inevitable social isolation and the disruption of the family unit make this disorder a nightmare.
While ME is not unique on the issue of laboratory tests which support but do not diagnose it definitively, the same can also be said of the diagnoses of multiple sclerosis, lupus erythematosus and mononucleosis, which are often supported by non-diagnostic tests.
It is appropriate to quote from the testimony of one of the world's leading experts on ME / CFS: in his Testimony Before the FDA Scientific Advisory Committee on 18th February 1993, Dr Paul Cheney testified as follows:
" I have evaluated over 2,500 cases. At best, it is a prolonged post-viral syndrome with slow recovery. At worst, it is s nightmare of increasing disability with both physical and neurocognitive components. The worst cases have both an MS-like and an AIDS-like clinical appearance. We have lost five cases in the last six months. The most difficult thing to treat is the severe pain. Half have abnormal MRI scans. 80% have abnormal SPECT scans. 95% have abnormal cognitive- evoked EEG brain maps. Most have abnormal neurological examination. 40% have impaired cutaneous skin responses to multiple antigens. Most have evidence of T-cell activation. 80% have evidence of an up-regulated 2-5A antiviral pathway. 80% of cases are unable to work or attend school. We admit regularly to hospital with an inability to care for self".