| According to the 1994 Fukuda definition[2] | | | | temperature. Many CFS patients frequently run |
| there are eight main categories of symptoms | | | | a low fever, or report fever-like symptoms |
| in CFS: | | | | (sweating, feeling too hot or cold, etc.) |
| | | | without measurable fever temperature. |
| Fatigue: People with CFS experience profound, | | | | |
| overwhelming exhaustion, both mental and | | | | Sleep problems: "Unrefreshing sleep" and rest |
| physical, which is worsened by exertion, and | | | | is a hallmark of CFS, and insomnia is also |
| is not relieved (or not completely relieved) | | | | common. Maintaining a sleep schedule is |
| by rest. To receive a diagnosis of CFS, this | | | | extremely difficult for many patients. Vivid, |
| fatigue state must last for six months. | | | | "feverish" dreams are a symptom in many |
| | | | people with CFS, exacerbating disturbed sleep |
| Pain: Pain in CFS may include muscle pain, | | | | patterns. Patients report that exercise, |
| joint pain (without joint swelling or | | | | unlike in healthy persons, worsens the |
| redness, and may be transitory), headaches | | | | insomnia and unrefreshing sleep symptoms |
| (particularly of a new type, severity, or | | | | alike. |
| duration), lymph node pain, sore throats, and | | | | |
| abdominal pain (often as a symptom of | | | | Psychological/Psychiatric symptoms: emotional |
| irritable bowel syndrome). Patients also | | | | lability, anxiety, depression, irritability, |
| report; bone, eye and testicular pain, | | | | and sometimes a curious emotional |
| neuralgia and painful skin sensitivity. Chest | | | | "flattening" (most likely due to exhaustion), |
| pain has been attributed variously to | | | | may manifest in CFS patients. Many of these |
| microvascular disease or cardiomyopathy by | | | | symptoms can be directly caused by the CFS |
| researchers, and many patients also report | | | | mechanism or, in some cases, may be secondary |
| painful tachycardia. | | | | symptoms created by the syndrome, as many |
| | | | chronic pain or illness patients also show |
| Cognitive problems: people with CFS may | | | | similar psychiatric issues. CFS patients with |
| experience forgetfulness, confusion, | | | | pre-existing psychiatric symptoms may report |
| difficulty thinking, concentration | | | | that these worsen with the onset of CFS. |
| difficulties, and "mental fatigue" or "brain | | | | Treatment for psychiatric symptoms alone does |
| fog". Additional signs may be experienced; in | | | | not relieve the physical symptoms of CFS, |
| the 2003 Canadian Definition these include | | | | indicating that the disease is not |
| aphasia, agnosia, and loss of cognitive body | | | | psychological in nature. |
| map[7][8]. | | | | |
| | | | Disturbances in the autonomic nervous system |
| Hypersensitivity: people with CFS are often | | | | and hormones: |
| sensitive to light, sound, and multiple | | | | |
| chemicals and foods. Many CFS patients report | | | | People with CFS often have abnormalities in |
| an increase in allergic-type sensitivity to | | | | the autonomic nervous system such as low |
| foods, scents, and chemicals, and many also | | | | blood volume, orthostatic intolerance, |
| report a sensitivity to medications, which | | | | dizziness and light-headedness, especially |
| can complicate treatment. Patients with | | | | when standing up quickly. |
| pre-existing allergies, asthma, and similar | | | | |
| conditions often report a worsening of | | | | Hormonal abnormalities may include abnormal |
| symptoms. Sensory overload is commonly | | | | vasopressin metabolism and a blunted ACTH |
| reported by patients, leading to increased | | | | response, leading to hypothyroidism and/or |
| fatigue and even migraine or seizures. | | | | low cortisol and reduced ability to respond |
| | | | to physiological and emotional stress. |
| Poor temperature control: people with CFS | | | | Patients sometimes show abnormally low levels |
| often report either feeling too hot or too | | | | of testosterone, growth hormone and other |
| cold, possibly due to involvement of the | | | | important hormones. |
| hypothalamus, which regulates body | | | | |