PVFS meaning in Medical ?

Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) and ME/CFS, is a complex, fatiguing, long-term medical condition diagnosed by required primary symptoms and criteria, and often involves a broad range of symptoms. Distinguishing core symptoms are lengthy exacerbations or "flares" of the illness after ordinary minor physical or mental activity, known as post-exertional malaise (PEM); greatly diminished capacity to accomplish tasks that were routine before the illness; and sleep disturbances.: 7 Orthostatic intolerance (difficulty sitting and standing upright) and cognitive dysfunction are also diagnostic. Other common symptoms may involve numerous body systems, and chronic pain is common.

While the cause is not understood, proposed mechanisms include biological, genetic, infectious, and physical or psychological stress affecting the biochemistry of the body. Diagnosis is based on the patient's symptoms because no confirmed diagnostic test is available. The fatigue in CFS is not due to strenuous ongoing exertion, is not significantly relieved by rest, and is not due to a previous medical condition. Fatigue is a common symptom in many illnesses, but the unexplained fatigue and severity of functional impairment in CFS are relatively rare in these other illnesses.

Persons with CFS may recover or improve over time, but some will become severely affected and disabled for an extended period. No therapies or medications are approved to treat the cause of the illness; treatment is aimed at symptomatology. The CDC recommends pacing (personal activity management) to keep mental and physical activity from making symptoms worse. Limited evidence suggests that rintatolimod, counseling, and graded exercise helps some patients.

About 1% of primary-care patients have CFS; estimates of incidence vary widely because epidemiological studies define the illness dissimilarly. It has been estimated that 836,000 to 2.5 million Americans and 250,000 to 1,250,000 people in the United Kingdom have CFS. CFS occurs 1.5 to 2 times as often in women as in men. It most commonly affects adults between ages 40 and 60 years; it can occur at other ages, including childhood. Other studies suggest that about 0.5% of children have CFS, and that it is more common in adolescents than in younger children.: 182 Chronic fatigue syndrome is a major cause of school absence.: 183 CFS reduces health, happiness, productivity, and can also cause socio-emotional disruptions such as loneliness and alienation, however, there is controversy over many aspects of the disorder. Physicians, researchers, and patient advocates promote different names and diagnostic criteria; and evidence of proposed causes and treatments is often poor or contradictory.