Modern medicine can be divided, broadly speaking, in two. On the one hand, there are “organic” diseases, in which investigative tools can identify a material change from the norm – a “pathology”. This might be an abnormal blood test, a shadow on an X-ray, cancerous transformation in cells studied under a microscope, impaired blood flow through a blocked artery shown on a scan, and so on.
The other group of illnesses are the “functional” conditions. In these, blood tests, scans and biopsies all appear normal; no objective cause for the patient’s symptoms can be identified. Common examples include irritable bowel syndrome, fibromyalgia and chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME).
The term “functional” is often taken to mean that, because there is no identifiable organic pathology, the symptoms must arise from ill-understood disturbances in otherwise healthy organs or bodily systems. And for many doctors, “functional” has acquired unhelpful connotations: there isn’t actually anything “wrong”; these patients’ symptoms must be psychosomatic, a term that has become highly pejorative (“it’s all in the mind”).
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This division into organic and functional is artificial and arbitrary, however, and arises from the limitations of existing biomedical science. It is a lesson that Covid-19 is beginning to teach us on a grand scale.
A year ago, Covid was thought of as a binary disease: you either got a flu-like illness that would be over within a fortnight, or you got seriously sick and required hospitalisation. Even the 4 per cent with severe Covid had an essentially binary outcome: recovery (albeit sometimes having sustained permanent organ damage) or death.
Yet, as last year’s first wave receded, a new clinical entity began to be described: a relapsing-remitting disease that has become known as Long Covid (LC). LC affects around 10 per cent of infected individuals, and symptoms persist for months on end, characteristically aggravated by physical activity (“post-exertional malaise” or PEM). There are plenty of first-wave LC patients who are still suffering a year on.
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It has been a dispiriting experience for most. Tests often return normal results. The notion of this being a functional condition has rapidly taken root in parts of the medical world and LC patients describe being dismissed by doctors at a loss to explain their symptoms. They are told there is nothing wrong – that their symptoms must be due to anxiety.
The sheer number of LC patients has stimulated a big research effort. Some of the first breakthroughs are coming thanks to novel imaging techniques that enable metabolic activity in tissues to be visualised.
A team from Marseilles in France has shown diminished metabolic activity in certain brain regions in LC patients. There is a strong correlation with the kinds of symptoms described: brain regions involved in taste/smell, balance and memory are selectively impaired. Research at the Royal Brompton Hospital in London is reportedly identifying marked abnormalities of blood flow to regions of the lungs in LC patients with persisting breathlessness.
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These novel techniques are not widely available outside the research setting, yet they are beginning to uncover organic pathology where conventional tests have returned normal results. What the virus has set in train in the lungs and brain (and other organs) needs much more research to be understood. The effort to elucidate the condition will help not only LC sufferers, but will also yield insights into other illnesses such as CFS/ME and fibromyalgia. As the science evolves, the artificial divide between organic and functional illness should eventually be broken down.
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This article appears in the 21 Apr 2021 issue of the New Statesman, The unlikely radical