Breaking Down The Causes And Symptoms Of 'long Covid'

DEAR DR. ROACH: I read last year that nearly 20 million Americans were living with long COVID, but I understand that the number is much higher now. Can you explain exactly what long COVID is and how it is treated? -- J.S.B.

ANSWER: Persistent symptoms after an infection are not unique to COVID. Many people will have cough or asthma exacerbations for weeks or even months after a bad flu infection.

Likewise, many people have symptoms (relating to many different body systems) after recovering from COVID. The Centers for Disease Control and Prevention and the World Health Organization differ on the amount of time after an infection that has to pass for it to be considered "long COVID" -- four weeks and three months, respectively.

The most common physical symptoms of long COVID are fatigue, shortness of breath and muscle aches. In one study of people who survived the initial wave of COVID, 45% had at least one persistent physical symptom.

The most common and persistent neurological/psychological symptoms are anxiety, depression, post-traumatic stress disorder and cognition problems ("brain fog"). Up to 25% of COVID survivors had one of these symptoms after their physical recovery. This was higher than other respiratory viruses, such as influenza.

For those who required an stay in the intesive care unit, over 75% had physical, psychological or cognitive symptoms after their discharge. These survivors are at the highest risk for prolonged and severe long-COVID symptoms.

There are many hypotheses for the underlying cause of long COVID symptoms, and although there is some evidence, it's not clear whether there is one single cause or whether multiple mechanisms are possible.

I wish I could get better results from the available treatments. Essentially, we treat each patient's concerns the same way we would if the person hadn't had COVID. Emphasis on sleep, nutrition and exercise are critical. But we should still recognize that many people with long COVID have symptoms that are very similar to myalgic encephalomyelitis/chronic fatigue syndrome. As such, exercise should not be overdone, since this can worsen post-exertional symptoms.

DEAR DR. ROACH: Do MRI tests, especially of the head, contribute to hearing loss even when earplugs are used? -- M.D.

ANSWER: MRI scans are very loud, and exposure to loud noises can cause hearing loss. However, it's the prolonged and repeated exposure to loud noises that is most likely to cause hearing damage, so MRI scans are not likely to be a problem. Earplugs are still a good idea, though.

There is nothing about the strong magnetic field in an MRI machine that adversely affects hearing. They just make a lot of noise due to the moving electrical coils. Some machines can cause levels up to 110 decibles -- as loud as a rock concert.

New MRI technology is coming that will dramatically reduce the amount of noise made during a scan.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.