Long COVID: Another Great Pretender

George D. Lundberg, MD

Has COVID replaced syphilis as the great imitator? At the turn of the 20th century, Sir William Osler was quoted as saying, "He who knows syphilis knows medicine."

If you have any doubts about the "imitator" analogy, simply use any broad search engine or AI portal and enter "what is the differential diagnosis of primary syphilis, or secondary syphilis, or tertiary syphilis?" A plethora of diseases across many body systems appears.

Another Great Pretender?

Did you or do you now have long COVID? How do you know? Do you even know what long COVID is? How would you diagnosis it?

When asked about long COVID, this is what large language model source bard.google.com had to say:

Long COVID, also known as post-COVID conditions or PASC, is a complex condition that can occur in people who have had COVID-19, even if their initial illness was mild or even asymptomatic. It's characterized by a wide range of symptoms that can last for weeks, months, or even years after the initial infection.

Symptoms of long COVID can include: fatigue, shortness of breath, brain fog (trouble thinking or concentrating), loss of smell or taste, sleep problems, muscle pain, joint pain, headache, dizziness, depression or anxiety, heart palpitations, gastrointestinal problems.

Duh!!! It reads much like a continuation of the symptoms of acute COVID. Bard continued:

The exact cause of long COVID is still unknown, but there are several theories. One possibility is that the virus itself can damage organs and tissues, leading to ongoing symptoms. Another possibility is that the immune system's response to the virus can continue to cause inflammation even after the virus is gone.

Human intelligence source Wikipedia says this:

Long COVID or long-haul COVID is a group of health problems persisting or developing after an initial COVID-19 infection. Symptoms can last weeks, months or years and are often debilitating. The World Health Organization defines long COVID as starting three months after infection, but other definitions put the start of long COVID at four weeks.

Highly varied, including post-exertional malaise (symptoms made worse with effort), fatigue, muscle pain, shortness of breath, chest pain, and cognitive dysfunction (brain fog).

Acute COVID to Long COVID

The World Health Organization estimates that 36 million people in the European region have developed long COVID in the first 3 years of the pandemic. That's a lot.

We all know that the common signs and symptoms of acute COVID-19 include fever or chills, a dry cough and shortness of breath, feeling very tired, muscle or body aches, headache, loss of taste or smell, sore throat, congestion, runny nose, nausea, vomiting, and diarrhea. Except for the taste and smell findings, every one of these symptoms or signs could indicate a different virus infection or even some type of allergy. My point is the nonspecificity in this list.

Uncommon signs and symptoms of acute COVID include a flat skin rash covered with small bumps, discolored swollen areas on the fingers and toes (COVID toes), and hives. The skin of hands, wrists, or ankles also can be affected. Blisters, itchiness, rough skin, or pus can be seen.

Severe confusion (delirium) might be the main or only symptom of COVID-19 in older people. This COVID-19 symptom is linked with a high risk for poor outcomes, including death. Pink eye (conjunctivitis) can be a COVID-19 symptom. Other eye problems linked to COVID-19 are light sensitivity, sore eyes, and itchy eyes. Acute myocarditis, tinnitus, vertigo, and hearing loss have been reported. And 1-4 weeks after the onset of COVID-19 infection, a patient may experience de novo reactive synovitis and arthritis of any joints.

So, take your pick. Myriad symptoms, signs, diseases, diagnoses, and organ systems — still present, recurring, just appearing, apparently de novo, or after asymptomatic infection. We have so much still to learn.

What big-time symptoms, signs, and major diseases are not on any of these lists? Obviously, cancer, atherosclerotic cardiovascular diseases, obesity, bone diseases, and competitive infections. But be patient; the lingering effects of direct tissue invasion by the virus as well as a wide range of immunologic reactions may just be getting started. Mitochondrial damage, especially in muscles, is increasingly a pathophysiologic suspect.

Human diseases can be physical or mental; and in COVID, that twain not only meet but mix and mingle freely, and may even merge into psychosoma. Don't ever forget that. Consider "fatigue." Who among us, COVID or NOVID, does not experience that from time to time?

Or consider brain fog as a common reported symptom of COVID. What on earth is that actually? How can a person know they have brain fog, or whether they had it and are over it?

We need one or more lab or other diagnostic tests that can objectively confirm the diagnosis of long COVID.

Useful Progress?

A recent research paper in Science reported intriguing chemical findings that seemed to point a finger at some form of complement dysregulation as a potential disease marker for long COVID. Unfortunately, some critics have pointed out that this entire study may be invalid or irrelevant because the New York cohort was recruited in 2020, before vaccines were available. The Zurich cohort was recruited up until April 2021, so some may have been vaccinated.

Then Medscape came along in early January 2024 with an article about COVID causing not only more than a million American deaths but also more than 5000 deaths from long COVID. We physicians don't really know what long COVID even is, but we have to sign death certificates blaming thousands of deaths on it anyway? And rolling back the clock to 2020: Are patients dying from COVID or with COVID, according to death certificates?

Now, armed with the knowledge that "documented serious post–COVID-19 conditions include cardiovascular, pulmonary, neurological, renal, endocrine, hematological, and gastrointestinal complications, as well as death," CDC has published clear and fairly concise instructions on how to address post-acute COVID sequelae on death certificates.

In late January, Medscape painted a hopeful picture by naming four phenotypes of long COVID, suggesting that such divisions might further our understanding, including prognosis, and even therapy for this condition. Among the clinical phenotypes of (1) chronic fatigue–like syndrome, headache, and memory loss; (2) respiratory syndrome (which includes cough and difficulty breathing); (3) chronic pain; and (4) neurosensorial syndrome (which causes an altered sense of taste and smell), overlap is clearly possible but isn't addressed.

I see these recent developments as needed and useful progress, but we are still left with…not much. So, when you tell me that you do or do not have long COVID, I will say to you, "How do you know?"

I also say: She/he/they who know COVID know medicine.

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