#556 - Testing for Viruses, Diagnosing Lipedema, Thanks COVID
Take 3 – Practical Practice Pointers©
From the Infectious Disease Society of America (IDSA) and the CDC
1) A Review of Testing for Respiratory Viruses
As we wind up summer, get ready for flu shot season, and finish battling a new wave of COVID-19 infections, it may be useful to review our testing practices for viral respiratory viruses. As the severity of the COVID infections has decreased and isolation procedures have relaxed for non-healthcare personnel, practices may have defaulted to less stringent policies for COVID testing. Those who continue to use PCR testing in offices may have begun using these expensive tests for rapid diagnosis of other respiratory pathogens like influenza and respiratory syncytial virus (RSV).
Below is a summary of information from the IDSA guidelines on COVID-19 testing and the CDC’s guidance for non-hospitalized patients with acute upper respiratory infection.
Nucleic acid amplification testing (NAAT) using polymerase chain reaction (PCR):
- Considered to be the reference standard for testing – assumed to be 100% sensitive and specific for clinical use.\
- Can be used to rule out infections in patients for whom the likelihood of further transmission is important, like healthcare workers, or patients living in group facilities.
- Can be used for testing both symptomatic patients and, in certain cases, asymptomatic patients with known exposures.
- COVID-19 testing using NAAT is covered by insurances, and desktop test processing machines are available for primary care practices.
- Influenza and RSV testing using NAAT is indicated for hospitalized patients or patients who may be returning to a nursing facility or similar living situation – mainly to facilitate any necessary isolation. It is not needed for most outpatients.
- The inclusion of NAAT testing for influenza and RSV can increase COVID NAAT testing costs by 4-6x. (e.g., ~$150 per test to ~$700-1000)
- The point-of-care desktop machines take usually less than 1 hour for a result.
COVID-19 antigen testing
- Sensitivity – between 81 and 89% - higher sensitivities are seen in patients who have been symptomatic for < five days. After five days, the sensitivity falls to 54%.
- Specificity – high, 97-99% - positive tests do not need reconfirmation.
- Sensitivity in asymptomatic patients is only 64%.
- One-time antigen testing cannot RULE OUT infection, especially in symptomatic patients.
- CDC guidance suggests that antigen testing may be used in series (2 or 3 tests, each separated by 48 hours) for a known exposure and/or in high-risk individuals.
- Healthcare workers cannot be returned to work with only a single negative antigen test and NAAT testing is recommended (required in many places).
Influenza antigen testing
- Antigen tests are considered to have low-moderate sensitivity and high specificity.
- Their ability to rule out disease depends on prevalence; when influenza is circulating, a negative test is less helpful.
- The best use of antigen testing is when it would change management.
- A high-risk patient with typical influenza symptoms when influenza is circulating does not really need testing, and a negative test should not deter antiviral use.
- A low-risk patient for whom antivirals would not be recommended generally does not need testing.
- A high-risk patient with intermediate likelihood of flu is a good candidate for testing.
- Patients at high-risk for influenza complications include: < 5 years (especially < 2 years), over age 64, pregnancy or immediate post-partum, chronic neurologic or other medical disease.
One potential use of outpatient viral testing is to reduce antibiotic use for viral upper respiratory illness. There have been few studies, and the evidence is mixed at best, so viral testing for this reason cannot yet be recommended.
John’s Comments:
- Unfortunately, a strategy of “universal” testing of symptomatic patients for flu and COVID without consideration of risk, employment, living situations, etc. can both lead to waste as well as cause errors in clinical decision-making for high-risk patients.
- The tried-and-true question, “Will this test change your management?” is still the best guide to appropriate testing. We just have to think a little more broadly about our “management” (patient living situations, return to work guidelines, etc.)
- CDC’s FluView and the corresponding state databases can be used to monitor influenza activity to help guide decisions.
- At Carilion Clinic, acutely symptomatic employees are not considered COVID negative without a NAAT (PCR) test.
References:
- Hayden MK, Hanson KE, Englund JA, et al. The Infectious Diseases Society of America Guidelines on the Diagnosis of COVID-19: Antigen Testing (January 2023). Clinical Infectious Diseases. 2024;78(7):e350-e384. Link
- Hayden MK, Hanson KE, Englund JA, et al. The Infectious Diseases Society of America Guidelines on the Diagnosis of COVID-19: Molecular Diagnostic Testing (December 2023). Clinical Infectious Diseases. 2024;78(7):e385-e415. Link
- Clinical Guidance for Patients with Acute Respiratory Illness Not Being Hospitalized When SARS-CoV-2 and Influenza Viruses are Co-Circulating | CDC. July 16, 2024. Accessed August 14, 2024. Link
- Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa. Clinical Infectious Diseases. 2019;68(6):e1-e47. Link
From the Literature
2) Lipedema – Are You Missing This Diagnosis?
Lipedema (adiposis dolorosa, or painful fat syndrome) is a subcutaneous lipodystrophy found exclusively in females characterized by increased palpable nodular and fibrotic adipose tissue deposits most commonly the buttocks, hips, and lower extremities while sparing the feet (“cuff sign”) and out of proportion to the rest of the body. Its prevalence is unclear due to likely significant underdiagnosis and widely varying estimates.
The etiology and pathophysiology of lipedema are not well understood, but it is thought to be triggered by hormonal changes during puberty, childbirth, or menopause. Estrogen is theorized to play a role, as it regulates lipid and glucose metabolism and female-associated adipocyte distribution. A cross-sectional study found the prevalence of lipedema increased with weight and body mass index, and obesity is believed to be an aggravating factor for lymphatic harm and edema leading to lymphatic overload.
Classic symptoms of lipedema include an aching discomfort at rest, limb pain on palpation, and a feeling of heaviness of the legs. Signs include easy bruising and prominent malleolar fat pads in the presence of normal feet.
There are two common conditions that are often confused with lipedema – obesity and lymphedema. While both obesity and lipedema can have a similar appearance, early on in those with lipedema the upper portion of the body is not affected.
The majority of lymphedema is due to a known injury to the lymphatic system (secondary lymphedema). Risk factors are commonly present and include; cancer treatment (radiation therapy and lymphatic resection for cancer of the breast, head, or neck and other malignancies); soft-tissue infection (and cellulitis); chronic venous insufficiency; injury; trauma; and surgery; and obesity. Unlike lipedema, there is not usually tenderness or pain with lymphedema in the absence of infection, there is foot involvement, and there is usually an absence of increased fatty tissue unless the patient has obesity as well.
The 3 conditions can co-exist as lipedema with superimposed obesity-induced lymphedema. If the diagnosis is in doubt, a lymphoscintigram can be obtained and dual-energy x-ray absorptiometry (DEXA) can be useful in assessing fat mass and lean body mass. There are no blood tests that are diagnostic for lipedema,
Treatment for lipedema can be challenging. Patient education is essential, recognizing that conservative treatment, including aggressive weight management, regular physical activity, and compressive therapies for edema management when indicated may help relieve symptoms but will have minor effects on the appearance of the extremities (<10% volume reduction). More aggressive and definitive treatment can include surgical weight loss and liposuction. Referral to a physician who has expertise in management is essential.
Mark’s Comments:
A few months ago a patient asked me what I knew about lipedema as she suspected she may have it, and at the time my answer was “next to nothing” (I even spelled it incorrectly – lipidema, in my initial search). Since then I’ve diagnosed it in two patients, including with one of our residents this week. I reached out to Matthew Joy, MD, a colleague in our Section of Plastic and Reconstructive Surgery and Director of Lymphatic and Reconstructive Microsurgery to get his insights. It turns out this is an area for which he has great clinical interest and has developed expertise. He replied, “Ideally these patients should also be optimized medically and with compressive therapies prior to considering surgery. That usually includes addressing obesity if this is a significant issue as well as working with PT/OT and possible lymphedema therapies depending on the clinical picture.” Some of my additional reading also indicated that earlier treatment can lead to more favorable outcomes, so keeping this on your radar as a clinical possibility is important. The first reference below has a wonderful Table (1) that outlines the distinctions between lipedema, lymphedema, and obesity and has a memorable picture of the “cuff sign.”
References:
From PeerRxMed ( www.PeerRxMed.org )
3) Becoming More Human – Thanks for the Reminder, COVID
Medical culture is steeped in a tradition of stoicism, where showing vulnerability is often misconstrued as weakness." Danielle Ofri, MD, author of "What Doctors Feel: How Emotions Affect the Practice of Medicine
“It’s positive.” More than 1,500 days after COVID-19 was declared a public health emergency in the US, and having likely been exposed thousands of times without getting ill, the virus had caught up to me, and I joined the hundreds of millions of others around the world who have been infected. While this seemed inevitable and I was fortunate to experience a relatively mild infection, what struck me most was how quickly my professional programming kicked into gear.
At first, there was denial when the symptoms appeared. I thought, “It’s probably just a summer cold or allergies.” Then came the immediate heroic stance: “I’ll heal in no time” and “Let’s pivot to virtual.” I felt a sense of indispensability—“I don’t have time for this,” and “They need me at that meeting.” There was also the predictable feeling of weakness for getting sick at all: “What have I been doing that has depressed my superhuman immune system?” And, of course, I found myself humorously trying to trace where I might have been exposed—patient care, the obvious answer, only came to mind after several other possibilities.
What didn’t surface initially, though, was any sense of grace for myself and my body, despite my decades of work advancing clinician and care team well-being. I realized that I was once again living out the socialization ingrained in us during medical training, which instills a sense of duty, responsibility, and self-sacrifice. We’re implicitly, if not explicitly, encouraged to downplay our own health concerns. It’s second nature in a culture that insists “the patient always comes first” and views “illness as weakness,” even as we treat the ill daily.
This mindset is often beneficial, even necessary, in high-pressure situations, allowing us to perform at our best. However, it can create blind spots when recognizing and addressing our own health issues. For many healthcare professionals, admitting illness can feel like admitting defeat. There’s an unspoken stigma attached to being sick—a sense that we should be invulnerable to the very ailments we treat. This feeling is especially pronounced in the context of COVID-19, where clinicians were initially hailed as “heroes.”
As I’ve recovered, those initial feelings of vulnerability and even embarrassment have lessened. I recognize how fortunate I was to have had only a “moderate cold” and inconvenience. Being transparent about my experience has prompted many colleagues to share their own “COVID stories” and even some who have opened up about other illnesses or injuries they’ve been struggling with. This openness has been particularly true among my PeerRx partners. The time in isolation has allowed me to refresh my priorities, approach my health differently, and strengthen my “self-compassion muscle.” In doing so, I’ve somehow become more human. And that, to me, is a good thing. So thanks for the reminder COVID. Now, if you would only go away ….
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Mark and John
Carilion Clinic Department of Family and Community Medicine
Feel free to forward Take 3 to your colleagues. Glad to add them to the distribution list.
Email: mhgreenawald@carilionclinic.org