Month: January 2020

Eponym debate: The case for biologically-descriptive names

Naming a disease after the scientist who discovered it, like Hashimoto’s thyroiditis or Diamond-Blackfan anemia, just doesn’t work anymore, some physicians say.

A main argument against eponyms is that plain-language names — which describe the disease symptoms or underlying biological mechanisms —  are more helpful for patients and medical trainees. For example, you can probably out a bit about acquired immunodeficiency syndrome (AIDS), whooping cough or pink eye just from their names.

“The more obscure and opaque the name — whether due to our profession’s Greek and Latin fetish or our predecessors’ narcissism — the more we separate ourselves from our patients,” says Caitlin Contag, MD, a resident physician at Stanford.

Stanford endocrinologist Danit Ariel, MD, agrees that patients are often confused by eponyms.

“I see this weekly in the clinic with autoimmune thyroid disease. Patients are often confusing Graves’ disease with Hashimoto’s thyroiditis because the names mean nothing to them,” says Ariel. “So when I’m educating them about their diagnosis, I try to use the simplest of terms so they understand what is going on with their body.”

Ariel says she explains to her patients that the thyroid is overactive in Graves’ disease and underactive in Hashimoto’s.

Ariel says she believes using biological names also helps medical students better understand the underlying mechanisms of diseases, whereas using eponyms relies on rote memorization that can hinder learning. “When using biologically-descriptive terms, it makes inherent sense and students are able to build on the concepts and embed the information more effectively,” Ariel says.

Medical eponyms are particularly confusing when more than one disease is named after the same person, Contag argues. For example, neurosurgeon Harvey Williams Cushing, MD, has 12 listings in the medical eponym dictionary. 

Stanford resident physician Angela Primbas, MD, agrees that having multiple syndromes named after the same person is confusing. She says it’s also confusing to have diseases named differently in different countries. In fact, the World Health Organization has tried to address this, along with other issues, by providing best-practice guidelines for naming infectious diseases. (Genetic disorders, however, lack a standard convention for naming.)

In addition, Primbas said she thinks naming a disease after a single person is an oversimplification of a complex story. “Often many people contribute to the discovery of a disease process or clinical finding, and naming it after one person is unfair to the other people who contributed,” she says. “Plus, it’s often disputed who first discovered a disease.”

Also, few disease names recognize the contributions (or suffering) of women and non-Europeans. And some eponyms are decidedly problematic, like those named after Nazi doctors. A famous example is Reiter’s syndrome named for Hans Reiter, MD, who was convicted of war crimes for his medical experiments performed at a concentration camp.

“Reiter’s syndrome is now called reactive arthritis for the simple reason that Reiter committed atrocities on other human beings to conduct his ‘science.’ Such people should not have their name tied to a profession that espouses the principles of beneficence and nonmaleficence,” says Vishesh Khanna, MD, a resident physician at Stanford. He says medicine is swinging away from using these controversial eponyms to describe them on the basis of their biology instead.

Personally, Khanna also admits that naming a disease after himself wouldn’t sit well.

“Receiving credit for discovering something can certainly be a wonderful feather in a physician’s career cap, but the thought of actually naming a disease after myself makes me cringe,” says Khanna. “Patients and doctors would utter my name every time they had to bring up a disease.”

Such sentiments may be why Contag’s example of a good disease name — cyclic vomiting syndrome — is in plain English. Was no one eager to lend his or her name to it?

While the debate over medical eponyms continues, Khanna suggests a potential solution. “Perhaps a reasonable approach to naming going forward is to allow the use of already established eponyms without dubious histories, while only naming newly discovered diseases based on pathophysiology,” he says.

Everyone I spoke with agrees that changing the medical eponyms will only happen slowly, if at all, since it is difficult to change language. However, it can be done, according to Dina Wang-Kraus, MD, a Stanford resident in psychiatry and behavioral sciences.

“I looked through our diagnostic manual and we do not have diseases named after people in psychiatry. This shift happened quite some time ago so as to avoid confusion and to allow clinicians from all over the world to have a unified language,” says Wang-Kraus. “In psych, we often say that we wish other specialties would adopt a universal nomenclature too.”

This is the conclusion of a series on naming diseases. The first part is available here.

Photo by 4772818

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Eponym debate: The case for naming diseases after people

Is it better to name a genetic disorder Potocki-Lupski syndrome or the 17p11.2 duplication syndrome? What about Addison’s disease as opposed to adrenal insufficiency? Or Tay-Sachs disease versus hexosaminidase alpha-subunit deficiency (variant B)?

If you have a strong opinion about which is preferable, you aren’t alone: there is an ongoing controversy on how to name diseases. In Western science and medicine, a long-standing tradition is to name a disease after a person. However, many physicians now argue that these eponyms should be abandoned for biologically-descriptive names.

First, a bit about how eponyms are created.

Although the media sometimes comes up with a catchy name that sticks, like swine flu, diseases are typically named by scientists when they first report them in scientific publications.

Oftentimes, diseases are named after prominent scientists who played a major role in identifying the disease. The example that leaps to my mind is Hodgkin’s disease — a type of cancer associated with enlarged lymph nodes — because I was diagnosed and treated for Hodgkin’s at Stanford years ago. Hodgkin’s disease was named after Thomas Hodgkin, an English physician and pathologist who described the disease in a paper in 1832.

Less frequently, diseases are named after a famous patient. For example, amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig’s disease, was named after the famous New York Yankee baseball player who was forced to retire after developing the disease in 1939.

As these examples show, one of the reasons to keep eponyms is that they are embedded with medical traditions and history. They include some kind of story. And, oftentimes, they honor key people associated with the disease.

“I think the people who discover these conditions deserve recognition,” explains Angela Primbas, MD, a resident physician at Stanford. “I don’t think the medical community would know their names otherwise.”

Some physicians also feel eponyms bring color to medicine. “The use of eponyms in medicine, as in other areas, is often random, inconsistent, idiosyncratic, confused, and heavily influenced by local geography and culture. That is part of their beauty,” writes Australian medical researcher Judith Whitworth, MD, in an editorial in BMJ.

Other proponents of eponyms are more practical. They argue that eponymous disease names provide a convenient shorthand for doctors and patients.

Medical eponyms are also widely used by patients, physicians, textbooks and websites. According to a dictionary of medical eponyms, thousands of eponyms are used throughout the world particularly in the United States and Europe. They are even prominent in the World Health Organization’s international classification of diseases.

So is a massive effort to purge these eponyms worth it, or even realistic?

“There are certainly examples where eponymous disease names are so inculcated in medical vernacular that changing them to a pathology-based name might not be worth the effort,” says Vishesh Khanna, MD, a resident physician at Stanford. He gives the examples of Alzheimer’s disease and Crohn’s disease.

Jimmy Zheng, a medical student at Stanford, agrees that eponyms are here to stay. “At the level of medical school, eponyms are broadly dispensed in class, in USMLE study resources and in our clinical training,” Zheng says. “While some clinicians have called for the complete erasure of eponyms, this is unlikely to happen.”

Zheng and Stanford neurologist Carl Gold, MD, recently assessed the historical trends of medical eponym use in neurology literature. They also surveyed neurology residents on their knowledge and attitude towards eponyms. Their study’s findings were published in Neurology.

“Regardless of ‘should,’ our analyses demonstrate that eponyms are increasingly prevalent in the scientific literature and that new eponyms like the Potocki-Lupski syndrome continue to be coined,” Gold says. “Despite awareness of both the pros and cons of eponyms, the majority of Stanford neurology trainees in our study reported that historical precedent, pervasiveness and ease of use would drive the continued use of eponyms in neurology.”

So the debate rages on. According to my informal and small survey, some Stanford physicians favor eliminating eponymous disease names — stay tuned to find out why.

This is the beginning of a two-part series on naming diseases. The conclusion will appear this week.

Photo via Good Free Photos

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Measuring depression with wearables

Depression and emotional disorders can occur at any time of year — and do for millions of Americans. But feeling sad, lonely, anxious and depressed may seem particularly isolating during this holiday season, which is supposed to be a time of joy and celebration.

A team of Stanford researchers believes that one way to work towards ameliorating this suffering is to develop a better way to quantitatively measure stress, anxiety and depression.

“One of the biggest barriers for psychiatry in the field that I work in is that we don’t have objective tests. So the way that we assess mental health conditions and risks for them is by interview and asking you how do you feel,” said Leanne Williams, MD, a professor in psychiatry and behavioral sciences at Stanford, when she spoke at a Stanford Reunion Homecoming alumni celebration.

She added, “Imagine if you were diagnosing and treating diabetes without tests, without sensors. It’s really impossible to imagine, yet that is what we’re doing for mental health, right now.”

Instead, Stanford researchers want to collect and analyze data from wearable devices to quantitatively characterize mental states. The multidisciplinary team includes scientists from the departments of psychiatry, chemical engineering, bioengineering, computer science and global health.

Their first step was to use functional magnetic resonance imaging to map the brain activity of healthy controls compared to people with major depressive disorder who were imaged before and after they were treated with antidepressants.

The researchers identified six “biotypes” of depression, representing different ways brain circuitry can be disrupted to cause specific symptoms. They classified the biotypes as rumination, anxious avoidance, threat dysregulation, anhedonia, cognitive dyscontrol and inattention.

“For example, threat dysregulation is when the brain stays in alarm mode after acute stress and you feel heart racing, palpitations, sometimes panic attacks,” presented Williams, “and that’s the brain not switching off from that mode,” Williams said.

The team, which includes chemical engineer Zhenan Bao, PhD, then identified links between these different brain biotypes and various physiological differences, including changes in heart rate, skin conductance, electrolyte levels and hormone production. In particular, they found correlations between the biotypes and production of cortisol, a hormone strongly related to stress level.

Now, they are developing a wearable device — called MENTAID — that measures the physiological parameters continuously. Their current prototype can already measure cortisol levels in sweat in agreement with standard laboratory measurements. This was an incredibly challenging task due to the extremely low concentration and tiny molecular size of cortisol.

Going forward, they plan to validate their wearable device with clinical trials, including studies to assess its design and user interface. Ultimately, the researchers hope MENTAID will help prevent and treat mental illness — for example, by better predicting and evaluating patient response to specific anti-depressants.

Photo by Sora Sagano

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Floppy vibration modes explain negative thermal expansion in solids

Animation showing how solid crystals of ScF3 shrink upon heating. While the bonds between scandium (green) and fluorine (blue) remain relatively rigid, the fluorine atoms along the sides of the cubic crystals oscillate independently, resulting in a wide range of distances between neighboring fluorine atoms. The higher the temperature, the greater the buckling in the sides of the crystals leading to the overall contraction (negative thermal expansion) effect. Credit: Brookhaven National Laboratory

Matching the thermal expansion values of materials in contact is essential when manufacturing precision tools, engines, and medical devices. For example, a dental filling would cause a toothache if it expanded a different amount than the surrounding tooth when drinking a hot beverage. Fillings are therefore comprised of a composite of materials with positive and negative thermal expansion, creating an overall expansion tailored to the tooth enamel.

The underlying mechanisms of why crystalline materials with negative thermal expansion (NTE) shrink when heated have been a matter of scientific debate. Now, a multi-institutional research team led by Igor Zaliznyak, a physicist at Brookhaven National Laboratory, believes it has the answer.

As recently reported in Science Advances, the scientists measured the distance between atoms in scandium trifluoride powder, a cubic NTE material—at temperatures ranging from 2 K to 1099 K—using total neutron diffraction. The research team determined the probability that two particular atomic species would be found at a given distance. They studied scandium trifluoride because it has a simple atomic structure in which each scandium atom is surrounded by an octahedron of fluorine atoms. According to the prevailing rigid-unit-mode (RUM) theory, each fluorine octahedron should vibrate and move as a rigid unit when heated — but that is not what they observed.

“We found that the distances between scandium and fluorine were pretty rigidly-defined until a temperature of about 700 K, but the distances between the nearest-neighbor fluorines became ill-defined at temperatures above 300 K,” says Zaliznyak. “Their probability distributions became very broad, which is basically a direct manifestation of the fact that the shape of the octahedron is not preserved. If the fluorine octahedral had been rigid, the fluorine-fluorine distance would have been as well defined as scandium-fluorine.”

With the help of high school researcher David Wendt and condensed matter theorist Alexei Tkachenko, Zaliznyak developed a simple model to explain these experimental results. The team went back to the basics—the fundamental laws of physics.

“When we removed the ill-controlled constraint that there must be these rigid units, then we could explain the fundamental interactions that govern the atomic positions in the [ScF3] solid using just Coulomb interactions.”

The team developed a negative thermal expansion model that treats each Sc-F bond as a rigid monomer link and the entire ScF3 crystal structure as a floppy, under-constrained network of freely jointed monomers. Each scandium ion is constrained by rigid bonds in all three directions, whereas each fluorine ion is free to vibrate and displace orthogonally to its Sc-F bonds. This is a direct three-dimensional analogy of the well-established behavior of chainlike polymers. And their simple theory agreed remarkably well with their experiments, accurately predicting the distribution of distances between the nearest-neighbor fluorine pairs for all temperatures where NTE was observed.   

“Basically we figured out how these ceramic materials contract on warming and how to make a simple calculation that describes this phenomenon,” Zaliznyak says.

Angus Wilkinson, an expert on negative thermal expansion materials at the Georgia Institute of Technology who is not involved in the project, agrees that Zaliznyak’s work will change the way people think about negative thermal expansion in solids.

“While the RUM picture of NTE has been questioned for some time, the experimental data in this paper, along with the floppy network (FN) analysis, provide a compelling alternative view,” says Wilkinson. “I very much like the way the FN approach is applicable to both soft matter systems and crystalline materials. The floppy network analysis is novel and gives gratifyingly good agreement with a wide variety of experimental data.”

According to Zaliznyak, the next major step of their work will be to study more complex materials that exhibit NTE behavior now that they know what to look for.

Read the article in Science Advances.

This is a reposting of my news brief, courtesy of MRS Bulletin.