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Top 10 Baffling Phenomena That Medicine Can’t Fully Explain

by Shelby Hoebee
fact checked by Jamie Frater

Modern medicine has advanced so dramatically in the last century that it’s hard to believe that so much is still unexplained. But doctors are often faced with medical mysteries, those phenomena that currently lack a confirmed cause or full explanation.

Although we can’t list every medical mystery here, these 10 examples are a great way to illustrate how medicine continues to grow and transform over time. They also show how much new research is always needed.

10 Medical Student Syndrome

Nearly everyone has had those fleeting thoughts that they’re experiencing a symptom from a severe, undiagnosed disease. Throughout medical school, future doctors learn about thousands of diseases with various signs and symptoms that they are expected to recognize in their own patients one day. An interesting phenomenon that seems to occur in some of these people is known as “medical student syndrome.”

This occurs when medical students believe they are experiencing the symptoms of a disease that they are studying. As opposed to illness anxiety disorder, these delusions are transient.[1]

It is unknown exactly why this occurs. But researchers believe that medical students create a mental schema as they learn about a disease and some students begin to recognize normal bodily sensations as part of this disease schema.

One study found that up to 78.8 percent of randomly sampled medical students suffer from a form of medical student syndrome. For some, this illness anxiety can be debilitating and lead to unnecessary medical bills. Despite widespread knowledge of this syndrome, it continues to propagate and affect hundreds of students each year.

9 Chemo Brain

Many cancer survivors use the term “chemo brain” to describe the thinking and memory problems that occur after chemotherapy treatment. Symptoms can vary from person to person—from difficulty concentrating to memory problems or difficulty multitasking. This is an extremely frustrating phenomenon for those who are undergoing chemotherapy.

For years, many doctors did not believe in this phenomenon. As it became more common, however, physicians began to recognize that this was a real and debilitating experience. Currently, there is no consensus on what is causing chemo brain, but it is believed to be due to more than just chemotherapy treatment. Researchers are trying to find the source of the cognitive difficulties but have been unsuccessful so far.[2]

8 Klippel-Trenaunay Syndrome

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First described in 1900, Klippel-Trenaunay syndrome (KTS) is an extremely rare disease. Affecting blood vessels, bones, and soft tissues, this condition results in three characteristic features: a red birthmark known as a port-wine stain, abnormal bone and soft tissue overgrowth, and venous malformations. The increased size of bone and soft tissue can result in oversized limbs, usually in the lower body and legs. The venous malformations can result in large blood clots.

Famous cases of KTS include Billy Corgan, the lead singer for The Smashing Pumpkins, and Matthias Schlitte, a professional arm wrestler. Notably, Matthias is known for his Popeye-like right forearm that allows him to be an extremely successful arm wrestler. His condition causes the bone in his right forearm to be 33 percent larger than the one in his other forearm. Currently, there is no cure for the condition and physicians have little explanation as to the cause of the disease.[3]

7 Rip Van Winkle Syndrome

The disease sounds like the work of a fairy tale, but Rip Van Winkle syndrome is far from fantasy. Also known as Kleine-Levin syndrome (KLS), this disease has only a few reported cases and its physiological cause has not been confirmed.

At age 13, Stephen Maier became a victim of KLS following an upper respiratory infection. Out of nowhere, his parents were unable to wake him up. When they finally did, he was completely incoherent.

After many tests, all of which were negative, Stephen was left with no answers. Even tests on brain activity showed no abnormalities. Maier would go through sleeping spells of up to 22 hours a day for 10 to 20 consecutive days. As mysteriously as the disease appeared, it gradually faded away in his twenties.[4]

In another case of KLS, a 17-year-old female from Pennsylvania experienced a sleeping episode that lasted 64 days—from Thanksgiving to January. She was reported to have slept 22–24 hours a day. When she did awaken to eat and use the bathroom, she was in a sleepwalking state.

In addition to this sleepiness, sufferers can experience increased appetite, hallucinations, anhedonia, childlike behavior, and hypersexuality. Between these episodes, however, the patients are completely asymptomatic.

Although it may seem appealing to some to get so much sleep, patients end up missing out on large parts of their lives. A few theories about the origin of this disease range from a virus to autoimmunity, but its cause is still largely unknown.

6 Cannabinoid Hyperemesis Syndrome

First described in 2004 by J.H. Allen and colleagues, this odd disorder presents with intractable nausea, vomiting, and GI distress. With further study, the researchers found that all these patients shared a common background of long-term cannabis use.

Although little is known about the cause of this phenomenon, two theories have been put forth. The first holds that the toxic buildup of cannabinoids may be the cause. The second has to do with the functionality of cannabinoid receptors in the brain. During these episodes, some patients have reported temporary symptom relief from a hot shower or bath or psychiatric medications. The only known cure is stopping the use of cannabis. Improvement can be seen within one to three months.

These vomiting episodes tend to last for one to two days. What is extremely odd about this disorder is that marijuana is known for its anti-vomiting effect. This paradox is especially problematic for people who use marijuana to treat nausea and vomiting and then end up feeling more nauseated. It is unclear as to why some chronic users develop this disorder while others do not.[5]

Cannabinoid hyperemesis syndrome is extremely complex, and researchers are still searching for explanations. As the use of marijuana increases, it is an area that will require much more research.

5 Abscopal Effect

Photo credit: Nedzzzz

Michael Postow and his colleagues put forth a paper describing a patient whose metastatic melanoma tumors began shrinking after the person received the drug ipilimumab and radiotherapy. Published in the New England Journal of Medicine, this report got a lot of attention in the medical community.

The abscopal effect refers to the bizarre phenomenon where metastatic tumors throughout the body shrink in response to localized treatment of a tumor. For many years, there was no explanation for this interesting reaction. In 2004, it was first hypothesized that the immune system may play a role in this systemic shrinking. While researchers are continuing to investigate the cause of what is happening, a firm explanation has yet to be established.[6]

4 The Lazarus Phenomenon

An 11-month-old girl in the intensive care unit at the University of Rochester Medical Center had been pronounced dead after aggressive cardiopulmonary resuscitation (CPR), seven doses of epinephrine, two bags of fluid, and four shocks to her chest. After two minutes of asystole, the official time of death was called out at 1:58 PM.

The girl’s family was devastated and asked for her breathing tube to be removed so that they could have some time with their daughter. Fifteen minutes after she was pronounced dead, the tube was removed. Suddenly, the girl began to breathe spontaneously. Her heart began beating again, her color came back, and her gag reflex reappeared. The physicians had never seen anything like this.[7]

The Lazarus phenomenon is a rare occurrence in which patients experience a delayed return of spontaneous circulation after CPR has been stopped. This bizarre syndrome was initially described in 1982. It was named “Lazarus” after the man who was resurrected by Christ four days after his death.

The explanation for this miraculous ability to come back to life has continued to evade physicians and researchers alike. Some believe that there may be more than one mechanism at work, such as the delayed action of drugs or high potassium.

3 Smoking Aversion From Hepatitis

Thousands of people try various methods to quit smoking every year. While many researchers are learning more about the causes behind nicotine addiction, much less is known about the roots of smoking aversion. However, one interesting trigger has been discovered for immediate smoking aversion—the development of hepatitis A.[8]

There are various presentations when a person is infected with hepatitis A, depending upon its stage. The first phase (aka the viral replication phase) is largely asymptomatic in most patients. Moving into the prodromal or second phase, patients can experience anorexia, nausea, vomiting, muscle aches, fatigue, itching, and an aversion to smoking. The disease then begins to affect the liver and GI system before resolving.

Although aversion to smoking is a documented effect of acute hepatitis A, little is known about its cause. More research is definitely warranted in this area as the discovery of the cause of the aversion may be extremely helpful to millions of smokers throughout the world.

2 Meat Allergy From Ticks

Photo credit: USA Today

Last year, the researchers at the National Institute of Allergy and Infectious Diseases were stumped by the increasing number of US cases of anaphylaxis to a molecule found in red meat. Alpha gal is a sugar molecule that is naturally found in beef, pork, lamb, and other red meats.

As researchers delved deeper into the histories of patients with this allergy, they found that most were located in the Southeast and certain parts of New York, New Jersey, and New England. Even more interestingly, all the patients had a history of bites from the lone star tick.

This allergy was particularly hard to diagnose because it presented 3–6 hours after ingestion, unlike common anaphylaxis that presents within 5–30 minutes. The symptoms of this odd anaphylaxis ranged from hives to GI distress to itching and swelling. However, there was no throat swelling. Common allergy tests do not routinely scan for antibodies against alpha gal, so these patients are commonly misdiagnosed.

Dr. Thomas Platts-Mills initially discovered the alpha gal connection.[9] Some of his patients with a history of lone star tick bites experienced anaphylaxis from the cancer drug cetuximab, which contains alpha gal. Although the source of the allergy has been discovered, the reason that lone star tick bites are associated with alpha-gal allergies remains a mystery.

1 Cellular Memory

Cellular memory is a controversial hypothesis that the body itself is capable of storing memories rather than only the brain. As there is mostly anecdotal evidence to support this theory, many consider it to be pseudoscientific.

Many have linked phantom pain to cellular memory for past trauma to a joint or limb. Cellular memory has also come into play in certain stories of organ transplant patients who develop the traits of their donors.

Researchers at the University of Hawaii evaluated whether organ transplant recipients experienced personality changes following their transplants and if any of these changes paralleled the history of their donors. In a study of 10 patients, each one showed 2–5 changes after the completion of a heart transplant that paralleled his or her donor’s history. These changes in preference occurred in areas such as food, art, recreation, career, and even sex.[10]

One case involved Claire Sylvia, who received a heart from an 18-year-old male who died in a motorcycle crash. When she awoke from the surgery, she had a strong craving for beer and chicken nuggets, which was out of the ordinary for her. Additionally, she continued to have recurring dreams about someone named Tim L. After searching obituaries, she found that her heart had come from a man named Tim and later discovered that he loved all the foods that she had begun craving.

In a study done by Tufts University, researchers trained a worm and then removed its head and brain, which shrank it to 1/279th of its original size. The worm was then regrown in the lab and still showed signs of its previous training.

The research on cellular memory has a long way to go before this phenomenon is proven to be real. Nevertheless, we still don’t have any explanations for these odd parallels in numerous transplant stories.

Shelby Hoebee is a third-year medical student. While she doesn’t have much free time anymore, she still enjoys writing top 10 lists when inspiration strikes.


For more medical mysteries and anomalies, check out 10 Baffling Medical Mysteries From Around The World and Top 10 Bizarre Medical Anomalies.

fact checked by Jamie Frater