Zoobiquity (20 page)

Military physicians from the U.S. Navy and Marine Corps noted as early as the 1960s that during the intense repetitive calisthenics of basic training, recruits sometimes developed the exhaustion, muscle breakdown, and cola-colored urine seen with rhabdomyolysis.
Extreme athletes like cyclists, runners, weight lifters, and even high school football players occasionally report similar symptoms after grueling workouts. Animal athletes are also vulnerable to rhabdo, racehorses in particular. Extreme athletes—whether animal or human—push themselves to perform, often through pain, which sometimes results in rhabdo. “Mind over myocardium” can trigger quiet but deadly effects in both humans and animals.

But sometimes wildlife veterinarians finger capture myopathy as the killer even in cases in which there has been no prolonged chase, no skeletal muscle breakdown, no rhabdomyolysis.

A form of capture myopathy can appear when an animal is simply
handled, noosed, netted, corralled, crated, penned, or transported. “Running for your life” is terrifying, but at least you have a fighting chance. Being caught, on the other hand, is the step right before the worst-case scenario: “game over.”

As Dan Mulcahy put it, for an animal, “the only time they’re caught is when something’s going to eat them.” Restraint usually means one thing: another animal wants you not to move. Capture and restraint, from an evolutionary perspective, spell a single state of affairs: imminent predation or death. Understandably, brains have evolved an all-systems-go response, a massive, last-ditch catecholamine tsunami.

Examples of animals dying when they’ve been captured or restrained abound. In species as varied as Irish hares, white-tailed deer, cotton-top tamarins, and antelopes, this combination can equal death. Experts on pikas, the rabbitlike “tundra bunnies” of South America, have learned the hard way that holding a captured pika firmly around its middle can scare it to death. A safer approach is to allow it to stand, unrestrained, in your open hands. And the risk exists not just for flighty prey animals. Top carnivores like brown bears, lynxes, wolverines, and gray wolves have died after being trapped.

Loud noises and heat can intensify the hazard of entrapment.
Bighorn sheep in California’s Mojave Desert that were rounded up for a relocation program fared especially poorly when a thundering helicopter hovered nearby.
Pet rabbits have been known to expire in the presence of blaring rock music and even loud arguments between their owners.
Fireworks blasts have reportedly startled and killed pets and livestock from parrots to sheep.

In Copenhagen in the mid-1990s, the Royal Danish Orchestra was performing Wagner’s
Tannhäuser
in a public park. Abutting the park was the Copenhagen Zoo. As the chorus keened and the soloists belted out their highest pitches, a six-year-old okapi anxiously circled her enclosure and tried to escape. After struggling for several stressful minutes, she keeled over and died. The vets diagnosed capture myopathy.

Loud, frightening noises—not only those passing through a soprano’s warbling epiglottis—have recently been shown to be risk factors for adverse cardiac effects in a variety of populations.
One study published in the journal
Occupational and Environmental Medicine
found that people laboring in workplaces so persistently noisy they had to shout to
have a normal conversation had twice the risk of serious cardiac events as people whose workplaces were quieter. And in some inherited cardiac conditions, startling loud noises can trigger a disturbance in the heart rhythm that leads to death.
^c

Interestingly, there’s a breed of dog that seems to have evolved a defense against noise’s jolting effects.
Dalmatians born with long QT syndrome, and therefore susceptible to noise-induced sudden death, fortuitously sometimes also carry a genetic mutation that causes deafness. The auditory disability becomes a cardiac blessing in disguise as their muffled experience of sound may protect their vulnerable hearts from fatal cardiac arrhythmias.

Startling sounds and the feeling of confinement signal danger to animals and humans. Like the okapi trapped at the opera, noise and the perception of entrapment can be enough to ignite a fatal brain-heart reaction. Animal and human sensory systems provide information about the outside world that their brains convert to evasive action. But it’s not just noise or restraint that can create terror.

In some cases, the mere thought of restraint can induce comparable physiology. Like the anxious and scared humans watching the events of 9/11 on TV, other animals, too, can experience an intense brain-heart reaction simply by seeing a threat.

Four captive zebras at a zoo in Vancouver once died from what was diagnosed as capture myopathy. They hadn’t been chased. The stressor was the simple presence of two intimidating Cape buffalo that had been placed in the zebras’ enclosure, an enclosure whose fences and moat would prevent their escape.

A sudden and unexpected appearance of predatory threat can also endanger animals.
Some bird-watchers described observing a flock of cinnamon-bellied shorebirds called red knots calmly wading along the
water of an Australian beach. Suddenly, a raptor swooped down and grabbed one of the unsuspecting waders with its lethal talons. As the raptor flew off, the observers noticed something interesting. Although untouched by the predator, several nearby birds suddenly became unsteady and weak. Some fell over when they tried to walk.

Ornithologists call this kind of stress-induced muscle disease “cramp.” The adrenaline spew would have affected the birds’ heart muscles, too. The red knots, like the zebras, succumbed after merely witnessing a terrifying sight.

Circumstances that are not directly life-threatening can induce potent physiologic responses in humans, too. If, while traveling at ten thousand feet, your airplane hits an air pocket and plunges, your adrenal glands and brain release catecholamines. Your heart rate accelerates and your blood pressure rises. You may feel as though you’re going to die. And, worse, as with a restrained animal facing predation, your inability to escape heightens your body’s physiologic response.

Your brain processes the threat, but your body generates the response. That sickening, activated state you feel is fear. And fear, say veterinarians, is a key factor in capture myopathy. Some say it’s the single
most
important factor. This leads us to an internal but dangerous contributing element to capture myopathy: the captured animal’s activated emotional state.

We’ve seen that animal brains, human and nonhuman, respond and in some cases overrespond to entrapment.
It’s possible that our imaginative human minds take it a step further, triggering heart responses to traps that are not actually physical: an abusive relationship, crushing debt, an impending prison sentence.

Consider disgraced Enron chief Kenneth Lay’s cardiac arrest weeks before being sentenced for an embezzlement conviction. Douglas P. Zipes, an expert in sudden cardiac death (SCD) and the editor in chief of the journal
Heart Rhythm
, told a Florida journalist, “
We know that stress about which you can do nothing—the death of a spouse, the loss of a job, or facing life imprisonment—can be associated with sudden cardiac death. I can’t crawl into [Lay’s] head, but there is no question that the head talks to the heart and can have an impact on heart function.”

Overwhelming fear responses to entrapment and threat may not be all that different whether you’re a zebra facing a glowering Cape buffalo or a white-collar criminal facing life in prison.
Indeed, studies have demonstrated
that abusive, unfair bosses; negative, conflict-ready spouses; and suffocating debt substantially up the risk of heart-related death.

Given the power of fear and restraint to cause harm in humans and animals, it’s surprising there’s not a diagnostic term for these types of deaths. Because capture myopathy in animals and fear-induced cardiac effects in humans are related but complex, it might be helpful to find a way to identify cases in which fear and restraint were at fault. More than a decade ago the Harvard neurologist Martin A. Samuels called for “
a unifying hypothesis … to explain all the forms of sudden death based on the anatomic connection between the nervous system and the heart and lungs.”

The takotsubo moment that started my zoobiquitous journey began with placing the features of stress-induced heart failure in humans side by side with capture myopathy in animals and seeing the many similarities. When doctors notice a pattern of symptoms or physical findings, we create syndromes, which we then name. Veterinarians and physicians might consider adopting a new, common term to describe the role of fear in capture myopathy in animals and sudden cardiac death in humans. I propose the acronym FRADE: fear/restraint–associated death events. FRADE is broad enough to describe emotionally triggered fatalities in both animals and humans but narrow enough to filter out nonemotional causes. It would centralize the clinical anecdotes emerging from both human ERs and wild animal field sites. It could link, say, a takotsubo death in a terrified elderly woman to a capture myopathy death in a trapped okapi. In medicine, as in other fields, commonalities go unnoticed until they’re named. Eventually, the neuroanatomical and neuroendocrine systems underlying fear- and restraint-related deaths will be fully characterized and better understood. But until then, using a common term to classify this particular kind of death will help veterinarians and physicians compare these sudden fatal events in ways that may lead to prevention strategies.

Many physicians are only now acknowledging the link between fear and cardiovascular events. But across cultures and throughout history, this dangerous connection has been noted.
Voodoo curses and overly ominous thoughts, for example, have created deadly outcomes that are hard to explain from a purely physical point of view.

Many surgeons would sooner hang up their scrubs than operate on
patients who are certain they will die on the operating table. “
Surgeons are wary of people who are convinced that they will die,” Herbert Benson, a founder of the Benson-Henry Institute for Mind Body Medicine at Massachusetts General Hospital told the
Washington Post
.
Arthur Barsky, a psychiatrist at Brigham and Women’s Hospital in Boston, concurs that these patients create a “self-fulfilling prophecy.”

It’s called the nocebo (Latin for “I will harm”) effect, the opposite of the placebo (Latin for “I will please”). Unlike the well-known effects of the placebo, a nocebo is a harmless agent that, when perceived by the patient to have malignant qualities, produces
negative
effects. If you’ve ever wondered whether voodoo death is real, the nocebo effect offers a reason why the answer may be yes. When the person delivering the hex is convincing enough—and the victim open-minded enough—the heart-mind connection may initiate that deadly cascade seen in stress-induced cardiac death. Some call this “homicide by heart attack.” Genetics probably plays a role, since voodoo deaths tend to cluster in specific ethnicities and regions.
^d

FRADE may connect to these deaths, too. The link between folklore-laced voodoo deaths and straightforward animal capture myopathy lies in the shared biology of animal and human nervous systems.

Over millennia, animals have developed variations—and some improvements—in the ways they can convert sensations of external danger into safety-seeking behavioral responses. Some release toxins or odors or sting with electricity or poison. Sea anemones retract when prodded and release a squirt of seawater. Flies zoom away from the swatter. But the link between threat and catecholamine release is especially pervasive and ancient. Its origins date back two billion years—before the separation of plants and animals.
Potato leaves and tubers, for example,
respond to stressors like cold, drought, and chemical burns by releasing catecholamines. This seems to increase the plant’s resistance to infection and other threats.

For plants, fleeing is not an option. For vertebrates, however, a responsive heart that can accelerate in a “fleeing escape” or slow profoundly for a “hiding escape” has often meant the difference between life and death. But this elegant and effective system has a fatal flaw. Because underestimating danger even just once in a wild animal’s life can spell death, the warning system may be calibrated toward overreaction.
The evolutionary medicine expert Randolph Nesse explains these overresponses through the analogy of a smoke detector. Although the alarm can sound at the wrong time, many false alarms are better than one missed true one. As the behavioral ecologists Steven Lima and Lawrence Dill wryly note, “
Being killed greatly decreases future fitness.”
^e

Overresponse can be found throughout biological systems. Our immune systems may “overreact” in the course of trying to protect us, causing autoimmune disorders such as rheumatoid arthritis and lupus. Eczema and keloid scar tissue are other examples of the body’s exuberant response to injury. Fevers that are possibly meant to battle microorganisms can get too high and cause seizures and brain damage. Coughing that is meant to clear vital airways can devolve into bronchospasm or cracked ribs. And in psychiatry, anxiety disorders, panic attacks, and phobias can be conceived of as pathologic overreactions to danger that stem from protective instincts.

FRADE describes another overcalibration. Adaptively, a surge of catecholamines allows a zebra to gallop away full throttle or madly wrestle free from a lion. Maladaptively, that torrent of stress hormones may break down the animal’s muscles, destroy its kidneys, or even stop its heart. It’s counterintuitive that your brain and heart can sometimes
work in concert to kill you. But FRADE is a reminder that safety systems must be powerful and can be calibrated to overrespond—especially in dangerous settings with no “do-overs.”

Unless you’re a veterinarian, work in a pet store, or just got elected dog catcher, it’s a safe bet you don’t need to capture an animal very often. And here in the enlightened twenty-first century, we certainly don’t capture and pin down human beings all that much. Or do we?