A Triathlete's Head Rushes Revealed a Rare Disorder

By Amanda Gardner

When Megan Kenny was five years old, they began to exhibit a strange and troubling symptom: Every time Megan stood up for more than two minutes, Megan collapsed.

The episodes were particularly bad after Megan had been sitting or lying down for prolonged stretches, such as when Megan woke up in the morning or walked between classes at school.

"Church was always a disaster," Mary Kenny, Megan's mother, recalled. After sitting or kneeling for a time, Megan would stand up with the congregation and invariably fall down.

As Megan got older, other worrisome signs emerged. Megan's eyelids began to droop. Megan continued to wet the bed and got constant bladder infections. And, about once a week, Megan experienced extreme hypoglycemic episodes—a sudden drop in blood sugar levels—that left Megan shaking and unable to function for the rest of the day.

The Kenny's visited numerous healthcare providers and specialists who considered, and ultimately ruled out, a multitude of diagnoses: epilepsy, diabetes, cancer, liver failure, and kidney failure.

One time, after testing Megan for epilepsy, a neurologist observed that Megan appeared to have a severe form of orthostatic hypotension, a not-unusual condition in which a person's blood pressure drops suddenly upon standing or sitting up, causing the sensation known as a head rush.

The neurologist was only half right. Megan did have orthostatic hypotension, but the underlying cause was a far more exotic condition that wouldn't be diagnosed until Megan was an adult. In the meantime, Megan had to cope with having blood pressure that could dive from a relatively normal 110/70 when lying down to 50/30 upon standing.

"I've seen dead people with higher blood pressure," one nurse told Megan.

Primary Causes of a Head Rush

A study published in the journal Canadian Family Physician in 2018 explained what orthostatic hypotension, also known as postural hypotension is, and what causes it. The definition of orthostatic (or postural) hypotension is a drop of at least 20 mm Hg in systolic blood pressure and a drop of at least 10 mm Hg in diastolic blood pressure within three minutes of standing.

Systolic blood pressure is the top number in a blood pressure reading, and diastolic blood pressure is the bottom number. So, in Megan's case, when their blood pressure went from 110 (systolic)/70 (diastolic), to 50/30, this was a significant episode of orthostatic hypotension.

When an individual goes from laying down to standing, it can result in 10-15% of a person's blood pooling in their lower extremities, per the 2018 study. This is what can cause that head rush feeling.

The body's autonomic nervous system typically reacts and adjusts when an individual goes from laying down or sitting to standing. Per MedlinePlus, the autonomic nervous system is responsible for controlling involuntary functions of the body, such as blood pressure and body temperature.

However, StatPearls explains if an individual has a condition that affects their autonomic nervous or is significantly dehydrated, this may cause orthostatic hypotension. Certain medications can also make an individual more at risk for episodes of orthostatic hypotension.

A Family Affair

It was clear from the first minute of her life that Megan wasn't in good health. Megan was a small baby, barely five pounds, in a family that had a history of strapping, nine-pound newborns. Megan immediately required oxygen for respiratory distress. "She was literally blue," Mary remembered.

Later, as an infant, Megan's sucking reflux was so poor that Megan's mother wasn't able to nurse Megan. Orthopedists said Megan's motor coordination was below average and referred Megan for physical therapy.

When Megan was eight years old, Megan's brother, Brendan, was born. As Brendan grew up, Brendan too would develop symptoms similar to Megan's, suggesting the mysterious condition had a genetic component. Megan's parents continued visiting healthcare providers, seeking explanations for what ailed the two siblings.

While some people get the occasional head rush or dizzy spell, Megan and Brendan experienced the sensation almost constantly. "Mostly it was a feeling as if you're going to black out, like walking through life with permanent black spots," said Megan.

Megan learned how to compensate for the strange spells. At school, if Megan had to climb a flight of stairs to get to a class, Megan would sit on the landing to regain their composure or lean over and pretend to tie their shoes. Megan even played softball throughout high school, though Megan needed a teammate to run the bases.

Megan and Brendan lived like this for years. Finally, after Megan had graduated from college and was living independently in San Francisco, a psychiatrist at the University of Connecticut began to unravel the mystery.

After hearing a description of the Kenny children, the psychiatrist said some of their symptoms resembled those of a rare disorder they were researching: dopamine beta-hydroxylase deficiency (DBHD).

As the name suggests, people with DBHD lack dopamine beta-hydroxylase, an enzyme needed to convert the neurotransmitter dopamine into norepinephrine and epinephrine (also known as adrenaline), hormones that are critical to maintaining normal blood pressure. Without this enzyme, the body's autonomic nervous system isn't able to function appropriately, per MedlinePlus.

The psychiatrist suggested the Kenny's fly Brendan, who was still in high school and living at the family home in Connecticut, to see a specialist at Vanderbilt University in Nashville, TN.

"It was like winning the lottery," said Megan.

An “Extraordinarily Rare” Condition

David Robertson, MD, a neurologist at Vanderbilt's Institute for Clinical and Translational Research, is a DBHD expert. In 1986, Dr. Robertson was the first person to identify the disorder, in a 33-year-old female who hadn't opened her eyes for the first five days of her life—a common feature of DBHD.

After performing blood work and numerous other tests on the individual, Dr. Robertson and colleagues recognized that her abnormally low norepinephrine levels were caused by a genetic defect in dopamine beta hydroxylase.

It was thought that no one could survive for long without norepinephrine, but that individual lived to be 62. If people with DBHD are in a situation where they're unable to sit or fall down safely, the resulting loss of blood flow to the brain can be fatal. However, most people with the condition learn how to compensate and can live a relatively long life, according to Dr. Robertson.

Dr. Robertson confirmed the suspicions of the UConn psychiatrist and diagnosed 15-year-old Brendan with DBHD. The diagnosis put Brendan in very exclusive company.

"DBHD is extraordinarily rare," said Dr. Robertson, who is also the principal investigator of the Autonomic Rare Disease Consortium at the National Institutes of Health. It is so rare, in fact, that the 10 patients Dr. Robertson personally has seen represent the lion's share of the documented cases worldwide. Another eight patients have been identified in Europe and Australia, though Dr. Robertson says there could be thousands more still undiagnosed.

A Night and Day Treatment

In the late 1980s, Dr. Robertson began to formulate a drug to treat the norepinephrine deficiency associated with DBHD, but Dr. Robertson soon learned that such a drug was already being marketed in Japan. Droxidopa, also known as L-DOPS, was used in that country for Parkinson's disease, a movement disorder characterized by dopamine deficiency, per the National Institute on Aging.

Dr. Robertson's first patient responded immediately to droxidopa. "The drug allowed us to replace the norepinephrine not only in the blood but even in the nerve cells of the body," Dr. Robertson said.

Brendan, too, responded to droxidopa within days. Two years later, Brendan ran a victory lap of sorts across the Golden Gate Bridge in San Francisco while Megan watched.

Megan had visited Vanderbilt soon after Brendan. Not surprisingly, Dr. Robertson diagnosed Megan with DBHD, too. However, due to a protocol change in the clinical trial, Dr. Robertson was leading, Megan had to wait three years before taking droxidopa too. When Megan finally did, the results were just as dramatic.

"I felt different immediately," Megan said. "This feeling of strength—being able to walk up a hill in San Francisco at the same pace as my friends, or actually [being] able to do it without sitting down—was incredible."

Megan also took a sprint across the Golden Gate Bridge as part of their training for the New Orleans Marathon. Megan finished that race in a little over six hours in the winter of 2005.

In 2010, Megan completed an Olympic-length triathlon: a 1,500-meter swim, 40-kilometer bike ride, and 10K run. "For me, it was like checking this off the list," said Megan. "I was so grateful for my new physicality."

Megan takes 300 milligrams of droxidopa three times a day, and even now, a decade after the diagnosis, Megan feels lightheaded if a dose is missed. Megan no longer runs marathons but climbs San Francisco's steep hills with ease.

"It's such a small thing in the grand scheme of things, being able to walk a block up the hill," Megan said. "People take it for granted. I was like, 'This is incredible.'"

A Quick Review

Most cases of head rushes are not caused by DBHD. However, for Megan and Brendan, this rare condition was the cause of their symptoms. With the appropriate treatment and diagnosis, they have been able to improve their symptoms and quality of life.

If you are experiencing head rushes or lightheadedness, reach out to a primary care provider or specialist. They can help advise you on changes you may need to make to your lifestyle or medication regimen and can also provide a physical exam or referral if needed.