What caused this teenager’s weight loss, fatigue, and passing out? | Medical Mystery

A previously healthy 17-year-old girl went to the emergency department after she had passed out while trying to walk up the stairs at home.

Fortunately, she wasn’t seriously injured as her mom caught her. The girl said she had been very tired and had unintentionally lost about 20 pounds over the last few months.

In the Emergency Department, her blood pressure was a little bit low at 100/60, with normal being closer to 120/80. On examination, she looked tired but was otherwise stable. Blood and urine samples went to the lab, and she was admitted for further workup.

Unintentional weight loss, fatigue, and syncope (fainting) are often nonspecific symptoms that can be caused by a variety of conditions, including nervous system, blood, and hormone disorders.

Sometimes, the nervous system does not respond appropriately when a person moves from sitting to standing. The sympathetic nervous system should ramp up and increase heart rate and blood pressure to make sure the brain gets the blood and oxygen it needs.

This can go awry in patients who are very dehydrated or have less responsive nervous systems. In such cases, the result can be low blood pressure when standing up (called orthostatic hypotension) and passing out.

This patient did not have any signs of dehydration, and her blood pressure stayed low whether she was sitting, prone, or standing. Sometimes drugs or medications can cause such symptoms, but her urine drug screen was negative, and she did not report taking any medications.

Blood disorders, such as anemia or cancer, are a more concerning cause of these symptoms. Anemia is when there are not enough red blood cells or hemoglobin to carry oxygen throughout the body, which can cause shortness of breath and fatigue.

Cancers can cause an increase in metabolism, also resulting in weight loss and fatigue. Thankfully, her exam and blood tests ruled these diagnoses out.

Another potential culprit might have been type 1 diabetes, in which the immune system mistakenly targets and destroys the pancreas, causing low insulin production. This can lead to high blood sugar, weight loss, and fatigue. However, this patient’s blood sugar level was slightly low in the Emergency Department, rather than elevated.

High thyroid hormones can cause high heart rate, weight loss, and anxiety; while low thyroid hormones can cause fatigue, weight gain, and depression. The patient’s thyroid levels were normal on her blood tests, so this ruled out thyroid disease as a cause.

One more possibility could have been her adrenal glands, which release several hormones that regulate metabolism, as well as blood pressure and “fight or flight” responses.

Decreased adrenal hormones, particularly cortisol, can cause decreased appetite and weight loss, low blood pressure, and low blood sugar — all symptoms that she had. A test of her morning cortisol showed a very low level, and a follow-up test showed that her adrenal glands were not producing any cortisol in response to triggers.

This finding suggested that adrenal insufficiency was the cause of her symptoms, though the root cause was still unclear.

There are many possible causes of adrenal insufficiency. Some children are born with dysfunctional adrenal glands due to genetic conditions. Injuries during birth, infections, or medications can cause decreased blood flow or direct damage to the adrenal glands and subsequently decreased function.

Autoimmune disorders, where the immune system accidentally attacks its own organs instead of infections, can cause adrenal damage. More rarely, brain injuries or tumors can cause decreased adrenal hormone production through various mechanisms.

One final laboratory test found that this patient had antibodies in her blood which were attacking her adrenal glands. This confirmed the diagnosis of adrenal insufficiency, which in this case is called Addison’s disease.

By the time of this diagnosis, she was feeling better and went home with medications to replace the missing hormones. She will likely be on replacement adrenal hormones for the rest of her life to manage symptoms.

Vague symptoms can be common in many different conditions, some more serious than others. Children and adolescents with unintentional weight loss and prolonged unexplained symptoms such as fatigue should see their doctor to be screened for potentially dangerous causes. This may include blood work, imaging, or other tests to help determine the underlying diagnosis.

Rebecca Mirochnik is a third-year pediatric resident and Hayley Goldner is a pediatrician in the adolescent medicine department at Nemours Children’s Hospital, Delaware.