Unexplained weight gain is an unwelcome development for almost anyone; indeed, apart from body builders and certain other types of athletes, few people actually want to gain weight. Yet, to medical professionals, true unexplained weight gain is not the same thing as weight gained because a person is unexpectedly in a calorie surplus. As much as that might surprise us, it is still explainable due to dietary choices (often among other factors). A rare but accurate example of this kind of weight gain can be seen with the condition known as Cushing’s syndrome.
Cushing’s syndrome, like any other syndrome, is a set of signs and symptoms that are known to cluster together. In this case, the signs and symptoms of Cushing’s syndrome are related to the overproduction of cortisol, a type of steroid hormone produced by the adrenal gland. Cortisol, also sometimes known as the “stress hormone,” is part of the glucocorticoid class of hormones and helps the body respond to stress, reduce inflammation, regulate blood sugar and metabolism, and maintain blood pressure levels. As valuable as cortisol is, too much in the body can cause a variety of health problems.
There are two types of Cushing’s syndrome (also sometimes known as Cushing syndrome) that are differentiated by the basic cause: endogenous and exogenous. Endogenous Cushing’s syndrome means that the prolonged increase in the hormone cortisol came from some reason inside the body; this type is very rare, affecting only about 70 people out of a million each year. Exogenous Cushing’s syndrome, by contrast, means that the increase in cortisol came from an external source. While it is unclear quite how prevalent exogenous Cushing’s syndrome is, it is by far the most common type.
The symptoms that define and identify Cushing’s syndrome are the same regardless of whether it is endogenous or exogenous. Most patients develop at least a few of the associated symptoms, and they do tend to get worse over time. Generally speaking, the type and severity of symptoms depend on the amount of excess cortisol in the body and the duration of this excess. Below are the most common symptoms:
The most common cause of Cushing’s syndrome is the long-term use of high-dose glucocorticoid medications. These oral medications (corticosteroids like prednisone) are used to treat inflammatory conditions like asthma and rheumatoid arthritis. It is also possible for Cushing’s to develop as a result of using injectable corticosteroids; injections like these are often used for joint pain and back pain. In both cases, the medication causes a higher than normal amount of cortisol to be present in the body.
If the cause of Cushing’s syndrome can’t be explained by glucocorticoids, then the next most likely cause is a tumor in the pituitary gland. The pituitary gland is located at the base of the brain and produces adrenocorticotropic hormone (ACTH), a hormone that signals the adrenal glands to make cortisol. When a tumor is present, the pituitary gland makes an excess amount of ACTH; that, in turn, causes the adrenal glands to make too much cortisol. The National Institute of Diabetes and Digestive and Kidney Diseases estimates that 8 of 10 non-medication-related cases are due to a pituitary tumor.
Another similar type of tumor occurs in the adrenal glands; tumors located in the adrenal glands tend to also cause an increase in cortisol production. There are also some tumors that can lead to Cushing’s in an indirect way. These are known as ectopic ACTH-producing tumors, and they involve the tumor causing an organ to produce ACTH that would not normally produce ACTH. The most common example of this is tumors in the lungs, but it can also happen in the thymus, pancreas, and thyroid. Like in the pituitary gland, these tumors cause an increase in the production of ACTH that subsequently causes an increase in the production of cortisol. Ectopic ACTH-producing tumors can sometimes be cancerous.
Cushing’s syndrome is primarily a disorder of the endocrine system, the network of glands that acts as the body’s messenger system. Therefore to diagnose Cushing’s, a patient experiencing some of the symptoms listed above will usually require tests from an endocrinologist. Determining the current cortisol levels is naturally one of the first steps, and this can be done via urine tests and blood tests. In some cases the doctor will utilize a low-dose dexamethasone suppression test; if you have Cushing’s syndrome, the low dose of dexamethasone will be unable to suppress cortisol production as it would in an otherwise healthy person.
Once a diagnosis has been confirmed, further blood tests are needed to determine the precise cause. Magnetic resonance imaging (MRI) may be used to visualize the pituitary gland, adrenal glands, lungs, and abdomen. If a tumor in the pituitary gland is suspected, the doctor may next use a corticotropin-releasing hormone test; if a tumor is present, the corticotropin-releasing hormone (CRH) will cause an increase in ACTH and cortisol levels. Low levels of ACTH in general may indicate the presence of tumors in the adrenal glands. A further clarifying test is the high-dose dexamethasone suppression test; this helps the doctor determine if a tumor elsewhere may be present by examining the effect of dexamethasone on the suppression of cortisol.
Depending on the underlying cause determined by a doctor, the treatment can vary greatly. Many cases of Cushing’s syndrome turn out to be exogenous and specifically due to taking high doses of glucocorticoids like prednisone that were prescribed for another condition (like rheumatoid arthritis). In such cases, simply discontinuing the medication will usually resolve the symptoms.
If a tumor is detected in the pituitary gland (typically a pituitary adenoma), surgery is the standard procedure. If surgery isn’t able to restore normal cortisol production, the doctor may look to medication; examples include cabergoline and mifepristone. As with other types of tumors, radiation therapy may be used in conjunction with surgery. In rare cases, surgical removal of the adrenal glands may be required; this method then requires lifelong daily hormone replacement therapy.
Cushing’s syndrome may involve some unexplained weight gain, but for most people the explanation is much more simple. But even if lifestyle choices were ultimately the cause of your weight gain, the solution usually requires a different approach. At True You Weight Loss, we provide alternative weight loss solutions that can help you lose weight and keep it off permanently. If you’d like to learn more about our services, please contact us today to request a consultation.