Cushing’s Disease: Does it Cause Pituitary Tumors?

Cushing’s disease is a medical condition which causes the body to procedure excess amount of cortisol hormone. The cortisol hormone is normally secreted in the body in the morning, while exercising or during periods of stress.

The main function of the cortisol hormone is to:

  • Suppress the immune system
  • Metabolize carbohydrates and fats
  • Increase blood sugar levels

The excessive production of cortisol can be caused due to various factors, however, it is mostly caused due to pituitary-dependent Cushing’s disease (PDCD), or simply Cushing’s disease, as it is commonly known. This is caused due to a tumor growing in the pituitary gland.

In many cases, this tumor in the pituitary gland tends to be non-cancerous (benign) in nature (called as pituitary adenomas). The pituitary tumor results in the gland to produce abnormally excessive amounts of pituitary Adrenocorticotropic hormone (ACTH) which in turn results in the abnormal increase in the level of cortisol in the body.

Obesity and easy bruising are among the most common complications seen with Cushing’s disease.


What causes Pituitary-Dependent Cushing’s Disease (PCDC)?

The pituitary tumor is the main cause of PCDC rather than the disease being the cause of the tumor. The tumor causes the pituitary gland to create excessive amount of ACTH (Adrenocorticotropic Hormone). This leads to the adrenal gland releasing increased amount of cortisol into the body. This pituitary tumor surgery recovery may takes a year or more.

What are the signs and symptoms of Pituitary-Dependent Cushing’s Disease (PDCD)?

The symptoms of PCDC mainly develop when the body starts to react to the high levels of cortisol. As the body is unable to metabolize the fats at the required pace this leads to fat accumulation in the body and eventually obesity is seen. The fat is mainly deposited around the torso (middle portion of the body) and is stubborn in nature which makes it hard to lose it.

Other more common signs and symptoms of PDCD are:

  • Thin skin
  • Easy bruising
  • Weakened muscles 

How is the Pituitary-Dependent Cushing’s Disease (PDCD) diagnosed?

The main tests for diagnosing the presence of PDCD are measuring the level of cortisol and ACTH in the body.

As the level of cortisol normally tends to vary during different times of the day the test may be performed at multiple times in the day. The level of cortisol in the body can be easily measured with the help of a blood test or a spit test. In the spit test the cortisol levels are checked at regular intervals (4 times) during the day. These samples are then sent for a detailed analysis to the pathology laboratory.

The doctor might also use imaging tests (such as CT scans or MRI tests) to gain a clear image of the tumor which helps to determine the best-suited treatment method for it.

How is Pituitary-Dependent Cushing’s Disease (PDCD) treated?

The cost for PDCD is mainly aimed at halting the excessive production of ACTH by the pituitary gland. Usually, this is achieved by removing the tumor using surgical methods. In some extreme cases, the surgeon might have to remove the entire pituitary gland if it is excessively affected by the tumor.

These are the other less common treatment methods for PDCD:

  • Bilateral Adrenalectomy (BA) – This involves removing one or both of the adrenal glands
  • Gamma Knife Radiosurgery (GK) – This uses a high-energy and sharp beam of laser to destroy the tumor without damaging the surrounding healthy tissue.
  • Pituitary-Directed Radiation – This is another form of radiation therapy which is aimed directly at the pituitary gland itself.

After the initial treatment is done, the doctor will most likely prescribe certain medication to replace the cortisol which the pituitary glands are not able to produce anymore.

In most of the cases, the body naturally recovers and begins to produce cortisol itself after some time. In some cases the patient is required to take cortisol replacement drugs throughout their life to maintain the right level of cortisol in the body.

Thus it is safe to say that the Cushing’s disease is not caused by the pituitary tumor but rather the tumor in the pituitary gland is the cause for the development of Cushing’s disease in a person.


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