Cushing’s Disease/Syndrome Nursing Review

Cushing’s occurs due to elevated cortisol secretion within the body.

To remember this, keep in mind that Cushing’s begins with C (for cortisol) and includes “HI” to denote high levels.

Don’t forget to watch the lecture on Cushing’s Disease/Syndrome and to take the free Cushing’s quiz after reviewing this material.

So, what exactly is cortisol? It’s produced by the adrenal glands (specifically the cortex), which are small but essential glands located atop the kidneys. Cortisol is a stress hormone that assists our body in managing stressful situations.

What role does the stress hormone cortisol play in our bodies?

• Facilitates the processing of fats and proteins
• Raises blood glucose levels
• Stimulates hunger
  • (provides extra energy to manage stress and aid tissue repair)
• Affects mood (enhances focus and awareness), but high levels can lead to depression and anxiety
• Regulates blood pressure (ensures adequate cardiac output)
• Influences the inflammation process (acts as an anti-inflammatory), although excessive amounts can compromise the immune system and lead to infections

Cortisol can be beneficial when needed, but it should be present in small amounts and for limited durations.

How is cortisol secreted?

When stress occurs or cortisol levels are low, the hypothalamus releases corticotropin-releasing hormone (CRH). This hormone then acts on the anterior part of the pituitary gland, prompting it to release adrenocorticotropic hormone (ACTH). In turn, ACTH stimulates the adrenal cortex to produce cortisol. Once cortisol is no longer needed, this feedback system slows down, reducing the release of CRH and ACTH.

However, if there is an issue that triggers excessive cortisol production, such as a tumor on the pituitary or adrenal glands, or prolonged use of corticosteroids (like dexamethasone, hydrocortisone, and prednisone—many generic names end in “sone”), it can lead to complications.

Cushing’s Disease: excessive cortisol caused by a tumor on the pituitary gland that leads to excessive ACTH release.

Cushing’s Syndrome: excessive cortisol resulting from tumors or problems with the adrenal glands or from long-term use of corticosteroids.

Signs and Symptoms of Cushing’s

“STRESSED” because these body are stressed out:

Skin Fragility (Thinning)

• Excess cortisol disrupts protein metabolism, particularly affecting collagen, a structural protein. This leads to a loss of skin tightness and resilience. Additionally, fat metabolism is altered, resulting in uneven subcutaneous fat distribution, making the skin more delicate. Wounds may take longer to heal due to a suppressed immune system.

Truncal Obesity

• Elevated cortisol levels influence the body’s fat processing and storage, as well as appetite and blood glucose regulation. This can result in weight gain, with fat accumulating in central areas such as the abdomen, face, and upper back, leading to the appearance of a buffalo hump and moon face. In contrast, the extremities may appear thin due to altered protein metabolism, which causes muscle wasting.

Reproductive issues (such as amenorrhea, irregular cycles, infertility, and erectile dysfunction) affect how glands release hormones like estrogen, testosterone, progesterone, luteinizing hormone, and follicle-stimulating hormone.

Elevated blood pressure

• Cortisol plays multiple roles in regulating blood pressure. In excessive amounts, it mimics a hormone called aldosterone, which causes the kidneys to retain sodium (leading to hypernatremia) and water while excreting potassium (causing hypokalemia). This process ultimately increases blood volume and blood pressure.

Striae on abdomen, back, and thighs

• This is a result of cortisol’s impact on collagen production, which reduces skin elasticity, combined with rapid skin stretching due to fat accumulation.

Sugar high: polyuria, polydipsia, and infections

• Cortisol raises blood glucose levels through several mechanisms. One method is enhanced gluconeogenesis, a fascinating liver process where non-glucose substances are converted into glucose for energy. Additionally, elevated cortisol makes cells resistant to insulin, preventing them from effectively using the glucose in the bloodstream, which leads to hyperglycemia.

Excessive body hair

• This includes coarse, dark hair growing on the center of the body, such as the face, back, and chest, along with the outer extremities, due to increased secretion of androgens.

Decreased potassium and calcium levels

• Enhanced aldosterone function causes the kidneys to waste potassium, resulting in hypokalemia. High cortisol levels also impair calcium reabsorption, leading to loss through urine, along with a reduced ability to activate vitamin D, which is essential for calcium absorption and overall bone health.

Nursing’s Role with Cushing’s

Labs

• Increased Glucose and Sodium
• Decreased Potassium and Calcium
  • Management: Low sodium diet; foods rich in calcium, vitamin D, and potassium.
• CBC: Increased white blood cells indicating infection, with symptoms such as fever, cough, fatigue, and slow wound healing.
• Elevated Cortisol Levels: Cortisol levels naturally vary throughout the day, being highest in the morning and lowest at midnight. In Cushing’s disease, cortisol levels are elevated and do not fluctuate.
• ACTH (Adrenocorticotropic Hormone) Blood Test: Results vary depending on the cause of high cortisol levels.
• Elevated ACTH: Indicative of Cushing’s disease (pituitary gland cause).
• Decreased ACTH: Indicative of Cushing’s syndrome (adrenal glands or chronic corticosteroid usage).

Medications

• Steroidogenesis Inhibitors: These inhibit the formation of steroid hormones by affecting enzymes involved in cortisol production. Examples include Ketoconazole and Metyrapone.
• ACTH Inhibitors: These lower ACTH secretion. An example is Pasireotide.
• Glucocorticoid Receptor Antagonists: Mifepristone blocks the action of cortisol.

Surgery/Treatments

• Radiation Treatment: Used to shrink tumors, especially pituitary tumors. Chemotherapy is less commonly used for this purpose.
• Remove Pituitary Tumors: This can decrease ACTH levels or involve the removal of the pituitary gland.
• Remove Adrenal Gland: If the entire gland is removed, lifelong glucocorticoid (cortisol) replacement is necessary. If only part of the gland is removed, temporary glucocorticoid therapy may be needed until adrenal function returns to normal. It is important to taper off medication gradually to avoid adrenal insufficiency, which can lead to Addison’s disease.

_References:

_{Centers for Disease Control and Prevention. (2019, June 14). Cushing’s syndrome. https://www.cdc.gov/diabetes/library/features/cushings-syndrome.html}

_{MedlinePlus. (2022, March 15). Cushing’s syndrome. U.S. National Library of Medicine. https://medlineplus.gov/cushingssyndrome.html}

_{Nieman, L. K., & Biller, B. M. (2019). Cushing’s syndrome: Diagnosis and treatment. Journal of Clinical Endocrinology & Metabolism, 104(12), 5794-5802. https://doi.org/10.1210/jc.2019-00963}

_{U.S. National Library of Medicine. (2022). Cushing’s syndrome. PubMed Health. https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001392/}