Is it Addison’s disease or Cushing syndrome?

Roger Monroe, age 53, complains of back pain. His wife states he has been irritable and has gained weight recently. To treat his emphysema, he has been on long-term, high-dose
corticosteroid therapy. His vital signs are blood pressure (BP) 160/90 mm Hg, heart rate (HR) 92 beats/minute (bpm), respiratory rate (RR) 22 breaths/minute, and temperature 36.8° C (98.4° F). Purple striae appear on his abdomen. His complete blood count (CBC) is normal except for an elevated white blood cell count. Blood chemistry tests show a potassium chloride value of 3.2 mEq/L, a sodium value of 150 mEq/L, and a blood glucose value of 180 mg/dL.


Regina Larson, age 57, has been complaining of fatigue, weight loss, anorexia, and increased skin pigmentation. She has a history of breast cancer and had bilateral pneumonia 1 month ago. Her vital signs are BP 100/60 mm Hg, HR 94 bpm, RR 20 breaths/minute, and temperature 36.8° C (98.4° F). Her CBC shows a hemoglobin of 10.1 g/dL and hematocrit of 30.3%. Blood chemistry results are normal except for a potassium value of 5.5 mEq/L; a sodium value of 130 mEq/L; and a blood glucose value of 65 mg/dL.


Roger Monroe and Regina Larson both have endocrine disorders. One has Addison’s disease, the other, Cushing syndrome. Both are complex disorders that involve the adrenal glands and are marked by abnormal cortisol levels. Based on the above synopses, which patient do you think has which condition?

Addison’s disease

Addison’s disease is marked by deficiencies of aldosterone and cortisol, hormones produced in the adrenal glands. Aldosterone deficiency impairs water and sodium retention, which may lead to dehydration and hypovolemic shock. Cortisol deficiency impairs carbohydrate and protein metabolism, which reduces blood glucose values and causes generalized weakness. In response to cortisol deficiency, the pituitary gland produces more corticotropin, which increases the melanin level; as a result, skin pigmentation darkens (especially noticeable in the palmar creases, nail beds, and mucous membranes). If cortisol deficiency isn’t treated adequately, a life-threatening adrenal crisis (addisonian crisis) may arise. (See Adrenal and pituitary glands by clicking the PDF icon above.)

Addison’s disease most often stems from an autoimmune response related to infection or cancer. Other causes include adrenal-gland inhibition caused by prolonged use of steroids (such as prednisone), adrenal-gland infarction, sarcoidosis, amyloidosis, congenital adrenal hypoplasia or hyper­plasia, human immunodeficiency virus, Wilson’s disease, and certain medications.

Evaluation

Signs and symptoms of Addison’s disease may be nonspecific, making diagnosis difficult. They include:


  • weakness
  • weight loss
  • anorexia
  • vomiting and diarrhea
  • fatigue
  • depression
  • skin hyperpigmentation.

Diagnosis includes the adrenocorticotropic hormone (ACTH) stimulation test, in which blood cortisol levels are measured before and after synthetic ACTH administration. The cortisol level should rise in response to ACTH injection; failure to rise suggests adrenal malfunction. Other abnormal laboratory findings include anemia, hypoglycemia, elevated blood urea nitrogen, hyperkalemia, hyponatremia, hypochloremia, and a low urinary free cortisol level. An electrocardiogram may show peaked T waves. Magnetic resonance imaging (MRI) and computed tomography (CT) scans may reveal adrenal or pituitary calcifications.

Treatment

Addison’s disease is treated with lifelong hormone replacement therapy. Hydrocortisone, prednisone, or dexamethasone is prescribed P.O. in divided doses to raise the blood cortisol level. In addition, a mineralocorticoid
typically is given for aldoster­one replacement—usually fludrocortisone acetate 0.1 mg P.O. taken daily in the morning. Be aware that these drugs can cause serious adverse effects, such as elevated blood glucose, GI irritation, bone-density loss, immunosuppression, and edema.

Nursing care

Take the patient’s vital signs every 4 hours; for addisonian crisis, take them every 15 minutes until the patient has stabilized. Administer a glucocorticoid and mineralocorticoid, as prescribed. Know that glucocorticoid administration should be increased during times of stress. Monitor fluid and electrolyte imbalance and weight the patient daily. During an addisonian crisis, administer I.V. saline solution, if prescribed, to increase sodium levels. Be sure to teach the patient about disease management. (See Patient teaching for Addison’s disease by clicking on the PDF icon above.)

Cushing syndrome

Cushing syndrome occurs when body tissues are exposed to excessive cortisol levels for prolonged periods. Cortisol excess can lead to high blood pressure, bone loss, and diabetes mellitus, along with characteristic changes in physical appearance. (See ADD it all up and CUT to the chase by clicking on the PDF icon above.)

Cushing syndrome can result from long-term use of high-dose glucocorticoid therapy to treat rheumatoid arthritis, asthma, or certain other diseases. Other causes include excessive cortisol production by the body; adrenal cortex tumors; benign pituitary adenomas that secrete excessive ACTH; and tumors arising outside the pituitary gland (such as in the lung, pancreatic islet cells, or thyroid). Pituitary-dependent Cushing syndrome most often stems from a pituitary tumor that increases ACTH production.

Evaluation

Signs and symptoms of Cushing syndrome include:

  • truncal obesity with thin extremities
  • “buffalo hump”
  • edema of the lower extremities (from sodium and fluid retention)
  • osteoporosis
  • muscle weakness or wasting
  • backache
  • moon facies
  • fatigue
  • irritability or euphoria
  • weakness
  • poor wound healing
  • acne
  • thin, weakened skin
  • skin ulcers
  • hirsutism
  • purpura
  • purple striae on the abdomen and buttocks
  • anorexia
  • amenorrhea or other menstrual irregularities
  • hyperglycemia
  • hypokalemia
  • gynecomastia in males.

Diagnostic tests typically include a 24-hour urine test for free cortisol (50 to 100 mcg/day indicates Cushing syndrome), high-dose dexamethasone suppression test, plasma cortisol and plasma ACTH measurement, MRI and CT scans to detect tumors, and blood chemistry, CBC, and coagulation tests. Hypertension and cardiac hypertrophy are common findings.

Treatment

Treatment depends on the underlying cause. If Cushing syndrome results from corticosteroid therapy, the drug should be discontinued or its dosage decreased.

For patients with pituitary tumors, a transsphenoidal selective adenomectomy is recommended because it usually leaves pituitary function intact; afterward, the patient may need to take glucocorticoid replacement for 4 to 12 months. Bilateral adrenalectomy can achieve a cure, but necessitates lifelong glucocorticoid replacement. If adrenalectomy fails or the patient is a poor surgical risk, radiation is recommended.

Choice of medication varies with the primary cause of Cushing syndrome. Pituitary-dependent Cushing syndrome calls for drugs that inhibit cortisol production, such as ketocon­a­zole, mitotane, metyrapone, and aminoglutethimide. Ketoconazole usually is the drug of choice; the recommended dosage is 200 mg/day P.O. in divided doses. Adverse effects include headache, nausea, vomiting, and hepatic dysfunction.

The recommended mitotane dosage is 2 to 6 g/day P.O. in three or four divided doses. Common adverse effects are GI disturbances and central nervous system changes, such as lethargy, vertigo, somnolence, dizziness, and depression. Metyrapone is started at 250 mg P.O. three times daily (dosage may be increased up to 6 g/day); common adverse effects include hypertension, hirsutism, nausea, vomiting, and edema. Aminoglutethi­mide 250 mg P.O. is given three times daily; adverse effects include pruritic rash, nausea, somnolence, dizziness, and blurred vision.

Usually, drug dosages must be increased as cortisol levels decrease. Urinary free cortisol levels are measured to gauge the patient’s response to medication.

Nursing care

Monitor the patient’s vital signs and stay alert for hypertension and signs of edema. Use meticulous skin care to maintain skin integrity. Monitor fluid intake and output, and measure weight daily. Minimize stress, and ensure that the patient gets adequate rest. Also, protect the patient from infection sources and take measures to prevent falls. Provide a low-calorie, low-sodium diet high in protein, calcium, potassium, and vitamin D. To help the patient maintain muscle tone, provide range-of-motion exercises. (For teaching points, see Patient teaching for Cushing syndrome by clicking the PDF icon above.)

Matching the patient to the diagnosis

Based on what you’ve learned about Addison’s disease and Cushing syndrome, which diagnosis do you think applies to Mrs. Larson and which to Mr. Monroe?

If you guessed Mrs. Larson has Addison’s disease, you’re right. Hints include her history of breast cancer and pneumonia (both of which may disrupt adrenal function or may require treatment that disrupts it), along with her fatigue, weight loss, anorexia, skin hyperpigmentation, anemia, hyponatremia, and hypoglycemia. Appropriate treatment is long-term hormone replacement therapy. An expected outcome is that she’ll maintain therapeutic blood cortisol levels.

Mr. Monroe has Cushing syndrome. Hints include his long-term steroid use, backache, recent weight gain and irritability, and purple striae on his abdomen. Appropriate treatment is steroid withdrawal or dosage reduction. An expected outcome is that Mr. Monroe will maintain steady blood cortisol levels to maintain homeostasis and prevent complications.

Selected references

Gilbert R, Lim EM. The diagnosis of Cushing’s syndrome: an Endocrine Society Clinical Practice Guideline. Clin Biochem Rev. 2008 Nov;29(3):103-6.

Gross BA, Mindea SA, Pick AJ, Chandler JP, Batjer HH. Medical management of Cushing disease. Neurosurg Focus. 2007;23(3):E10.

Lewis SL, Dirkse SR, Heitkemper MM, Bucher L, Camera I. Medical-Surgical Nursing Assessment and Management of Clinical Problems. 8th ed. St. Louis, MO: Mosby; 2010.

National Endocrine and Metabolic Diseases Information Service; National Institute of Diabetes and Digestive and Kidney Diseases. Adrenal insufficiency and Addison’s disease. May 2009. www.endocrine.niddk.nih.gov/pubs/addison/addison.htm. Accessed November 19, 2011.

National Endocrine and Metabolic Diseases Information Service; National Institute of Diabetes and Digestive and Kidney Diseases. Cushing’s syndrome. July 2008. www.endocrine.niddk.nih.gov/pubs/cushings/cushings.htm. Accessed November 19, 2011.

Neighbors M, Tannehill-Jones R. Human Diseases. 3rd ed. Florence, KY: Delmar Cengage Learning; 2009.

Deborah Hunt is an assistant professor of nursing at The College of New Rochelle in New Rochelle, New York.

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