Cushing's syndrome

Cushing's Syndrome

Cushing's syndrome is a complex endocrine disorder characterized by excessive levels of cortisol in the blood. This condition can result from various causes, including endogenous overproduction of cortisol by the adrenal glands or exogenous sources such as glucocorticoid medications.

Etiology

Cushing's syndrome can be classified into two main categories based on its etiology:

Endogenous Cushing's Syndrome

• Pituitary Adenoma: Also known as Cushing's disease, this is the most common cause of endogenous Cushing's syndrome. It involves a benign tumor of the pituitary gland that secretes adrenocorticotropic hormone (ACTH), leading to increased cortisol production by the adrenal glands.
• Adrenal Tumors: These can be either benign or malignant and directly produce cortisol.
• Ectopic ACTH Syndrome: This occurs when ACTH is produced by non-pituitary tumors, such as small cell lung cancer.

Exogenous Cushing's Syndrome

• Glucocorticoid Therapy: Long-term use of glucocorticoid medications for conditions such as asthma or rheumatoid arthritis can lead to Cushing's syndrome.

Pathophysiology

Cortisol is a steroid hormone produced by the adrenal cortex. It plays a crucial role in regulating metabolism, immune response, and stress. In Cushing's syndrome, the excessive cortisol levels disrupt normal physiological functions, leading to a wide range of symptoms.

Clinical Features

The clinical presentation of Cushing's syndrome can vary, but common features include:

• Weight Gain: Particularly in the face (moon face), abdomen, and upper back (buffalo hump).
• Hypertension: Elevated blood pressure is a frequent finding.
• Hyperglycemia: Increased blood sugar levels, which may lead to Diabetes Mellitus.
• Muscle Weakness: Due to protein catabolism.
• Osteoporosis: Increased risk of fractures due to bone resorption.
• Skin Changes: Thinning of the skin, easy bruising, and purple striae.
• Psychiatric Symptoms: Depression, anxiety, and cognitive dysfunction.

Diagnosis

The diagnosis of Cushing's syndrome involves a combination of clinical evaluation and laboratory tests:

• 24-hour Urinary Free Cortisol Test: Measures cortisol excretion in urine.
• Dexamethasone Suppression Test: Assesses the feedback inhibition of cortisol production.
• Salivary Cortisol Test: Measures cortisol levels in saliva, particularly useful for detecting diurnal variation.
• Imaging Studies: CT or MRI scans to identify pituitary or adrenal tumors.

Treatment

The treatment of Cushing's syndrome depends on the underlying cause:

• Surgical Resection: Removal of pituitary adenomas or adrenal tumors.
• Radiation Therapy: Used for pituitary tumors when surgery is not feasible.
• Medications: Drugs such as ketoconazole or metyrapone to inhibit cortisol synthesis.
• Lifestyle Modifications: Diet and exercise to manage weight and blood pressure.

Prognosis

The prognosis of Cushing's syndrome varies based on the cause and treatment success. Early diagnosis and appropriate management can lead to significant improvement in symptoms and quality of life.

See Also

• Adrenal Gland Disorders
• Endocrinology
• Hormonal Imbalance