Cortisol is a hormone secreted by the adrenal glands. It plays a critical role in many bodily functions including stress responses, growth and metabolism. Hormonal control regulates the release of cortisol and produces rises falls in blood levels throughout the day. Diseases which affect the adrenal glands or produce excess hormones can lead to abnormal cortisol levels in pediatric patients.
Significance
Cortisol affects multiple body systems and functions including bone growth, immune function, nervous system function, metabolism, and cardiovascular development and function. It also serves as a key mediator in the stress response. Alterations leading to high or low levels of cortisol can have profound effects that can lead to additional complications in pediatric patients including disruption of growth and development.
Testing
Common methods for determination of abnormal cortisol levels include blood and urine testing. Under normal conditions, cortisol levels rise and fall on a 24-hour cycle. Therefore, blood tests may miss peak levels depending on the time of testing. Urine collection over 24 hours provides a more accurate determination of cortisol levels. Urine tests also prevent unnecessary blood draws from pediatric patients. Additional stimulation tests may be necessary to identify the cause of low cortisol levels.
Signs and Symptoms
Recognition and diagnosis of abnormal cortisol levels in pediatric patients remains complicated. In addition to signs and symptoms that may be present in adult patients, alterations in growth and development can occur. The severity of these alterations may be affected by the age of the patient. High levels of cortisol can cause abdominal obesity, a rounded face, fat pads in the neck and thinning of the extremities. In children, excess cortisol often results in obesity and stunted growth. Low levels of cortisol produce more vague symptoms. Low cortisol levels primarily produce metabolic effects including hypoglycemia and nausea and vomiting. Additional symptoms include fatigue and weakness. Severe cases can cause hypotension and electrolyte abnormalities.
High Cortisol Levels
High cortisol levels lead to Cushing's syndrome. Cushing's syndrome can be caused by excess cortisol production by an adrenal tumor or by a hormone-secreting tumor that stimulates cortisol release. Cushing's syndrome is very rare in the pediatric population, representing about 10 percent of the 10 to 15 million new cases diagnosed annually. Adrenal tumors, which secrete cortisol, represent the most common cause of Cushing's syndrome in pre-pubertal children. Hormone secreting tumors in the brain contribute to the greatest number of cases of excess cortisol in older children.
Low Cortisol Levels
Adrenal insufficiency causes low cortisol levels and can occur at any age. Low cortisol levels can result from a failure of the adrenal gland to develop properly, genetic abnormalities, damage to the adrenal glands by drugs, toxins or autoimmune disease and a lack of stimulating hormones from the pituitary gland. Low cortisol levels may also be transiently present in patients who have discontinued glucocorticoid treatment.
