Monitoring Investigations for CAH on Fludrocortisone and Hydrocortisone
Patients with congenital adrenal hyperplasia on fludrocortisone and hydrocortisone should be reviewed at least annually with assessment of health and well-being, measurement of weight, blood pressure, and serum electrolytes. 1
Core Monitoring Parameters
Clinical Assessment (At Each Visit)
- Weight and growth velocity in children, as hydrocortisone dose adversely affects height velocity and final height 2, 3
- Blood pressure in supine and standing positions to evaluate mineralocorticoid adequacy 1
- Assessment for salt cravings or lightheadedness, which indicate under-replacement of mineralocorticoid 1
- Peripheral edema, which may indicate mineralocorticoid over-replacement 1
- Overall sense of well-being and energy levels to assess glucocorticoid adequacy 1
Laboratory Investigations
Essential Tests (Annual Minimum)
- Serum electrolytes (sodium and potassium) to monitor mineralocorticoid replacement adequacy 1
- Morning 17-hydroxyprogesterone (17-OHP) to assess disease control, though elevated levels may be acceptable if growth and clinical parameters are normal 4, 2
- Plasma renin activity or direct renin concentration to guide fludrocortisone dosing 1
Additional Monitoring in Children
- Height velocity standard deviation score at each visit, as this is adversely affected by hydrocortisone dose 2
- Bone age assessment every 1-2 years to monitor for accelerated bone maturation 4, 5
- Androstenedione and testosterone levels to assess androgen control 2, 6
- ACTH levels periodically, as higher ACTH correlates with better growth outcomes and may indicate under-treatment 2
Frequency of Monitoring
- Children: Every 3-6 months during active growth, with more frequent monitoring during puberty when hydrocortisone requirements increase 2
- Adults: At least annually, with assessment of weight, blood pressure, and serum electrolytes 1
Screening for Complications
Glucocorticoid-Related Complications
- Bone mineral density every 3-5 years to assess for glucocorticoid-induced osteoporosis 1
- BMI monitoring at each visit, as overweight remains a clinical challenge in CAH 3
Autoimmune Screening
- Occasional monitoring for development of new autoimmune disorders, particularly hypothyroidism with TSH and thyroid peroxidase antibodies 1
Important Caveats
Do not rely solely on 17-OHP levels to guide therapy. Higher 17-OHP levels may be acceptable if growth velocity, bone maturation, and clinical parameters remain normal, as excessive glucocorticoid dosing to normalize 17-OHP impairs final height 2, 3
Avoid using prednisolone in growing children, as it is associated with shorter final height and higher BMI compared to hydrocortisone alone, even at equivalent total glucocorticoid doses 3
The lowest effective hydrocortisone dose should be used, particularly during puberty, to optimize pubertal growth spurt and final height 2
Urinary steroid profiling by LC-MS/MS represents a useful non-invasive alternative to frequent plasma measurements, particularly in children, and can discriminate between controlled and uncontrolled patients 6