Flash glucose monitoring system was applied to cortisol treatment for a patient with congenital adrenal hyperplasia and 17α-hydroxylase deficiency

Background Congenital adrenal hyperplasia (CAH) with 17α-hydroxylase deficiency is a rare disease; patients often require lifetime cortisol treatment. In this case report, we presented a patient with CAH and 17α-hydroxylase deficiency, who was previously misdiagnosed as having primary aldosteronism. Furthermore, the flash glucose monitoring system (FGMS) was used to ascertain a suitable cortisol therapeutic regimen for this patient. Case presentation A 29-year-old woman presented with sex dysgenesis, hypertension and hypokalaemia. She had been diagnosed with primary aldosteronism at a local hospital. The re-measured aldosterone level in our hospital was below the normal range after antihypertensive medication adjustment, suggesting that the primary aldosteronism was a misdiagnosis. The patient was finally diagnosed as having CAH with 17α-hydroxylase deficiency according to the endocrine profile, adrenocorticotropic hormone stimulation test, and genetic analysis. Then, the patient was recommended cortisol treatment, during which the endocrine profile, blood pressure, plasma potassium level, and blood glucose level were observed to ascertain a suitable dosage. The FGMS was used to monitor blood glucose level, which indicated that the patient’s glucose metabolism was maintained normally under the final treatment dosage. Conclusion The misdiagnosis might have been because of the effects of the antihypertension medications on aldosterone and renin levels. The final dosage of cortisol treatment achieved a normal endocrine profile, while maintaining the homeostasis of blood glucose level, plasma potassium level and blood pressure. FGMS may be an effective method to ascertain a suitable cortisol therapeutic regimen for patients with CAH and 17α-hydroxylase deficiency.