Group 3: Strategies for identifying the cause of adrenal insufficiency: diagnostic algorithms

Pediatric adrenal insufficiency: thirty years experience at a Portuguese hospital

BACKGROUND

Adrenal insufficiency (AI) is a life-threatening condition caused by an impaired secretion of the adrenal glucocorticoid and mineralocorticoid hormones. It comprises a heterogeneous group of primary, secondary and acquired disorders. Presentation differs according to the child's age, but it usually presents with nonspecific and insidious symptoms and signs. The main purpose of this study was to describe and compare patients with primary or secondary AI.

METHODS

Retrospective analysis of all patients with adrenal insufficiency followed at the Pediatric Endocrinology Unit in a tertiary care Portuguese hospital over the last 30 years. Data on family history, age at the first manifestation and at etiological diagnosis, and clinical presentation (symptoms, signs and laboratory evaluation) was gathered for all patients.

RESULTS

Twenty-eight patients with AI were included; 67.9% were male, with a median (25th-75th percentile, P25-P75) age of 1 (0.5-36) month at the first presentation. The principal diagnostic categories were panhypopituitarism (42.9%) and congenital adrenal hyperplasia (25%). The most frequent manifestations (75%) were vomiting and weight loss. They were followed for a median (P25-P75) period of 3.5 (0.6-15.5) years. In respect to neurodevelopmental delay and learning difficulties, they were more common in the secondary AI group.

CONCLUSIONS

Despite medical advances, the diagnosis and management of AI remains a challenge, particularly in the pediatric population, and clinicians must have a high index of suspicion. An early identification of AI can prevent a potential lethal outcome, which may result from severe cardiovascular and hemodynamic instability.

Anti-ZnT8 autoantibodies: A new marker to be screened in patients with anti-adrenal antibodies

Patients with autoimmune Addison's disease (AAD) can develop other autoimmune diseases. They often display autoantibodies other than anti-adrenal cortex autoantibodies (ACA) which could be of interest in predicting the development of other diseases such as type 1 diabetes (T1D). Among the well-established autoantibodies associated with T1D, anti-ZnT8 autoantibodies (ZnT8A) could be found in absence of anti-GADA and anti-IA2A. Thus, the aim of our study was to evaluate the prevalence of ZnT8A in a cohort of AAD patients. The presence of ZnT8A was studied in 36 patients (19 children and 17 adults) displaying ACA. ZnT8A were detected in both children and adults with an overall prevalence of 19%. The results also indicated that ZnT8A were associated with coexisting T1D in more than 70% of this population regardless of age. Even if the titer of ZnT8A for the one third of patients without T1D was low, they have to be followed due to the potential risk of developing T1D. ZnT8A in those cases could also be a marker of autoimmunity associated to the adrenal gland destruction in AAD. As ZnT8A screening has been included in the diagnostic investigation of T1D, it should also be incorporated in the autoantibodies screening panel of the AAD population.

Central adrenal insufficiency in children and adolescents

Central adrenal insufficiency (CAI) is a life-threatening condition caused by either pituitary disease (secondary adrenal insufficiency) or impaired hypothalamic function with inadequate CRH production (tertiary adrenal insufficiency). ACTH deficiency may be isolated or, more frequently, occur in conjunction with other pituitary hormone deficiencies and midline defects. Genetic mutations of the TBX19 causing isolated CAI are rare but a number of genes encoding transcription factors involved in hypothalamic-pituitary gland development, as well as other genes including POMC and PC1, are associated with ACTH deficiency. CAI is frequently identified in congenital, malformative, genetic, and epigenetic syndromes as well as in several acquired conditions of different etiologies. The signs and symptoms vary considerably and depend on the age of onset and the number and severity of associated pituitary defects. They may include hypoglycemia, lethargy, apnea, poor feeding, prolonged cholestatic jaundice, jitteriness, seizures, and sepsis in the neonate, or nonspecific signs such as fatigue, hypotension, vomiting and hyponatremia without hyperkalemia in children. The diagnosis of CAI relies on the measurement of morning cortisol concentrations along with dynamic test for cortisol release with different stimulating agents. Early recognition of CAI and its correct management are mandatory in order to avoid both morbidity and mortality in affected neonates, children and adolescents.