Adrenal Suppression in Pediatric Patients during Treatment for Acute Lymphoblastic Leukemia

Background: Hypothalamic-pituitary-adrenal (HPA) axis suppression is a form of adrenal insufficiency that can be found following the use of corticosteroids. Individuals with adrenal insufficiency may have non-specific symptoms or even no regular symptoms, however if presented with a physiologic stress such as infection, injury, or surgery, they are at risk of adrenal crisis. Adrenal crisis typically manifests with hypoglycemia, hypotension and critical illness; this condition is associated with significant morbidity and even mortality. Children being treated for leukemia are at increased risk of infection and may require surgical procedures, thus putting them at risk of adrenal crisis in the context of adrenal suppression.

It is known that adrenal suppression exists in the short term after the induction phase of treatment in patients with acute lymphoblastic leukemia (ALL), but the prevalence and duration of suppression is still not fully understood. In addition, adrenal suppression has not been specifically evaluated during the maintenance phase of therapy. During maintenance there may be ongoing adrenal suppression from steroid use in induction, or new suppression from steroid use for maintenance therapy itself. There does not yet exist an accepted protocol to monitor for adrenal insufficiency in ALL. Knowing the prevalence and duration of adrenal suppression in maintenance will enable care teams to better recognize and manage the condition, potentially preventing significant morbidity and mortality.

Methods: All cases of ALL treated at the Children's Hospital of Eastern Ontario from 2000 to 2014 were retrospectively reviewed for adrenal suppression. Patient characteristics, clinical features, laboratory data, treatment protocol utilized, adverse events and outcomes were examined.

Results: 176 patients were diagnosed with new ALL at The Children's Hospital of Eastern Ontario between 2000 and 2014. Prompted by clinical suspicion, 24 had testing done to investigate for adrenal suppression during this time period. 9 of those patients had cortisol levels indicative of adrenal suppression and required further management for the same. Adrenal suppression was identified in early phases of treatment for ALL. Adrenal suppression was also identified in patients during the maintenance phase of treatment. Many more patients had symptoms that could be attributed to adrenal suppression, but never had cortisol levels tested.

Conclusion: Adrenal suppression is found in children being treated for ALL, including during the maintenance phase of therapy. Adrenal suppression may have been present in greater numbers of children, but no routine testing protocol exists to identify these patients. Identifying and reviewing cases of adrenal suppression in children during treatment for ALL, including the maintenance phase, gives a better understanding of the risk of HPA axis suppression in this population. This study also provides background data for the development of a prospective study to further look at adrenal suppression in the maintenance phase of ALL. These studies will guide development of a testing protocol to better identify and manage adrenal suppression, thereby reducing its morbidity and mortality, in children being treated for ALL.