Diagnosis of DIDM during ALL directed chemotherapy
Diagnostic criteria used in literature for DIDM /hyperglycemia varies significantly with cut offs used, timing of test, number of abnormal tests used for diagnosis(20)(15)(21)(22). However, as per the most recent pediatric diabetes guidelines, diagnosis of DIDM is not different from Diabetes mellitus (DM) due to any other etiology (23)(24). Nevertheless, these criteria should be carefully applied considering the pharmacology of the offending drug, pathogenesis of DIDM and taking into account of its transient nature.
Measurement of fasting glucose alone will underestimate the incidence of DIDM when on intermediate acting glucocorticoids (prednisolone, methyl prednisolone) as a single morning dose considering their peak (4-6 hours) action and duration of action (12-16 hours). In such instances, measuring post lunch and/or pre dinner blood sugar values would be useful. When long acting glucocorticoids (Dexamethasone) or intermediate-acting glucocorticoids in divided doses are used post-lunch, pre-dinner and fasting glucose values would be helpful for diagnosis. Utility of oral glucose tolerance testing is limited in diagnosing DIDM during ALL treatment due to practical difficulty in conducting the test. Similarly, HbA1c is also not useful considering the acute onset of DIDM(25)(26). Hence post-lunch and/or pre-dinner glucose level ≥ 200 mg/dl, when on intermediate-acting glucocorticoids as single morning dose and additional fasting glucose ≥ 126 mg/dl when on long-acting steroids or intermediate acting steroids in divided doses are most useful for diagnosing glucocorticoid induced Diabetes Mellitus. For L-asparaginase induced Diabetes mellitus, random sugar value of ≥200 mg/dl, can be used for diagnosing DIDM as there is no fixed pattern of hyperglycemia seen. It is imperative to confirm the diagnosis by repeat testing in the absence of unequivocal hyperglycemia(23)(24).