Diabetes insipidus, secondary hypoadrenalism and hypothyroidism after traumatic brain injury: clinical implications.
Adequate ADH secretion, adrenal and thyroid functions are vital during the acute and post-acute phases of TBI. Deficiencies of these functions as a result of TBI are increasingly recognized. During the acute phase of TBI the incidence of severe DI is 2.9%; the incidence of less severe forms of DI is 21.6-26%. The development of DI seems to correlate with the severity of trauma. In most occasions DI is transient, but persisting DI may develop with an incidence of 6.9-7.5% amongst TBI victims. The assessment of the adequacy of adrenal function during the acute phase of TBI remains a diagnostic challenge. A few studies demonstrated an incidence of hypoadrenalism of 15-16% during the early phase of TBI. It should be noted that early hypoadrenalism may be due to either a structural damage at the level of the hypothalamo-pituitary unit or it may develop in the context of the so-called "relative adrenal insufficiency", a functional abnormality that is currently increasingly recognized during the course of severe illness. Secondary hypoadrenalism during the late phases of TBI appears with an incidence of 7.1-12.7%. The "low-T3 syndrome" compromises the assessment of thyroid function during the acute phase of TBI; the incidence of TSH insufficiency during the recovery phase varies widely between 1-21%. In summary, diabetes insipidus, secondary hypoadrenalism and hypothyroidism may develop in a small albeit significant proportion of patients during the course of TBI. Therefore, assessment of the integrity of ADH secretion, hypothalamic-pituitary adrenal (HPA) axis and thyroid axis is crucial to ensure survival and optimal rehabilitation of TBI patients.
Tsagarakis
S
S
Department of Endocrinology, Athens' Polyclinic, Athens, Greece. stsagara@otenet.gr
Tzanela
M
M
Dimopoulou
I
I
D000309:Adrenal Insufficiency / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology; D001930:Brain Injuries / Q000150:complications*; D020790:Diabetes Insipidus, Neurogenic / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology; D020249:Hormone Replacement Therapy; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology; D015994:Incidence