Endocrine Abstracts

Hypothalamic–pituitary insufficiency may have diverse causes. Infectious diseases of the central nervous system (CNS) may also affect the hypothalamus and/or the pituitary, although this has not been reported very often and not yet been studied systematically. It was the aim of this study to determine the incidence of hypothalamic–pituitary insufficiency in patients with previous infectious diseases of the CNS of different etiology.

Patient series. Basal and stimulated (insulin tolerance test) pituitary function testing was performed in 19 patients (13 males, 6 females, 38.7±11.7 years) with previous neuroborreliosis, encephalitis or meningitis of mild to moderate clinical course following an interval of 26.1±13.1 months after the acute event.

Four patients (21%, two males, two females) showed an isolated corticotrophic insufficiency (peak cortisol <181.25 μg/l). In patients reporting self-experienced fatigue (including all patients with a corticotrophic insufficiency) peak cortisol concentrations were lower than in patients not reporting fatigue (165.4±38.9 vs 213.6±18.4 μg/l; P=0.002). Two patients (11%, two males) showed an isolated borderline gonadotrophic insufficiency (basal testosterone between 2.4 and 3.0 μg/l). No patient had a somatotrophic or thyrotrophic insufficiency or diabetes insipidus, all had prolactin concentrations within the reference range.

Conclusions: Hypothalamic-pituitary dysfunction may develop in a relevant proportion of patients after infectious diseases of the CNS. Especially self-reported persisting fatigue might be suggestive for the presence of a corticotrophic insufficiency. The clinical picture of some patients might be misinterpreted as an ordinary postencephalitic syndrome. Further prospective studies investigating patients after infectious diseases of the CNS and the effects of hormone replacement therapy are warranted.