Hypothalamic pituitary dysfunction in acute nonmycobacterial infections of central nervous system

Acute and chronic central nervous system (CNS) infections are not uncommon in tropical countries and are associated with high morbidity and mortality if specific targeted therapy is not instituted in time. Effects of tubercular meningitis, a form of chronic meningitis on hypothalamic pituitary axis, are well known both at the time of diagnosis and after few months to years of illness. However, there are few reports of pituitary dysfunction in subjects with acute CNS infections. Therefore, this study was aimed at evaluating the pituitary hormonal profile in patients with nonmycobacterial acute meningitis at the time of presentation.

This prospective case series study included 30 untreated adult patients with acute meningitis, meningoencephalitis, or encephalitis, due to various nonmycobacterial agents, admitted and registered with Lok Nayak Hospital, Maulana Aazd Medical College, New Delhi, between September 2007 and March 2009. Patients with preexisting endocrine diseases, tubercular meningitis and patients on steroids were carefully excluded from the study. The basal pituitary hormonal profile was measured by the electrochemilumniscence technique for serum cortisol, luetinizing hormone (LH), follicular stimulating hormone (FSH), prolactin (PRL), thyrotropin (TSH), free tri-iodothyronine (fT3), and free thyroxine (fT4).

The cases (n = 30) comprised of patients with acute pyogenic meningitis (n = 23), viral meningoencephalitis (n = 4), brain abscess (n = 2), and cryptococcal meningitis (n = 1). The mean age of patients was 28.97 ± 11.306 years. Out of 30 patients, 14 (46.7%) were males and 16 (58.1%) were females. Adrenal insufficiency both absolute and relative was seen in seven (23.3%) and hyperprolactinemia was seen in nine (30.0%) of the patients. One study subject had central hypothyroidism and seven (23.3) showed low levels of LH and/or FSH. None of patients showed clinical features suggestive of central diabetes insipidus.

Acute infections of the CNS are associated with abnormalities in the pituitary hormone profile. Further studies are required to evaluate the hypothalamic pituitary axis using dynamic tests and imaging by MRI.