Prospective investigation of the hypothalamo–pituitary–adrenalaxis in patients with tularemia

Abstract

IntroductionTularemia is a bacterial zoonotic diseases caused by Francisella tularensis. It exhibits different clinical manifestations depending on bacterial subspecies, such as Francisella subspecies tularensis (type A) or holarctica (type B), and the route of transmission, such as by arthropod bites, inhalation, or the ingestion of contaminated water or food. Tularemia caused by type B is much less severe than tularemia caused by type A, and fatal cases are rare in type B (1). In Turkey, the most common form of tularemia is oropharyngeal, caused by the subspecies holarctica (2,3).The adrenal glands are affected in sepsis, brucellosis, and tuberculosis. Variations in adrenal response to tularemia are most prominent in volunteers with typical acute illness, and adrenal response is minimal or absent in those with mild symptoms (4,5). Sepsis-associated abnormal pituitary response may explain some factors, including anatomic damage, acute inflammation, and drug-related cell dysfunction (5). The hypothalamopituitary-adrenal (HPA) axis may become severely dysfunctional during sepsis (5-7). In the past, the adrenal response of acute tularemia patients has been examined in healthy volunteers ( 8), but it is unclear whether there is a permanent adrenal insufficiency in the postinfectious period. The aim of this study was to investigate the HPA axis by adrenocorticotropic hormone (ACTH) stimulation test in acute tularemia and after therapy in a prospective study. Materials and methodsAdult tularemia patients who attended Erciyes University's Department of Infectious Diseases between 2011 and 2013 were included in this study. The study was approved by the local ethics committee, and informed consent was obtained from each patient. Tularemia was diagnosed in patients who had findings and symptoms compatible with tularemia, such as fever, sore throat, conjunctivitis, lymphadenopathy, cough and malaise, and tularemia microagglutination titer (MAT) of ≥1/128 or a 4-fold increase in titer after 4 weeks. Three of 6 clinical forms of tularemia were defined including oropharyngeal, oculoglandular, and glandular (1,2). Patients who were Background/aim: To investigate prospectively the hypothalamo-pituitary-adrenal (HPA) axis by adrenocorticotropic hormone (ACTH) stimulation test.Materials and methods: Tularemia was diagnosed according to guidelines. An ACTH stimulation test (1 µg) and a dexamethasone suppression test (DST; 1 mg) were performed in patients in the acute phase of tularemia before antibiotic treatment and in the chronic phase.Results: Nineteen patients (mean age: 41.0 ± 13.2 years; 57.9% female) with tularemia were enrolled in the study in 2011 and 2012. Cortisol response to ACTH stimulation test was sufficient in all patients during the acute phase. After the DST, the cortisol was not suppressed during the acute phase in only one patient. The median control time of 11 patients after acute tularemia was 13 months. During the chronic phase, cortisol response to ACTH stimulation was normal in all patients, and after DST ...