Acute disseminated encephalomyelitis presenting as fever of unknown origin: case report

Here, we describe an atypical case of ADEM that initially manifested as several weeks of FUO in a fifteen years old boy.This case report suggests a new possible syndromic association between ADEM and FUO, which should be considered in the clinical examination of patients with FUO, especially in the presence of also modest neurologic or neuropsychiatric symptoms.Fever of unknown origin (FUO) can be defined as a body temperature higher than 38.3°C on several occasions over more than 3 weeks, the diagnosis of which remains uncertain after 1 week of evaluation [1]. Evaluation of FUO in children is complex, because of a wide range of possible etiologies. The most common causes of FUO in childhood are viral infections, while in older patients frequent causes are inflammatory illnesses (rheumatic diseases, vasculitides, polymyalgia rheumatic, sarcoidosis), infections and neoplasms [1,2]. Acute disseminated encephalomyelitis (ADEM) is uncommon inflammatory demyelinating disease of the central nervous system (CNS) with a wide range of clinical manifestations. The highest incidence of ADEM is observed during childhood and it usually occurs following a viral or bacterial infection or, more rarely, following a vaccination, or without a preceding cause [3]. Onset of the disorder is sudden. According to the classic definition, ADEM is a monophasic disease, but it can also present a relapsing course, being described as "recurrent" if the affected districts are always the same or "multiphasic" if there is dissemination in space and time of the lesions [4]. Irritability and lethargy are common first signs of ADEM. Fever and headache are reported about in half of patients. Fever in ADEM is frequently associated with the development of neurologic symptoms, which can occur after hours or weeks from the onset of illness. The most common neurologic symptoms are visual field deficits; language disturbances; mental status abnormalities ranging from irritability and lethargy to coma; psychi