Neurosarcoidosis presenting as spontaneously remitting hypersomnia

Abstract

A 38-year-old woman was first admitted to our hospital in November 2007 because of excessive daytime somnolence and short-term memory disturbance. She reported that her speech had gradually become slower starting in April 2007. Severe fatigue and somnolence had developed at the beginning of August 2007. She felt very sleepy and had to take long naps, generally sleeping all day except for at meal times, and she was therefore unable to do housework. Hypersomnia and chronic fatigue persisted after she was admitted to the hospital. On admission, her body temperature was 35.8 C, heart rate was 99 beats/min, and blood pressure was 118/56 mm Hg. Physical and neurological findings were uninformative with the exception of mild cognitive dysfunction; her MiniMental State Score was 23/30. She had daytime somnolence and her Epworth Sleepiness Score [4] was 18 points. Blood cell counts and serum levels of sodium, potassium, creatinine, and urea nitrogen as well as liver enzymes, glucose, angiotensin-converting enzyme (ACE), and adenosine deaminase (ADA) were all within normal ranges. However, cerebrospinal fluid (CSF) cell count (17/ll) and protein level (139 mg/dl) were elevated. Activity of ACE (0.2 U/l) and ADA (2.2 IU/l) in the CSF were within the normal range, and CSF culture and cytology were negative. CSF hypocretin-1 (orexin A) concentration was decreased (82.8 pg/ml: lower limit of normal = 110 pg/ml) [5]. T2-weighted magnetic resonance imaging (MRI) showed high-intensity signals in the brainstem, hypothalamus, basal ganglia, and white matter surrounding the lateral ventricle (Fig. 1a). Gadolinium-enhanced T1weighted MRI (Gd-MRI) demonstrated numerous small spots of high intensity in the bilateral thalamus, hypothalamus, and basal ganglia (Fig. 1b). Bilateral hilar lymphadenopathy (BHL) was absent on chest X-ray. Neither chest computed tomography (CT) nor whole body gallium scanning revealed abnormal lesions. The patient was clinically diagnosed with central nervous system (CNS) sarcoidosis associated with secondary hypersomnia, although the diagnosis was not confirmed by laboratory data at that time. The hypersomnia spontaneously and gradually improved. Therefore, no medication was initiated, and she was discharged from the hospital in December 2007. Six months later, the hypersomnia and memory disturbance had disappeared completely. The high-intensity areas in the bilateral thalamus and basal ganglia on MRI T2-weighted imaging, as well as the numerous small spots on gadolinium-enhanced T1-weighted imaging, had disappeared by May 2008 (Fig. 1c, d). Mild memory disturbance recurred in September 2008, and new bilateral cerebral white matter lesions were seen on brain MRI, which demonstrated foci of abnormal signal intensity in the bilateral white matter; these showed decreased signal Y. Nakazato (&) S. Kondo A. Ohkuma Y. Ito N. Tamura N. Araki Department of Neurology, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan e-mail: nakachan@saitama-med.ac.jp