A 63-year-old man with headaches and behavioral deterioration

A 63-year-old, right-handed man presented to his local hospital with headaches and recent behavioral and cognitive deterioration. One year prior to presentation, he noted nonspecific increasing fatigue and sinus problems that he attributed to recent woodworking with moldy wood and exposure to fine dust. In early February 2000, he developed headaches, which he identified as being different from his usual “migraine headache.” They were frontal, throbbing, and severe, classified as “10 out of 10” on a pain scale and they occasionally awoke him from sleep. He was evaluated by local physicians, including a neurologist, ophthalmologist, and otolaryngologist, was diagnosed with sinus headaches, and was treated unsuccessfully with antihistamines, antibiotics, and a short course of oral corticosteroids of unknown dose. The headaches continued and he was seen in a local emergency room on two separate occasions and treated with neuroleptics and sumatriptan without benefit. A sedimentation rate was normal. In March 2000, the patient had imbalance and was noted to veer often to the left. Prominent behavioral changes also were identified in that he was more irritable, disinhibited, impatient, and oppositional. He had less interest in his hobbies, was more forgetful, and was fidgety. Superimposed on these changes were episodes of more marked confusion. He voluntarily stopped driving as he felt he was unable to make quick decisions. The patient also experienced nausea and vomiting on a nearly daily basis. He would not eat for up to 2 days because of these symptoms and lost 20 pounds in 2 months. During the first week of March, he was hospitalized locally in Arizona. Erythrocyte sedimentation rate, antinuclear antibodies, fungal serology, serum protein electrophoresis, B12, and folate were tested and were normal or negative. MRI of the brain revealed scattered T2 hyperintensities in the bilateral subcortical and deep white matter, some of which …