Case Presentation:
A 46-year-old Japanese man who had cognitive impairment visited our department. He began working after finishing vocational school at the age of 20, but he changed jobs often beginning at the age of 25. He started to doze off and make careless mistakes during the daytime despite sleeping well at night. He visited the psychiatrist and was diagnosed with narcolepsy at the age of 38. He was administered modafinil, and his symptoms were relieved. Modafinil was discontinued. He was able to work at the age of 40. He started to become fatigued easily, exhibited anorexia and weight loss and was diagnosed with eosinophilic gastroenteritis and hypereosinophilia at the Department of Internal Medicine, A Hospital, at the age of 44. Afterwards, the anorexia improved, but the fatigue was so severe that he took a leave of absence from work. He temporarily returned to work, but due to fatigue and somnolence, he was placed on leave again. He visited the psychiatrist, and he was diagnosed with adjustment disorder. He received rehabilitation and returned to work at the age of 45. He began to make incoherent remarks and wipe his nose with his hand, which were not appropriate behaviors for his age, at the age of 46. His Mini Mental State Examination-Japanese (MMSE-J) score was 25/30 points. The Wechsler Adult Intelligence Scale, Third Edition (WAIS-III) showed impairment (Full-Scale IQ 70, Verbal IQ 76, Performance IQ 69, Verbal Comprehension Index 78, Perceptual Organization Index 66, Working Memory Index 85, Processing Speed Index 81). His MRI showed mild cerebral atrophy, and he was suspected to have dementia. When he visited our department, his facial expression was anxious, his speech was polysyllabic and unorganized, he had difficulty sustaining attention, and he exhibited impulsiveness and restlessness. The scores of the MMSE-J and clock-drawing test (CDT) using the Freedman method were 25/30 and 14/15, respectively. The Japanese Adult Reading Test (JART) yielded a predicted total IQ of 110, a predicted verbal IQ of 111 and a predicted performance IQ of 106 at the time of examination. The patient showed mild cognitive impairment. Blood tests showed decreased ACTH, cortisol and free thyroxine (FT4) levels and increased thyroid-stimulating hormone (TSH) levels. He was diagnosed with hypopituitary secondary adrenal hypofunction based on the absence of cortisol in the rapid ACTH stress test, the response of urinary cortisol in the continuous ACTH stress test, and the absence of both ACTH and cortisol in the corticotropin-releasing hormone (CRH) stress test (Table 1). IAD was diagnosed because secretion of other anterior pituitary hormones was maintained. With regard to hypothyroidism, the FT4 level was low, the TSH level was high, and the thyrotropin-releasing hormone (TRH) stress test showed a positive response to TSH, leading to the diagnosis of primary hypothyroidism (Table 1). He was started on hydrocortisone (15 mg) as adrenal corticosteroid replacement therapy. By 1 month after starting hydrocortisone, his physical complaints, including anorexia, somnolence, and general fatigue, had disappeared, as had his forgetfulness and difficulty concentrating. His cognitive functions had recovered, and his MMSE-J score was 30/30. The WAIS-III scores improved (Full-Scale IQ 81, Verbal IQ 92, Performance IQ 72, Verbal Comprehension Index 92, Perceptional Organization Index 66, Working Memory Index 98, Processing Speed Index 81) after 3 months of hydrocortisone treatment. The hydrocortisone dose was decreased to 10 mg because his body weight increased during the same period. He returned to work after 5 months of hydrocortisone treatment and has been working stably since then with 10 mg of hydrocortisone. Hypothyroidism also recovered 7 months of hydrocortisone treatment.
