In Reply.—Dr Van Dop's contention that a decrease in the serum cortisol concentration may have been an "alternate cause for the pseudotumor cere
bri" of patient 1 appears unlikely. During liotrix treatment, the morning cortisol values of patient 1 were 2.8, 2.9, and 5.3 μg/dL (normal, 7 to 20 μg/dL), respectively, between 8 and 9 AM on three consecutive days. The morning corticotropin value was 26 pg/mL (normal, <120 pg/mL), the serum cortisol value was 2.2 μg/dL, and the cortisol response to insulin-induced hypoglycemia was only 10 μg/dL. The liotrix treatment was discontinued for four weeks prior to cortisone replacement, yet the serum cortisol value remained abnormally low (3.2 μg/dL), along with the serum thyroxine value (3.6 μg/dL [normal, 4.5 to 12 μg/dL]) and the thyrotropin value (5.2 μU/mL). Cortisone acetate replacement was then begun. Clinical evidence of pseudotumor cerebri continued during this period.
The authors acknowledge the association