To the Editor.—Cerebrospinal fluid examination has traditionally been considered of little value in the diagnosis of intermittent acute porphyria because it has been found to have a normal or marginally elevated protein level and cell court.1,2
We reviewed the cases of intermittent acute porphyria that were presented at our institution between 1974 and 1987.3 In 21 of the 37 cases found, the cerebrospinal fluid was studied. Twelve of the patients were female and 9 were male, with a mean age of 25 years (range, 13 to 42 years). The mean protein level was 0.71 g/L (range, 0.01 to 4/10 g/L) for the whole group and, in 14 cases (67%), it was over 0.45 g/L, which is the higher normal limit, with a mean of 1.10 g/L (range, 0.50 to 4.1 g/L). In 6 of the patients the protein elevation was coincident with a lack of cells in