Gout, with a section on ocular disease in the gouty

by Llewellyn J. Llewellyn

Variations in Uric Acid Content of Blood Independently of Diet

Considerable variations in the uric acid content of the blood, according to Pratt, may occur both in gouty and non-gouty subjects, and which cannot be attributed to any purin intake. Such oscillations, moreover, may ensue within a short time. A patient of his, admitted to hospital suffering from a severe attack of gout, was placed upon a purin-free diet. Twenty-four hours afterwards examination revealed only 2·7 mg. of uric acid in his blood. Subsequently, after having had no food containing purins for fifteen days, it contained 5·1 mg.

Marked variations in the uric acid content of the blood may likewise occur in non-gouty subjects. After being on a purin-free diet for two days, a patient of Pratt’s, with recurrent iritis, had 2·2 mg., while a few months after, when on a mixed diet, his blood contained only 0·8 mg.

Again, great oscillations in the blood content of uric acid, independent of diet, are sometimes found in cases of non-gouty arthritis. Thus, in one chronic case of this nature, the blood when first examined contained 7·6 mg. of uric acid, but a few months later, when on a purin-rich diet, only 0·8 mg. were present. In another instance of primary polyarthritis the same was strikingly exhibited. Aged twenty-two years, the subject in October was on ordinary diet. His blood at that period showed 2·7 mg. of uric acid per 100 mg. of blood; in December, on a purin-free diet, 5·0; and in May, on a similar dietary, 1·6 mg.

As to whether in healthy individuals, on a purin-free diet, similar variations in the uric acid content of the blood occur, is not sufficiently ascertained. The solitary example that may be cited is by McLester, who, as a result of four examinations of the blood in a normal person on a purin-free diet, found that its uric acid content was practically constant.

The deductions that may be drawn from the foregoing findings are:—

(1) That in gouty subjects pronounced variations of the uric acid content of the blood may occur which are not attributable to the purin content of the food.

(2) That in non-gouty arthritis similar fluctuations in the blood content of uric acid, irrespective of diet, also occur.

(3) That in normal persons, on a purin-free diet, the blood content of uric acid, as far as is ascertained, does not show such variations.