Hyper-Uricæmia in Non-Gouty Arthritis
Pratt, of Boston, has found that a condition of hyper-uricæmia is sometimes demonstrable in joint disorders other than gouty; but he maintains that the following distinction obtains, viz., that while in gout the hyper-uricæmia is generally constant, in other forms of arthritis it appears to be transient.
He cites a case of infective arthritis, not exhibiting the clinical features of gout, in which the first analysis of the blood by Denis revealed a uric acid content of 7·6 mg.; but on a subsequent examination, seven months later, only 0·8 mg. was found, this, though the patient at the time was on a purin-rich diet. This difference is response to exogenous purins in gouty, as opposed to non-gouty arthritics, is well illustrated in the following table.
According to Walker Hall, the following example illustrates the effect of purin-free as opposed to purin diet on the uric acid blood content in a gouty subject:—
| Uric acid. | Non-protein nitrogen. | Urea nitrogen. | |
|---|---|---|---|
| Mgs. per 100 gms. of blood. | |||
| Gout with purin dietary | 5·5 | 52 | 36 |
| Gout with purin-free food | 3·4 | 40 | 18 |
| Gouty Polyarthritis (Pratt). | |||
|---|---|---|---|
| Milligrams of uric acid in 100 gms. of blood. | Milligrams of uric acid in 100 gms. of blood. | ||
| D. N. Gout. Purin-free diet. | 3·1 | 52 hours after eating 280 grams haddock roe. | 5·8 |
| 3 days after eating 300 grams roast beef. | 6·2 | ||
| K. Gout. Purin-free diet. | 2·4 | 24 hours after eating 270 grams roast beef. | 3·0 |
| H. Gout. Purin-free diet. | 1·7 | 3 days after eating 150 grams thymus. | 3·6 |
| P. Gout. Purin-free diet. | 2·1 | 3 days after eating 160 grams thymus. | 3·4 |
| J. N. Gout. Purin-free diet. | 2·2 | 48 hours after eating 190 grams thymus. | 8·7 |
| Average | 2·2 | Average | 5·1 |
| Non-Gouty Polyarthritis (Pratt). | |||
| Milligrams of uric acid in 100 gms. of blood. | Milligrams of uric acid in 100 gms. of blood. | ||
| McC. Chronic polyarthritis. Purin-free diet. | 1·7 | 24 hours after eating 100 grams of thymus. | 2·2 |
| M. Chronic polyarthritis. Ordinary diet. | 2·0 | 24 hours after eating 225 grams of thymus. | 1·8 |
| H. Chronic polyarthritis. Ordinary diet. | 2·9 | 47 hours after eating 190 grams of thymus. | 2·5 |
| Average | 2·1 | Average | 2·2 |
As Pratt points out, if the figures in the two tables be compared, it will be seen that, prior to the sweetbread meal, the average uric acid content of the blood in the gouty and the non-gouty patients was identical. But twenty-four hours to three days, after the purin intake, the average uric acid content of the blood in the gouty was 5·1 mg., while in the non-gouty subjects it was only 2·2 mg.; in other words, in the five gouty individuals a pronounced hyper-uricæmia was produced from one to three days after a purin meal. On the other hand, in the non-gouty subjects the uric acid content was found to be practically unaltered twenty-four to forty-eight hours after the same purine intake.
It would seem, therefore, that some diagnostic importance may be attached to the hyper-uricæmia that is induced in gouty subjects after exogenous purines, as compared with its non-occurrence in non-gouty subjects.
Another interesting point elicited by Pratt was that in his gouty examples, although, after a purin meal, the uric acid content of the blood rose markedly, yet there was no apparent delay or diminution in the output of exogenous purin in the urine. Thus, in one example, after the intake of 190 grams of thymus gland, the uric acid in the blood, in the first twenty-four hours, rose from 2·2 mg. to 4·4 mg., reaching, on the third day, a maximum of 8·7 mg., which, on the fourth day, sunk to 2·7 mg. Nevertheless, 26·2 per cent. of the ingested purin nitrogen was excreted as uric acid. Now, as pointed out in the preceding chapter, it has been shown by many observers that in gouty subjects the excretion of exogenous purin is diminished and retarded. But Pratt’s study of the blood shows that a marked increase and retention of uric acid in the blood may result from the ingestion of purin bases, even when no evidence of retention is found on the examination of the urine.[23]
The clear inference from this is that it is desirable that our urinary findings in respect of uric acid should be reviewed and controlled in light of blood examinations to the same end.