Blood Count.
| Red corpuscles, per c. mm. | 3,692,000 | = | 73·8 | per cent. |
| Hæmoglobin | 80 | ” | ||
| Colour index | 1·08 | ” | ||
| Leucocytes, per c. mm. | 25,920 |
Differential Count.
| Lymphocytes | 8·0 | per cent. | = | 2,074 | per c. mm. |
| Large mononuclears | 3·5 | ” | = | 907 | ” |
| Polymorphonuclears | 87·0 | ” | = | 22,550 | ” |
| Eosinophiles | 0·5 | ” | = | 130 | ” |
| Mast cells | 1·0 | ” | = | 260 | ” |
| 100·0 |
The salient feature of the blood picture is the high grade leucocytosis of leucoid type with moderate anæmia—appearances quite compatible with, and suggestive of, an infective arthritis. To these interesting blood changes we shall again refer when dealing with the acute polyarticular variety, the above case being of monarticular type, i.e., the big toe.
Uric Acid Excretion.—If when on a purin-free diet a gouty subject develops a paroxysm, the curve of uric acid excretion in the urine is so characteristic as to be almost pathognomonic of the disorder. As His pointed out, immediately before the onset of the paroxysm the endogenous uric acid sinks to a lower level (termed by Umber the anacritical stage of depression). With the onset of the attack the uric acid content of the urine quickly increases, to reach its zenith on the second or third day. F. Pfeiffer, who first noted this point, termed it an uric acid wave. Subsequently, with the gradual subsidence of the paroxysm, it again drops into what Umber termed the post-critical stage of depression. While this curve of endogenous purin excretion may be modified by oft recurring exacerbations, still Umber holds that nevertheless it is of decided value in differential diagnosis.
Local Phenomena.—The site and character of the pain having been dealt with, we now pass on to consider the objective changes in the affected part. The local engorgement of veins that precedes the articular outbreak becomes more pronounced, extending from the vicinity of the painful joint as far as the leg. The overlying skin of the joint quickly becomes red and tumid. It is not a bright, but a dark red, the superjacent skin taking on a shining smoothness that has been compared to the peel of an onion. Indeed, in its more violent form it resembles but too closely the ordinary appearance of an abscess, over which the skin is becoming thin. The redness is not strictly confined to the surface of the joint, but spreads a little beyond, and where it ceases œdema is perceptible.
The redness in its intensity attains its zenith in from twenty-four to forty-eight hours, and then in hue becomes more violaceous. On the other hand, the œdema may go on increasing for some days. At first, owing to tension, the presence of œdema may not readily be elicited. But with the subsidence of inflammation the swollen parts readily pit on pressure. It is scarcely possible to detect intra-articular effusion unless it be the ankle joint that is involved.
According to Duckworth, in the more sthenic forms there may be local ecchymoses. With the crisis the redness, œdema, and venous turgescence die down. The previously distended skin becomes wrinkled, and with complete subsidence of inflammation desquamation ensues. This process is generally attended with troublesome itching. It is most noticeable about the feet and hands, but more rare at other sites. Scudamore said that in seventy-eight out of 234 cases no peeling occurred, but, as Garrod observed, it may readily be overlooked unless especially sought for.
The exquisite sensitiveness of the parts, as before noted, gives way to numbness. The diminished sensibility, coupled with stiffness of the joint, renders walking difficult for some days, and, indeed, a month or more may elapse before the joint, even in favourable cases, recovers its customary mobility.