Difficulty of detecting Tophi
Apart from the probability of such erroneous relegation to the “gouty” category of non-gouty arthritides, there remains this further consideration, the ease with which tophi, even when superficial, may be overlooked. We look for pearly white concretions, and if none are seen we straightway assume that tophi are absent. This, I am sure, is a very common pitfall. At their inception tophi are neither white nor hard. They are largely fluid and soft to touch. The skin over them may be unchanged in colour or reddened. Only when mature, and the overlying skin is thin, do they assume the ordinary aspects of a tophus. These observations apply not only to tophi in the ears, but to those in the vicinity of the small joints of the hands and feet or elsewhere. I would urge that in the case of all soft localised swellings of dubious nature in the neighbourhood of the phalangeal joints aspiration with a hypodermic syringe will often prove very helpful. If fluid can be withdrawn and the same microscopically examined, it will more often than is supposed reveal the presence of biurate crystals.
More information is badly needed as to the relationship of their formation to acute attacks of gout. Garrod on this point remarks: “The deposits are probably formed during an attack of gout, but occasionally they appear shortly afterwards. In one case, of which I have notes, the ears were carefully examined without result when the patient left the hospital, but within ten days, on re-examination, a deposit was found. Perhaps some fluid was effused during the fit, but being at first transparent, could not be easily distinguished.” Sir Dyce Duckworth, too, observes: “After acute attacks of gout have passed off there may follow renewed pain in the neighbourhood of the joint, and later there is discovered a nodular or soft swelling. In the latter case there may be fluctuation, indicating a liquid collection of urates. This should never be opened. In a few weeks this tumour tends to indurate, grow more compact, and a so-called ‘chalky’ concretion is established.”
Reflection upon the foregoing considerations leads me to the conclusion that not only was Garrod right in his affirmation that “gouty inflammation is invariably attended with the deposition of urate of soda,” but more that examples of true uratic arthritis which lack tophi are exceptional, and that in their absence their diagnosis as such cannot be with certitude established.
We have now, we trust, sufficiently defined our attitude towards the tophus, the salient objective stigma of a “gouty diathesis,” and the indispensable rôle it plays in enabling us to establish the diagnosis of articular gout.