When A Diabetic Foot Ulcer Is Complicated With Tophaceous Gout

Author(s): 
David M. Davidson, DPM

   We saw the patient weekly at our wound center. At each visit, we debrided the wound of biofilm and tophi, and used 4% topical lidocaine to minimize pain. We replaced the VAC therapy after each debridement and a visiting wound care nurse performed dressing changes during the week at the patient’s home.

   After two months, the wound base showed good granulation with no new tophi. We subsequently applied Apligraf (Organogenesis) four times over the following two months (see figures 7, 8 and 9).

   The patient’s wound healed uneventfully (see figure 10) and he was discharged from the wound center.

What You Should Know About Tophaceous Gout

Tophaceous gout occurs when the amount of serum uric acid in the bloodstream increases and monosodium urate crystals form. These crystals then grow into tophi and appear as chalky lumps. The levels of uric acid can remain high for many years before one sees symptoms of tophaceous gout. In this case, the patient’s peripheral vascular disease as well as his toe deformity combined with the urate crystal formation to create a dorsal wound. In addition, gout and type 2 diabetes often coexist in people with common physical characteristics and conditions, the most prominent being obesity.

   Obesity as a causative factor in gout is well documented.1 Diet may raise the serum uric acid by up to 2 mg per 100 ml, an amount sufficient to produce clinical gout in a previously mildly hyperuricemic person. Moreover, the incidence of both the “maturity onset” form of diabetes mellitus and gout rises sharply in late middle age.2

   Uric acid has a chemical similarity to alloxan, which can induce diabetes by necrosis of the w-cells of the islets of Langerhans.3 It is known that ketoacidosis will produce hyperuricemia by reducing the renal clearance of urate.

   Researchers have noted that the development of diabetes improves clinical gout.2 Conversely, hyperuricemia may diminish the clinical expression of diabetes. It would seem clear that the association of gout and diabetes mellitus is not uncommon.

Final Notes

In this case study, treatment was successful and involved multiple specialists including vascular surgery, nephrology, primary care and wound care. The wound care consisted of multiple modalities including debridement, negative pressure and bioengineered skin (Apligraf) over several months.

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