The Nail Plate Biopsy May Pick up Gout Crystals and Other Crystals

Abstract

The rewarding use of nail clippings processed histologically for the diagnosis of some nail diseases is well established. A new application of the nail plate biopsies (NPBs) is the detection of crystals in the subungual horn. Besides other subungual crystals, urate crystals are heretofore undescribed. This presentation adds to the advantages of an NPB: the detection of some cases of gout on which urate crystals are extruded subclinically. While searching for fungi, 2 cases of gout were diagnosed histologically, aided by unstained thick sections. A history of gout was then confirmed. No tophi were noted in or near the nail field. Chasing for crystals opens the study of fluids that may exude or transude into nail structures, a kind of "nail window" into hematic or metabolic abnormalities. In sum, the abundance of cytologic and histologic findings in an NPB can expand the armamentarium of physicians to evaluate nail diseases and even systemic diseases in a noninvasive manner.

Role of nail biopsy as a diagnostic tool

“…Tirado-Gonzalez et al proposed that fluids exude or transude into nail structures providing a kind of ''nail window'' into systemic hematologic or metabolic abnormalities. [14] Detection of urate crystals in the subungual horn of nails submitted for a suspected diagnosis of onychomycosis has been reported. [14] It is even proposed that gout may be monitored by means of the simple and noninvasive histological processing of nail clippings.…”

“…[14] Detection of urate crystals in the subungual horn of nails submitted for a suspected diagnosis of onychomycosis has been reported. [14] It is even proposed that gout may be monitored by means of the simple and noninvasive histological processing of nail clippings. However, for proper evaluation of the character of such crystals, nail plate specimens need to be submitted in alcohol rather than in formaldehyde.…”

“…The presence of characteristic cytologic and histologic findings in a nail plate biopsy can expand the armamentarium of physicians to evaluate nail diseases and even systemic diseases in a noninvasive manner. [14] Bolliger et al determined the urea, ammonia, and uric acid content of toenails in 11 patients with varying types and degrees of renal impairment and found a markedly elevated content of uric acid in patients with chronic nephritis and with long-standing severe gout. [36] PROS AND CONS OF NAIL BIOPSY From the aforementioned discussion, it is clear that NB offers certain special advantages.…”

“…The utility of NPB in systemic disease has also been explored extensively. [14] 2. Nail bed biopsy (NBB) is generally performed to distinguish between two or more conditions with a similar clinical pattern, like onycholysis or subungual hyperkeratosis, cases with discoloration of the nail bed, or any painful nail bed lesion.…”

Uric acid quantification in fingernail of gout patients and healthy volunteers using HPLC‐UV

“…The human fingernail has recently been attracting attention as a new noninvasive biosample in clinical examinations for endogenous metabolites (Rail, 1969;Tirado-González and González-Serva, 2011;Min et al, 2010). In addition, fingernail samples contain longterm histories of diseases and medicines used for treatment as compared with other biological samples.…”