Apatite Rheumatism and Chondrocalcinosis are Different Stages of the Same Metabolic Disorder: A Clinicopathologic Study of 21 Patients with Clinically Diagnosed Apatite Rheumatism or Chondrocalcinosis

Abstract

Miklós Bély* and Ágnes Apáthy

Introduction: Apatite rheumatism and chondrocalcinosis are considered to be different metabolic diseases and distinct clinical entities, although the clinical symptoms are the same, the most commonly affected joints overlap, and the currently available treatment is similar. Original descriptions, interdisciplinary studies and excellent clinicopathology manuals also support this view, since the Hydroxy Apatite (HA) crystals are virtually not existing in conventionally stained tissue sections, while the Calcium Pyrophosphate Dehydrate (CPPD) crystals may be retained. The introduction of the non-staining technique by Bély and Apáthy opened a new era in the diagnosis of crystal induced diseases, allowing the analysis of cholesterol, HA, CPPD, Mono Sodium Urate monohydrate (MSU) crystals, and others in traditionally fixed, paraffinembedded, non-stained tissue sections. The aim of this study was to analyze HA and CPPD deposits in 5 patients with clinically diagnosed apatite rheumatism, and in 16 patients with clinically diagnosed chondrocalcinosis.

Materials and Methods: Twenty-six joints of 21 patients with crystal induced metabolic diseases were operated; a total of 57 tissue samples were analyzed.

Results: Different amounts of HA and CPPD crystals were detected in tissue sections of all 21 patients by non-staining technique. Crystal induced metabolic diseases started with deposition of HA crystals, followed by CPPD, and amorphous calcium phosphate and/or carbonate deposition.

Discussion and Conclusions: The dominance of HA and/or CPPD crystals is much more characteristic of clinically diagnosed apatite rheumatism or chondrocalcinosis, in comparison to the similar clinical symptoms or affected joints. Crystal-induced metabolic diseases are progressive cumulative diseases, and apatite rheumatism and chondrocalcinosis may be considered different stages of the same metabolic disorder, rather than two separate entities. According to the “most common is the first” hypothesis, the metabolic disease caused by HA and CPPD crystals, begins in the synovial membrane of the knee joint.