[Pathophysiology and etiology of the Charcot foot]. / Pathophysiologie und Ätiologie des Charcot-Fußes.

BACKGROUND: Despite extensive research, the pathophysiology of Charcot foot is still not fully understood. In the case of late diagnosis and insufficient therapy, severe deformity may occur. OBJECTIVES: Different theories on the pathophysiology of the Charcot foot are presented and discussed. MATERIALS AND METHODS: This article presents different theories on the pathophysiology of the Charcot foot and presents studies on the cellular, immunological, and bone metabolism level. RESULTS: One theory is based on repetitive microtraumas in the sensoric deficient foot which lead to development of Charcot foot. Another theory is based on pathologic neurovascular innervation leading to morphologic changes. Probably both mechanisms are responsible in combination as etiological factors inducing neuropathy CONCLUSION: A combination of mechanical, vascular, and biologic factors induce the neuropathic foot and result in severe deformity if diagnosis is too late.

Sympathetic neuropathy in diabetes mellitus patients does not elicit Charcot osteoarthropathy.

AIM: The aim of the study was to determine the degree of neuropathy (autonomic and somatic) in patients with diabetes mellitus with or without Charcot osteoarthropathy (CA). METHODS: Forty-nine patients with diabetes mellitus type 1 or 2 were investigated. The patient population of interest was the patients with acute Charcot foot (n=17) or chronic Charcot foot (n=7). The inclusion criterion for an acute Charcot foot was a temperature difference of more than 2° between the two feet, oedema of the affected foot, typical hotspots in a bone scintigram and a typical clinical course. In addition, patients with first toe amputation (n=5), a high-risk group for development of CA, and two control groups consisting of diabetes patients with (n=9) or without somatic neuropathy (n=11) were investigated. Regional blood flow in the feet was measured by venous occlusion plethysmography. Quantitation of somatic neuropathy was done by the Neuropathy Disability Score and modified Neuropathy Symptom Score. Quantitation of autonomic neuropathy was done by measurements of local venoarteriolar sympathetic axon reflex in the feet and of heart rate variability during deep breathing and orthostatic challenge. RESULTS: The patients with acute Charcot foot and first toe amputation had an increased blood flow in the affected foot and weakened but not absent venoarteriolar sympathetic axon reflex. In the other patient groups, a normal venoarteriolar sympathetic axon reflex in the feet was found. CONCLUSIONS: Peripheral sympathetic neuropathy is not likely to be the pathophysiologic mechanism behind the hyperemia in the foot during an acute attack of CA. The hyperemia is more likely secondary to local inflammatory events.

Charcot's arthropathy secondary to herpetic encephalitis sequelae: an unusual presentation.

Neuropathic arthropathy (Charcot's arthropathy) is a progressive articular disease associated with a reduced sensorial and protector proprioceptive reflex. Its etiology includes many different conditions such as syringomyelia, traumatic lesion causing medullary deformity, spina bifida, diabetic neuropathy, leprosy neuropathy, neurofibromatosis, amyloid neuropathy, alcohol, and repetitive injection of hydrocortisone into joints, among others. However, the relationship between Charcot's arthropathy and herpetic encephalitis has not yet been described. Herpes encephalitis causes acute and chronic diseases of the peripheral or central nervous system. It can manifest as subacute encephalitis, recurrent meningitis, or myelitis. It can also resemble psychiatric syndromes, diplopia, sensory changes in the face and limbs, personality changes, frontal dysexecutive syndrome, stiff neck, subclinical alterations of the vestibular function, intracranial hypertension, convulsion, hemiparesis, and generally includes motor components, among others. On the other hand, pure peripheral sensory disturbance has not been described. In this article, we report the clinical case of a patient with Charcot's arthropathy secondary to pure peripheral sensory polyneuropathy as a consequence of progressive herpetic encephalitis sequelae. In this article, the authors report the first case of Charcot's arthropathy secondary to herpetic encephalitis.

Characteristics of T-cell large granular lymphocyte proliferations associated with neutropenia and inflammatory arthropathy.

INTRODUCTION: The purpose of this study was to analyze the data of patients with T-cell large granular lymphocyte (T-LGL) lymphocytosis associated with inflammatory arthropathy or with no arthritis symptoms. METHODS: Clinical, serological as well as histopathological, immunohistochemical, and flow cytometric evaluations of blood/bone marrow of 21 patients with T-LGL lymphocytosis were performed. The bone marrow samples were also investigated for T-cell receptor (TCR) and immunoglobulin (IG) gene rearrangements by polymerase chain reaction with heteroduplex analysis. RESULTS: Neutropenia was observed in 21 patients, splenomegaly in 10, autoimmune diseases such as rheumatoid arthritis (RA) in 9, unclassified arthritis resembling RA in 2, and autoimmune thyroiditis in 5 patients. T-LGL leukemia was recognized in 19 cases. Features of Felty syndrome were observed in all RA patients, representing a spectrum of T-LGL proliferations from reactive polyclonal through transitional between reactive and monoclonal to T-LGL leukemia. Bone marrow trephines from T-LGL leukemia patients showed interstitial clusters and intrasinusoidal linear infiltrations of CD3+/CD8+/CD57+/granzyme B+ lymphocytes, reactive lymphoid nodules, and decreased or normal granulocyte precursor count with left-shifted maturation. In three-color flow cytometry (FCM), T-LGL leukemia cells demonstrated CD2, CD3, and CD8 expression as well as a combination of CD16, CD56, or CD57. Abnormalities of other T-cell antigen expressions (especially CD5, CD7, and CD43) were also detected. In patients with polyclonal T-LGL lymphocytosis, T cells were dispersed in the bone marrow and the expression of pan-T-cell antigens in FCM was normal. Molecular studies revealed TCRB and TCRG gene rearrangements in 13 patients and TCRB, TCRG, and TCRD in 4 patients. The most frequently rearranged regions of variable genes were Vbeta-Jbeta1, Jbeta2 and Vgamma If Vgamma10-Jgamma. Moreover, in 4 patients, additional rearrangements of IG kappa and lambda variable genes of B cells were also observed. CONCLUSION: RA and neutropenia patients represented a continuous spectrum of T-LGL proliferations, although monoclonal expansions were most frequently observed. The histopathological pattern and immunophenotype of bone marrow infiltration as well as molecular characteristics were similar in T-LGL leukemia patients with and without arthritis.

Cytokine-induced osteoclastic bone resorption in charcot arthropathy: an immunohistochemical study.

BACKGROUND: Charcot arthropathy is a chronic, progressive destructive process affecting bone architecture and joint alignment in people lacking protective sensation. The etiologic factors leading to progressive bone resorption have not been elucidated. The purpose of this study was to histologically examine surgical specimens with Charcot arthropathy for cell type and immunoreactivity of known cytokine mediators of bone resorption. METHODS: Tissue samples of 20 specimens with known Charcot arthropathy were stained for Hematoxylin and Eosin (H&E) to quantify cell type. Nine of the specimens were stained with interleukin-1 (IL-1) antibody, nine with tumor necrosis factor (TNF) alpha antibody, and nine with interleukin-6 (IL-6) antibody. Distribution of staining was graded as focal (less than 10% of cells), moderate (10% to 50% of cells), and diffuse (more than 50% of cells) by two independent investigators. Inflammatory cells in tissue sections of rheumatoid synovium served as a positive control. RESULTS: Osteoclasts were seen in excessive numbers lining the resorptive bone lacunae. There was a disproportionate increase in osteoclasts to osteoblasts in the Charcot-reactive bone. In each case, osteoclasts demonstrated immunoreactivity for IL-1, IL-6 and TNF-alpha with a grade of moderate or diffuse reactivity. CONCLUSION: The findings of excessive osteoclastic activity in the environment of cytokine mediators of bone resorption (IL-1, IL-6, and TNF-alpha) suggest enhanced bone resorption through the stimulation of osteoclastic progenitor cells as well as mature osteoclasts. Alteration in the synthesis, secretion, or activity of these important regulatory molecules through the use of pharmacologic agents may, in turn, alter bone remodeling and loss and lead to accelerated healing without collapse or malalignment.

Charcot-like arthropathy: A newly-recognized subset of psoriatic arthritis.

OBJECTIVE: The aim of the study is to describe a group of patients with a highly destructive and asymptomatic form of psoriatic arthritis, mimicking a Charcot-like joint disease. METHODS: We studied 180 patients with psoriatic arthritis and identified 4 patients with arthritis mutilans mimicking a Charcot-like joint disease. Clinical history, physical exam, and immunological testing were performed as well as X-ray of affected joints. Synovial membrane and sural nerve biopsies were performed and diagnosis of psoriasis was confirmed by skin biopsy. RESULTS: Four patients with psoriatic arthritis mutilans according to Moll and Wright classification criteria (1) and Charcot-like joint disease were identified and evaluated. There were 2 males and 2 females, all Caucasians. The mean age +/- SD was 57.8 +/- 14.2 years. Mean arthritis duration +/- SD was 6 +/- 4.6 years and mean cutaneous duration +/- SD was 13 +/- 10.4 years. All patients had polyarthritis and a sudden onset of bilateral, painless, and highly destructive arthropathy involving large, non-weight bearing (elbows) and weight bearing (knees), and also small joint of hands and feet. Synovial membrane biopsy showed findings similar to those found in Charcot joint disease, including ischemic neuropathy. CONCLUSION: A newly-recognized subset of patients with psoriatic arthritis and Charcot-like joint disease according to clinical, radiographic and histological features is described. The proposed neurovascular theory may explain the pathogenesis of this presentation.

Symmetry, T cells and neurogenic arthritis.

Symmetry in clinical disease occurs more commonly than expected by chance and is unexplained. In this paper we focus on symmetry in arthritis and describe the neurogenic hypothesis. Neuropeptides are anatomically relevant to systemic arthritis and have been shown to have modulating effects on both the immune and circulatory systems. Neural networks project bilaterally and are involved in the development and propagation of inflammatory disease. These putative pathological neuro-feedback loops may derive from the existence of biologically protective symmetrical mechanisms.

Evaluation of 4 commercial test kits for parvovirus B19-specific IgM.

Four commercial test kits for parvovirus B19 IgM were evaluated by testing 491 sera assembled into 7 panels. The serum panels were designed to assess sensitivity and specificity of the commercial assays and to reflect the various clinical settings in which acute B19 infection forms part of the differential diagnosis. A mu-capture radioimmunoassay (MACRIA) was used as the reference test. With respect to MACRIA, the commercial B19 IgM assays showed an overall sensitivity of 70.1-84.1% and specificity of 92.2 to 97.4%. Assay performance varied in different clinical situations. In sera from adults with acute B19 arthropathy, all 4 assays were 100% sensitive, but in children with fifth disease, the sensitivity ranged from 44.1 to 88.6%. The sensitivity of all 4 assays was also low when testing samples collected more than 6 weeks after onset of symptoms and in women with B19-associated embryopathy. Specificity was greater than 97% in healthy blood donors, but varied from 70.9 to 83.3% in patients acutely infected with other viruses, including rubella. Although the IgM test kits here evaluated may be usefully introduced for B19 diagnosis in certain settings, knowledge of their limitations will be important when results have been interpreted.