Acroosteolysis in diabetes mellitus

Lost bones: differential diagnosis of acro-osteolysis seen by the pediatric rheumatologist

INTRODUCTION

Acro-osteolysis is a radiographic finding which refers to bone resorption of the distal phalanges. Acro-osteolysis is associated with various conditions and its presence should prompt the clinician to search for the underlying etiology. The aim of this review is to discuss disorders with which acro-osteolysis is associated and their distinguishing features, with a focus on the pediatric population.

METHODS

A targeted literature review was performed using the term "acro-osteolysis" in combination with other key terms. The primary search results were supplemented using reference citations. Articles published prior to the year 2000 were included if they described additional associations not encountered in the more recent literature.

RESULTS

Genetic disorders (particularly primary hypertrophic osteoarthropathy and skeletal dysplasias) and rheumatic diseases (particularly psoriatic arthritis and systemic sclerosis) are the most frequently encountered conditions associated with acro-osteolysis in children. Hyperparathyroidism, neuropathy, local trauma and thermal injury, and spinal dysraphism should also be included in the differential diagnosis.

CONCLUSION

Although acro-osteolysis is uncommon, its presence should prompt the clinician to consider a differential diagnosis based on clinical and radiographic features.

Brachyonychia Associated with Acroosteolysis in Chronic Kidney Disease: How Phalange Shape Influences Nail Morphology

Brachyonychia is a rare manifestation in patients with chronic kidney disease. Longtime disease, secondary hyperparathyroidism, and hemodialysis are common conditions among those who present it. We evaluated 8 cases who presented brachyonychia in the nephrology department and compared the clinical versus the radiographic findings, and evaluated how the tissue adjusts to the underlying bone structure, giving different forms to the nails. We conclude that brachyonychia and acroosteolysis in chronic kidney disease suggest long-term disease, secondary hyperparathyroidism, and hemodialysis, besides it being a good model on how the bony structure defines the soft tissue morphology.

Imaging of the spectrum of bony injuries in the diabetic foot: a case series with emphasis on non-Charcot fractures

Diabetes mellitus is associated with an increased risk of lower limb injuries. Peripheral neuropathy, often associated with diabetes, has been demonstrated to increase the risk of fracture almost two-fold and is associated with complications related to fracture healing. Detection of neuropathy-related foot injury is frequently delayed owing to the paucity of symptoms and low degree of suspicion by the clinician. Early recognition of fracture or bone injury and appropriate treatment are critical in preventing debilitating foot deformity and disability. Therefore, the astute radiologist cognizant of these potential injuries plays an essential role in early diagnosis of bony injuries in the diabetic foot. We present a series of radiological images that depict a range of osseous injuries in the diabetic foot and emphasize the role of the radiologist in early recognition of these abnormalities.

Acro-osteolysis

Acro-osteolysis is an osteolysis of the distal phalanges of the hands and feet and can affect the terminal tuft or the shaft of the distal phalanx (transverse or band acro-osteolysis). It is often associated with distal digital ischemia, digital calcinosis, or severe sensory neuropathy. Acro-osteolysis has been associated with a heterogeneous group of disorders, including occupational activities, infections, rheumatic disorders (systemic sclerosis, psoriatic arthritis), endocrinopathies, genetic disorders, and lysosomal storage disorders. Plain radiography is the gold standard for the detection of acro-osteolysis.

Association of Acroosteolysis With Enhanced Osteoclastogenesis and Higher Blood Levels of Vascular Endothelial Growth Factor in Systemic Sclerosis

OBJECTIVE

Bone resorption of distal phalanges, or acroosteolysis (AO), can develop in patients with systemic sclerosis (SSc), causing pain and functional limitation. This study was undertaken to investigate whether AO may be associated with abnormal osteoclastogenesis in SSc patients and whether hypoxia may be involved in this process.

METHODS

Peripheral blood mononuclear cells (PBMCs) obtained from 26 SSc patients (11 with AO and 15 without AO) and 14 healthy controls were cultured in the presence of RANKL and macrophage colony-stimulating factor for 9 days. Tartrate-resistant acid phosphatase-positive multinucleated giant cells (MGCs) containing 3 or more nuclei were counted as osteoclasts. Plasma levels and effects of vascular endothelial growth factor (VEGF) on osteoclast formation were evaluated.

RESULTS

SSc patients with AO formed significantly more osteoclasts after 9 days than did patients without AO (mean ± SD 142.4 ± 67.0 versus 27.2 ± 17.6 MGCs/well; P < 0.001) or healthy controls (mean ± SD 18.7 ± 27.0 MGCs/well; P < 0.001). No significant difference in osteoclast formation was noted between the patients without AO and healthy controls. Plasma levels of VEGF were higher in SSc patients with AO compared to those without (mean ± SD 142.4 ± 69.6 pg/ml versus 88.1 ± 38.2 pg/ml; P < 0.005) or healthy controls (54.2 ± 24.6 pg/ml; P = 0.018). Priming with VEGF-A for 24 hours significantly increased osteoclast generation by 5.3 ± 1.9 fold (P = 0.0018). The radiographic extent of AO was associated with increased osteoclast formation (Spearman's ρ = 0.741, P = 0.01).

CONCLUSION

Our findings indicate that increased osteoclast formation and higher VEGF levels may contribute to AO in SSc patients. Further studies are needed to elucidate whether targeting osteoclastogenesis may provide a specific therapeutic option for SSc-associated AO.