Hypertrophic Osteoarthropathy Workup

Updated: Apr 16, 2015
  • Author: Richa Dhawan, MD, CCD; Chief Editor: Herbert S Diamond, MD  more...
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Workup

Laboratory Studies

The erythrocyte sedimentation rate may be elevated in persons with pachydermoperiostosis and is often elevated in those with secondary hypertrophic osteoarthropathy. [13] .

Serum alkaline phosphatase levels may be elevated secondary to periosteal new bone formation. [13] These bone markers can be used to follow-up the disease activity. Isolated reports have shown an increase in some bone formation markers and resorption such as TAP, BAP, BGP, carboxyterminal propeptide of type I procollagen, or NTX (see N-Terminal Telopeptide) in patients with either primary or secondary hypertrophic osteoarthropathy, suggesting that its measurement could be useful for monitoring disease activity. Moreover, an increase in the serum levels of IL-6 and receptor activator of nuclear factor (NF)-κB ligand have been recently related to the increased bone resorption observed in some of these patients, suggesting a possible role of these cytokines in the regulation of bone turnover in this process. [61]

Studies in patients with PDP or PHO evidenced increased plasma levels of several substances, such as endothelin-1, β-thromboglobulin, platelet-derived factor, von Willebrand factor, and vascular endothelial factor, among others, which could have a role in disease progression and periosteal proliferation. [61]

Biallelic HPGD mutations are found in most patients with typical PHO, and sequencing of the HPGD gene is a highly specific first-line investigation for patients presenting in this way, particularly during childhood. [90]

Finally, as commented above, data indicate that mutations in 15-hydroxyprostaglandin dehydrogenase, the main enzyme of prostaglandin degradation, can be the cause of PHO. Homozygous individuals with this mutation also show elevated levels of prostaglandin E2 and its metabolite, PGE-M, thus suggesting that its measurement can be useful in early investigations of patients with hypertrophic osteoarthropathy.

If an effusion is present, the synovial fluid is noninflammatory (cell count < 500/µL), with a predominantly lymphocytic and monocytic infiltrate.

The combination of symptoms of proliferation of skin, bone, and capillaries with periostosis of the long bones should initiate an intensive search for an underlying malignant disease usually of thoracic organs. [5]

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Imaging Studies

Distinguishing between clubbed and nonclubbed fingers, in vivo, using plain radiograph is possible. [91]

Plain radiographs show 2 types of changes, bone formation with hypertrophy and bone dissolution with acroosteolysis. [17]

Periosteal thickening occurs along the shafts of long and short bones, initially appearing in the distal diaphyseal regions of the long bones. Periosteal changes are seen as a continuous thin line of sclerotic new bone separated from the cortex by a radiolucent space. Over time, the periosteal new bone thickens and fuses with the cortex, and the process extends proximally to the diaphysis and metaphysis. These changes are most commonly observed in the tibia, radius, ulna, fibula, and femur. PHO is distinguished by more exuberant periosteal new bone formation that extends to the epiphyseal regions. [13] But there are documented HOA cases without radiographically detectable periostitis. [72]

Acroosteolysis may be seen in the distal tufts in patients with long-standing hypertrophic osteoarthropathy.

Radionuclide bone scan using technetium Tc 99m polyphosphate shows increased uptake of the tracer in the periosteum, often appearing pericortical and linear in nature. Because of its ability to delineate the subtleties in progression and regression of the disease these findings can be present even when findings from plain radiographs are doubtful. The clubbed digits may also show increased uptake in early passage flow studies, as depicted in the images below. [13, 52]

Clubbing associated with hypertrophic osteoarthrop Clubbing associated with hypertrophic osteoarthropathy can be classified into 3 topographical groups (ie, symmetrical, unilateral, unidigital). This is symmetrical clubbing; it involves all the fingers.
Joint symptoms of hypertrophic osteoarthropathy ra Joint symptoms of hypertrophic osteoarthropathy range from mild to severe arthralgias that involve the metacarpal joints, wrists, elbows, knees, and ankles. The range of motion of affected joints may be slightly decreased. When effusions are present, they usually involve the large joints (eg, knees, ankles, wrists).
For hypertrophic osteoarthropathy diagnosis, radio For hypertrophic osteoarthropathy diagnosis, radionuclide bone scan using technetium Tc 99m polyphosphate shows increased uptake of the tracer in the periosteum, often appearing pericortical and linear in nature. These findings can be present even when findings from plain radiographs are doubtful. The clubbed digits may also show increased uptake in early passage flow studies.

More recently,99m Tc-diphosphonate complexes has emerged as the most sensitive tool for the detection and evaluation of the extent of hypertrophic osteoarthropathy. [72]

Angiography findings may demonstrate hypervascularization of the finger pads. [92, 19]

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Other Tests

An evaluation for the primary condition is warranted in patients with possible secondary hypertrophic osteoarthropathy; for example, search for an intrathoracic malignancy or infection.

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Histologic Findings

Biopsy of the skin and bone marrow may show an exacerbated proliferation of fibroblasts, which are associated with diffuse epidermal hyperplasia and lymphohistiocytic infiltration with collagen redistribution.

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