Diagnosis of acute Charcot neuroarthropathy
Original article:
Biochemical and ultrasound tests for the early diagnosis of active
neuro-osteoarthropathy (NOA) of the diabetic foot. Piaggesi A, Rizzo L,
Golia F, Costi D, Baccetti F, Ciaccio S, De Gregorio S, Vignali E, Trippi D,
Zampa V, Marcocci C, Del Prato S. Diabetes Res Clin Pract 2002; 58: 1–9.
Summary
Over a 12-month period, Piaggesi and colleagues studied all patients
referred to their regional center in Pisa, Italy, with a diagnosis of acute
Charcot neuroarthropathy (CN), and compared the findings with those of nine
patients with chronic stable CN, 14 with uncomplicated diabetic neuropathy,
13 non-neuropathic diabetic patients and 15 healthy controls. Markers of
bone turnover were measured in all subjects: bone-specific alkaline
phosphatase (B-ALP), osteocalcin (BGP), carboxy-terminal collagen
telopeptide (ICTP) and urinary excretion of deoxypyridinoline (DPD).
Ultrasound tests included quantitative ultrasound of the calcaneum and
dual-energy x-ray absorptiometry of the lumbar spine and femur.
The main findings included lower quantitative ultrasound of the calcaneum in
those with active CN (Table I), whilst urinary DPD was higher in the
neuropathic non-CN group. ICTP was higher in both CN groups (Table II).
Table I: High-resolution ultrasound of bone mass
density (BMD), quantitative ultrasound index (QUI), broadband ultrasound
attenuation (BUA) and speed of sound (SOS).
Table II: Biochemical measures in the patient and
control groups.
The results suggest that in neuropathic patients, elevated urinary
DPD might indicate high risk of CN, whereas abnormalities of ICTP might
confirm the presence of CN.
The authors conclude that they have described a possible integrated approach
for the diagnosis and monitoring of CN.
Comment
Piaggesi and colleagues should be applauded for their valiant efforts to
improve the diagnostic criteria for CN. However, there are a number of
problems with the study which are not necessarily the fault of the authors.
Studies in CN are fraught with difficulties as the condition is relatively
rare and, even in regional centers, such as that of the authors in Pisa, the
number of new referrals is small. Thus, only 15 patients with acute CN were
seen during 1998. However, in a high-risk population of neuropathic diabetic
patients, evidence of Charcot changes on radiographs are not uncommon [1].
Another problem with the current study is that it is cross-sectional and it
is not therefore possible to estimate the predictive value of any of the
biochemical or ultrasound investigations.
A further problem with CN is that there are no internationally accepted
diagnostic criteria as to what constitutes acute CN. Thus, a patient with
edema, erythema and tenderness could have been included in this study
whereas the same individual might not have been diagnosed with CN in another
center.
The present report does provide leads for future prospective studies which
would, by necessity, have to be multicenter, following a very high-risk
group. Urinary DPD excretion might identify high-risk or even very early
acute CN. Serum ICTP might also be a useful marker.
In the meantime, any neuropathic patient with a unilaterally warm, swollen
foot, with or without a history of trauma, should be considered as having
acute CN until proven otherwise. Initial treatment should include
offloading, usually by some form of casting, and possibly a bisphosphonate
[2].
References
1. Cavanagh PR, Young MJ, Adams JE et al. Radiographic
abnormalities in the feet of neuropathic diabetic patients. Diabetes Care
1994; 17: 201–9.
2. Jude EB, Selby PL, Burgess J et al. Bisphosphonates in the treatment of
Charcot neuroarthropathy: a double-blind, randomized controlled trial.
Diabetologia 2001; 44: 2032–7.
Summary and Comment:
Andrew J.M. Boulton, Miami, FL, USA
