The evaluation of nailfold capillaroscopy pattern in patients with fibromyalgia, 2021, Benlidayı et al

[ola_cohn]

Abstract
Objectives: This study aims to evaluate nailfold capillaroscopic pattern in patents with fibromyalgia and to assess the relation of capillaroscopic parameters with clinical variables and disease-related measures.

Patients and methods: This cross-sectional, case-control study included 60 participants (4 males, 56 females; mean age: 44.0±8.2 years; range, 26 to 64 years) between August 2019 and November 2019. All participants were divided into two groups as the primary fibromyalgia group (n=30) who met the 2016 modified American College of Rheumatology Diagnostic Criteria for Fibromyalgia and the control group (n=30) consisting of age- and sex-matched healthy individuals. Nailfold capillaroscopy was performed by a digital microscope under a magnification of 200X. Capillary density, capillary loop diameter, number of dilated, giant and neoangiogenic capillaries, capillary shape, number of avascular areas, micro-aneurysms and micro-hemorrhages were evaluated by an assessor who was blind to the group allocation. In the fibromyalgia group, Widespread Pain Index, Symptom Severity Scale scores, and Fibromyalgia Severity scores were calculated. Health status and presence of benign joint hypermobility syndrome (BJHS) were evaluated using the Fibromyalgia Impact Questionnaire (FIQ) and revised Brighton criteria, respectively.

Results: Of the capillaroscopic parameters, the mean capillary loop diameter, number of micro-aneurysms, avascular areas, and neoangiogenic capillaries were significantly higher in the patient group compared to the controls (p<0.001, p=0.016, p=0.038, and p=0.04, respectively). Nailfold capillaroscopic findings did not significantly differ between the patients with (n=16) and without concomitant BJHS (n=14). Of the disease-related measures, only FIQ score showed a weak correlation with the number of dilated capillaries (p=0.324).

Conclusion: Patients with fibromyalgia have distinct capillaroscopic patterns than healthy population. Capillaroscopic features, in general, are not related to clinical variables and disease-related measures.

Keywords: Capillaries, capillaroscopy, fibromyalgia, nailfold capillaroscopy

Open access full text
https://archivesofrheumatology.org/full-text/1206

 

[Jonathan Edwards]

If these results are real they are extremely important - identifying microvascular structural change in FM.

Unfortunately, I suspect the chances of replicability to be small.

 

[Trish]

It would seem to be a breakthrough biomarker if it is replicated. Why do you think it is unlikely to be replicable?

 

[FMMM1]

At least they published it --- so it can be scrutinised.

 

[Jonathan Edwards]

I have done a nail fold study myself and it is one of those things where sampling is a huge problem.
It is claimed that the observers did not know which were patients and which controls. It would be interesting know how this was ensured.

The other thing is that the features reported as different are well known features of other diseases -not new characteristics. They are seen in scleroderma and dermatomyositis for instance. And in those conditions there is a well understood structural pathology in severe cases to match.

 

[Trish]

Presumably using a digital microscope means that photos can be kept and can be assessed by other experts also blinded to which are patients. That should help with the blinding problem.

 

[Jonathan Edwards]

Presumably using a digital microscope means that photos can be kept and can be assessed by other experts also blinded to which are patients. That should help with the blinding problem.

Maybe not. It all depends on which areas someone chooses to photograph. There is a compulsion to photograph bits that look the way you think they should!

 

[DokaGirl]

This might be interesting to see in pwME as well, if it hasn't already been investigated.

 

[Milo]

If these results are real they are extremely important - identifying microvascular structural change in FM.

Unfortunately, I suspect the chances of replicability to be small.

Can you explain why microvascular structural changes is important and what it means, both in the rheumatology context and in the fibromyalgia context?

Is the microscopic examination available widely for research purposes?

 

[Jonathan Edwards]

Can you explain why microvascular structural changes is important and what it means, both in the rheumatology context and in the fibromyalgia context?

Is the microscopic examination available widely for research purposes?

Microscopic examination of capillaries in the nailbed is simple and just requires allow power microscope or magnifying glass. To make it objective and consistent is more difficult because it would need some systematic way to sample images. So it is easily available but rarely used in research.

It is important because you see directly the damage to small blood vessels. The best example is in scleroderma where small blood vessels die off and the tissues become short of nutrition (ischaemic). You can actually see this happening with the naked eye and it is a very useful way to confirm the diagnosis. In dermatomyositis small vessels break down but are replaced so you see a 'tatty' appearance.