Nailfold Video-Capillaroscopy in Sarcoidosis: New Perspectives and Challenges

Abstract

Introduction: Nailfold video-capillaroscopy (NVC) is a non-invasive cost-effective technique involving the microscopic examination of small blood vessels of the distal nailfold with a magnification device. It provides valuable information regarding the microcirculation including anomalies such as tortuous or dilated capillaries, hemorrhages, and avascular areas, which can characterize connective tissue diseases. The utility of NVC in the diagnosis and monitoring of systemic sclerosis (SSc) has been investigated in numerous studies allowing the distinction of the specific microvascular pattern of scleroderma from different conditions other than scleroderma (non-scleroderma pattern). Sarcoidosis (SA) is a systemic inflammatory disease that can affect various organs, including the lungs, skin, and lymph nodes. The purpose of our review was to evaluate the current state of the art in the use of NVC in the diagnosis of SA, to understand the indications for its use and any consequent advantages in the management of the disease in different settings in terms of benefits for patients.

Materials and methods: We searched for the key terms "sarcoidosis" and "video-capillaroscopy" in a computerized search of Pub-Med, extending the search back in time without setting limits. We provided a critical overview of the literature, based on a precise evaluation. After our analysis, we examined the six yielded works looking for answers to our questions.

Results: Few studies have evaluated that microcirculation is often compromised in SA, with alterations in blood flow and consequent tissue damage.

Discussion: Basing on highlighted findings, NVC appears to be a useful tool in the initial evaluation of sarcoidosis patients. Furthermore, capillaroscopy is useful in the evaluation of the coexistence of sarcoidosis and scleroderma spectrum disorder or overlap syndromes.

Conclusions: In conclusions, no specific pattern has been described for sarcoidosis, and further re-search is needed to fully understand the implications of nailfold capillaroscopy find-ings in this disease and to establish standardized guidelines for its use in clinical practice.

Keywords: connective tissue disease; inflammatory disease; nailfold video-capillaroscopy (NVC); sarcoidosis.

Figure 1

Publication trend concerning NVC over the years, from 1990 to the present day, which shows the growing interest in this technique. The x-axis shows the years from 1990 to the present, the y-axis the number of publications according to PubMed, Scopus and Google Scholar.

Figure 2

The figure shows the components for performing a capillaroscopy: a video-capillaroscopic probe with a magnifying lens (×50 to ×500) is used, equipped with a focusing ring and light adjustment system. The probe is connected to a screen to display real-time images and capture them via a foot pedal. The images are then analyzed using image digitizing software (Software Videocap 200® Reumatologia Release 11.00.02), which allows measurements and capillary counts to be taken.

Figure 3

Normal capillary bed image showing good visibility of capillaries with regular architecture. The capillary count per linear mm results in 8–9 capillaries/mm (the number of capillaries is normal). Next to normal capillaries, there are some tortuous and crossed capillaries (magnification ×200). Operators: B.R. and L.M., Pulmonology Unit, University of Trieste).

Figure 4

Capillaroscopic image at x200 showing granular blood flow, sign of slowing flow (marked with black arrow). microhemorrhage is also visible in the circle. Operators: B.R. and L.M., Pulmonology Unit, University of Trieste).

Figure 5

Examples of four nailfold video-capillaroscopy images recorded among four different sarcoidosis patients, all in the remission stage from five years. (Magnification 200×). Black stars (A,B) indicate the presence crossing capillaries. Black arrows (A–D) indicate the tortuosity of capillaries. The capillary count per linear mm results in 9–10 capillaries/mm (normal number) (Operators: B.R. and L.M., Pulmonology Unit, University of Trieste).

Figure 6

Examples of four nailfold video-capillaroscopy images recorded among four different sarcoidosis patients (A–D) all in the active stage of disease. (Magnification 200×). Black stars (A–C) indicate the presence crossing capillaries. Black arrows (D) indicate the tortuosity of capillaries. Black triangles (B) show the presence of hemosiderin deposits due to microhemorrhages. Black rhombus (C) indicates the presence of “bushy” capillaries. The capillary count per linear mm results in 7 capillaries/mm (slightly reduced) (Operators: B.R. and L. M., Pulmonology Unit, University of Trieste).