Ultrasound Assessment of Sarcopenia in Patients With Sarcoidosis

Quadriceps femoris muscle ultrasound in sarcoidosis: an observational case-control study

BACKGROUND

Although loss of muscle mass may be associated with general weakness, intolerance to physical activity and fatigue, it is underestimated and poorly understood in patients with sarcoidosis.

AIM

To compare the quadriceps femoris muscle (QFM) thickness measured by ultrasonography (US) between the female patients with sarcoidosis and controls, secondly to assess the correlation between the muscle strength, fatigue and QFM thickness.

DESIGN

Observational, case-control study.

SETTING

Physical Medicine and Rehabilitation Department of a University Hospital.

POPULATION

Thirty-one women with sarcoidosis and 27 healthy volunteers were included in the study.

METHODS

The participants were evaluated for the following outcomes: 1) handgrip strength; 2) QFM thickness measured using US; and 3) sonographic thigh adjustment ratio (STAR). The sarcoidosis group was also evaluated with the 30-second chair stand test (30s-CST) and Fatigue Severity Scale (FSS).

RESULTS

The QFM thickness and STAR values of the patients with sarcoidosis were significantly lower than those of the controls (P=0.0001). However, no statistically significant difference was observed between the handgrip strengths of the groups (P=0.581). There was no statistically significant correlation between the STAR values and handgrip strength in the sarcoidosis group; however, there was a significant positive correlation between the STAR values and 30s-CST (r=0.467, P=0.008).

CONCLUSIONS

Loss of muscle mass is one of the musculoskeletal conditions in patients with sarcoidosis that may be associated with nonspecific symptoms, such as general debility, intolerance to physical activity, and fatigue. In the present study, no difference was observed in hand grip strength between the groups, while we found that QFM thickness was affected in patients with sarcoidosis when compared to the controls. The ultrasonographic QFM evaluation seems to be an innovative tool which may be used at all stages of sarcoidosis patient follow-up.

CLINICAL REHABILITATION IMPACT

The grip strength is a commonly used test to detect muscle weakness, but onset of a decrease in muscle mass in the lower extremities may occur earlier. Considering the increased burden of musculoskeletal problems in this population, performing 30s-CST and sonographic QFM thickness is practical methods to identify risky patients.

Ultrasound Versus Computed Tomography for Diaphragmatic Thickness and Skeletal Muscle Index during Mechanical Ventilation

Background: Diaphragmatic alterations occurring during mechanical ventilation (MV) can be monitored using ultrasound (US). The performance of computed tomography (CT) to evaluate diaphragmatic thickness is limited. Further, the association between muscle mass and outcome is increasingly recognized. However, no data are available on its correlation with diaphragmatic thickness. We aimed to determine correlation and agreement of diaphragmatic thickness between CT and US; and its association with muscle mass and MV parameters. Methods: Prospective observational study. US measurements of the diaphragmatic thickness were collected in patients undergoing MV within 12 h before or after performing a CT scan of the thorax and/or upper abdomen. Data on skeletal muscle index (SMI), baseline, and ventilatory data were recorded and correlated with US and CT measures of diaphragmatic thickness. Agreement was explored between US and CT data. Results: Twenty-nine patients were enrolled and the diaphragm measured by CT resulted overall thicker than US-based measurement of the right hemidiaphragm. The US thickness showed the strongest correlation with the left posterior pillar at CT (r = 0.49, p = 0.008). The duration of the controlled MV was negatively correlated with US thickness (r = -0.45, p = 0.017), the thickness of the right anterior pillar (r = -0.41, p = 0.029), and splenic dome by CT (r = -0.43, p = 0.023). SMI was positively correlated with US diaphragmatic thickness (r = 0.50, p = 0.007) and inversely correlated with the duration of MV before enrollment (r = -0.426, p = 0.027). Conclusions: CT scan of the left posterior pillar can estimate diaphragmatic thickness and is moderately correlated with US measurements. Both techniques show that diaphragm thickness decreases with MV duration. The diaphragmatic thickness by US showed a good correlation with SMI.