Lymphatic Filariasis Increases Tissue Compressibility and Extracellular Fluid in Lower Limbs of Asymptomatic Young People in Central Myanmar

Abstract

When normal lymphatic function is hampered, imperceptible subcutaneous edema can develop and progress to overt lymphedema. Low-cost reliable devices for objective assessment of lymphedema are well accepted in clinical practice and research on breast-cancer related lymphedema but are untested in populations with lymphatic filariasis (LF). This is a cross-sectional analysis of baseline data in a longitudinal study on asymptomatic, LF antigen-positive and -negative young people in Myanmar. Rapid field screening was used to identify antigen-positive cases and a group of antigen-negative controls of similar age and gender were invited to continue in the study. Tissue compressibility was assessed with three tissue tonometers, and free fluids were assessed using bio-impedance spectroscopy (BIS). Infection status was confirmed by Og4C3 antigen assay. At baseline (n = 98), antigen-positive cases had clinically relevant increases in tissue compressibility at the calf using a digital Indurometer (11.1%, p = 0.021), and in whole-leg free fluid using BIS (9.2%, p = 0.053). Regression analysis for moderating factors (age, gender, hydration) reinforced the between-infection group differences. Results demonstrate that sub-clinical changes associated with infection can be detected in asymptomatic cases. Further exploration of these low-cost devices in clinical and research settings on filariasis-related lymphedema are warranted.

Addition of Lymphatic Stimulating Self-Care Practices Reduces Acute Attacks among People Affected by Moderate and Severe Lower-Limb Lymphedema in Ethiopia, a Cluster Randomized Controlled Trial

“…In our study, mid-calf circumference and tissue compressibility fluctuated the most among moderate and stage 0 cases in both countries and stage P cases in Ethiopia. Although there was no observable swelling present on stage 0 and stage P legs, the notable changes in tissue compressibility at baseline were similar to those detected among young asymptomatic people infected with LF in Myanmar [27], and suggest a covert accumulation of extracellular fluid typical of latent lymphedema. Monitoring for very early and subclinical change is a key strategy in preventing cancer-related lymphedema [26] and investigation on early detection and intervention strategies among LF-and podoconiosis affected populations are also warranted.…”

Effect of an Enhanced Self-Care Protocol on Lymphedema Status among People Affected by Moderate to Severe Lower-Limb Lymphedema in Bangladesh, a Cluster Randomized Controlled Trial

“…After adjusting for stage at baseline, leg dominance was not a significant factor in this cohort, and Indurometer and circumference data were analyzed as right and left legs. In keeping with previous studies on lymphedema, a change of either ≥10% or ≥2cm in circumference score was considered clinically relevant and for Indurometer scores a change of ≥10% was used [30,31]. Adherence to the self-care protocol was assessed as performance of the allocated self-care regimen on at least 5 days per week.…”

“…There were clinically relevant within-group changes (≥10%) in both groups with the largest change observed on legs affected by severe lymphedema in the intervention group at 12 weeks It should be noted that lymphedema stage as an indicator of skin pathologies and tissue fibrosis, and limb circumference as an indicator of limb swelling, both have a linear relationship with lymphedema progression [1,31]. However, since tissue compressibility is determined by multiple tissue components, Indurometer scores may capture changes in skin pathologies, extracellular fluid loads and connective tissue fibrosis, and the direction of change should be interpreted in association with other available objective measures [1,30,31].…”

Neglected and Emerging Tropical Diseases in South and Southeast Asia and Northern Australia

“…They each contribute to a much better understanding of Neglected and Emerging Tropical Diseases in South and Southeast Asia and Northern Australia. The contributions to these topics can be summarized as follows: four submissions on LFs [ 2 , 3 , 4 , 5 ], four submissions on STHs [ 6 , 7 , 8 , 9 ], two submissions on rickettsial diseases [ 10 , 11 ], and one submission on arboviral diseases [ 12 ]. A systematic review and meta-analysis leads the opening section on LF [ 2 ], which reviews prevalence and disease burden of LF in southeast Asia [ 2 ].…”

“…Two studies in Myanmar review the utility of dried blood spots on filter paper for sampling for detection Bm14 antibody and Og4C3 antigen in cases of LF [ 3 , 4 ], with the latter indicating need for reconciliation between different sampling methods. A further study in Myanmar examined the usefulness of low-cost devices for measuring tissue compressibility and extracellular fluid, used and accepted in other clinical settings, for objective assessment of lymphedema [ 5 ]. A review paper leads the other major section on STH, which focuses on the prevalence of STHs in different groups, including immigrants, travellers, military personnel and veterans in Australia and Asia [ 6 ].…”