Lymphatic Filariasis: A Method to Identify Subclinical Lower Limb Change in PNG Adolescents

Abstract

Lymphedema related to lymphatic filariasis (LF) is a disabling condition that commonly manifests in adolescence. Fifty-three adolescents, 25 LF infected and 28 LF non-infected, in age and sex-matched groups, using the Binax ICT rapid card test for filarial antigen were recruited to the study. None of the participants had overt signs of lymphedema. Lymphedema assessment measures were used to assess lower limb tissue compressibility (tonometry), limb circumference (tape measure), intra- and extra-cellular fluid distribution (bioimpedance) and joint range of motion (goniometry). The mean tonometric measurements from the left, right, and dominant posterior thighs were significantly larger in participants with LF compared to participants who had tested negative for LF (p = 0.005, p = 0.004, and p = 0.003, respectively) indicating increased tissue compressibility in those adolescents with LF. ROC curve analysis to define optimal cut-off of the tonometry measurements indicated that at 3.5, sensitivity of this potential screening test is 100% (95%-CI = 86.3%, 100%) and specificity is 21.4% (95%-CI = 8.3%, 41.0%). It is proposed that this cut-off can be used to indicate tissue change characteristic of LF in an at-risk population of PNG adolescents. Further longitudinal research is required to establish if all those with tissue change subsequently develop lymphedema. However, thigh tonometry to identify early tissue change in LF positive adolescents may enable early intervention to minimize progression of lymphedema and prioritization of limited resources to those at greatest risk of developing lifetime morbidity.

Measurement Properties of Instruments for Measuring of Lymphedema: Systematic Review

“…Intrarater reliability ranged from 0.88 -0.99. (11,32,33) In upper extremities, for the subgroup with lymphedema ICC was 0.95 and without lymphedema 0.81. (32) Pooled ICCintra for lower extremities showed an ICC of 0.89 (95%CI 0.88 -0.90).…”

“…In five studies the included patients were both female and male. (11,(20)(21)(22)(23) <<Insert figure 1 about here>> Fifteen studies reported reliability using ICC; SEM was reported in nine studies and SDC in two studies. Concurrent validity was reported in 16 studies, convergent validity in eight studies.…”

“…(32) Pooled ICCintra for lower extremities showed an ICC of 0.89 (95%CI 0.88 -0.90). (11,33) Reliability for measuring lymphedema using the Moisturemeter® was described in one study: Weighted mean SEM was 2.8% (σ = 3.2%) and weighted mean SDC was 6.6% (σ = 2.6%). (9, 10, 32, 43, 44, 46) SDC for lower extremities was reported in one study (intra-rater difference 264.1 ml; inter-rater difference 1014.5 ml), not recalculated to percentual change.…”

“…: median score of the risk of bias section is medium; -: mean score of the risk of bias section is high Open boxes: no comparison test applied Chen 16 UE + + ? + + ----------Gordon 11 LE + + + + + ? -?…”

“…(10) In later stages accumulation of adipose tissue and fibrotic alterations change the consistency of the lymphedema, and especially stage 3, the resistance in the skin and subcutaneous tissue can be measured by tonometry. (11) Prevention and early detection of lymphedema is important, because early treatment results in less burden for the patient and is cost-effective. (12) The most common treatment for lymphedema consists of manual lymphatic drainage, compression therapy, exercises and skin care.…”