Understanding Clinical Characteristics of Muscle Weakness.

BACKGROUND: Muscle weakness is a debilitating condition that can lead to frailty, falls, and functional decline. Muscle weakness is found across many diseases; therefore, understanding what constitutes this condition is paramount. The National Library of Medicine provides 2 definitions of muscle weakness, both from a disease perspective. These definitions are narrow and do not account for overlapping causes of muscle weakness. Nurses are holistic practitioners, so they need to understand the clinical characteristics of muscle weakness, regardless of underlying disease processes. METHODS: Secondary analysis of data from an earlier qualitative study. Using content analysis of transcripts of semistructured interviews with a multidisciplinary group of 12 experts in the management of muscle disorders, we identified characteristics of muscle weakness from the clinicians' perspectives. RESULTS: Muscle weakness has characteristics of debility, loss of function, and asymmetry. The characteristics of debility include lack of strength, atrophy, and fatigue. Muscle weakness does coexist with muscle tightness. CONCLUSIONS: The characteristics of muscle weakness identified in our study are markedly different from those included in National Library of Medicine definitions. As a condition, muscle weakness has both subjective and objective traits. Therefore, clinician assessment and patient input combined capture the comprehensive nature of muscle weakness. Nurses' awareness of what constitutes muscle weakness, regardless of diagnosis, is the first step in optimal management of this condition.