MSA

MSA is an acronym used for several unrelated concepts across medicine, geography, and quality management. This article outlines the most common meanings in a concise, neutral form.

Multiple System Atrophy (MSA) is a rare, progressive neurodegenerative disorder characterized by autonomic failure and parkinsonian or cerebellar features. Onset typically occurs in middle to older age. Core features include orthostatic hypotension, urinary incontinence, parkinsonism, and/or cerebellar ataxia. Levodopa often provides limited or transient benefit. The disease progresses over years with increasing disability; median life expectancy after symptom onset is about 6 to 10 years. Diagnosis is clinical, supported by imaging and autonomic testing, and there is no disease-modifying treatment. Management focuses on symptom relief, blood pressure support, and multidisciplinary care. Research continues into underlying mechanisms, including alpha-synuclein accumulation in glial cells.

Metropolitan Statistical Area (MSA) is a U.S. geographic unit defined by the Office of Management and Budget and used by the Census Bureau for statistical purposes. An MSA consists of a core urban area with a population of at least 50,000, plus adjacent counties with strong social and economic ties, typically measured by commuting patterns. Boundaries are revised with decennial censuses and are not political jurisdictions. MSAs are used in demography, economics, urban planning, and market analysis to describe regional characteristics; they can form Combined Statistical Areas when linked to nearby MSAs.

In manufacturing and quality management, MSA stands for Measurement Systems Analysis. It evaluates the accuracy and precision of the measurement process used to collect data on a product or process. A typical MSA assesses repeatability and reproducibility, often via gage R&R studies, to determine whether the measurement system introduces unacceptable variation. Standards from industry groups guide the implementation of MSA within quality programs.