atrophie

Atrophie, in medical usage, refers to a decrease in size or wasting of tissue or an organ, resulting from a reduction in cellular size or a loss of cells. It can be focal or systemic and may arise from reduced workload, denervation, aging, malnutrition, chronic disease, or hormonal disturbances. The clinical consequences depend on the tissue involved and can include weakness, reduced function, or sensory and cognitive changes.

Common forms include muscular atrophy (such as age-related sarcopenia or disuse atrophy after immobilization), neurogenic muscle atrophy due to nerve injury or motor neuron disease, cerebral atrophy with loss of brain parenchyma, and ocular atrophy from optic neuropathies or retinal degeneration. Glandular atrophy can occur with prolonged hormonal deficiency. Atrophy must be distinguished from hypoplasia, where tissue development is incomplete, or from necrosis, where tissue is destroyed.

Pathophysiology involves an imbalance between protein synthesis and degradation, with increased proteolysis via the ubiquitin-proteasome system and autophagy, reduced anabolic signaling, and, in aging, diminished mitochondrial function and capillary density. These changes lead to a reduction in cell size and sometimes cell number.

Diagnosis relies on clinical history and examination, supported by imaging (such as MRI or CT) showing reduced tissue volume, and, when appropriate, biopsy or laboratory tests to identify nutritional, metabolic, or endocrine causes. Management focuses on treating the underlying cause and supporting tissue maintenance through nutrition, physical therapy, and correction of hormonal deficiencies. Reversibility varies by tissue and etiology; disuse atrophy is often reversible, whereas neurodegenerative-related atrophy is more often progressive.