Atroofia

Atroofia, or atrophy in some languages, refers to the wasting or decrease in size of an organ or tissue due to loss of cellular mass. It is a process, not a disease, and can affect muscles, nerves, brain, skin, or other tissues. Atroofia can be physiologic, as seen with aging, or pathologic, arising from disease or injury. In many organs, atrophy involves reduced cell size (cellular atrophy) while the number of cells is preserved; in some contexts, the organ may be gradually smaller with loss of tissue.

Causes include disuse or immobilization, denervation, ischemia or reduced blood supply, malnutrition or cachexia, hormonal depletion, chronic inflammation, and aging. Mechanisms involve decreased synthesis of structural proteins, increased protein degradation via the ubiquitin-proteasome pathway, activation of autophagy; loss of mitochondria and other organelles, cytoplasmic shrinkage, and sometimes replacement by fibrous tissue or fat.

Morphology: histology shows smaller cells, reduced cytoplasm, and fewer organelles; in organs, overall size is reduced and function can be diminished correspondingly.

Examples include skeletal muscle atrophy during prolonged bed rest, cast immobilization, or nerve injury; brain or cortical atrophy in neurodegenerative diseases; testicular or breast atrophy due to hormonal changes; and atrophy in other tissues such as skin or adipose tissue in chronic illness.

Diagnosis and treatment rely on clinical context and imaging or biopsy when needed. Treatment focuses on addressing the underlying cause, for example physical therapy and nutrition for disuse and malnutrition, treating ischemia, or hormonal replacement where appropriate. Prevention includes maintaining activity, adequate nutrition, and management of chronic diseases.