Atrofi

Atrofi is a general term for a decrease in size, function, or mass of a tissue or organ. It can be cellular or organ-wide and often results from a reduction in cell size rather than cell death, although some conditions involve loss of cells as well. Common examples include skeletal muscle atrophy and cerebral atrophy.

Causes and types include disuse atrophy from prolonged inactivity or immobilization; denervation atrophy after nerve injury; ischemic or cachectic atrophy in chronic disease; and hormonal or nutritional deficiencies. Physiological aging can lead to senile atrophy. Atrophic changes can be adaptive or pathological, and in many tissues the atrophy may be reversible if the underlying cause is addressed early.

Mechanisms involve reduced protein synthesis and increased protein degradation, with activation of pathways such as the ubiquitin-proteasome system and autophagy. Histologically, cells shrink and tissue weight decreases. In skeletal muscle, fibers become smaller and may appear angular; neurogenic atrophy often shows fiber type grouping and more pronounced structural changes due to nerve loss.

Diagnosis and assessment rely on clinical history and imaging to measure organ size. MRI or CT can quantify brain atrophy, while ultrasound can assess muscle wasting. Biopsy may help distinguish atrophy from other pathology, and laboratory tests can reveal nutritional, metabolic, or endocrine factors contributing to the atrophic process.

Treatment and prognosis focus on addressing the underlying cause. Interventions may include physical therapy and progressive resistance training, nutritional optimization, and management of hormonal or metabolic disorders. The prognosis varies: disuse atrophy is often reversible with rehab, whereas neurogenic or age-related atrophy can be less reversible and progressive.