What is Atrophy?
Atrophy is a decrease in size of a part of a body. This can affect an organ, tissue or cell. Atrophy may be attributed to a decrease in size of individual cells or a reduced number of cells in the affected organ or tissue. Atrophy is usually acquired, meaning it is the result of a disease (pathological atrophy) or some change in condition within the body (physiological atrophy).
Atrophy is commonly referred to as ‘wasting’ and while it usually affects one or a few areas of the body at a time, it can also affect large parts of the body. This generalized wasting which is usually associated with fatigue and a lack of appetite or malnutrition is seen in certain chronic diseases like cancer or AIDS and is known as cachexia. Atrophy in these cases may not be reversible, especially in the latter stages of the disease that precede death. Depending on the cause, severity and site that is affected, atrophy may be reversed although this may take a long period of time and require medical treatment and other therapeutic measures.
Causes of Atrophy
Atrophy may be caused by :
- Malnutrition which results in generalized atrophy.
- Reduced functional activity which may also be known as disuse atrophy. This may be seen when parts of the body are immobilized and the lack of physical activity will cause atrophy of the muscles.
- Age where atrophy may be due to wear and tear, reduced activity or other factors like chronic diseases.
- Reduced blood supply causes a reduction in nutrients and oxygen leading to ‘shrinking’ as only a certain amount of cells or size of cells can be maintained in the affected area.
- Interference of nerve supply may lead neuropathic atrophy.
- Pressure atrophy which may be due to a reduced blood supply.
- Endocrine disorders may cause a reduction in hormonal stimulation of an organ leading to atrophy.
What is degeneration?
Degeneration, in medicine, means the deterioration of certain organs, tissues or cells, resulting in a gradual loss of their structure and function. Recovery is often not possible with degeneration. Degenerative disorders usually end with -osis. Although the body’s innate mechanisms ensures that any damage or degradation can be minimized and normal function restored by the action of cell replication, in degeneration these mechanisms are either impaired or may not exist for certain cells like nerve cells.
Degeneration vs Atrophy
A separate concept to degeneration that is sometimes mistaken for being the same phenomenon is atrophy. In atrophy there is a gradual shrinkage in size of the cells, tissues or organs and sometimes there is even a decrease in the number of cells. Atrophy is a consequence of under-utilization although it can be a result of other disease processes. It can usually be reversed with cells replicating or expanding is size with increased use.
Degeneration may result from :
- Physical wear and tear, like in supraspinatus tendinosis (degeneration of the supraspinatus tendon in the shoulder)
- Aging, like in macular degeneration of the retina
- Metabolic disorders, like in fatty degeneration (steatosis) of the liver
- Genetic disorders, like cystic fibrosis
Simply, atrophy means reduction in size while degeneration means erosion.
Degenerative Disorders and Diseases
Degenerative disorders should be distinguished from inflammatory disorders that end with -itis, for example, rheumatoid arthritis, hepatitis, and so on. Sometimes, both inflammation and degeneration may occur simultaneously at the single site or follow concurrently. An example is supraspinatus tendinitis followed by supraspinatus tendinosis.
Degenerative disorders and diseases are often considered serious, and rightfully so. The body needs all its organs and tissues functioning optimally to maintain the state of equilibrium associated with good health that is known as homeostasis. With degenerative diseases, this is however not possible.
Of all the degenerative diseases, it is probably the neurodegenerative disorders that receive widespread attention these days. In neurodegenerative diseases, part of or the entire nerve cell (neuron) is damaged or dies. Since nerve cells can repair but not replicate, a loss of these neurons eventually leads to degradation of the functions that it controls. Many of these diseases occur for unknown causes, may be due to hereditary factors or even be associated with alcohol misuse, prescription drugs and substance abuse. A typical example is Parkinson’s disease and parkinsonism which has become quite prevalent these days.