Atrophy: Introduction, Types, Treatment

Atrophy can be defined as the weakening, degeneration, shrinkage, or wasting away of a cell, tissue, or organ because of age, lack of use, or disease. Environmental changes, nutritional deficiency, health conditions, and even faulty genes can cause atrophy in humans. Atrophy can be of many types. Muscle atrophy affects the skeletal muscles therefore, it weakens them. It is common in patients who are paralyzed. Spinal Muscular Atrophy affects the neurons in the spinal cord, damaging the nerves because of which their functionalities are impacted. Vaginal atrophy impacts the lining of the vagina which can be caused by low estrogen.

Also read: Blood Group Test

Key Terms: Atrophy, degeneration, Muscle Atrophy, Spinal Muscular Atrophy, Vaginal Atrophy, Respiratory Muscle Weakness

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What is Atrophy?

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The medical definition of atrophy is the gradual loss of muscle or flesh due to the lack of use or disease. This progressive decline causes reduction in the functionality of the part of the body that is affected. It is a physiological process that breaks the tissues down and apoptosis happens at the cellular level which is the death of cells. Although atrophy can happen at the cellular level, it is when multiple cells or tissues atrophy that the size of the major tissue or organ diminish in size.

What is Atrophy?

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Types of Atrophy

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The different types of atrophy are:

1. Atrophy of the muscles
2. Spinal Muscular Atrophy
3. Vaginal Atrophy

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Atrophy of Muscles

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Muscle atrophy is the degeneration, wasting or the loss of muscle in the body. Muscle atrophy can be categorized into three types namely – physiologic, pathologic and neurogenic.

Physiologic Muscle Atrophy 

This is caused when the muscles are not used actively. In most cases, this type of atrophy can be reversed with adequate exercise or movement of the muscles. It is most common in people who are bed-ridden because of medical reasons due to which movement in their body is restricted. Paralysis and stroke can cause this restricted movement in a patient resulting in atrophy. Humans in space can also be prone to physiologic atrophy because of the lack of gravity. Since there is no gravity in space, our muscles do not have active function as opposed to living on earth. Due to this muscle mass decreases because of atrophy.

Pathologic Muscle Atrophy 

This type of atrophy is caused due to aging, nutritional deficiencies, reduced blood supply, etc. Injury, cancer can also cause this type of atrophy. Sometimes, an enlarged growth like a benign tumor compresses tissues around it due to which pathologic atrophy of those tissues occur. When observed, the cells of these tissues tend to contain less mitochondria and endoplasmic reticulum.

Neurogenic Muscle Atrophy 

Lack of muscle use can cause a disruption of the motor nerve supply to the muscle hence causing a neurogenic muscle atrophy. The destruction of nerve cells will cause the muscle to deteriorate and become paralyzed.

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Spinal Muscular Atrophy

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Spinal Muscular Atrophy is classed as a genetic disorder. It causes weakness and degeneration of muscles, specifically skeletal muscles. Motor neurons are responsible for muscle movement. The cells in these neurons get weakened and lose function. This weakness is mostly concentrated towards the proximal area of the body rather than the distal part of the body. It tends to worsen with age.

There are different types of Spinal Muscular Atrophy based on severity. They are discussed below.

Type 0: This type is the rarest and the most severe form of Spinal Muscular Atrophy and is recognized before birth itself. Infants are observed to move less when they’re in the womb, have low muscle mass and are born with bone deformities. Due to this condition, their respiratory muscles are weak and hence they don’t survive too long after birth. Infants with Spinal Muscular Atrophy tend to have heart defects as well.

Type 1 (Werdnig-Hoffman Disease): This type is the most common form. It is severe and quite apparent within the first few months of the life of the infant born with this type of spinal muscular atrophy. Children living with it have trouble swallowing resulting in growth abnormalities. They are unable to control head movements and require assistance to sit down. Their respiratory muscles are weak which causes them to have respiratory issues. Children with Type 1 Spinal Muscular Atrophy tend not to survive past childhood due to respiratory failure.

Type 2 (Dubowitz Disease): This type of the condition causes muscle weakness in children between the ages of 6-12 months. At the early stage, children with this condition can cope but as they grow older, the muscle weakness gets worse. They are unable to sit or walk without aid. They also tend to have tremors, scoliosis which is the spine curving side to side and also weakness of the respiratory muscle. The lifespan of individuals having type 2 spinal muscular atrophy is usually 20-30 years.

Type 3 (Kugelberg-Welander Disease): This type usually begins after early childhood. Muscle weakness causes standing and walking difficulty. At the early stage, individuals can cope without using any aid but as they get older, they are unable to stand or walk without aid and often require wheelchairs. Life span however is not greatly affected and tends to be normal.

Type 4: This type of spinal muscular atrophy is rare and begins in adulthood. Muscle weakness, breathing problems and tremors are experienced by the individuals. Life span is not affected.

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Vaginal Atrophy

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Vaginal atrophy is also called atrophic vaginitis. It occurs due to less estrogen due to which the walls of the vagina become thin. It occurs mostly after menopause. Vaginal atrophy can also cause urinary tract infections (UTI). Not only does it occur during menopause, it can occur in younger women whose estrogen levels are affected.

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Things to Remember

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• Atrophy is defined as the degeneration, wasting away or weakening of tissues or organs. Some of the causes of atrophy are lifestyle, environmental changes and genetic disorders.
• Progressive decline of muscles causes the functionality of the affected part to diminish.
• Muscle atrophy is broadly classified into physiologic, pathologic and neurologic atrophies.
• Physiologic muscle atrophy is caused when the muscles are not used actively.
• Pathologic atrophy is caused due to aging, nutritional deficiencies and reduced blood supply.
• Neurologic atrophy is nerve cell degeneration.
• Spinal Muscle Atrophy is a genetic disorder. It causes weakness and degeneration of muscles, specifically skeletal muscles. Motor neurons are responsible for muscle movement.
• There are 5 types of SMA ranging from Type 0 to Type 4.
• Vaginal Atrophy is caused due to low estrogen levels during menopause. It can also occur in younger females due to the imbalance of the estrogen hormone. It causes vaginal dryness and, in some cases, it can cause UTI.
• Although most forms of atrophy caused by genetic abnormalities cannot be reversed, some forms of muscle atrophy can be reversed by adequate exercise, nutrition, surgery, physical and ultrasound therapy.