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What is muscle wasting medically termed as?

Muscle wasting, which is the weakening and breakdown of muscle tissue, is medically termed as muscular atrophy or sarcopenia. It involves the progressive loss of muscle mass, strength, and function. Muscle wasting can occur due to various reasons, ranging from disuse and inactivity to chronic diseases and aging.

What causes muscle wasting?

There are several potential causes and risk factors for muscle wasting:

  • Aging – Age-related muscle loss (sarcopenia) begins around age 30 and progresses with advancing age.
  • Inactivity – Lack of physical activity can cause muscles to weaken and atrophy over time.
  • Poor nutrition – Inadequate protein, calories, vitamins, and minerals can impair muscle maintenance.
  • Diseases – Certain illnesses like cancer, AIDS, kidney disease, heart failure, and rheumatoid arthritis increase muscle wasting.
  • Nerve damage – Conditions that affect motor neurons such as amyotrophic lateral sclerosis (ALS) cause nerve damage and muscle wasting.
  • Injuries – Trauma, burns, fractures, and being immobilized in a cast can lead to loss of muscle mass.
  • Medications – Drugs like corticosteroids, chemotherapy, and those that suppress the immune system can trigger muscle wasting.
  • Prolonged bed rest – Being bedridden for long periods due to illness or hospitalization contributes to muscle loss and weakness.
  • Weightlessness – Astronauts can experience significant muscle atrophy due to extended periods in space with little physical activity.

In many cases, muscle wasting arises when a combination of factors are present. The most severe muscle loss typically occurs with advanced age, chronic diseases, and compounding lifestyle issues like poor diet and sedentary habits.

What are the symptoms of muscle wasting?

Some common signs and symptoms of muscle wasting include:

  • Loss of muscle bulk, tone, and strength
  • Feeling physically weak and fatigued
  • Reduced ability to engage in daily activities
  • Difficulty swallowing or breathing (in advanced cases)
  • Weight loss
  • Frequent falls or physical instability
  • Loose, sagging skin where muscles have atrophied
  • Joint stiffness and achiness

The symptoms are often most noticeable in the muscles that are used regularly for movement and mobility, such as the arms, legs, neck, and trunk. People may first notice reduced strength and endurance during physical tasks, trouble rising from a chair, climbing stairs, or walking short distances.

How is muscle wasting diagnosed?

Doctors use several methods to diagnose muscle wasting and identify underlying causes:

  • Medical history – Discussing symptoms, risk factors, family history, medications, and other health conditions.
  • Physical exam – Assessing loss of muscle mass, reduced strength, and difficulty with motor function.
  • Blood tests – Checking complete blood count, electrolytes, thyroid, and markers of tissue damage or inflammation.
  • Urinalysis – Looking for signs of impaired kidney function.
  • Imaging – X-rays, CT scans, or MRI to visualize changes in muscle composition and mass.
  • Muscle biopsy – Taking a small sample of muscle tissue to examine under a microscope.
  • Nerve conduction study – Measuring how well and how fast nerves transmit electrical signals.
  • Electromyography – Evaluating electrical activity of muscles during rest, slight contraction, and forceful contraction.

These tests help determine whether muscle wasting is present and evaluate for specific disorders that could be causing it. The results also guide treatment approaches for the muscle loss itself and any underlying condition.

What are the complications of muscle wasting?

Some potential complications of muscle wasting include:

  • Impaired mobility and increased fall risk
  • Loss of independence in daily living
  • Reduced quality of life
  • Social isolation and depression
  • Bone loss and higher fracture risk
  • Impaired breathing
  • Digestive problems
  • Poor wound healing
  • Higher mortality in some cases

The complications arise largely from the progressive functional impairment and frailty that can occur with worsening muscle atrophy. People may lose the ability to care for themselves, raise their risks of dangerous falls, and experience reduced lifespans.

How is muscle wasting treated?

Treatment focuses on preserving existing muscle, rebuilding lost muscle, and addressing any underlying medical condition contributing to wasting. Some approaches include:

  • Exercise – Particularly strength training and resistance exercises to maintain and strengthen muscles.
  • Nutrition – Consuming adequate protein and calories, and supplements like creatine or amino acids if deficits exist.
  • Medications – Drugs that can slow muscle loss include testosterone, growth hormone, anabolic steroids, and angiotensin-converting enzyme (ACE) inhibitors.
  • Reducing inflammation – Anti-inflammatory drugs, antioxidants, and balancing hormones may help minimize wasting.
  • Treating underlying illness – This includes cancer therapy, controlling diabetes and heart failure, or replacing thyroid hormone if deficient.
  • Surgery – Repairing nerves or removing tumors pressing on nerves may improve muscle function in some cases.
  • Physical therapy – Stretching, massage, and range-of-motion exercises can maintain flexibility and mobility.

Treatment needs to be tailored to each patient, taking into account the severity of wasting, cause, prognosis, age, and overall health status. The focus is on maximizing quality of life through symptom management.

What are the risk factors for muscle wasting?

Some key risk factors that raise a person’s likelihood of experiencing muscle wasting include:

  • Advanced age (over 60 years)
  • Sedentary lifestyle and physical inactivity
  • Chronic diseases like cancer, kidney failure, COPD, heart disease
  • Neurodegenerative diseases such as ALS, multiple sclerosis, Parkinson’s
  • Nerve damage from injury, surgery, or immobilization
  • Malnutrition, vitamin/mineral deficiencies
  • High doses or prolonged use of corticosteroids
  • Prolonged bed rest or hospitalization
  • Space travel and weightlessness
  • Low testosterone levels
  • Genetic predisposition in some cases

The more risk factors present, the higher the susceptibility to significant muscle loss. People at highest risk tend to be older adults affected by multiple medical conditions that limit mobility.

What are some preventive measures against muscle wasting?

Some tips to help prevent and minimize the risk of muscle wasting include:

  • Engage in regular exercise – Mix of strength training, aerobics, stretching, and balance exercises
  • Maintain good nutrition – Eat adequate protein, fruits, vegetables, healthy fats
  • Stay hydrated – Drink plenty of fluids daily
  • Manage chronic illnesses – Follow treatment plans for medical conditions
  • Avoid long bed rest – Get up and move periodically when ill or hospitalized
  • Use assistive devices – Canes, walkers to prevent falls and promote activity
  • Consider supplements – Creatine, vitamin D, amino acids can help support muscles
  • Don’t smoke – Smoking exacerbates muscle wasting
  • Treat hormone deficiencies – Replace low testosterone, growth hormone

While muscle loss cannot always be avoided entirely, proactively minimizing the contributing factors can help delay onset and reduce the impacts if it does occur.

What are the stages of muscle wasting?

Muscle wasting typically progresses through the following general stages:

  1. Pre-sarcopenia – Early subtle muscle loss, starting as early as age 30.
  2. Sarcopenia – Accelerated muscle loss with impaired strength and function.
  3. Severe sarcopenia – Significant wasting with impact on activities of daily living.
  4. Cachexia – Extreme loss approaching 30% of total body mass.

It can take years to progress from pre-sarcopenia to severe muscle wasting. The stages are somewhat overlapping rather than strictly defined. Cachexia represents advanced, often end-stage muscle loss occurring in chronic illness.

How quickly does muscle wasting occur?

The speed of muscle wasting can vary substantially depending on the underlying cause:

  • Age-related sarcopenia – Gradual loss of 1-2% of muscle per year after 30 years old.
  • Inactivity – Shuttle astronauts can lose up to 30% muscle mass if immobile for prolonged periods.
  • Starvation – Marked muscle wasting is seen after only a few weeks of fasting.
  • Diseases – Cancer or AIDS patients may lose over 30 pounds of muscle in a few months.
  • Nerve damage – Rapid atrophy can occur within weeks if nerves are severed or compressed.

While muscle wasting tends to be a gradual process for older adults, certain situations like paralysis, malnutrition, or end-stage disease can quickly lead to profound loss of muscle tissue in just weeks to months.

What are some statistics on muscle wasting?

Some key statistics on the prevalence and impacts of muscle wasting include:

  • Up to 30% of all people over 60 years old are affected by age-related muscle loss.
  • Sarcopenia affects over 50 million people worldwide.
  • Muscle strength declines 15% per decade after age 50.
  • Severely ill hospitalized patients can lose up to 1 lb of muscle per day.
  • Muscle wasting is 3 times more common in people with cancer than healthy adults.
  • Chronic kidney disease patients lose 5-15% of muscle mass in 1-3 years.
  • Muscle wasting contributes to 20% of deaths in patients with cancer.
  • Sarcopenia is estimated to cost the U.S. healthcare system $18 billion annually.

Muscle wasting is increasingly common with an aging population and growing burden of chronic diseases. It takes a tremendous physical, emotional and financial toll on those affected and the healthcare system.

What types of doctors treat muscle wasting?

Some of the main specialists involved in treating muscle wasting include:

  • Primary care doctor – Initial evaluation and coordination of care.
  • Geriatricians – Treat muscle loss in older patients.
  • Rheumatologists – Evaluate inflammatory muscle disorders.
  • Neurologists – Assess nerve-related causes of muscle atrophy.
  • Oncologists – Manage cancer-associated muscle wasting.
  • Nephrologists – Treat kidney disease patients with muscle loss.
  • Cardiologists – Evaluate heart failure patients with cachexia.
  • Endocrinologists – Evaluate/treat hormone deficiencies contributing to wasting.
  • Rehabilitation doctors – Prescribe exercise and mobility aids for sarcopenia.

Depending on the underlying cause, multiple specialists may collaborate to address the various factors leading to someone’s muscle wasting.

Conclusion

Muscle wasting, known medically as sarcopenia or cachexia, is a complex phenomenon with a variety of potential causes. Aging, sedentary lifestyles, chronic diseases, nerve damage, medications, and poor nutrition all contribute to the loss of muscle tissue. While treatment can help slow progression, severe muscle wasting leads to disability, impaired quality of life, and higher mortality. Proper exercise, nutrition, and disease management are key to preventing muscle loss. With an aging population and increasing chronic illness, muscle wasting will likely continue to be a challenging issue in the future.