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Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Amyotrophic Lateral Sclerosis


Text Only Home | Graphic-Rich Site | Overview | Risk and Causation | Diagnosis | Treatment | Prognosis | Differential Diagnosis | Specialists | Rehabilitation | Comorbid Conditions | Complications | Factors Influencing Duration | Length of Disability | Ability to Work | Failure to Recover | Medical Codes | References

Medical Codes

ICD-9-CM:
335.20 - Amyotrophic Lateral Sclerosis; Motor Neuron Disease

Related Terms

  • ALS
  • Lou Gehrig's Disease
  • Motor Neuron Disease

Overview

Amyotrophic lateral sclerosis (ALS) is a rare, progressive neurological disorder in which nerves that control the body's muscle activity deteriorate (degenerate). ALS affects the nerves (motor neurons) located in the brain (medulla and cortex) and the spinal cord. Because of the neuron degeneration, electrical and chemical messages (impulses) originating in the brain do not reach the muscles they are meant to activate. The result is progressive weakness and wasting (atrophy) of the muscles. ALS is characterized by the presence of extremity (distal) weakness with the presence of upper motor neuron signs, as opposed to the presence of proximal weakness with the absence of upper motor neuron signs common in Progressive Muscular Atrophy (PMA). Typically, ALS is more rapidly progressive and more disabling than PMA.

The cause of ALS is not known. Some theoretical causes are genetic or inherited factors, environmental poisons (toxins), viral infections, or dysfunction of the body's defense system (immunological factors). A specific genetic defect that leads to mutation of the enzyme known as superoxide dismutase one (SOD1) is responsible for approximately 20% of all inherited cases ("Amyotrophic"). Researchers are focusing on this mutation in their search for possible causes of neuron death. Other causes may be overexposure to glutamate (a naturally occurring brain chemical), attacks by highly charged destructive molecules called free radicals, the presence of abnormal clumps of proteins possibly toxic to the nerve cells, and an abnormal tangling of the filaments that carry nutrients to the ends of the neurons.

Incidence and Prevalence: An estimated 20,000 individuals have ALS, and an estimated 5,000 new cases will be diagnosed each year ("Amyotrophic").

Source: Medical Disability Advisor



Causation and Known Risk Factors

The onset of ALS occurs between the ages of 40 and 60. Men are more likely develop the disease than women. Ninety to ninety-five percent of all ALS cases occur at random with no clearly associated risk factors; approximately 5% to 10% of all ALS cases are inherited ("Amyotrophic").

Source: Medical Disability Advisor



Diagnosis

History: The first symptoms of ALS may include muscle twitching, cramping, stiffness or weakness in an arm or leg. Individuals may complain of difficulty swallowing (dysphagia), have slurred or nasal speech, or problems forming words (dysarthria). There may be difficulty holding objects and performing tasks that require fine hand movements such as writing or buttoning a shirt. Individuals may report more frequent tripping or stumbling depending on which muscles in the body are damaged first. There may be exaggerated reflexes and an overactive gag reflex.

Muscle atrophy and weakness eventually spread to other parts of the body.

Physical exam: The physical exam is focused on assessing the individual's general state of health as well as the ability to walk and manipulate objects, swallow, and use the muscles controlling respiration. The existence of musculoskeletal pain should also be determined. As with any serious illness, individuals presenting with the symptoms of ALS may be anxious or depressed.

Tests: An electromyography (EMG) study of the muscles may reveal abnormal nerve activity. A diagnosis of ALS, however, should not be confirmed unless nerve degeneration (denervation) is present in three extremities. To rule out other diseases, additional testing may include biopsy of a wasted muscle, blood studies (serum creatine kinase may be elevated), x-ray study of the spinal cord after injected with dye (myelography), CT or MRI, and examination of the cerebrospinal fluid.

Source: Medical Disability Advisor



Treatment

The drug riluzole was approved in 1997, and its objective is to slow the progression of ALS by decreasing the amount of glutamate in the brain. In clinical trials, this drug has shown to delay death by a few months. Pharmaceutical research is underway to find a multidrug "cocktail" for treating neurodegenerative diseases based on the model used in the treatment of AIDS and cancer. Antidepressants can treat accompanying depression. Antibiotics are used to treat respiratory and urinary tract infections that can result from being immobile. Medication can also be prescribed to relieve musculoskeletal pain.

Other treatment is supportive rather than therapeutic and is intended to keep the individual as comfortable as possible. It may include grief therapy, physical therapy, occupational therapy, skin and mouth care, bowel and bladder care, nutrition support by feeding the individual directly through a surgically placed stomach tube, tracheostomy and mechanical ventilation for breathing problems. Caregivers need to be especially attentive with regard to the maintenance of bowel and bladder function, oral hygiene, protective eye care, and careful positioning so as to decrease the likelihood of pressure sores.

Source: Medical Disability Advisor



Prognosis

The progress of ALS is especially devastating because individuals with the disease retain their mental powers (cognition) while their bodies gradually waste away. Individuals in the end stages of ALS are totally paralyzed, unable to speak, move, or breathe on their own. While death from ALS usually occurs 2 to 6 years after the onset of the disease, some individuals have lived more than 20 years after diagnosis.

The focus of treatment and rehabilitation is to support the individual in performing daily activities and to forestall further deterioration for as long as possible. Early diagnosis offers an opportunity to plan retirement from work, arrange for financial management, discuss the management of future medical problems, and make informed end-of-life decisions in advance (advanced directives).

Source: Medical Disability Advisor



Differential Diagnosis

  • Chronic inflammatory disease of the spinal cord and meninges
  • HTLV
  • Human immunodeficiency virus (HIV)
  • Intrinsic diseases of the muscles
  • Lyme disease
  • Multifocal motor neuropathy
  • Multiple sclerosis
  • Post-polio syndrome
  • Primary lateral sclerosis
  • Progressive bulbar palsy
  • Progressive spinal muscular atrophy
  • Pseudobulbar palsy
  • Spinal cord compression by tumor or cerebral spondylosis

Source: Medical Disability Advisor



Specialists

  • Neurologist
  • Physiatrist (Physical Medicine and Rehabilitation Specialist)

Source: Medical Disability Advisor



Rehabilitation

Helping the individual to remain comfortable and as functional as possible is the overall goal of rehabilitation. A physical therapist may use various techniques to help strengthen overall progressive muscle weakness, including the respiratory muscles. Exercises to maintain balance and mobility are also stressed. The intensity and progression of exercise depends on the stage of the disease and the individual's overall health. A physical therapist can also provide assistance in determining types of special equipment that might be of help.

Source: Medical Disability Advisor



Comorbid Conditions

  • Chronic obstructive pulmonary disease (COPD)
  • Obesity

Source: Medical Disability Advisor



Complications

Individuals with ALS are susceptible to all the acute and chronic diseases and conditions common to other chronically ill and weakened individuals with impaired mobility. These include cancer, heart and vascular disease, stroke, blood clots, choking and aspiration, infectious disease, gastrointestinal disorders, diabetes, respiratory disease, and pressure sores. If surgical intervention is required for any of these conditions, the individual is subject to the usual surgical complications (infection, adverse reaction to the anesthetic, pneumonia, and poor wound closure).

Source: Medical Disability Advisor



Factors Influencing Duration

Factors influencing the length of disability may include the general health and fitness of the individual before the diagnosis of ALS, evidence of pre-existing diseases (such as diabetes, chronic obstructive lung disease, and chronic heart disease) affecting any of the major body systems, diagnosis of an acute disease or condition requiring surgery, the individual's mental and emotional stability, access to rehabilitation facilities and home health care, and the strength of the individual's support system. Disability eventually will become permanent.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Work is often therapeutic and the individual may strive to continue working as long as possible. Work activities may be limited depending on the nature of the work and the individual's degree of muscular weakness. The individual's workspace may need to be changed to accommodate a wheelchair and provide a safe environment. Safety issues and accommodations revolve around the individual's weakness and physical instability and the tendency to choke easily.

Source: Medical Disability Advisor



Failure to Recover

If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.

Regarding diagnosis:

  • Does individual complain of weakness of the hands, arms, or legs?
  • Do small areas of the muscle quiver or twitch involuntarily (fasciculate)?
  • Does individual complain of difficulty swallowing (dysphagia) and a tendency to choke on food or liquid?
  • Does individual complain of impaired speech (dysarthria) or of muscle cramping and stiffness making it difficult to hold objects and perform tasks that require fine hand movements?
  • Is breathing impaired?
  • Does individual appear depressed or anxious?
  • Was diagnosis of ALS confirmed?
  • Were other tests such as a biopsy of a wasted muscle, blood studies (serum creatine kinase may be elevated), x-ray study of the spinal cord after injected with dye (myelography), CT or MRI, and examination of the cerebrospinal fluid, done to rule out other diseases?

Regarding treatment:

  • Has riluzole been administered? Are any other medications available at this time?
  • Would individual benefit from an antidepressant?
  • Does individual require medication to relieve pain?
  • Is individual receiving appropriate supportive care such as physical therapy, occupational therapy, home care or nutrition support?
  • Do individual and/or family have realistic views about future care needs?
  • Would social services be beneficial in helping create a long-range plan?
  • Would family counseling be beneficial to help family members understand and cope with increasing demands?

Regarding prognosis:

  • What stage of the disease is individual currently experiencing?
  • Has family contacted, or are they willing to contact hospice, for end-stage care and support?
  • Has individual developed any conditions (i.e., infections, malnutrition, vascular disease) associated with being chronically ill or weakened?

Source: Medical Disability Advisor



References

Cited

"Amyotrophic Lateral Sclerosis." National Institute of Neurological Disorders and Stroke. National Institutes of Health (NIH). 13 Sep. 2004 <http://www.ninds.nih.gov/health_and_medical/pubs/als.htm#who>.

Source: Medical Disability Advisor