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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.

Huntington's Chorea


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 | Maximum Medical Improvement | Failure to Recover | Medical Codes | References

Medical Codes

ICD-9-CM:
333.4 - Huntingtons Chorea

Related Terms

  • Huntington's Disease

Overview

Huntington's chorea is an incurable inherited neurological disease resulting from degeneration of nerve cells (neurons) in certain areas of the brain (basal ganglia and cerebral cortex) involved in controlling movement, coordination, speech, thoughts, memory, and perception.

Adult-onset (usually mid 30s and 40s) uncontrollable jerking movements (chorea) are the hallmark of this disorder. Huntington's chorea is also associated with depression and progressive intellectual loss. A child of a parent with Huntington's chorea has a 50% chance of developing the disease (autosomal dominant inheritance with complete penetrance). A specific gene for Huntington's disease has been identified. The gene produces an abnormal protein called huntingtin. It is not yet known how this protein is linked to the selective death of groups of nerve cells.

Incidence and Prevalence: In the US, only about 30,000 people have Huntington's chorea (prevalence 4.1-8.4 per 100,000). The prevalence in Europe ranges from 1.64 to 9.95 per 100,000 population. Certain regions such as the Lake Maracaibo area of Venezuela, Tasmania, and Mauritius have a substantially higher prevalence, while the lowest prevalence is found in Japan and Finland (Revilla).

Source: Medical Disability Advisor



Causation and Known Risk Factors

The disease is inherited. It is found in all ethnic groups with an equal number of males and females affected. The age of onset varies, but adult-onset chorea usually begins at middle age and continues to deteriorate with death occurring 15 to 25 years later.

Source: Medical Disability Advisor



Diagnosis

History: As Huntington's chorea is a familial disease passed from parent to child, family history is extremely important for diagnosis. Individuals may report moodiness (mood swings), irritability, sadness, depression, apathy, insomnia, or anger. Impairment of memory, judgment, and other cognitive functions may also occur before the involuntary movements are noticed. Mental deterioration usually is accompanied by antisocial behavior and a dementia syndrome. Individuals may report feeling depressed and may discuss thoughts of suicide. Psychiatric disorders may include obsessive-compulsive disorder, mania, or bipolar disorder.

Some individuals with Huntington's chorea have initial complaints of involuntary movements or rigidity. The movement disorder consists of uncontrolled dance-like jerking movements (chorea) in the fingers, feet, face, and trunk. These may resemble piano-playing movements of the fingers, facial grimaces, or a dancing gait. Clumsiness and problems with balance and coordination may be reported as the disease progresses. Intellectual deterioration and jerky movements of the extremities and face worsen until individuals eventually lose the ability to care for themselves as they become unable to walk and function intellectually.

Physical exam: Abnormalities of eye movement may be evident. Initially, periodic twitching in the face or extremities is seen. These movements become more pronounced and frequent as the disease progresses. Walking becomes unsteady; posture and balance are also impaired. More generalized and sustained writhing motions are later observed with the muscles becoming more rigid (dystonia). Speech becomes hard to understand and swallowing becomes difficult.

Tests: Genetic testing (DNA analysis) reveals the specific gene associated with Huntington's disease. Brain imaging testing such as computed tomography (CT) and magnetic resonance imaging (MRI) show shrinking (atrophy) of the deep structures involved in movement control (basal ganglia) in later stages. Levels of certain neurochemicals may be decreased including gamma-aminobutyric acid (GABA) and glutamic acid decarboxylase.

Source: Medical Disability Advisor



Treatment

There is no treatment to stop or reverse the course of the disease. Only the symptoms of Huntington's chorea are treated and not the disease itself. Abnormal movements and mental disturbances may be alleviated with antipsychotic drugs that may have severe side effects including sedation. The dopamine-depleting agent tetrabenazine was recently approved by the FDA for treatment of the movement disorder (chorea); however, this drug should also be used cautiously due to the high risk of side effects.

For depression, serotonin reuptake inhibitors may be used. Tranquilizers may help anxiety and other medications may be used to control obsessive-compulsive behavior. Genetic counseling should be offered to the children of individuals with Huntington's chorea. DNA testing determines whether the offspring also carry the affected gene and are at risk of developing the disease and/or passing the risk to their children. Psychological counseling should be offered both before and after genetic testing to help the individual cope with emotional issues uncovered by the results.

Source: Medical Disability Advisor



Prognosis

The prognosis is poor, and most individuals require constant care in an institutional setting at the end stage of the disease. In some individuals, the disease may progress to the point where speech is slurred and vital functions such as swallowing, eating, speaking, and walking decline. Some individuals may not be able to recognize their family members. Problems with balance and coordination manifest initially and develop into dance-like (choreic), irregular, spasmodic, involuntary movements as the disease progresses. Problems with walking may result in an increase of falls. Individuals who develop symptoms of Huntington's chorea by age 35 often become bedridden within 15 to 20 years. Death usually occurs 15 to 25 years after neurological or psychological impairment begins and may be caused by pneumonia or heart failure. There is a significant risk for suicide soon after diagnosis.

Source: Medical Disability Advisor



Differential Diagnosis

Source: Medical Disability Advisor



Specialists

  • Neurologist
  • Physiatrist (Physical Medicine and Rehabilitation Specialist)

Source: Medical Disability Advisor



Rehabilitation

Because of the progressive nature of Huntington's chorea, rehabilitation is focused on maintaining the individual's optimal quality of life. The physical, occupational, and speech therapist can help in the individual's maintenance of functional skills and advise the family on adaptive equipment. Adaptive equipment becomes important with activities needed throughout daily living such as self-care, walking, and eating. Physical therapists instruct the individual on the proper use of a cane or walker to assist with walking, whereas occupational therapists are helpful in teaching techniques for easier dressing and other self-cares. Occupational therapists also offer instruction in the use of adaptive equipment such as splints for the hand and/or wrist to aid in eating or other devices to aid in reaching and/or grasping objects.

Traditional relaxation exercises are helpful early in the disease and include gentle rocking and/or rotation of the extremities in a sitting position. With progression of Huntington's chorea, techniques of stretching help reduce uncontrolled muscle spasm and inflexibility (muscle tone). These techniques, offered by both physical and occupational therapy, reduce movements associated with this disease. Passive stretching exercises to the affected limbs/joints are performed and described as the therapist places the muscle and/or joint in a mild stretch without any assistance or resistance coming from the individual.

Increasing stability about the shoulders, trunk, neck, and hips will help maintain function. Treatment is then focused on techniques such as placing the individual in a seated position in a chair with hips tucked back, feet flat on the floor, and elbows supported by a lap table, or pillow. The goal is to have the individual lift the head and hold it steady. To progress and promote trunk control, less support to the elbows from the pillows is used. Sitting control is then improved by sitting in a chair that does not have arms or back while the therapist applies mild pressure to various regions of the trunk while instructing the individual to resist movement by the therapist. Individuals are then instructed regarding exercises such as shifting their weight in all directions while sitting progressing to the same activities in a standing position. Standing exercises are advanced to activities such as placing one foot forward and backward on a straight line and walking between parallel lines. If the individual is able to continue working early in the disease process and job duties require fine motor movements, job reassignment and vocational rehabilitation may be needed.

Speech therapy can be helpful in maintaining oral (mouth) motor control as the condition progresses and swallowing and speech become difficult. Speech therapy is also helpful in addressing loss of memory and perception. A dietitian is consulted for assistance to teach family members how to prepare balanced meals that are easy to swallow for the individual with swallowing difficulties.

Eventually goals are aimed at preventing total loss of mobility for the individual afflicted with Huntington's chorea. Later in the process, the rehabilitation team assists caretakers/family in learning how to perform proper and safe transfers and how to use additional adaptive equipment as needed.

Source: Medical Disability Advisor



Comorbid Conditions

  • Neurological or psychiatric disorders

Source: Medical Disability Advisor



Complications

Complications of the illness include gradual loss of mental faculties that evolve into dementia. Severe depression may result in suicide. The involuntary movements progress to more uncontrolled movements resulting in the inability to walk, feed oneself, or perform toilet and hygiene activities. Weight loss may be dramatic due to excessive calories burned by constant involuntary movements.

Source: Medical Disability Advisor



Factors Influencing Duration

Duration depends on severity of manifestations. This condition progresses to permanent disability.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

The individual usually cannot perform fine motor tasks such as typing, writing legibly, or repetitive finger or hand activities. Because of involuntary movements, individuals cannot work around moving machinery or in any position that would put them in danger of injury to others or themselves. Behavioral manifestations usually prevent individuals from interacting with the public.

Risk: The amount of risk from working with Huntington's chorea is dependent on the extent of the individual's cognitive deterioration, involuntary movements, and loss of coordination and mobility. As the disease progresses, affected individuals present an increasing safety risk to themselves and their coworkers, which may become inconsistent with employment.

Capacity: Capacity may become increasingly affected as the disease progresses; work limitations may be appropriate.

Tolerance: The personality changes (e.g., moodiness, depression, apathy, anger) found with Huntington’s chorea may become an obstacle secondary to changes in the individual’s motivation.

Source: Medical Disability Advisor



Maximum Medical Improvement

360 days.

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 have a family history of the disease?
  • Does individual report mood swings, irritability, depression, apathy, or anger?
  • Does individual report impairment of memory, judgment, and other cognitive functions?
  • Does individual have suicidal ideation?
  • Does individual have uncontrolled dance-like jerking movements (chorea) in the fingers, feet, face, and trunk? Do they resemble piano-playing movements of the fingers, facial grimaces, or a dancing gait?
  • Does individual have clumsiness and problems with balance and coordination?
  • Is individual's condition deteriorating? Is individual able to perform self-care tasks?
  • On physical exam, were rapid eye movements, periodic twitching in the face and extremities present? Have these become more pronounced?
  • Does individual have an unsteady gait?
  • Is it hard to understand individual's speech?
  • Does individual have difficulty swallowing?
  • Has individual had DNA analysis? Neurochemical testing?
  • Has individual had a CT scan and MRI?
  • Have conditions with similar symptoms been ruled out?

Regarding treatment:

  • Is individual receiving symptomatic treatment?
  • Is individual being treated with antipsychotic drugs for the abnormal movements and mental disturbances? Serotonin reuptake inhibitors? Tranquilizers? The dopamine-depleting agent tetrabenazine?
  • Have individual's children been offered genetic counseling?
  • Has individual received psychological counseling?

Regarding prognosis:

  • Does individual exercise regularly?
  • If individual is able to work, is their employer able to accommodate any necessary restrictions?
  • Does individual have any conditions that may affect the course of the disease? Does individual have any complications such as dementia, severe depression, suicidal ideation, inability to walk, or weight loss?

Source: Medical Disability Advisor



References

Cited

Revilla, Freddy J. , et al. "Huntington Disease." eMedicine. 10 Dec. 2014. Medscape. 24 Apr. 2015 <http://emedicine.medscape.com/article/1150165-overview>.

Source: Medical Disability Advisor