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.

Astrocytoma


Related Terms

  • Adult Noninfiltrating Astrocytoma
  • Anaplastic Astrocytoma
  • Glioblastoma
  • Glioblastoma Multiforme
  • Low Grade Astrocytoma
  • Pilocytic Astrocytoma

Differential Diagnosis

Specialists

  • Neurologist
  • Neurosurgeon
  • Oncologist
  • Radiologist

Comorbid Conditions

Factors Influencing Duration

The length of disability will be influenced by the specific location of the tumor, the grade of the tumor at the time of diagnosis, the method of treatment (surgery, radiation, chemotherapy), response to treatment, age (older individuals have shorter survival times), and performance status (individuals who are neurologically normal live longer than those with a neurological deficit).

Medical Codes

ICD-9-CM:
191.0 - Malignant Neoplasm of Brain; Cerebrum, except Lobes and Ventricles; Basal Ganglia; Cerebral Cortex; Corpus Striatum; Globus Pallidus; Hypothalamus; Thalamus
191.1 - Malignant Neoplasm of Brain; Frontal Lobe
191.2 - Malignant Neoplasm of Brain; Temporal Lobe, Hippocampus, Uncus
191.3 - Malignant Neoplasm of Brain; Parietal Lobe
191.4 - Malignant Neoplasm of Brain; Occipital Lobe
191.5 - Malignant Neoplasm of Brain; Ventricles, Choroid Plexus, Floor of Ventricle
191.6 - Malignant Neoplasm of Brain; Cerebellum NOS, Cerebellopontine Angle
191.7 - Malignant Neoplasm of Brain; Brain Stem; Cerebral Peduncle; Medulla Oblongata; Midbrain; Pons
191.8 - Malignant Neoplasm of Brain; Other Parts of Brain; Corpus Callosum; Tapetum
191.9 - Brain, Unspecified; Cranial Fossa NOS
192.9 - Neoplasm, Nervous System, Malignant, Part Unspecified

Overview

Astrocytoma is a malignant brain tumor composed of astrocytes. Astrocytes are the cells' surrounding the nerve cells, that form support tissue for the brain and spinal cord. Astrocytomas are a subgroup of gliomas, tumors that arise from within the nervous system itself rather than those that originate in other organs and spread to the brain via the vascular system.

Although all types of astrocytomas are serious, they are classified in order of increasing malignancy. Astrocytomas are graded according to how invasive (how quickly they infiltrate nearby tissue) they are on a scale of 1 to 4. Grade 1, a slow-growing tumor, may spread widely throughout the brain and be present for many years before causing any symptoms. A grade 4 astrocytoma, on the other hand, is a very fast-growing tumor, rapidly causing disabling symptoms. Grades 1 and 2 are considered "low-grade." A highly malignant variety of astrocytoma is known as glioblastoma multiforme.

Astrocytomas can occur anywhere in the central nervous system, including the cerebrum, cerebellum, brainstem, spinal cord, and optic nerve. The cause is unknown although astrocytomas have been linked to genetic diseases and disturbances. Astrocytomas are the most common type of tumor arising from supporting cells within the nervous system (glioma). Individuals with the nervous system diseases neurofibromatosis and tuberous sclerosis are at higher risk for developing low grade astrocytomas.

Incidence and Prevalence: Astrocytomas of all grades represent the most common form of glioma. Of the approximately 19,000 cases of brain and nervous system tumors reported in the US in 2006, about 38% of the brain tumors were anaplastic astrocytomas and glioblastomas ("Adult Brain Tumors").

Source: Medical Disability Advisor



Causation and Known Risk Factors

Radiation of the skull of young people being treated for malignant blood diseases may increase risk for developing astrocytoma. Exposure of workers in rubber processing, petrochemical, and pesticide industries has been found to increase risk of brain tumors, though no specific chemical agent has been identified as a cause.

Astrocytomas are slightly more common in whites than blacks, and in males than females. It occurs most often in adults with a mean age of 35 to 40 years (Wessels).

Source: Medical Disability Advisor



Diagnosis

History: The location of the astrocytoma typically determines the symptoms the individual may experience. Complaints may include headache, nausea, vomiting, a vague feeling of discomfort or illness (malaise), vision or speech problems, personality or emotional changes, seizures, or lack of coordination on one side of the body. Seizures may be the first symptom if the tumor is located in the temporal or frontal lobes of the brain.

Physical exam: Examination may reveal muscle weakness, lack of muscle coordination (ataxia), visual or other sensory disturbances, rapid movements of the pupils (nystagmus), or swelling of the optic disc (papilledema). Increased pressure inside the skull (increased intracranial pressure) may also be present.

Tests: Imaging studies such as a CT scan and / or MRI are used to detect a mass and define its location, shape and size. Positron emission tomography (PET) scanning produces three-dimensional images that reflect metabolic activity in tissue and may be used to determine the type of tumor. PET may be used with a new MRI technology, proton magnetic-resonance spectroscopy, in the future to more precisely diagnose the type and grade of tumors.

Angiography (x-ray study of blood vessels after they have been injected with a contrast medium) may show stretching or displacement of normal cerebral vessels by the tumor. Angiography can also detect the presence of tumor vascularity (system of blood vessels), which may be necessary to distinguish a tumor mass from an arterial aneurysm (abnormal enlargement of a blood vessel). An electroencephalogram (EEG) records the electrical activity of the brain, and provides supporting information as to whether the tumor is causing a focal (limited) or widespread disturbance.

A biopsy (minor surgical removal of a tissue sample) is usually performed to examine tumor cells, confirming the exact type of tumor and the stage of malignancy.

Source: Medical Disability Advisor



Treatment

With few exceptions, astrocytomas are not curable. Treatment is aimed at lengthening survival time and reducing symptoms. The type of treatment depends on the site of the tumor and the condition of the individual. By the time it is diagnosed, total surgical removal of an astrocytoma is usually impossible. A biopsy may be performed to examine cells in tissue surrounding the tumor to help determine if the tumor is spreading and how quickly. Brain mapping using MRI or CT scan is often used prior to surgery or in combination with surgical guidance systems to enable the surgeon to remove the maximum amount of tumor cells while preserving as much function as possible. Even though it may not be possible to remove all of the tumor, removing part of it can help reduce intracranial pressure and relieve symptoms (craniotomy with internal decompression or stereotactic volumetric reduction). Surgery may be followed by radiation therapy, depending on the specific location of the tumor.

Astrocytomas, however, do not always respond to radiation therapy. Chemotherapy is seldom used for low-grade astrocytomas (grades 1 and 2) because the benefit is too short term for slow-growing tumors, but is frequently used in association with surgery and / or radiation for rapidly spreading or more chemosensitive (greater potential for response) tumors. Chemotherapeutic agents such as temozolomide may be used for higher grade astrocytomas (grades 3 and 4) in conjunction with radiation therapy as the primary treatment. Monoclonal antibodies that can locate and destroy tumor cells without harming normal brain cells are also being increasingly utilized for those with recurrent grade 3 or 4 astrocytomas. Newer antineoplastic drugs show potential for increasing survival and improving quality of life in patients with recurrent mixed-grade tumors. Glucocorticoids are given to reduce brain swelling and decrease symptoms. A shunt may be inserted to drain excess cerebrospinal fluid in individuals with increased intracranial pressure. Because astrocytomas have been shown to stem from genetic disturbances, gene therapy may eventually be used in the treatment of both low-grade and more malignant lesions.

Source: Medical Disability Advisor



Prognosis

Outcome depends on the extent of the disease. Individuals with low-grade astrocytomas (grades 1 and 2) have a median survival time of 7.5 years, although some individuals with grade 1 tumors have lived as long as 30 years or more after diagnosis. Individuals with very slow growing tumors in which complete surgical removal (stereotactic volumetric reduction) is possible may experience total remission. Individuals with grade 2 astrocytoma have a 5-year survival rate, about 34% of patients without treatment and about 70% with radiation therapy, and a median survival time of 4 years. Individuals with grade 3 astrocytoma have a median survival time of 18 months with treatment (radiation and chemotherapy). Individuals with grade 4 astrocytoma have a median survival time of 17 weeks without treatment, 30 weeks with radiation, and 37 weeks with surgical removal of most of the tumor followed by radiation (Kelly). Younger patients survive longer; tumors in older patients are usually at more advanced stages. Even with aggressive treatment, astrocytomas of all types tend to recur, making the prognosis generally poor.

Source: Medical Disability Advisor



Complications

Complications are determined by the site of the tumor and extent of invasion of normal brain tissue, and can include blindness and endocrine disturbances. Up to 30% of individuals with malignant brain tumors develop blood clots (deep venous thrombosis). They are also prone to seizures and infections of the lung and urinary tract. In spite of treatment, tumor recurrence usually occurs within 6 to 12 months.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Work ability will depend upon the neurological changes or deficits that accompany the tumor. For example, the presence of seizures would prevent the individual from driving and operating heavy equipment. Vision problems could result in any number of possible work restrictions.

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:

  • Did individual present with a new-onset of seizures or other symptoms suggestive of a brain tumor?
  • Did neurological exam reveal nervous system disorders that are consistent with the diagnosis of a brain tumor?
  • Would individual benefit from consultation with a specialist (neurologist, neurosurgeon, neuroradiologist, neurooncologist)?
  • Was presence of a tumor visualized on an MRI, CT or PET?
  • Was a tissue biopsy performed to distinguish the tumor type and aid in staging the malignancy?
  • If diagnosis was uncertain, were other conditions with similar symptoms ruled out?

Regarding treatment:

  • Was surgical resection of the tumor performed?
  • Did neurological symptoms persist or worsen? If so, were other measures done to relieve symptoms, such as administration of glucocorticoids to reduce swelling or insertion of shunts to relieve hydrocephalus?
  • Were additional tumor suppressing interventions such as radiation therapy and / or chemotherapy done?
  • Was individual compliant with treatment recommendations (i.e., surgery, chemotherapy, radiation therapy)?
  • Would individual and their family members benefit from additional counseling or brain tumor support groups?

Regarding prognosis:

  • Based on the size, location and stage of the tumor, what was the expected outcome?
  • Did individual experience any complications that may have impacted recovery and prognosis?

Source: Medical Disability Advisor



References

Cited

"Adult Brain Tumors." JNCI Cancer Spectrum. 16 Feb. 2006. Journal of the National Cancer Institute. 14 Apr. 2006 <http://jncicancerspectrum.oxfordjournals.org/cgi/pdq/jncipdq;CDR0000062900>.

Kelly, Patrick J. "Astrocytomas." Brain Tumor Foundation. 18 Dec. 2002. 20 Dec. 2004 <http://www.braintumorfoundation.org/tumors/astro.htm>.

Wessels, P. H., W. E.J. Weber, and G. Raven. "Supratentorial Grade II Astrocytoma: Biological Features and Clinical Course." Lancet Neurology 2 7 (2003): 395-403.

Source: Medical Disability Advisor






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