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.

Carotid Artery Occlusion


Related Terms

  • Carotid Insufficiency

Differential Diagnosis

Specialists

  • Cardiovascular Internist
  • Internal Medicine Physician
  • Neurologist
  • Neurosurgeon
  • Vascular Surgeon

Comorbid Conditions

  • Cardiovascular disease
  • Diabetes mellitus
  • Hypertension
  • Obesity

Factors Influencing Duration

Age and response to medical or surgical treatment may influence length of disability. Additionally, many individuals with coronary artery occlusion suffer a stroke, which would significantly affect length of disability.

Medical Codes

ICD-9-CM:
433 - Occlusion and Stenosis of Precerebral Arteries
433.1 - Occlusion and Stenosis of Precerebral Arteries; Carotid Artery Occlusion
433.10 - Occlusion and Stenosis of Precerebral Arteries; Carotid Artery Occlusion; without Mention of Cerebral Infarction

Overview

Carotid artery occlusion is a narrow, partially obstructed area in one of the carotid arteries of the neck that prevents crucial blood flow to the brain. If blood flow to the brain continues to be blocked, transient ischemic attacks (TIAs), stroke, brain damage, and death can occur.

The occlusion is commonly caused by the deposit of fat cells within arterial walls (atherosclerosis), hardening and thickening of arterial walls (arteriosclerosis), or a tumor-like mass of plaque (atheroma). The blood clots (thrombi) that form as a result of these conditions can dislodge (emboli) and travel throughout the arteries in the body, causing potentially devastating consequences. Carotid artery occlusion can be compounded by the extension of cholesterol and calcium deposits into branches of the carotid arteries.

Other causes of carotid artery occlusion include inflammation of arteries (arteritis) or rheumatic heart disease. Thrombi and emboli from a bacterial infection of the heart (endocarditis), an irregular beat of the upper chamber (atrium) of the heart (atrial fibrillation) or from a heart attack (myocardial infarction) can also cause occlusion. Use of cocaine and amphetamines may possibly cause carotid artery occlusion.

Incidence and Prevalence: Symptomatic carotid artery occlusion occurs in about 6 in 100,000 persons in the US annually (Flaherty).

Source: Medical Disability Advisor



Causation and Known Risk Factors

Individuals at risk for carotid artery occlusion include those with atherosclerosis, arteriosclerosis, atheroma, hypertension, and diabetes mellitus. Blacks have an increased risk as do those individuals who smoke, are obese, have hyperlipidemia, and are male.

Source: Medical Disability Advisor



Diagnosis

History: Individual may complain of fainting (syncope), dizziness, lightheadedness, confusion, headache, or nausea. Numbness, weakness (hemiparesis), or temporary or permanent paralysis on one side of the body (hemiplegia) may also occur. Additional complaints may include blurred vision, difficulty with speech (aphasia), or decreased consciousness.

Physical exam: Applying light pressure with the fingertips (palpation) and listening with a stethoscope (auscultation) to the carotid arteries may reveal a soft, abnormal sound (bruit) indicating a decrease in blood flow. This may not always be audible due to a high degree of occlusion or lack of experience in the listener. Blood pressure may be increased (hypertension).

Tests: Laboratory blood tests include a complete blood count (CBC), electrolytes, blood urea nitrogen (BUN), creatinine, blood fats (lipid) profile, and blood coagulation tests (prothrombin time [PT]/activated partial thromboplastin time [aPTT]). A test that uses sound waves (ultrasonography) to determine if the blood flow is impaired in the carotid artery is done. Patients with suspicious ultrasound outcomes or related intracranial lesions are referred for gadolinium-enhanced magnetic resonance angiography to better define plaque composition and intracranial circulation. A chest x-ray should be taken to search for a primary lung tumor and cardiovascular disorders; an electrocardiogram (ECG) should be done to determine if the individual is having a heart attack or other heart problems. CT or MRI of the brain helps differentiate between lack of blood flow (ischemia), internal bleeding (hemorrhage), or a tumor. An x-ray view of the artery after injection of contrast medium (arteriography) may also be performed, but, because of its invasive nature, usually only when the diagnosis is not definite using other tests.

Source: Medical Disability Advisor



Treatment

Artery occlusion greater than 70% usually requires a surgical procedure in which an incision is made into the neck, the artery exposed, and the obstruction removed (carotid endarterectomy). Controversy exists between researchers on how to approach asymptomatic occlusions in some patients. The decision to operate is a case by case decision that takes into consideration many factors including other risk factors. Heparin is usually administered during the procedure. Closure of the artery may involve the use of a synthetic patch or graft. Chronic hypertension must be successfully treated before surgery. Active coronary artery disease may put the individual at too great a risk, thus eliminating surgery as a possible treatment choice. Individuals who are considered to be at high surgical risk are treated with medications that inhibit clotting and prevent further build up of occlusive plaque or fat cells.

Arteries less than 30% occluded are best managed by medically treating underlying causes, in much the same way treatment is given to those who are at high surgical risk. This often includes medications for increased blood pressure (hypertension), coronary artery disease, and diabetes (oral hypoglycemics or insulin). Drugs that decrease blood clotting, such as aspirin or anticoagulants, may also be given.

Source: Medical Disability Advisor



Prognosis

The outcome for individuals depends on the site and size of the occlusion. If blood flow to the brain is impeded for very long, clots will form; if they break free, stroke, brain damage, and/or death can occur. The tissues of the brain will recover, however, if blood flow is interrupted for less than 1 hour.

Individuals who require only medical treatment for the occlusion often have a good prognosis; for those who have undergone surgical removal of the obstruction (carotid endarterectomy), the outcome is variable. Anyone who has symptomatic coronary artery occlusion has about an 8% chance of stroke within 30 days of diagnosis, 10% at 1 year, and 14% at 5 years (Flaherty). The prognosis for individuals whose disease has progressed to a stroke is difficult to predict and depends mainly on the type of brain damage sustained.

Source: Medical Disability Advisor



Rehabilitation

Physical therapy benefits individuals with carotid occlusion by applying principles of aerobic conditioning to increase the elasticity of the walls of the carotid arteries. As commonly used in developing a program for related cardiac diseases, rehabilitation is often planned in several progressive phases. Phase 1 often begins at low levels of intensity with individuals monitored for heart rate and rhythm, blood pressure, and symptoms of dizziness. At this stage, exercise is used primarily to prevent the hazards of bedrest, reduce episodes of low blood pressure when changing positions (orthostatic hypotension), and maintain overall mobility of the body. Exercise at this initial stage often begins with the individual on his or her back (supine position). The individual advances to sitting and eventually to standing exercise. Progressive walking (ambulating) with continuous monitoring for 2 to 5 minutes and progressing to 15 to 20 minutes is also part of this phase. Eventually stair climbing becomes an important part of individual's exercise program often while still hospitalized. Sessions may be as short as 5 to 10 minutes with the physical therapist. Intensity is gradually increased until discharge from the hospital. At 10 days to 2 weeks, the use of a stationary bicycle set at 50 revolutions per minute (rpm) for 3 minutes is performed under supervision.

Phase 2 usually begins after the individual is discharged from the hospital. However, individuals who have not been hospitalized usually begin at this phase. This stage consists of similar exercises as applied in phase 1 with progression of time and intensity varying from individual to individual. Goals are to improve functional capacity by increasing physical endurance to promote return to activity. This is often accomplished in an outpatient setting such as a rehabilitation center. Individuals typically are also attached to an electrocardiograph (ECG) monitor during the exercise session. An electrocardiograph is a device used to record the continuous electrical activity of the heart muscle.

Phase 3 continues in an outpatient setting and 3 to 6 months generally have lapsed from the start of rehabilitation to this point. A physical therapist experienced in cardiac rehabilitation keeps a daily log of the individual's blood pressure, heart rate, and cardiac rhythm. Individuals may continue to be monitored with an electrocardiograph to observe activity of the heart muscle.

Depending on the individual's condition, this phase may last for several months. Individuals may stay involved with an outpatient program for up to a year to accomplish all of the their goals while still at modified work duty. Eventually higher levels of exercise comprise this phase with the addition of recreational activities such as swimming and hiking. Light jogging at approximately 5 miles per hour, and cycling at approximately 12 miles per hour is appropriate as long as the individual is tolerating the rehabilitation program well.

Phase 4 of cardiac rehabilitation for carotid occlusion occurs at 12 months after discharge from the hospital. Long-term maintenance of performance levels reached during phase 2 and 3 are concerns at this time. aerobic exercises that increase cardiovascular fitness are emphasized and include walking briskly, running, jogging, swimming, climbing stairs, or bicycling. The American Heart Association, the Centers for Disease Control and Prevention (CDC), and the American College of Sports Medicine recommend 30 to 60 minutes of aerobic activity 3 to 4 times a week to help keep high blood pressure and cardiovascular diseases such as carotid occlusion under control. Throughout all phases, it is important to allow the heart rate to gradually return to normal by cooling down slowly after exercise.

Modifications may need to be made to the rehabilitation program, as surgery may have been needed to remove the arterial occlusion. Additional changes or additions are made to the program if any significant brain damage resulted from the occlusion because of the lack of oxygen to this vital organ of the body.

Source: Medical Disability Advisor



Complications

Possible complications include small stroke-like attacks (transient ischemic attack), stroke, clot formation (thrombi), or bleeding (hemorrhage). A more severe stroke involving an entire hemisphere of the brain may occur from the release of a large clot moving distally, which may occur before, during, or after an endarterectomy procedure. Such an event may be life-threatening, or may result in a hemiparalysis with or without aphasia, the inability to understand and/or produce speech.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Depending upon the extent of the disease and treatment required, the individual may need to refrain from strenuous physical activity. Transfer to a modified duty or sedentary job may be required. If the physician has ordered a rehabilitation program, individuals will require time off to participate. Individuals who have suffered a stroke may require either a leave of absence or permanent disability.

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:

  • Has ultrasonography been done to evaluate blood flow in the carotid artery? Has diagnosis of carotid artery occlusion been confirmed? If diagnosis is doubtful, has arteriography been performed?
  • Have conditions with similar symptoms been ruled out?
  • Have coexisting conditions that may impact recovery, such as hypertension, diabetes mellitus, obesity, and other cardiovascular diseases, been identified or ruled out? If present, are these conditions responding to treatment?

Regarding treatment:

  • If artery occlusion is greater than 70%, is individual candidate for carotid endarterectomy? Has individual been experiencing stroke-like symptoms?
  • If active coronary artery disease has put individual at too great a risk for surgery, what are treatment alternatives? Is individual suitable for surgical intervention at later date?
  • If artery occlusion is less than 30%, has medical treatment been successful? If not, what additional therapy is being considered?

Regarding prognosis:

  • Depending on site and size of occlusion, what is prognosis for individual if treated medically? Is individual now, or ever, candidate for surgical intervention?
  • If treated by endarterectomy, how successful was procedure?
  • If disease has progressed to a stroke, what type of brain damage was sustained? To what extent is recovery expected?

Source: Medical Disability Advisor



References

Cited

Flaherty, Matthew L., et al. "Population-Based Study of Symptomatic Internal Carotid Artery Occlusion. Incidence and Long-Term Follow-Up." Stroke 35 (2004): 349.

Source: Medical Disability Advisor






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