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.

Vitamin B12 Deficiency


Related Terms

  • Cyanocobalamin Deficiency
  • Pernicious Anemia

Differential Diagnosis

Specialists

  • Family Physician
  • Gastroenterologist
  • Geriatric Specialist
  • Hematologist
  • Internal Medicine Physician
  • Neurologist
  • Psychiatrist

Comorbid Conditions

  • Autoimmune diseases of the thyroid
  • Chronic gastrointestinal disorders
  • Folate deficiency
  • Type 1 diabetes

Factors Influencing Duration

The period of disability will be determined by the type and severity of symptoms, the promptness of treatment, the job description, and the presence of an underlying cause. If symptoms include neurological problems, the disability may be permanent. If another disease is causing/contributing to vitamin B12 deficiency, that disease must be successfully treated for full recovery. Individuals who are unable or unwilling to follow a diet containing adequate amounts of vitamin B12 may need lifelong supplements; however, this should not affect their ability to work.

Medical Codes

ICD-9-CM:
266.2 - B-complex Deficiencies, Other; Deficiency Cyanocobalamin, Folic Acid, Vitamin B12
281.1 - Vitamin B12 Deficiency Anemia, Other; Anemia, Vegans, Vitamin B12 Deficiency (Dietary), Due to Selective vitamin B12 Malabsorption with Proteinuria; Syndrome, Imerslunds, Imerslund-Gräsbeck

Overview

Vitamin B12 deficiency is a nutritional disorder caused by either a lack of this vitamin in the diet or by the body's inability to use it. Cobalamin are compounds found in nature which contain the nucleus of vitamin B12.

Vitamin B12 has many important functions. It is required for the formation and regeneration of red blood cells, it has an important role in maintaining a healthy nervous system, it is required for proper digestion, it aids in the absorption of calcium, and it promotes growth in children. Vitamin B12 is mostly produced by animals, so we need to eat animal products (e.g., meat, dairy products, poultry, fish) to get enough of this vitamin in our diets. Vegetarians can obtain small quantities of vitamin B12 from consuming legumes (e.g., green beans, peas). In the stomach, acid and enzymes separate the vitamin from the proteins that carry it. The free vitamin is then passed into the small intestine and absorbed into the bloodstream. Some is used immediately, and some is stored in the liver or bone marrow.

Vitamin B12 deficiency has two possible causes. The most obvious cause is a diet that lacks a sufficient amount of this vitamin. Because vitamin B12 is abundant in a wide variety of readily available foods, this type of dietary deficiency is not very common. In fact, it generally only occurs in strict vegetarians (often referred to as vegans) who do not eat meats, dairy products, eggs, or fish. In addition, alcoholics and individuals with eating disorders such as anorexia nervosa or bulimia nervosa tend to have inadequate diets, which put them at risk for this vitamin deficiency.

The other cause of vitamin B12 deficiency is the body's inability to use the vitamin once it has been ingested. As described above, this vitamin must be processed in the stomach before it can be utilized. It also has to be absorbed in the small intestine so that it can enter the bloodstream. If the stomach does not produce enough of the required acid or enzymes, or if the small intestine does not absorb the nutrient, a deficiency will result. Diseases of the small intestine such as Crohn's disease, or surgical removal of a portion of the small intestine, can result in too little of the vitamin being absorbed. Certain medications such as colchicine (used to treat gout), phenytoin (used to treat seizures), metformin (for treatment of diabetes) may interfere with vitamin B12 absorption, as do acid-reducing drugs that are used to treat ulcers. Excessive alcohol consumption can impair vitamin B12 absorption, and individuals with AIDS also have trouble absorbing this nutrient.

Additional causes include stomach surgery, diseases of the pancreas, overgrowth of bacteria in the gastrointestinal tract, or the presence of a fish tapeworm. As we age, our stomachs produce less acid, so less vitamin B12 is freed from its carrier protein, and less is available for absorption. Thus, elderly people are at increased risk for this condition. A disease called pernicious anemia can also lead to vitamin B12 deficiency. Pernicious anemia is associated with the deficiency of a substance called intrinsic factor. Intrinsic factor is produced in the stomach, and used in the small intestine for absorbing vitamin B12. Mean age of onset for PA is 50 years in blacks, and 60 years in the white population (Diamond). Congenital deficiencies in transport-protein can lead to vitamin B12 deficiency as well.

Incidence and Prevalence: While the precise prevalence of vitamin B12 deficiency is not known, it is estimated to affect anywhere between 300,000 to 3 million individuals in US (Diamond). Some studies suggest that general population is affected with an incidence of 3% to 40% (Dharmarajan 99). One study found evidence of vitamin B12 deficiency in about 15% of elderly persons over 65 years (Pennypacker 1197). The prevalence of cobalamin deficiency in Europe is 1.6% to10% (Diamond).

Source: Medical Disability Advisor



Causation and Known Risk Factors

Prevalence of pernicious anemia (PA) may be lower in black and Hispanic people, and higher in white population. Pernicious anemia affects men and women equally in US, but it is more prevalent in elderly women as compared to men (1.5:1) in Africa and Europe. While PA can affect people of any age, it occurs more frequently between 40 and 70 years of age (Diamond).

Source: Medical Disability Advisor



Diagnosis

History: Individuals may complain of tiredness (fatigue), shortness of breath, sore tongue, weakness, headaches, heart palpitations, a "pins and needles" (paresthesia) sensation in their extremities, disturbed coordination and balance, decreased appetite, impaired senses of smell and taste, as well as gas, heartburn, constipation or diarrhea. They may also be aware of depression, confusion, memory loss, loss of visual acuity, disorientation, and nervousness (anxiety). Some patients may report chest pains (angina) and episodes of fainting.

Physical exam: The individual may be pale or the skin may have a yellowish color (jaundice). The heart rate may be abnormally fast (tachycardia). The exam may detect changes in the eyes (e.g., involuntary constant cyclical eyeball movements [nystagmus], wasting away [atrophy] of part of an optic nerve), elevated body temperature (fever), an enlarged liver (hepatomegaly), enlarged spleen (splenomegaly), signs of congestive heart failure (CHF) and a smooth, red, swollen tongue. Ankle reflexes may be absent. Wide based way of walking (gait) may be observed. Depending on disease severity, the loss of temperature sensation, light touch, and pinprick may be noted.

Tests: Blood tests will show a low level of vitamin B12 in the blood. That and the presence of clinical evidence of the disease confirm the diagnosis. Complete blood count (CBC) may indicate anemia. In addition, the doctor may order a Schilling test, a procedure during which the individual is given vitamin B12 injections and tablets before tests are run to determine whether the vitamin is being absorbed properly. If the vitamin B12 levels in blood are borderline, tests for blood levels for metabolites (e.g., homocysteine and methylmalonic acid) could be performed in order to either confirm or rule-out the diagnosis of cobalamin deficiency. A bone-marrow test may be performed in some cases, to allow for examination of cells under the microscope in order to further confirm the diagnosis.

Source: Medical Disability Advisor



Treatment

The first goal of treatment is to reverse the vitamin deficiency. This is done with vitamin B12 supplements (given orally or injected). When a dietary lack of vitamin B12 is responsible, the individual will be educated on good sources of this nutrient and the benefits of a well-balanced diet. Individuals who refuse to eat animal products will be prescribed oral vitamin B12 supplements for daily use. In cases where an underlying condition is contributing to/causing the vitamin deficiency, treatment of that underlying disease is critical to successful management of vitamin B12 deficiency. If the individual has progressed to the complications caused by vitamin B12 deficiency (e.g., myelopathy), those conditions will need to be adequately treated. Patients with encephalopathy may benefit from neuropsychological care, and patients with balance and gait abnormalities may need occupational and physical therapy.

Source: Medical Disability Advisor



Prognosis

Individuals usually see a dramatic improvement in their symptoms and well being within 5 to 7 days (if there is little neurological involvement). Some individuals will require vitamin therapy for the remainder of their lives. Patients who had motor abnormalities as a result of cobalamin deficiency for over 6 months may have only minimal response to treatment. In severe cases (when treatment has been delayed for 6 months or longer since the onset of neurological involvement), the individual may be left with permanent neurological problems, including the possibility of paralysis. While rare, death may also occur. Individuals with congenital vitamin B12 deficiency have a less favorable prognosis than those with acquired disease.

Source: Medical Disability Advisor



Complications

Some individuals with vitamin B12 deficiency with prolonged vitamin B12 deficiency will develop a condition called pernicious anemia. Patients with pernicious anemia have an increased risk of developing stomach cancers (risk is 3 times higher for developing gastric carcinoma, and 13 times higher for developing gastric carcinoid tumors). Untreated, this condition can lead to serious neuropathies (including optic neuropathy), myelopathy, and encephalopathy. Individuals whose diets are lacking vitamin B12 may also lack other essential nutrients. In such cases, vitamin B12 deficiency may be complicated by a variety of other nutritional disorders.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

No work restrictions or accommodations should be necessary for most individuals. If the individual is experiencing a loss of balance, working in high places should be avoided. A "pins and needles" feeling in the extremities may make certain tasks difficult, such as standing or walking for a prolonged time, as well as grasping or carrying objects. If the individual's job requires these types of activities, reassignment to a different position may be helpful. In the rare case of paralysis, the individual will require workplace accommodations for a device such as a wheelchair, cane, or walker. If the individual is depressed, confused, or disoriented, he or she may need extended sick leave for recovery. Individuals who have suffered irreversible damage to the eyes (loss of visual acuity) as a result of the vitamin B12 deficiency, and whose job requires a certain degree of visual acuity, may need to be assigned tasks that they'll be able to do given their impaired eyesight.

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:

  • Is the individual a vegan? If yes, does the individual fail to take vitamin supplements, which include vitamin B12?
  • Is the individual elderly, and has poor diet?
  • If the individual is not a vegan, was the cause of the vitamin B12 deficiency established (e.g., anorexia nervosa, bulimia, alcohol abuse, gastrointestinal surgery, bacterial overgrowth, fish tapeworm, deficiency in transport protein, etc)?
  • Does the individual take medications that may interfere with B12 absorption (e.g., metformin, phenytoin, acid-reducing drugs, etc)?
  • Did the blood tests confirm low levels of vitamin B12?
  • Did the blood tests show anemia?
  • If the level of vitamin B12 was borderline, were tests for metabolites in the blood performed? If yes, were they found to be elevated?
  • Has a Schilling test been done to determine whether the vitamin B12 is being absorbed properly?
  • Have the differential diagnoses been ruled out?

Regarding treatment:

  • Has the individual been aggressively treated with vitamin B12 either orally or by injections?
  • Is individual taking the vitamin supplementation as prescribed?
  • Has individual received dietary consultation by a dietitian?
  • Has individual been compliant in dietary recommendations?
  • Has individual been re-evaluated to determine if he or she is responding appropriately to treatment?
  • Were the underlying causes of vitamin B12 deficiency treated appropriately?
  • If the deficiency was due to specific medications (e.g., metformin, etc), were they discontinued or changed? If they weren't discontinued or changed, were appropriate vitamin B12 supplements prescribed to be taken for the duration of treatment with these drugs?

Regarding prognosis:

  • Based on the underlying cause of the deficiency, what was the expected prognosis?
  • Will this course of treatment resolve the condition?
  • Was the therapy started too late in the course of disease, leaving the individual with permanent symptoms (e.g., motor and/or neurological involvement)?
  • Has individual experienced associated conditions (e.g., stomach cancer) or complications (e.g., encephalopathy, myelopathy, optic neuropathy) that would impact recovery and prognosis?
  • If so, how does this impact their occupation and activities?
  • Have appropriate accommodations been made so individual can return safely to work?

Source: Medical Disability Advisor



References

Cited

Dharmarajan, T. S., and E. P. Norkus. "Approaches to Vitamin B12 Deficiency. Early Treatment May Prevent Devastating complications." PostGraduate Medicine 110 1 (2001): 99-105.

Diamond, Alan L., and Rene Diamond. "Vitamin B12 Associated Neurological Diseases." eMedicine. Eds. Christopher C. Luzzio, et al. 11 Oct. 2004. Medscape. 11 Oct. 2004 <http://emedicine.com/neuro/topic439.htm>.

Pennypacker, L. C. "High Prevalence of Cobalamin Deficiency in Elderly Outpatients." Journal of the American Geriatrics Society 40 12 (1992): 1197-1204.

Source: Medical Disability Advisor






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