Vitamin B 12

Vitamin B12 Deficiency - Article

ABSTRACT: Vitamin B12 (cobalamin) deficiency is a common cause of macrocytic anemia and has been implicated in a spectrum of neuropsychiatric disorders. The role of B12 deficiency in hyperhomocysteinemia and the promotion of atherosclerosis is only now being explored. Diagnosis of vitamin B12 deficiency is typically based on measurement of serum vitamin B12 levels; however, about 50 percent of patients with subclinical disease have normal B12 levels. A more sensitive method of screening for vitamin B12 deficiency is measurement of serum methylmalonic acid and homocysteine levels, which are increased early in vitamin B12 deficiency. Use of the Schilling test for detection of pernicious anemia has been supplanted for the most part by serologic testing for parietal cell and intrinsic factor antibodies. Contrary to prevailing medical practice, studies show that supplementation with oral vitamin B12 is a safe and effective treatment for the B12 deficiency state. Even when intrinsic factor is not present to aid in the absorption of vitamin B12 (pernicious anemia) or in other diseases that affect the usual absorption sites in the terminal ileum, oral therapy remains effective.

Initial Evaluation of the Patient with Suspected Dementia - Article

ABSTRACT: Dementia is a common disorder among older persons, and projections indicate that the number of patients with dementia in the United States will continue to grow. Alzheimer's disease and vascular dementia account for the majority of cases of dementia. After a thorough history and physical examination, including a discussion with other family members, a baseline measurement of cognitive function should be obtained. The Mini-Mental State Examination is the most commonly used instrument to document cognitive impairment. Initial laboratory evaluation includes tests for thyroid-stimulating hormone and vitamin B12 levels. Structural neuroimaging with noncontrast computed tomography or magnetic resonance imaging also is recommended. Other testing should be guided by the history and physical examination. Neuropsychologic testing can help determine the extent of cognitive impairment, but it is not recommended on a routine basis. Neuropsychologic testing may be most helpful in situations where screening tests are normal or equivocal, but there remains a high level of concern that the person may be cognitively impaired.

Evidence for the Use of Intramuscular Injections in Outpatient Practice - Article

ABSTRACT: There are few studies comparing the outcomes of patients who are treated with oral versus intramuscular antibiotics, corticosteroids, nonsteroidal anti-inflammatory drugs, or vitamin B12. This may lead to confusion about when the intramuscular route is indicated. For example, intramuscular ceftriaxone for Neisseria gonorrhoeae infection and intramuscular penicillin G benzathine for Treponema pallidum infection are the treatments of choice. However, oral antibiotics are the treatment of choice for the outpatient treatment of pneumonia and most other outpatient bacterial infections. Oral corticosteroids are as effective as intramuscular corticosteroids and are well-tolerated by most patients. High daily doses of oral vitamin B12 with ongoing clinical surveillance appear to be as effective as intramuscular treatment. Few data support choosing intramuscular ketorolac over an oral nonsteroidal anti-inflammatory drug unless the patient is unable to tolerate an oral medication. For other indications, the intramuscular route should be considered only when the delivery of a medication must be confirmed, such as when a patient cannot tolerate an oral medication, or when compliance is uncertain.

Is Oral Vitamin B12 as Effective as Intramuscular Injection? - Cochrane for Clinicians

Anemia in Older Persons - Article

ABSTRACT: Anemia in older persons is commonly overlooked despite mounting evidence that low hemoglobin levels are a significant marker of physiologic decline. Using the World Health Organization definition of anemia (hemoglobin level less than 13 g per dL [130 g per L] in men and less than 12 g per dL [120 g per L] in women), more than 10 percent of persons older than 65 years are anemic. The prevalence increases with age, approaching 50 percent in chronically ill patients living in nursing homes. There is increasing evidence that even mild anemia is associated with increased morbidity and mortality. Anemia warrants evaluation in all older persons, except those at the end of life or who decline interventions. About one third of persons have anemia secondary to a nutritional deficiency, one third have anemia caused by chronic inflammation or chronic kidney disease, and one third have unexplained anemia. Nutritional anemia is effectively treated with vitamin or iron replacement. Iron deficiency anemia often is caused by gastrointestinal bleeding and requires further investigation in most patients. Anemia of chronic inflammation or chronic kidney disease may respond to treatment of the underlying disease and selective use of erythropoiesis-stimulating agents. The treatment of unexplained anemia is difficult, and there is little evidence that treatment decreases morbidity and mortality, or improves quality of life. Occasionally, anemia may be caused by less common but potentially treatable conditions, such as autoimmune hemolytic anemia, malignancy, or myelodysplastic syndrome.

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