Vitamin D is stored in the liver. Vitamin D2 and D3 are not active in the body they are metabolized by the liver and kidneys into an active form which is called calcitriol. The active form allows absorption of calcium and phosphorus from the intestine. Calcium and phosphorus are included into bones to make them strong and dense. Therefore vitamin D is important for the formation, growth, and repair of bones. Vitamin D also increases immune function and improves muscle strength. As people age requirements for vitamin D increases
High doses of Vitamin D can cause toxicity and a high calcium level in the blood. Early symptoms include symptoms of hypercalcaemia such excessive thirst and polyuria which are the symptoms presented by George. Other symptoms which can be present in a person with high levels of vitamin D include loss of appetite, nausea vomiting, weakness, nervousness, and high blood pressure. Due to calcium levels being high, calcium can be deposited throughout the body, especially in the kidneys, blood vessels, lungs, and heart. The kidneys can be damaged and malfunction, which can result in kidney failure.
Excess Vitamin D is diagnosed when blood tests detect a high calcium level in a person who takes high doses of vitamin D. The diagnosis is confirmed by measuring the level of vitamin D in the blood. George’s symptoms of thirst and polyuria are probably due to too much exposure to sunlight as vitamin D3 is formed when the skin is exposed to direct sunlight. However George’s diet needs to be taken into consideration which would help to determine whether it includes high intake of vitamin D3 food supplements such as dairy products.
Treatments would include: Having reviewed George’s symptoms, his blood tests and the five potential diseases, it is evident that George is suffering from either Hyperparathyroidism or Sarcoidosis. As is often the case, there is no clear cut diagnosis and there is evidence pointing in the direction of both diseases. Sarcoidosis is characterised by hypercalcaemia and there are raised levels of calcium in George’s blood. However this is also true of Hyperparathyroidism.
An increase in the blood levels of alkaline phosphatise is also associated with sarcoidosis, however, these levels are normal in Georges case. George has undergone a chest radiograph and this has revealed increased hilar shadowing. This finding is consistent with a diagnosis of Sarcoidosis. The presence of granulomas is also associated with Sarcoidosis. These granular abnormalities usually appear first in the lungs but there is no evidence of their presence in George’s chest radiograph.
Hyperparathyroidism is characterised by high serum calcium levels and these raised levels are present in George’s results. Decreased serum phosphate levels are indicative of hyperparathyroidism, however, in Georges case these levels are normal. Alkaline phosphatise levels may increase in secondary hyperparathyroidism but not in primary hyperparathyroidism and in Georges case these levels are normal which may possibly lend towards a diagnosis of hyperparathyroidism. George’s levels of phosphate are normal however there is an inverse relationship between calcium and phosphate.
Hydrocortisone (glucocorticoid) tablets were given which reduced the serum calcium to 2.80 mmol/l. Glucocorticoids lower calcium levels if there is an increase in vitamin D or there are high levels of calcium which is present in sarcoidosis. Glucocorticoids are usually given to suppress the immune response or suppress inflammation and are of a great value when used to treat conditions that cause hypersensitivity. Cortisol also known as Hydrocortisone is a natural glucocorticoid.
When administered orally they are more active comparing to when given by any other route. Receptors for cortisol are found in many tissues; Glucocorticoids inhibit the transcription of the genes for synthesis of cyclooxygenase (COX-2) This then inhibits cytokine release which leads to a decrease in action of TNFa and interleukins IL-1, IL-2 and IL-5. Glucocorticoids also block the synthesis of arachidonic acid which then inhibits the action of phospholipase A2 therefore reduces the synthesis of prostaglandins. B lymphocyte maturation and T helper lymphocyte profilatation is reduced. Glucocorticoids also decrease histamine release form basophils, decrease IgG production and decrease generation of induced nitric oxide, (Walker, Renwick, Hillier 2001, a).
These results show evidence for the proposition that George may be suffering from either Sarcoidosis or Hyperparathyroidism. It is necessary, therefore, to carry out further tests. These tests will serve to either confirm one of the diseases or possibly eliminate the other. In the case of sarcoidosis an increase in the levels of serum angiotensin converting enzyme is indicative of the disease. If this test was carried out it would give a better indication as to the possible diagnosis of Sarcoidosis. To exclude hyperthyroidism serum TSH can to be done.
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