Wednesday, July 26, 2006

What is Anaemia ??

Anaemia… wat is it?

Anaemia is defined as haemoglobin concentration in blood below the lower limit of the normal range for the age and sex of the individual. In adults, the lower extreme of the normal haemoglobin is taken as 13 g% for males and 11.5% for females. New born infants have higher haemoglobin levels and therefore, 15% is taken as the lowr limit at birth, whereas at 3 months , the lower limit is taken as 9.5%. Although haemoglobin value is employed as the only parameter for determining whether or not anaemia is present, the red cell counts, haematocrit(PCV) and absolute values (MCV, MCH and MCHC) provide alternate means of assessing anaemia.

What are the symptoms of anaemia?
· Tiredness
· Easy fatiguability
· Generalized muscular weakness
· Lethargy
· Headache
· In older patients- there maybe symptoms of cardiac failure, angina pectoris, intermittent claudication, confusion and visual disturbances.

What actually happens in an anaemic person?

Subnormal level of haemoglobin causes lowered oxygen- carrying capacity of the blood. This in turn, initiates compensatory physiologic adaptations such as:
· Increased release of oxygen from haemoglobin;
· Increased blood flow to the tissues;
· Maintainance of the blood volume; and
· Redistribution of blood flow to maintain the cerebral blood supply.
Eventually, however, tissue hypoxia (lack of oxygen) develops causing impaired functions of the affected tissues. The degree of functional impairment of individual tissues is variable depending upon their oxygen requirements. Tissues with high oxygen requirement such as the heart, CNS and the skeletal muscle during exercise, bear the brunt of clinical effects of anaemia

Sunday, July 02, 2006

What is Mesothelioma

Mesothelioma is an uncommon tumour arising from mesothelial lining of serous cavities, most often in the pleural (covering of lungs) cavity, and rarely in peritoneal (coverings of abdomen) cavity and pericardial (covering of the heart) sac. They are of two types --- benign (solitary) and malignant (diffuse). The biological behavior of the mesothelioma’s can be usually predicted by their gross appearance; thoses forming solitary, discrete masses are generally benign, whereas those, which grow diffusely, are usually malignant.
Benign or solitary mesothelioma is also called pleural fibroma. Asbestos exposure plays no role on the etiology of benign mesothelioma. Grossly it consists of of a solitary, circumscribed, small, firm mass, generally less than 3cm in diameter. Cut surface shows whorls of dense fibrous tissue. Microscopically, the tumour is predominantly composed of whorls of collagen fibres and reticulin with interspersed fibroblasts. Rarely, mesothelial-lined clefts are seen in the tumour. Benign mesothelioma causes no symptoms and is detected as an incidental radiologic finding. Sometimes the tumour is associated with systemic syndrome of osteoarthropathy or hypoglycemia. Removal of the tumour is generally curative.

Malignant or diffuse mesothelioma is rare. It is a highly malignant tumour associated with high mortality. The tumour is significant in view of its recognized association with occupational exposure to asbestos for a number of years, usually 20-40 years. About 90% of malignant mesothelioma’s are asbestos –related. Mechanism of carcinogenecity by asbestos is not quite clear but it appears that prolonged exposure of amphibole type of asbestos is capable of inducing oncogenic mutation in the mesothelium. However prolonged exposure is considered more significant rather than heavy exposure as documented by its occurrence in the family of asbestos workers.
Although combination of cigarette smoking and asbestos exposure greatly increases risk to develop bronchgenic carcinoma, there is no such extra increased risk of developing mesothelioma in asbestos workers who smoke. Recently, SV40 (simian vacuolating virus) has also been implicated in the etiology of mesothelioma.