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POPULAR CARDIOLOGIST IN KATTIGENAHALLI, BANGALORE Cyanotic congenital heart disease Some of the more common cyanotic lesions are discussed below. There are, however, a number of problems common to patients with cyanotic heart disease. 1 Erythrocytosis. Chronic cyanosis causes an increase in red cell numbers as a way of increasing oxygen carrying capacity. The platelet count is sometimes reduced and the white cell count normal. The increased blood viscosity associated with the high red cell mass causes a slight increase in the risk of stroke.37 Most patients have a stable elevated haemoglobin level, but venesection is recommended if this is greater than 20 g/dL and the haematocrit is greater than 65%. Levels as high as this can be associated with the hyperviscosity syndrome: headache, fatigue and difficulty concentrating. Recurrent venesection can cause iron depletion and the production of microcytic red cells, which are stiffer than normal cells and so increase viscosity further. 2 Bleeding. Reduced platelet numbers, abnormal platelet function and clotting factor deficiencies mean these patients have an increased risk of haemorrhage. The most dangerous problem is pulmonary haemorrhage but bleeding from the gums and menorrhagia are more common. The use of anticoagulation must be restricted to those with a strong indication for treatment. 3 Gallstones. Chronic cyanosis and increased haem turnover are associated with an increased incidence of pigment gallstones. 4 Renal dysfunction and gout. Congestion of the renal glomeruli is associated with a reduced glomerular filtration rate and proteinuria. This and the increased turnover of red cells lead to urate accumulation and gout. 5 Pulmonary hypertension. Lesions associated with increased flow through the pulmonary circulation (e.g. a large atrial septal defect) can lead to a reactive rise in pulmonary arterial resistance. This is more likely to occur if the left to right shunt is large. Eventually these pulmonary vascular changes become irreversible, pulmonary pressures equal or exceed systemic pressures, and central cyanosis occurs because the intra-cardiac shunt reverses (Eisenmenger’s syndrome). Flow is now from right to left. There is then no benefit in attempting to correct the underlying cardiac abnormality. Earlier and more successful treatment of children with congenital heart disease has reduced the number of patients with this inexorable disease. Careful management of these conditions can nevertheless improve patients’ symptoms and survival. Reasonable exercise tolerance is usually maintained into adult life for most patients but progressive deterioration then occurs. Haemorrhagic complications, especially haemoptysis, are common. Thrombotic stroke, cerebral abscess and pulmonary infarction can also occur.
CARDIOLOGISTS IN H S R LAYOUT BANGALORE Cyanotic congenital heart disease Some of the more common cyanotic lesions are discussed below. There are, however, a number of problems common to patients with cyanotic heart disease. 1 Erythrocytosis. Chronic cyanosis causes an increase in red cell numbers as a way of increasing oxygen carrying capacity. The platelet count is sometimes reduced and the white cell count normal. The increased blood viscosity associated with the high red cell mass causes a slight increase in the risk of stroke.37 Most patients have a stable elevated haemoglobin level, but venesection is recommended if this is greater than 20 g/dL and the haematocrit is greater than 65%. Levels as high as this can be associated with the hyperviscosity syndrome: headache, fatigue and difficulty concentrating. Recurrent venesection can cause iron depletion and the production of microcytic red cells, which are stiffer than normal cells and so increase viscosity further. 2 Bleeding. Reduced platelet numbers, abnormal platelet function and clotting factor deficiencies mean these patients have an increased risk of haemorrhage. The most dangerous problem is pulmonary haemorrhage but bleeding from the gums and menorrhagia are more common. The use of anticoagulation must be restricted to those with a strong indication for treatment. 3 Gallstones. Chronic cyanosis and increased haem turnover are associated with an increased incidence of pigment gallstones. 4 Renal dysfunction and gout. Congestion of the renal glomeruli is associated with a reduced glomerular filtration rate and proteinuria. This and the increased turnover of red cells lead to urate accumulation and gout. 5 Pulmonary hypertension. Lesions associated with increased flow through the pulmonary circulation (e.g. a large atrial septal defect) can lead to a reactive rise in pulmonary arterial resistance. This is more likely to occur if the left to right shunt is large. Eventually these pulmonary vascular changes become irreversible, pulmonary pressures equal or exceed systemic pressures, and central cyanosis occurs because the intra-cardiac shunt reverses (Eisenmenger’s syndrome). Flow is now from right to left. There is then no benefit in attempting to correct the underlying cardiac abnormality. Earlier and more successful treatment of children with congenital heart disease has reduced the number of patients with this inexorable disease. Careful management of these conditions can nevertheless improve patients’ symptoms and survival. Reasonable exercise tolerance is usually maintained into adult life for most patients but progressive deterioration then occurs. Haemorrhagic complications, especially haemoptysis, are common. Thrombotic stroke, cerebral abscess and pulmonary infarction can also occur. 364 PRACTICAL CARDIOLOGY In a recent European survey, survival for patients with simple defects and Eisenmenger’s was to 32.5 years, but only 25.8 years for those with Eisenmenger’s resulting from complex abnormalities.38 There is a 50% maternal mortality risk with pregnancy. Quite minor surgical procedures are associated with high risk. Trials with endothelin antagonists are being conducted and continuous oxygen treatment can provide symptomatic relief. Lung and heart lung transplant should be considered for some of these patients. 6 Endocarditis. Most patients with congenital heart disease have a lifelong risk of infective endocarditis. Constant reminders of this risk should be given to the patients and their usual doctors. As well as appropriate antibiotic prophylaxis . before procedures, a high index of suspicion is very important. A febrile illness should not be treated with antibiotics until at least two sets of blood cultures have been taken. Early referral
HEART SPECIALISTS IN YELAHANKA NEW TOWN BANGALORE The causes of coronary symptoms The symptoms of coronary artery disease are caused by the reduction of myocardial perfusion that results from narrowing of the lumen of one or more of the coronary arteries. This narrowing is most often the result of atherosclerosis. Other much less common causes include: 1 coronary artery spasm (often in an already diseased segment of artery but sometimes as a result of the use of cocaine) 2 thrombosis (usually on an already diseased, or occasionally aneurismal, segment) 3 embolism (e.g. from an infected aortic valve) 4 congenital coronary abnormality 5 vasculitis. Numerous other cardiac symptoms and problems can be the eventual result of atheromatous coronary disease. These include myocardial infarction , cardiac failure cardiac arrhythmias and some cardiac valve problems. Risk factor mechanisms of action Atherosclerosis is thought to result primarily from a disturbance of the vascular endothelium. The final common pathway for the effects of endothelial dysfunction is largely through abnormalities of nitric oxide (NO) production. This chemical, released by a healthy endothelium, is a potent vasodilator and has anti-inflammatory and other favourable actions on the arteries. Causes of this disturbance can be: n mechanical (hypertension) n chemical (oxidised lipids, components of cigarette smoke, hyperinsulinaemia) or n due to immunological injury. The damaged endothelium attracts inflammatory mediators, platelets and circulating lipids and promotes fibroblast and smooth muscle proliferation. This results in the formation of a plaque, which may narrow the arterial lumen. Plaques can remain stable (or sometimes regress), enlarge, rupture or erode (more common in diabetics). Most acute ischaemic events (acute coronary syndromes or acute myocardial infarctions) are thought to be the result of further luminal narrowing caused by the formation of partly or fully occlusive thrombus on a ruptured or eroded plaque. Coronary risk factors may therefore operate because they are atherogenic or thrombogenic. Plaque rupture Plaque rupture may be at least partly an inflammatory process involving inflammatory cells, cytokines and even bacteria. This may explain the association between inflammatory markers such as high-sensitivity C reactive protein (hsCRP) and a risk of acute coronary events. Although this association seems well established, there is still uncertainty about its role in overall risk assessment Plaques at risk of rupture are called vulnerable plaques. They typically have a thin fibrous cap. The shoulde of these caps are at risk of rupturing and allowing material from within the plaque to come
SAMIKSHA HEART AND DIABETIC CARE ''CONNECTIVE TISSUE DISORDERS'' ''Marfan Syndrome'' Marfan syndrome is a systemic connective tissue disorder with a frequency of 2 to 3 in 10, 000. The disorder is characterized by manifestations involving the cardiovascular, skeletal, and ocular systems. Current diagnostic criteria are based on involvement of above organ systems and family history. Cardiovascular manifestations include mitral valve prolapse, progressive aortic root enlargement, and ascending aortic aneurisms, possibly leading to aortic regurgitation, dissection, or rupture. Some characteristic skeletal manifestations of this syndrome include disproportional increase of linear bone growth resulting in malformations of the digits (arachnodactyly), craniofacial abnormalities, pectus excavatum/carinatum, and scoliosis. A common ocular involvement is severe myopia and lens dislocation in one or both eyes (ectopia lentis). Marfan syndrome is an autosomal dominant disorder caused by fibrillin-1 gene mutations encoding for the extracellular matrix protein fibrillin (Fbn-1). Fibrillin is an integral component of both elastic and nonelastic connective tissue. The mechanism of fibrillin mutation in Marfan syndrome remains unclear. However, animal models of Fbn-1 have demonstrated a role of TGF-beta signaling. In some patients with phenotypes similar to Marfan syndrome but without fibrillin- 1 gene mutations, TGF-beta receptor mutations have been identified, suggesting a significant role of TGF-beta pathway in the pathogenesis of Marfan syndrome features. Aortic root involvement remains the leading cause of death in patients with Marfan syndrome. Echocardiography is recommended to routinely screen and to follow aortic root dilation. In addition, all first-degree relatives of the family should have screening echocardiography. Patients should be advised against strenuous exercises. Medical therapy for Marfan syndrome includes beta-blockers to reduce myocardial contractility and pulse pressure. Animal models of Marfan syndrome have demonstrated a possible benefit of losartan in preventing progression of the disease by inhibiting the TGF-beta pathway, and this therapy is the subject of an active clinical trial. Elective aortic root replacement remains the therapy of choice once the aortic root becomes significantly enlarged. Marfan patients who become pregnant need to be counseled not only about the 50% chance of transmitting the disease but also the substantially increased risk of aortic rupture/dissection during and after pregnancy. Important components of Marfan syndrome counseling are consideration of contraception and pregnancy management. Loeys-Dietz Syndrome Recently, an aortic aneurysm syndrome has been identified with TGF-beta receptor mutations. Loeys-Dietz syndrome is an autosomal dominant condition with a characteristic triad of arterial tortuosity/aneurysm, hypertelorism, and bifid uvula or cleft palate. There is significant overlap with Marfan syndrome, and the management is similar in terms of cardiovascular manifestation. Early, elective, surgical intervention should be considered in patients with significant aneurysmal dilation of the aorta. Some clinicians have argued for much earlier surgical intervention for the dilated aorta in this condition, compared with Marfan syndrome, since there appears to be a much greater risk of rupture and dissection at earlier ages and smaller aortic sizes. Pregnancy counseling is also an integral part of therapy. Ehlers-Danlos Syndrome Ehlers-Danlos syndrome is a group of disorders that affect connective tissue development due to defects in collagen and connective tissue biosynthesis. Prevalence of the disease is about 1 in 400, 000 people in the United States. Cardiac manifestations include spontaneous rupture of medium to large sized arteries including the aorta. Frequently, extracardiac presentations include hyperextensible skin and hypermobile joints. To date, 11 types of the disorder have been recognized, but collagen defects have been described in only 6 types. Although all types of Ehlers-Danlos syndrome affect the joints and the skin, clinical features vary by type. Different features characterize each type of the syndrome. Type IV carries the poorest prognosis, especially due to spontaneous ruptures of arteries and organs. Extreme caution needs to be taken if surgical intervention is needed due to weakened connective tissue structures. Many genes, including ADAMTS2, COL1A1, COL1A2, COL3A1, COL5A1, COL5A2, PLOD1, and TNXB, have been implicated in the pathogenesis of Ehlers- Danlos syndrome, but the predominant cardiovascular concern exists in the Type IV vascular form of Ehlers-Danlos associated with mutations in the COL3A1 gene and aortic dilation/aneurysms. Other less commonly associated anomalies include ventricular septal defect, patent ductus arteriosus, bicuspid pulmonic valve, and Ebstein’s anomaly. Bicuspid aortic valve has been shown to demonstrate familial clustering. However, identifying culprit genes have been difficult due to variable penetrance and the common nature of the disorder.
CARDIOLOGISTS IN YELAHANKA NEWTOWN BANGALORE Plaque rupture Plaque rupture may be at least partly an inflammatory process involving inflammatory cells, cytokines and even bacteria. This may explain the association between inflammatory markers such as high-sensitivity C reactive protein (hsCRP) and a risk of acute coronary events. Although this association seems well established, there is still uncertainty about its role in overall risk assessment Plaques at risk of rupture are called vulnerable plaques. They typically have a thin fibrous cap. The shoulder regions of these caps are at risk of rupturing and allowing material from within the plaque to come in contact with the blood stream. This material is intensely thrombogenic. Stable fibrous plaques are much less likely to rupture in this way. Efforts are underway to develop tests that can identify vulnerable plaques. This is not yet possible, but multi-slice CT scanning and possibly MRI angiography may i
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