Wednesday, March 14, 2007

A lesson in blood clot complications and sudden deaths

Niyi Akinnaso and Kofo Odusote

In 2003, former Health Minister, Professor Olikoye Ransome-Kuti, and an American journalist, David Bloom, died suddenly of complications from a blood clot. The former died in his sleep in a London hotel after a long-haul flight from Lagos, while the latter died after spending days cramped in a Humvee in which he was covering the Iraq war. Hundreds of thousands of people have since died of similar complications worldwide. In the United States alone, blood clot complications kill up to 200,000 people yearly; that is more than AIDS and breast cancer combined. Yet, unlike these recognizable killer diseases, early diagnosis of a blood clot is often missed because patients themselves may not notice any significant symptoms until complications arise. Nevertheless, early detection of a blood clot is quite possible and blood clot complications are preventable. The purpose of this article is to educate the public about the causes, symptoms, diagnosis, and treatment of a blood clot and thus prevent its fatal complications. A blood clot is technically known as a thrombus, which forms in one of the deep veins of the body. This is why this type of clot is technically known as DVT (Deep Vein/Venous Thrombosis).
DVT typically occurs in the veins inside the calf and thigh muscles of the leg. It can also occur in the deep veins of the arm, shoulder, or pelvis. Like visible veins just below the skin, invisible deep veins carry blood towards the heart. When a DVT occurs, blood flow in a deep vein is partially or completely blocked, depending on whether the blood clot partially or completely fills the width of the vein. The blockage often results from sluggish or disturbed blood flow, which gives room for blood to gather or “pool” and to subsequently coagulate or clot. The factors responsible for the formation of a blood clot range from family and health history to environment and lifestyle. Approximately one in every four cases of DVT is due to inherited clotting disorders. This makes family history or genetic inheritance one of the leading risk factors for DVT. People with Blood type A are also at risk for DVT. A person’s own health history is another important factor. People who have had one or more of the following health conditions are at greater risk for DVT: certain types of cancer and cancer therapy; heart failure; COPD (Chronic Obstructive Pulmonary Disease); varicose veins; obesity; paralysis; and a stroke. Certain types of medication, such as contraceptive pills and hormone replacement therapy, which contains estrogen, pose an increased risk of DVT. Another risk factor for DVT is age. Although DVT also affects young people, the risk increases with age, particularly after 40. Moreover, a previously diagnosed case of DVT increases the risk of developing the condition again. Reduced movement or immobility, which slows down blood flow in the veins, can also increase the risk of DVT. Factors responsible for reduced movement or immobility include injuries, especially to the leg; surgery; hospitalization; pregnancy; and cramped position. Travellers are one group in whom DVT is becoming more widely reported. It is assumed that there is a particular risk with air travel because of the combination of physical restriction, inactivity, and dehydration, which makes the blood stickier. However, the extent of the correlation between long-distance travel and DVT remains controversial. While some studies show that journeys more than five hours long by car, plane, or train increase the risk of DVT two to fourfold, others insist that there is only about one DVT for every 6,000 journeys that last four hours or more. It is further argued that only a tiny fraction of DVT-related deaths are linked to air travel. If autopsies were performed on many sudden deaths that did not involve any travel at all, it might be discovered that quite a number could be due to DVT. However, DVT deaths associated with air travel tend to get reported widely because of the relatively high social standing of most air travellers. The key point of this controversy is that it makes sense to look to other risk factors for air travelers who have DVT since the vast majority of travellers do not.

What are the symptoms of DVT? Quite often, there are no symptoms at all, especially at the initial stages. As the clot endures, there may be cramps, pain, tenderness, raised skin temperature, and sudden swelling around the area of the clot. The problem with these symptoms is that they easily could be misdiagnosed, because they could be symptoms of something else as well, such as a muscle strain or infection. However, if these symptoms are present, it is better to rule out (or confirm) DVT through two commonly used tests. One is the D-dimer blood test that detects fragments of the by-products of a blood clot. The more fragments are detected, the more likely is there a clot. Another test is an ultrasound scan of the leg, which can often detect a clot in a vein. A PTT (partial thromboplastin time) test is useful in measuring clotting time in blood plasma; it is not useful in detecting a DVT or its specific site. What are the treatment options? If DVT is confirmed, it easily could be treated through medication or surgery. Commonly used anticoagulants are heparin injection (which acts fast) and warfarin tablets (which act more slowly). A doctor should prescribe and monitor the administration of these medications in order to ensure appropriate dosage and effectiveness. A more radical treatment is an operation known as thrombectomy where a large clot is surgically removed. A DVT is itself not life threatening. However, if left untreated, it could lead to fatal complications. A piece of the clot, known as embolus, might “break off” and travel upstream towards the heart, the lung, or the brain. Depending on its size, the embolus can subsequently get stuck in a blood vessel supplying the heart, the lung, or the brain. The result could be partial or complete stoppage of blood flow, which could lead to heart failure, a collapsed lung, or a stroke, each of which could mean instant death. The most common of the three complications is PE (Pulmonary Embolism), involving a stuck embolus in a blood vessel going to a lung. It is estimated that about 1 in 10 people with untreated DVT develop a pulmonary embolus large enough to cause symptoms or death. The symptoms of PE are much more pronounced than those of DVT. Unfortunately, however, the diagnosis is missed far more often than it is made. For one thing, the symptoms are often vague and nonspecific, because they could be associated with other health problems. Moreover, symptoms tend to show up almost when PE complications are irreversible. This is why PE diagnosis is often not made until autopsy in nearly 80 per cent of cases. Initially, PE patients may complain of abdominal pain, high fever, productive cough, or even hiccoughs. After 24-72 hours, a range of symptoms may become evident, including shortness of breath; painful respiration; rapid pulse; sharp chest pain; back pain; shoulder pain; very low blood pressure; anxiety or nervousness; excessive sweating; fainting; lower extremity edema; and cough that may produce a bloody sputum. Since no single patient manifests all these symptoms, it is important that anyone experiencing several of them at once should go to a hospital immediately and request the doctor to rule out PE. Two quick tests could be conducted. A chest CT scan can image blood clots and a lung scan can identify areas of decreased blood flow in the lung tissue, if PE is present. If PE is confirmed (and quickly enough), it might be possible to dissolve or surgically remove the embolus and manage the originating clot. Fibrinolytic therapy (such as alteplase administered through IV infusion) has been found to be particularly effective in combating massive or unstable PE in some patients. Apart from the breaking off of an embolus that could prove fatal, untreated DVT might lead to “post-thrombotic syndrome”, especially if the DVT originated in the calf tissue. Pain, swelling, rashes, and even an ulcer on the skin of the calf may develop as a result of stagnation of blood in the area due to the blockage. How might DVT be prevented in order to avoid its fatal complications? The best tactics are risk assessment and preventive measures. It is important that everyone stay aware of his or her DVT risk factors as discussed above. Those who plan to be off their feet for an extended period of time due to surgery (especially abdominal surgery), hospitalisation requiring prolonged stay in bed, or a long journey should discuss their DVT risk with their doctors. Any of the medications mentioned above could be prescribed as a prophylaxis. In this regard, it should be noted that aspirin may not be helpful at preventing DVT. While aspirin is effective at preventing blood clots in arteries, which can cause strokes and heart attacks, it does not seem to be effective at preventing clots in veins. Besides medication, compression stockings, also known as anti-embolism stockings, might help to reduce the risk of DVT by enhancing the flow of blood through the legs by means of compression. It is advisable for air travellers to wear these stockings, especially if they suspect that they are at risk for DVT. Additional measures are also recommended for those on long journeys, particularly long-haul plane trips, in order to prevent travel-related DVT. The measures include regular exercise of the calf and foot muscles; walking up and down the aisle every hour or so; drinking plenty of water (to avoid dehydration); and avoiding too much alcohol and sleeping tablets as they may induce immobility. A little walk right at the end of the journey is also recommended as a way of getting blood circulation going normally again.

The inspiration for this article came from the loss of a dear friend, Babatunde Amusu, to complications from pulmonary embolism. The article is dedicated to his memory.
•Prof. Akinnaso teaches Anthropology and Linguistics in the United States; Dr. Odusote is Director of Health Services, University of Lagos.
CULLED from The PUNCH, Wednesday April 05, 2006


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