Pulmonary Embolism

When an artery in the lungs gets blocked, it is referred to as a medical condition of Pulmonary embolism. This condition can be life threatening. Often deep vein thrombosis (DVT) can lead to pulmonary embolism. The blood clots may originate in any other part of the body such as the arm, pelvis or legs. These clots travel through the bloodstream and enter the pulmonary arteries. Recent surgery or injury can lead to a blood clots. Persons with heart disease or those on estrogen therapy are at increased risk of pulmonary embolism. Typical symptoms experienced by those suffering from pulmonary embolism are chest pain, sudden shortness of breath and rapid heartbeat. A patient might have wheezing and weak pulse. The symptoms of pulmonary embolism depend on the extent and size of clots. Embolus can also be the result of fat from the bone marrow that has escaped into the bloodstream. It can also occur due to air bubbles formed during intravenous infusion or surgery. While large emboli cause considerable distress such as chest pain, smaller ones cause shortness of breath. Patients suffering from pulmonary embolism tend to have cough that produces sputum. There may be bluish discoloration on the skin and pain in the legs. Fainting spells or seizures might occur due to sudden decrease in oxygen-rich blood to the brain and other organs. Bluish tint on the skin (cyanosis) is observed when one or more large pulmonary arteries are obstructed.

Diagnostic procedures to detect pulmonary embolism:

• Chest X-ray helps in identifying any lung infections
  
• CAT scan
  
• ECG
  
• Perfusion Scan of the lung - This test helps in outlining the blood flow to the lungs and helps in detecting any obstructions.
• V/Q scan involves a a nuclear ventilation-perfusion study of the lungs.
  
• Pulmonary angiogram involves injection of a special dye into the pulmonary arteries to detect obstructive clots.
  
• D-dimer test is a test that spots d-dimer molecules released by the clots.
  

One of the initial steps to help a person suffering from pulmonary embolism is administration of oxygen and analgesics. Oxygen is administered through a nasal cannulae or face mask. Blood clots are treated with anticoagulant drugs like heparin or warfarin. But the duration and dosage of anticoagulants needs to be monitored so that it does not result in bleeding in other body organs. Thrombolysis is a procedure whereby Thrombolytic agents (clot-dissolving agents) are injected into the bloodstream to dissolve existing blood clots. Surgery (Pulmonary embolectomy) is often resorted to for removal of clots.

Pulmonary Infarction

Infarction means 'tissue death' in medical terminology. It is caused by obstruction of blood supply to the tissue leading to lack of oxygen. Infarct, which refers to the resulting lesion is derived from Latin, 'infarctus' which means 'stuffed into'. Pulmonary infarction refers to the death of a small area of lung resulting from pulmonary embolism. It occurs in a small, dead end pulmonary artery.

How does pulmonary infarction occur ?

Pulmonary infarction results from free floating thrombus, when many material substances including fat, tumor, septic emboli, air, and amniotic fluid and injected foreign material may form an emboli and move to the pulmonary circulation. In other words, plugging of a branch of the pulmonary artery by a clot (thrombosis) or by a piece of clot carried by the blood stream to the lung from a thrombus located elsewhere can result in pulmonary infarction. The involved area of the lung ceases to function and complication of the thrombosed veins leads to heart disease.

Causes of pulmonary infarction

The most common cause of pulmonary infarction is pulmonary embolism, but there are other conditions which can cause pulmonary infarction including cancer, and autoimmune diseases such as lupus. Sometimes, this condition may occur following a surgery. Other underlying conditions especially in children with pulmonary emboli include sickle cell disease, nephrotic syndrome, chemotherapy and Inherited hyper coagulable state and Vasculitis.

Symptoms of pulmonary infarction

Symptoms associated with pulmonary infarction include shortness of breath, chest pain, and blood sputum or hemoptysis. Sudden piercing pain in the chest which often radiates to the shoulder is noticed. Difficulty in breathing, irritating cough and blood tinged sputum are other signs. Persistent hiccups are present. Most often the patient is anxious with a rapid pulse, sweats profusely and has an elevated body temperature. In some severe cases, the patient may be in a state of shock.

Diagnosis of pulmonary infarction

Reflex broncho constriction is often associated with pulmonary embolism. Increased breathing and decreased pulmonary compliance with diminished surfactant levels may occur due to pulmonary infarction. This contributes to increased work of breathing and diminished oxygen levels. In sickle cell disease, there is sickling of RBCs within the small blood vessels of the lungs due to dehydration as a result of fever, Tachypnea (rapid breathing) and decreased intake, which can precipitate in a cycle of relative de oxygenation that further exacerbates the sickling tendency. Many also suffer a component of reactive airway disease and oxygenation is further decreased due to this factor.

Morbidity may include pulmonary hypertension, right ventricular failure and Cor Pulmonale, paradoxical embolization in patients with intracardiac defects, and sometimes side effects of medications used to treat pulmonary embolism. If pulmonary embolism is large, there could develop right ventricular strain and right heart failure as there is sudden increase in pulmonary artery pressure leading to right heart failure. A sudden pressure in the right ventricle can cause a leftward shift of the intraventricular septum, which may result in a classic obstructive shock, thereby impairing left ventricular filling.

Treating pulmonary infarction

It is timely treatment that is vital. If symptoms of pulmonary infection develop while at home, consult a physician at once. In case, shock develops, it is essential to get first aid treatment. Many times, patients are already in the hospital when pulmonary infarction occurs. Administration of oxygen, use of anticoagulants and prevention of infection are some other suggested line of treatment. Surgery may also be indicated.

Blood thinners

Doctors prescribe medicines for varied reasons, to cure an ailment, to prevent or stop an infection, to ease symptoms, to reduce risks etc. But if there is one particular group of medicines where there is a need for rigorous monitoring regime when taken, it is blood thinners. Not without a reason. Though approved by the FDA, if not handled properly, prolonged use of blood thinners can be unsafe.

Need for Blood thinners

Blood thinners reduce the ability of the blood to clot. Blood thinners belong to a class of drugs called anticoagulants. Immediately after an injury, a scrape or a cut, the blood coagulates and seals the wound, forming a scab to protect from infection. The blood clots formed will be naturally dissolved in the body after the injury is healed. Here blood clotting is a saver and is essential for the body.

The mechanism is regarded as dangerous when blood clots form in the blood stream without an obvious injury and if the blood clot fails to dissolve naturally after the injury heals. The situation poses great risks as it can block circulation; the blood clot can travel to the arteries or veins in the brain, heart, kidneys, lungs and limbs. This in turn can lead to life-threatening conditions such as heart attack, stroke, damage body's organs and in extreme cases result in loss of life.

An updated (February 2014) American Academy of Neurology (AAN) guideline recommends people with an irregular heartbeat to take blood thinners to reduce the risk of stroke. As per doctor's prescription, every year around 2 million people take blood thinner medications every day. It is strongly recommended that blood thinner be taken only under medical supervision.

New vs. old blood thinners

Warfarin was introduced sixty years ago. It is regarded as the oldest anticoagulant blood thinner medication. For decades, Warfarin was the only blood thinner available to lower risks of stroke. There are new additions. A recent study has showed that new blood thinners might be more effective than older medications.

• Dabigatran (Generic name) approved by FDA in October 2010
  
• Rivaroxaban (Generic name) approved by FDA in October 2011
  
• Apixaban (Generic name) approved by FDA in December 2012.
  

Detailed studies comparing Warfarin with the new addition state the following:

• New drugs are similar or even better than warfarin in preventing stroke.
  
  
• As the optimal dose of Warfarin varies from patient to patient, blood levels of patients on Warfarin need to be checked periodically.
  
  
• New blood thinner medications are regarded as more convenient because the patients taking them do not need to have blood levels checked.
  
  
• A study on effectiveness reflected that new blood thinners were approximately 20% more effective in reducing the risk of stroke and 10 % more effective in reducing the risk of death when compared to warfarin.
  
  
• New blood thinners, in addition to being more convenient, are potentially more effective than and similar in safety to warfarin.
  
  
• New blood thinners are more expensive than Warfarin.
  
  
• Long-term safety and side effects of new blood thinners is not yet available.
  
  
• With Warfarin, it is easier to reverse the blood thinning effect if a patient is bleeding or needs urgent surgery.

Types of blood thinners

It is chemical formulations that contribute to preventing clotting in various ways. Broadly blood thinner medications are classified into anticoagulant and anti platelet blood thinners.

Anticoagulant blood thinners

Anticoagulant blood thinner medications help decrease the tendency of blood clot formation. There are two ways to decrease the formation of blood clots in the body. Anticoagulants can interfere with platelets or block the body's production of clotting substances. Anticoagulant blood thinners are prescribed for people who have had a condition caused by a blood clot or are at risk of developing one.

Anticoagulant blood thinners are usually given by mouth. In some cases anticoagulants are given intravenously or by injecting them just under the skin (subcutaneously).

Warfarin: Warfarin is the generic drug. In the US, Warfarin is sold under the brand names Coumadin and Jantoven. Doctors prescribe Warfarin for two reasons, to prevent the formation of harmful blood clots or treat an existing blood clot. Some conditions for which Warfarin is prescribed include:

• Atrial fibrillation
  
• Stroke
  
• After a heart attack
  
• Clotting disorder
  
• Heart valve disease or heart valve replacement
  
• Treatment or prevention of Deep Venous Thrombosis (blood clots in the veins) and/or pulmonary embolism (blood clots in the lungs).

Patients prescribed Warfarin ought to know how Warfarin works. Knowing helps limit the intake of vitamin K rich foods like dark green vegetables such as broccoli, spinach, turnip greens, green peas etc. At any time, the blood needs certain proteins to clot. These proteins are made in the liver. To enable the liver in the process, Vitamin K is required.

When Warfarin is administered, it reduces the liver's ability to use Vitamin K. Warfarin and Vitamin K work against each other. Thus, the formation of blood clot becomes harder. The interaction between Warfarin and Vitamin K explains the need to partake a diet that is constant in Vitamin K while on Warfarin. The dosage of Warfarin may vary from person to person. A blood test may be recommended to determine the dosage. This blood test, Prothrombin Time or International Normalized Ratio is required to monitor the body's response to Warfarin. Based on test results, Warfarin dose will be determined.

Side effects of Warfarin

Warfarin or Heparin, a common side effect of any anticoagulant medication is the risk of excessive bleeding. As these medicines prolong or lengthen or makes blood clot formation harder, it increases the time for formation of blood clots. If the time taken is too long, there is a possibility of excessive bleeding. There are other symptoms to look out for which are more common with Warfarin. Patients on Warfarin should immediately seek medical attention for any these common Warfarin side effects.

• passing blood in your urine or feces (stools)
  
• passing black feces
  
• severe bruising
  
• prolonged nosebleeds for more than 10 minutes
  
• bleeding gums
  
• blood while throwing up (vomiting)
  
• coughing up blood
  
• unusual headaches
  
• sudden severe back pain
  
• difficulty breathing or chest pain

Women who take Warfarin should contact health care provider if they experience heavy or increased bleeding during menstruation or any other bleeding from the vagina.

Irrespective of the gender, some patients may experience rashes, diarrhea, nausea, hair loss while on Warfarin. These are not common side effects but are termed as additional side effects of Warfarin.

Doctors do advice patients to seek help if the patient is involved in a major accident, experiences a significant blow to the head and finds it difficult to stop bleeding, if any. As Warfarin can interact with many other medicines, so do inform the doctor about all the medications being taken.

Warfarin during pregnancy: Warfarin should be avoided during pregnancy and women with certain health conditions like high blood pressure, ulcer in the digestive tract should not take Warfarin as it can lead to severe health complications.

Long terms risks of using Warfarin: Extensive research on prolonged use of Warfarin suggests that the risk increases with age. The patient is at risk of serious or even fatal bleeding including internal bleeding. In particular the risks are:

• Bleeding strokes, or brain strokes (hemorrhage strokes)
  
• Calcium build-up in the arteries and narrowing of the aortic valve that goes from the heart and carries oxygen to the body (aortic valve stenosis)

Heparin: Heparin is the generic name. In US, Heparin is available under the brand names Lipohepin, liquaemin and Panheparin. Heparin decreases the clotting ability of the blood and also prevents existing clots from getting larger. Thereby, the normal body systems dissolve the clots that are already formed. Heparin is usually administered as an injection. Heparin can be injected subcutaneously or as an intravenous infusion. The advantage of IV is that it can be turned off quickly for safety reasons. Heparin is prescribed for conditions such as:

• Deep venous thrombosis
  
• Arterial embolism
  
• Pulmonary embolism
  
• Prevention of blood clot during heart surgery, dialysis or blood transfusions
  
• Peripheral artery obstruction by a foreign substance or a blood clot
  
• Treatment to prevent peripheral artery thrombo-embolism.

It helps to know how heparin works. Heparin ensures that an anti-clotting protein which is present in the body works better, thus decreasing the clotting ability of the blood.

Available in different strengths, the doctor must prescribe the strength depending on the purpose for which it is prescribed. During the course of treatment, the doctor may increase or decrease the dosage.

Side effects of heparin

A unique possible side effect of Heparin is that several weeks after stopping the injection, bleeding episodes may occur. If the patient notices bruising or unusual bleeding such as a nosebleed, blood in the urine or stools, black or tarry stools or any other bleeding that doesn't cease, contact your healthcare provider.

Besides the common side effects of anticoagulant medications, Heparin's other side effects are visible at that point where the solution is injected.

• Swelling
  
• Pain
  
• Irritation
  
• Bruising

Herparin during pregnancy: FDA category for Heparin is C meaning there isn't established information that proves whether Heparin affects the fetus. It is best for pregnant women as well as breast-feeding mothers to use Heparin only if the medicine is prescribed by the doctor.

Long term risks of using Heparin

Prolonged use of Heparin particularly in the elderly may cause osteoporosis, a condition in which the bones become weak and may break easily.

Antiplatelet blood thinners

Antiplatelet blood thinner medications work to prevent the platelets (small cells in the blood) from clumping together to form a blood clot. This happens by inhibiting the production of thromboxane, a chemical that signals other platelets to come together. By inhibiting the production of thromboxane, platelets cease to come together to form the blood clot.

Thromboxane's role is helpful for a normal healthy individual who has suffered a wound. It acts as a self-sealing material. But, in the case of a stroke survivor, thromboxane's ability to bind and form a blood clot is potentially life-threatening. Hence, the need to use an antiplatelet blood thinner which are usually available in the form of tablets only.

Doctors prescribe antiplatelet Aspirin to patients who have had a stroke or TIA (transient ischemic attack) so as to reduce the risk of having another stroke. This is possible with Aspirin as it interferes with the blood's clotting action. The dosage varies from patient to patient and is largely guided by the patient's health condition.

Though Aspirin is available OTC (over the counter), doctors recommend low doses of Aspirin for patients with the following medical history.

• Patients who have had prior heart attacks
  
• Patients who have had prior strokes
  
• Patients with exertional and unstable angina
  
• Patients with TIAs (transient ischemic attack called mini-stroke)
  
• Patients at risk of atherosclerosis.

Aspirin is prescribed to patients who are considered to be at risk of having heart attack or stroke. Anyone with high cholesterol, high blood pressure, diabetic and smoke aggressively are regarded to be at risk of having heart attack or stroke.

Side effect of Aspirin

Most common side effect of taking low doses of Aspirin (100 mg dose) is heartburn and stomach upset. Seldom has there been a very serious side effect related to taking Aspirin as a blood thinner medication. However it is best to be aware of possible serious side effects such as bruising/bleeding, difficulty hearing, ringing in the ears, and change in urine amount, persistent or severe nausea /vomiting, unexplained tiredness, dizziness, dark urine, yellowing of eyes or skin.

Aspirin during pregnancy

The FDA has not assigned formally a pregnancy category. Aspirin is not recommended for use during pregnancy and while breast-feeding as it excretes into breast milk in small amounts.

Other antiplatelet blood thinners

Besides Aspirin, other antiplatelet medicines that are prescribed to prevent the platelets from sticking together include the following. Doctors prescribe a specific antiplatelet blood thinner taking into account the specific health condition and relative effectiveness of the blood thinner medicine. New drugs are continually added to the list with FDA approval.

• Aspirin plus clopidogrel (brand name Plavix) is prescribed for patients who are diagnosed with coronary syndrome such as unstable angina or have had a heart attack, if stent is implanted or if the patient has had a stroke or mini stroke.
  
  
• Aspirin plus extended dipyridamole (brand name Aggrenox) is prescribed for patients who have had a stroke or mini stroke (TIA).
  
  
• Clopidogrel (brand name Plavix) is recommended by doctors if Aspirin is not suitable for a patient who has been diagnosed with acute coronary syndrome or had a stent implanted.

Long term risks of using Aspirin

Daily use of aspirin can have serious side effects including internal bleeding. Prolonged use of aspirin at higher doses (> 500 mg) can cause stomach ulcers, and can also prolonged bleeding.