Thrombocythemia and Thrombocytosis
Thrombocythemia and thrombocytosis are blood clotting disorders in which clots form due to an excessive number of platelets in the blood. The distinction between these two conditions, though not always made, focuses on the fact that thrombocythemia is a primary disorder, usually of unknown origin, and thrombocytosis is a reactive disorder with definable causes. Patients with either condition may develop unexpected bleeding as well as blood clots.
While clotting seems to be the natural consequence of too many platelets in the blood, bleeding may also occur. Bleeding in patients with these conditions is the result of excessive clotting which uses up existing platelets. When there is further injury to the blood vessels, there are not enough of these blood cells available to clot.
Causes of Thrombocythemia
Also known as essential or primary thrombocytosis, thrombocythemia is the result of a bone marrow disorder. Platelets, like other blood cells, are produced in the bone marrow. When there is a dysfunction of the bone marrow, too many platelets may form and enter the bloodstream. The platelets created may be deformed or not fully functional. Most often, the cause of thrombocythemia is unknown, though in rare cases it may be the result of a genetic defect or mutation.
Causes of Thrombocytosis
In thrombocytosis, unlike in thrombocythemia, the platelets are normally constructed -- there are just too many of them. Thrombocytosis is more common than thrombocythemia, and is the result of a medical event or underlying condition. Thirty-five percent of patients with this disorder have an underlying cancer and, often, the high platelet count on a blood test is the first sign of that disease. Thrombocytosis may have a variety of other causes, including:
- Acute blood loss from trauma or surgery
- Pancreatitis
- Kidney disorder
- Heart attack
- Infectious or inflammatory disease
- Severe allergic reaction
- Hemolytic or iron deficiency anemia
- Splenectomy, or removal of the spleen
- Certain medications, including epinephrine
There are times when thrombocytosis is temporary. The condition may last only a short time when it is caused by one of the following:
- Serious short-term blood loss
- Excessive alcohol use or deficiency of vitamin B12
- Acute infection
- Short-lived inflammation, perhaps as a result of an allergic reaction
- Excessive strenuous physical activity
Symptoms of Thrombocythemia
Symptoms are much more common among patients with thrombocythemia and may include:
- Weakness
- Fainting
- Headache
- Dizziness or lightheadedness
- Chest pain
- Temporary vision changes
- Numbness or tingling of the hands and feet
Symptoms of Thrombocythemia and Thrombocytosis
In most cases of thrombocytosis there are no symptoms, except those of the underlying causative condition, and the excess of platelets is discovered as a result of a routine blood test.
Blood Clot Symptoms
When blood clots develop in a patient with primary thrombocythemia, they most often develop in the brain, hands, and feet. It is possible, however, for clots from this condition to develop anywhere in the body, including in the heart and intestines. When blood clots develop in the brain, they may cause chronic headaches and dizziness, and, in extreme cases, may result in a stroke.
When clots develop in the small blood vessels of the hands and feet, the patient may experience numbness, redness, tingling, burning or throbbing on the palms of the hands or the soles of the feet. Other symptoms of blood clots may include:
- Changes in speech
- Mental confusion
- Fainting
- Seizures
- Upper body discomfort in the arms, back, neck, jaw or abdomen
- Shortness of breath
- Nausea
In pregnant women, blood clots may result in miscarriage or problems with fetal development.
Excessive Bleeding Symptoms
If bleeding occurs in patients with either of these disorders, it most often affects patients whose platelets counts are exceedingly high. Signs of excessive bleeding may include:
- Unexplained bruising
- Nosebleeds
- Bleeding from the mouth or gums
- Blood in the stool
Diagnosis of Thrombocythemia and Thrombocytosis
Several steps may be taken to diagnose thrombocytosis or thrombocythemia. These will usually include a complete blood count, or CBC, to determine the number of platelets in the blood, and a blood smear to investigate the condition of the platelets. Further tests will be done to determine whether the patient has thrombocytosis and, if so, what the underlying cause of the condition is. If no underlying condition is present, the patient will be presumed to have thrombocythemia and a bone marrow aspiration and biopsy will be performed.
Treatment of Thrombocythemia and Thrombocytosis
Treatment for thrombocythemia and thrombocytosis depends on the severity of each individual case. Many patients require no treatment aside from a careful monitoring of their condition. For patients who have secondary thrombocytosis, treatment of their underlying conditions may prove effective in reducing platelet production. In more severe or symptomatic cases, the patient may require medication to lower platelet production. A complex procedure called platelet pheresis, in which blood is taken, filtered to remove platelets, and then returned to the patient, may also be performed.
Risks of Thrombocythemia and Thrombocytosis
If left untreated, thrombocythemia and thrombocytosis may eventually lead to stroke, heart attack or life-threatening blood clots. Patients are at greater risk for these complications if they are elderly, diabetic, smoke, have high blood pressure or are on birth control pills. While thrombocythemia cannot be prevented, it can usually be managed successfully. A patient with secondary thrombocytosis may have a similarly good prognosis if the underlying condition can be appropriately managed. In all cases, the more the patient is able to control risk factors, such as obesity and smoking, and the more vigilant the physician is in monitoring the condition, the better the outcome is likely to be.