16: Platelet Disorders: Thrombocytopenia, Platelet Dysfunction, and Thrombocytosis: Assessment, Analysis, and Associated Dental Management Guidelines

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Platelet Disorders: Thrombocytopenia, Platelet Dysfunction, and Thrombocytosis: Assessment, Analysis, and Associated Dental Management Guidelines

As discussed in previous chapters, platelets play a very important role in primary hemostasis. Platelet deficiency and/or platelet dysfunction can promote excessive oozing during surgery, and the oozing can continue beyond 24 hours postoperatively depending on the extent of the problem. Common platelet disorders are thrombocytopenia/platelet deficiency, platelet dysfunction, and thrombocytosis.

THROMBOCYTOPENIA/PLATELET DEFICIENCY

The average platelet count is 150,000–400,000/mm3. A patient is said to have thrombocytopenia if the platelet count is under 150,000/mm3. Spontaneous bleeding can occur when the platelet count is below 20,000/mm3.

Thrombocytopenia Causes

The following are etiological factors causing of thrombocytopenia:

  • Drugs such as heparin, chemotherapeutic agents, and alcohol
  • Leukemia, lymphoma, or bone marrow tumors
  • HIV, mumps, rubella, or parvovirus infections
  • Sequestration of the platelets by an enlarged spleen. Acute or chronic liver disease is the leading cause for an enlarged spleen.
  • Autoimmune destruction of the platelets by IgG antibodies, causing Idiopathic Thrombocytopenia Purpura (ITP). ITP is most common in children and young adults.

Thrombocytopenia Symptoms and Signs

Thrombocytopenia and platelet dysfunction causes easy bruising and easy bleeding. Small, superficial bruises; petechiae; and bleeding mucus membranes are common findings. Petechiae are pinpoint hemorrhagic flat lesions that occur in clusters. Petechiae can be seen on the oral mucosa and on the skin of the extremities.

Thrombocytopenia Laboratory Tests

Thrombocytopenia is associated with a prolonged bleeding time (BT) and a decreased platelet count.

Thrombocytopenia Treatment (Except ITP)

Thrombocytopenia (except ITP) can be treated as follows:

1. Platelet Rich Plasma (PRP) or Platelet Rich Concentrate (PRC) transfusion
2. Desmopressin/Stimate/DDAVP. DDAVP elevates the von Willebrand’s Factor level in the blood and stimulates platelet release

Platelet transfusion, when required, is given 20 minutes prior to the planned procedure. One platelet concentrate transfusion increases the platelet count by 10,000/μL.

Thrombocytopenia Dental Alerts

Spontaneous bleeding occurs when the platelet count is below 20,000/mm3. Routine dental treatment is contraindicated if the platelet count is below 50,000/mm3.

In the presence of significant thrombocytopenia, the CBC with platelet count should be assessed prior to dentistry. The test obtained should have been done within the past seven days and usually confirmed on the day of surgery in very severe cases following replacement therapy. For outpatient oral surgery or periodontal surgery the platelet count must be above 75,000/mm3, and for major dental surgical procedures done in the operating room (OR) under general anesthesia, it is best to have the platelet count above 100,000/mm3.

IDIOPATHIC THROMBOCYTOPENIC PURPURA (ITP)

Idiopathic thrombocytopenic purpura (ITP), also called immune thrombocytopenic purpura, affects both children and adults. Children often develop idiopathic thrombocytopenic purpura after a viral infection and usually recover fully without treatment. However, in adults the disorder is often chronic.

Symptoms

Easy or excessive bruising (purpura), petechiae typically on the lower legs, prolonged bleeding from cuts, spontaneous bleeding from gums or nose, blood in urine or stools, unusually heavy menstrual flows, and profuse bleeding during surgery can occur.

Causes

The exact cause of ITP is not known but it is well documented that the immune system malfunctions and begins attacking platelets as if they were foreign substances. Antibodies produced by the immune system attach to the platelets, marking the platelets for destruction. The spleen recognizes the antibodies and removes the platelets from the system.

Adults and children with ITP often have platelet counts below 20,000/μL. As the number of platelets decreases, the risk of bleeding increases. The greatest risk occurs when the platelet count falls below 10,000/μL. At this point, internal bleeding can occur despite a lack of any injury. In most children with ITP, the disorder follows a viral illness, such as the mumps or the flu. It may be that an infection sets off the immune system, triggering it to malfunction.

Risk Factors

Women are approximately twice as likely to develop ITP than are men. Once considered a young person’s disease, ITP is actually far more common in people older than 60 than it is in younger adults.

Recent viral infection: Many children with ITP develop the disorder after a viral illness, such as mumps, measles, or a respiratory infection. In most children, ITP clears on its own within two to eight weeks.

Complications

The biggest risk associated with idiopathic thrombocytopenic purpura is bleeding, especially bleeding into the brain (intracranial hemorrhage), which can be fatal. However, major bleeding is rare with ITP. Complications are more likely to arise from the treatments, corticosteroids, and surgery that are used for chronic or severe ITP. In fact, many therapies pose more serious potential risks than does the disease itself. Long-term use of corticosteroids can cause serious side effects including osteoporosis, cataracts, loss of muscle mass, increased risk of infection, high blood sugar, and even diabetes. Splenectomy may be performed if corticosteroids are ineffective, but splenectomy also makes the patient permanently more vulnerable to infection.

Pregnant women with mild ITP usually have a normal pregnancy and delivery, though antibodies to platelets can cross the placenta and affect the baby’s platelet count. The baby’s platelet count will improve without treatment, but if the count is very low, treatment can help speed reco/>

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Jan 4, 2015 | Posted by in General Dentistry | Comments Off on 16: Platelet Disorders: Thrombocytopenia, Platelet Dysfunction, and Thrombocytosis: Assessment, Analysis, and Associated Dental Management Guidelines
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