00:00 Now that we've discussed Fanconi anemia as a genetic cause of aplastic anemia, let's look at some of the other causes of aplastic anemia. 00:08 The first is medications. 00:09 These can be toxic to the bone marrow and can damage the pluripotent hematopoeitic stem cells before they differentiate to committed stem cells. 00:18 The onset of drug-induced aplastic anemia is variable and can be insidious. 00:23 This can occur days after the initiation of the medication up to months after the start of a new drug. 00:28 The average time is about 6 1/2 weeks after starting a medication. 00:33 It typically starts with neutropenia which is the low white blood cells followed by thrombocytopenia which is low platelets. 00:40 Finally anemia develops and this happens slowly due to that longer lifespan of the red blood cell. 00:46 Clinical features of drug-induced aplastic anemia depend on the degree to which each cell line is suppressed. 00:52 Medication-induced aplastic anemia is one of the few life threatening reactions to medications. 00:59 Common drug classes include cytotoxic chemotherapy We know this is a medication but this is also a toxin. 01:06 Chemotherapy is effective in killing off cancerous cells but the chemical sometimes ends up harming the healthy stem cells found in the bone marrow. 01:13 In fact, chemotherapy can cause blood cell counts to fall in the first week after starting treatment. 01:19 This reduces the number of red cells, white cells and platelets in the body. 01:23 Thankfully this reduction is usually temporary and it should improve after the chemotherapy has been successfully completed. 01:30 The next is certain medications that we used to treat rheumatoid arthritis, and certain antibiotics. 01:36 To stop the aplastic anemia caused by a medication, the patient will need to stop the medication, if able. 01:42 Remember this isn't always possible especially if the medication is being used to manage a serious condition. 01:48 The patient can also receive a blood transfusion to replace the components of the blood that are not being made by the marrow. 01:54 The prognosis is similar when caused by medications as when aplastic anemia is idiopathic. 01:59 These patients usually respond well to immunosuppressive therapy and stem cell transplantation. 02:05 Aplastic anemia can also be caused by viral infections. 02:08 It is thought of as a response to the persistent inflammatory feedback to the hematopoietis system which makes it difficult for the bone marrow to function normally. 02:17 Viruses that have been linked to the development of aplastic anemia include hepatitis, the Epstein-Barr virus and cytomegalovirus. 02:25 In addition, Parvovirus B19 and HIV have also been linked. 02:30 Both the virus in itself can ensue this immune response and this can have a tremendous impact on the hematopoeitic process resulting in aplastic anemia. 02:40 How about aplastic anemia in pregnancy? Well a woman who has aplastic anemia prior to becoming pregnant will typically have a worsening of her symptoms during her pregnancy and some women will develop aplastic anemia while pregnant which is thought of as a sort of autoimmune reaction. 02:55 There is significant maternal and neonatal morbidity and mortality in patients with aplastic anemia These women have complicated obstetric and anaesthetic management and will likely be managed by a high risk maternal fetal medicine specialist These women are at high risk for hemorrhage due their thrombocytopenia and up to 75% of these patients require a blood transfusion during or after delivery. 03:21 The platelet count can also be too low to perform a safe cesarean delivery. 03:26 Due to their neutropenic state, these women are at an increased risk for infections and sepsis. 03:32 Aplastic anemia is managed in the same way as a non-pregnant patient although there are some additional potential risks. 03:39 And immunosuppressants, this can interfere with breastfeeding and these women may need to formula feed their babies. 03:45 They can also receive blood transfusions and stem cell transplant. 03:50 Chemotherapy is unique as it fits into the medication category and it also fits into the toxin category because it's a cellularly toxic medication. 03:58 Some patients with cancer will also receive radiation therapy and this can also damage the healthy cells in the bone marrow. 04:04 This usually improves once the therapy is completed. 04:08 Certain chemicals including pesticides, insecticides and benzene which is an ingredient in gasoline have been implicated and causing aplastic anemia. 04:17 With elimination of the exposure to these chemicals, aplastic anemia usually resolves.
The lecture Secondary Causes of Aplastic Anemia (Pediatric Nursing) by Paula Ruedebusch is from the course Blood Disorders – Pediatric Nursing. It contains the following chapters:
What is the recommended treatment for aplastic anemia caused by medications? Select all that apply.
What are common causes of aplastic anemia from viral infections? Select all that apply.
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