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Hemato-Oncology-42-Eosinophilia approach


Question: Dr. Chiragbhai, thank you for explaining in last part about primary myelofibrosis, especially regarding its specific complications, need to avoid splenectomy, and new targeted treatment options like ruxolitinib, everolimus, and curative treatment with stem cell transplant. What is the next disorder we will be talking about.
Ans: We have covered all the common myeloproliferative neoplasms. In the first part of MPN, we listed one interesting category i.e. MPN of eosinophil cell line. This is an important category as eosinophilia is a very common issue, with only some of them being MPN, but now they have a molecular test to define with specific associated treatment with excellent results in those cases. So, let us discuss eosinophilia as a whole, and then its malignant subset.
Que: Yes eosinophilia is a common disorder in India. This would be interesting and very important for all.
Ans: Eosinophilia is a very wide subject. Patients may have no symptoms to mild to severe symptoms. Patients may have mild to severe eosinophilia. Patients may have obvious underlying etiology to no etiology after exhaustive work up. Patients may need no treatment for up to 6 months to starting immediate treatment.
First we need to understand the concept of Absolute Eosinophil Count or AEC. Most people see eosinophil percentage in white blood cell count differential. But AEC is what we need to monitor to judge progress. AEC is simply eosinophil percentage multiplied by total wbc count. So for example, if a patient has WBC count of 10,000 with eosinophil percentage 10%, his AEC is 1000. Now if his eosinophil percentage is 20% after one month, but total WBC is now 5000, AEC is still 1000. This means stable disease, not a doubling. A good differential count by peripheral smear is necessary to accurately count eosinophil numbers. DC given by machine is not sufficient. We need to assess following main points when we see a patient with eosinophilia:
1. Asymptomatic or symptomatic
2. Duration of eosinophilia
3. Degree of eosinophilia
4. Obvious underlying disease or not
Que: This sounds interesting, but complex. Can you explain more?
Ans: Of course, we will slowly go over all these issues to simplify this subject. When we see a patient with eosinophilia, we try to assess above four points to decide how many tests to order and urgency of starting any treatment.
Asymptomatic patient with mild eosinophilia is obviously not urgent and does not require extensive work up. There are no well defined grades, but AEC 500-1500 (once again remember, it is the AEC, not the percentage that is important) can be considered mild, and over 5000 as severe. Mild eosinophilia can be a result of many diseases. Common ones are many infections including parasitic infestation, fungal, sometimes even viral, most allergies (including seasonal, drug, skin diseases, respiratory). Collagen vascular disease (autoimmune diseases like SLE etc), malignancies such as lymphoma or leukemia, are uncommon causes of mild to moderate eosinophilia. Most of these are obvious from a good history and physical examination. Such patients need minimal work up, primarily to confirm the suspected diagnosis. There are other rare causes as well, such as many other types of cancers, hypoadrenalism, HIV related conditions.
Parasitic infestation is generally treated empirically, as diagnostic confirmation is frequently not possible or available with reliability.
Asymptomatic patients with mild eosinophilia are frequently given a course of albendazole as empiric treatment for worm infestation OR are monitored without any treatment, after minimal initial work up. Over several months (typically in less than six months), most such patients have spontaneous resolution of eosinophilia. It is important NOT to give empiric steroids, as it may mask underlying serious disorder or cause serious side effect.
Dr. Chirag A. Shah; M.D. Oncology/Hematology (USA), 079 26754001. Diplomate American Board of Oncology and Hematology. Ahmedabad. Shyam Hem-Onc Clinic. 402 Galaxy, Near Shivranjani, Opp Jhansi ki Rani BRTS, Ahmedabad.