8/11/16. Kevin Letz DNP, MSN, MBA, RN, CEN, CNE, FNP-C, PCPNP-BC, ANP-BC, FAANP

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1 Kevin Letz DNP, MSN, MBA, RN, CEN, CNE, FNP-C, PCPNP-BC, ANP-BC, FAANP Eosinophilia Eosinophilia refers to an absolute eosinophil count in the peripheral blood of 500 eosinophils/microl; this is considered abnormal in most laboratories [1,2]. The degree of eosinophilia can also be categorized as: mild (500 to 1500) moderate (1500 to 5000), or severe (>5000) Hypereosinophilia (ie, absolute eosinophil count 1500/microL) on at least two occasions Signs of organ dysfunction attributable to the eosinophilia Symptoms Symptoms of specific organ system involvement may suggest a potential cause of eosinophilia and/or the consequences of eosinophil-induced tissue damage. Assess the following: Fever, weight loss, fatigue Rash/pruritus Nasal involvement Wheezing/cough/chest congestion Gastrointestinal involvement/diarrhea Myalgia Nervous system symptoms Symptoms attributable to lymphadenopathy or hepatosplenomegaly Symptoms of cardiac dysfunction or myocarditis 1

2 The physical examination should focus on identifying lesions that suggest a possible cause of eosinophilia, and on determining the presence of organ involvement. Specifically assess the skin, eyes, nose, lymph nodes, gastrointestinal, cardiac, respiratory, and neurologic systems, and the presence of splenomegaly. HISTORY All patients should have a thorough history that addresses symptoms of organ involvement, medical conditions, exposures (medications, foods, over-the-counter remedies, travel, and occupational and recreational exposures), and prior eosinophil counts. Family history may also be helpful in rare cases of familial hematologic syndromes. New onset of eosinophilia suggests a new diagnosis, although it does not help narrow the diagnosis. Persistent eosinophilia without symptoms is reassuring and suggests that the evaluation can be done less urgently. Asthma & atopic disease most common Pay close attention to frequency of infections Food allergy & EoE Increase instance visceral larva migrans Decrease instance filaria Increase instance leukemia & lymphoma Decrease instance of solid tumors Occupational/recreational exposures Some occupations and/or recreational activities are associated with specific exposure risks. Examples include a risk for strongyloides infection in miners, a risk for ascariasis in slaughterhouse workers, and a risk for schistosomiasis in river rafters. Can be caused by almost any prescription or nonprescription drug, herbal remedy, or dietary supplement Does not always follow a consistent pattern Often accompanied by fever, rash, or other clinical manifestations, signs and symptoms may be absent 2

3 Dietary history should ascertain the ingestion of raw or undercooked meat because incompletely cooked pork containing encysted larvae is a source of trichinellosis. Ingestion of soil or vegetables contaminated by excrement from infected dogs or cats can cause toxocariasis, and undercooked or raw crab or crayfish can transmit paragonimiasis. A history of residence in or recent travel to a parasite-endemic area may be helpful in suggesting a parasitic etiology of eosinophilia. However, a lack of recent travel should not eliminate parasitic infection as a potential cause of eosinophilia, especially for helminths with a worldwide distribution and/or a long latency period. As an example, foreign military service, even decades earlier, could be a source of strongyloides infection, which occurs via penetration of the skin upon contact with soil or water contaminated by human feces. This history may be omitted unless it is specifically queried. Whom to test The initial tests for etiology and organ involvement listed below should be performed in the following patients: All patients with unexplained eosinophilia of 1500 eosinophils/microl on two separate occasions Patients with persistent eosinophils 500/microL and signs or symptoms of organ involvement (eg, rash, wheezing, abnormalities on chest radiography, elevated troponin) Patients with eosinophilia between 500 and 1500 eosinophils/microl who have a history of travel to a parasite endemic area, symptoms attributable to eosinophilia (with the exception of allergic symptoms), or other clinical findings of concern Complete blood count with differential to determine abnormalities of other cell lines. Absolute numbers of other white blood cells must be determined because relative percentages may be lowered in the setting of increased eosinophils. 3

4 Review of the peripheral blood smear (for immature white blood cells, dysplastic features that would suggest primary hematologic disorder) Serum chemistries, creatinine, urinalysis (for evidence of renal insufficiency, and in rare cases adrenal insufficiency) Serum B12 level (elevated in myeloproliferative neoplasms and autoimmune lymphoproliferative syndrome [ALPS]) Liver function tests (for evidence of hepatic involvement) Troponin (for evidence of subclinical eosinophil-associated myocarditis); those with elevated troponin should have electrocardiography and echocardiography. Chest radiography (for evidence of pulmonary involvement) Serologic testing for Strongyloides. Positive serology in an untreated patient is presumptive evidence of infection; however, serology remains positive after treatment, so it is not useful for documenting cure or reinfection. 4

5 Flow cytometry for lymphocyte subsets (may show clonality in lymphocytic hypereosinophilic syndrome, or lymphoid malignancy selective deficiencies in immunodeficiency syndromes). Toxocara serology Trichinella serology Other serologies Stool studies Viral serologies Testing of body fluids Parasite Serology Tb (prior to Tx) Immunoglobulins, CD4 Stool studies Cortisol testing ANCA CT Bone marrow evaluation Hematologic evaluation with bone marrow examination (aspiration and biopsy) is appropriate for any individual with a potential primary hematologic cause of eosinophilia. Acutely ill OR Eos >100,000 I Rare I Requires Admission I Work Up Likely High Dose Steroids 5

6 In some cases, eosinophilia resolves without treatment. Potential explanations for resolution of eosinophilia include removal of an offending agent (ie, transient exposure); clearance of an infection; and downregulation of host responses (as has been reported in the setting of chronic helminth infection). The expected time course of resolution of eosinophilia after a transient exposure is unknown, although in the case of drug hypersensitivity and removal of the offending agent, resolution can take many months. For a patient with signs of organ involvement who is not acutely ill or hospitalized, the pace of the evaluation and the need for specialist referral depends on the specific organ involved and the degree of organ dysfunction. In many cases, initial testing can be done in the outpatient setting. (continued) Specialist referral Referral to a specialist is appropriate for clinical evaluation and biopsy of a potentially affected tissue. Referral to a clinician who specializes in eosinophilia is appropriate if a thorough evaluation has been conducted and the cause of persistent eosinophilia is not found. (continued) 6

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