Twenty-one year old woman with severe eosinophilia and left bundle branch block.

Peripheral and tissue eosinophilia can occur in a wide variety of disease processes that include infectious, allergic, and primary hematologic disorders, and other more rare diseases such as hypereosinophilic syndromes (HES). We describe a case of a patient with severe eosinophilia and left bundle branch block. A 21-year-old woman with asthma and allergic rhinitis presented with neck pain and cough for >6 months with no other complaints. Physical exam was normal except for fever and minimal expiratory wheezes. Chest CT revealed diffuse airway inflammation with bronchiectasis. Admission electrocardiogram (EKG) was normal. Initial laboratory tests showed an absolute eosinophil count of 30,000 cells/mL. A thorough workup for eosinophilia was initiated, but the patient subsequently left against medical advice. The next day, in the outpatient pulmonary clinic, she was found to be tachycardic and an EKG showed sinus tachycardia with a new left bundle branch block. Laboratory tests revealed an eosinophil count of 33,200 cells/mL and elevated troponins. She was started on i.v. Solu-Medrol (Pfizer, Inc.). The next day, her EKG returned to normal. Three days later her absolute eosinophil count normalized. Identifying the cause of marked, persistent eosinophilia is a challenging problem. Excluding the more common causes of severe eosinophilia is required before making a diagnosis of HES and early therapeutic intervention can prevent morbidity from the disease.