Eosinophilia III

This is the conclusion of the case from the last two posts.

The eosinophil, an example of which is shown above, is a bizarre cell in the minds of medical students. A fairly rare type of white blood cell, it fights parasites and causes us grief with allergies and asthma. The word "eosinophil" means acid-loving because granules within the cell appear bright red after staining with eosin.

Most of the time, when I see an increased number of these eosinophils, I brush it off as related to allergic rhinitis (hayfever) or asthma since those conditions are so common. But eosinophilia of 20% as seen in this patient is highly unusual and prompted me to review a differential diagnosis I had never considered. Medication side effects were certainly possible, and this patient was on many medications for his multi-organ failure, but it was difficult to tease out the temporal relationship of starting new meds and the eosinophilia. Classically, parasites are taught as the cause of eosinophils, but this patient didn't have a travel history consistent with helminth infections like Strongyloides, hookworm, or Toxocara. Nevertheless, sending stool for ova and parasites was be a reasonable step. Fungal infections too could cause eosinophilia, and given the patient's asthma, we wondered about allergic bronchopulmonary aspergillosis. Since he has been in central California, we considered coccidioidomycosis. Lastly, given his asthma and neurologic symptoms, we toyed with the idea of Churg-Strauss syndrome. Adrenal insufficiency was also considered, especially given his profound weakness.

In the end though, given his multi-organ involvement, hematology/oncology began to favor a hypereosinophilic syndrome or neoplastic disorder. The cardiologists felt strongly that the echocardiogram was diagnostic of Loeffler endocarditis and that is most commonly seen in a primary eosinophilic syndrome, eosinophilic leukemia, carcinoma, or lymphoma (though it is so rare that we have only case series). Furthermore, this disease presents in different stages; the first necrotic stage involves the patient's initial symptoms: fever, sweats, lymphadenopathy, weight loss, biventricular failure. The patient probably entered the second phase - called the thrombotic stage - when he presented to the outside hospital and had multiple strokes. Lastly, when he came to us, he had evidence of the third stage, a restrictive myopathy.

The patient underwent multiple bone marrow and lymph node biopsies, but they did not demonstrate any cancer or myeloproliferative disorders. The final diagnosis was primary hypereosinophilic syndrome with cardiac and neurologic involvement. The patient responded to steroids.

Image is shown under GNU Free Documentation License, from Wikipedia.