Correspondence

Hypereosinophilic Syndrome

N Engl J Med 2000; 342:442-443February 10, 2000

Article

To the Editor:

Bain provides an overview of idiopathic eosinophilia in her editorial (Oct. 7 issue).1 However, she does not comment on the fact that eosinophilia may also be a useful marker of adrenal insufficiency. It has been documented that eosinophilia may be a sign of acute adrenal insufficiency in critically ill patients.2,3

Angelis et al.2 evaluated all the patients admitted to a surgical intensive care unit because of eosinophilia during a one-year period. Using as a definition of eosinophilia an eosinophil count that is greater than 3 percent of the peripheral white-cell count, they found that 32 of 1022 new patients (3 percent) had idiopathic eosinophilia. With use of the cosyntropin stimulation test, the diagnosis of adrenal insufficiency was confirmed in 7 of 31 patients (23 percent) with idiopathic eosinophilia. One patient died before testing could be performed. In a similar study, Beishuizen et al.3 found that 40 of 570 patients who could be evaluated (7 percent) had eosinophilia. Results of the low-dose corticotropin stimulation test were abnormal in 10 of these 40 patients (25 percent). In both series, steroid-replacement therapy resulted in hemodynamic improvement. Physicians caring for seriously ill patients should be aware of the usefulness of eosinophilia as a signal that acute adrenal insufficiency should be considered during the diagnostic evaluation.

Kevin R. Loughlin, M.D.
Brigham and Women's Hospital, Boston, MA 02115

3 References

1. 1

   Bain BJ. Eosinophilia -- idiopathic or not? N Engl J Med 1999;341:1141-1143
   Full Text | Web of Science | Medline

2. 2

   Angelis M, Yu M, Takanishi D, Hasaniya NW, Brown MR. Eosinophilia as a marker of adrenal insufficiency in the surgical intensive care unit. J Am Coll Surg 1996;183:589-596
   Web of Science | Medline

3. 3

   Beishuizen A, Vermes I, Hylkema BS, Haanen C. Relative eosinophilia and functional adrenal insufficiency in critically ill patients. Lancet 1999;353:1675-1676
   CrossRef | Web of Science | Medline

To the Editor:

In her editorial, Bain does not give a numerical definition of eosinophilia. Spry1 defined a blood eosinophil count of 0.55×10⁹ to 1.5×10⁹ per liter as “needing follow up,” a count of 1.5×10⁹ to 10×10⁹ per liter as “needing investigation soon,” and a count of more than 10×10⁹ per liter as “needing urgent assessment.”

Bain also did not mention the importance of a cardiac evaluation in patients with persistent eosinophilia. This aspect of the assessment is important, because cardiac manifestations of the hypereosinophilic syndrome are common.2 According to Spry's definitions, evidence of eosinophilic endomyocardial disease must be sought at least in patients with eosinophil counts greater than 1.5×10⁹ per liter or with degranulation of eosinophils.

José Luis Leone, M.D.
Clínica Bessone, 1663 San Miguel, Argentina

2 References

1. 1

   Spry CJF. Eosinophils: guide to the scientific and medical literature. New York: Oxford University Press, 1988.
   

2. 2

   Weller PF, Bubley GJ. The idiopathic hypereosinophilic syndrome. Blood 1994;83:2759-2779
   Web of Science | Medline

Author/Editor Response

Dr. Bain replies:

To the Editor: Loughlin's letter is a useful reminder of the value of the eosinophil count in alerting clinicians to the possibility of adrenal insufficiency in critically ill patients. However, it should be noted that these patients do not necessarily have hypereosinophilia, as it is conventionally defined.1 The criterion that has been suggested for suspecting adrenal insufficiency is that of relative eosinophilia — specifically, an eosinophil count of 3 percent or more.2,3 Depending on the total white-cell count and the actual percentage of eosinophils, such patients may have a normal absolute eosinophil count or they may have a slight or moderate elevation of the count.

I agree with Leone that Spry's criteria for deciding when to investigate high eosinophil counts are useful. However, it should be noted that, as Spry commented, “there is no direct relationship between the eosinophil count and the severity of the clinical complications.”4 The number of degranulated eosinophils may be more important than the total number of eosinophils. The presence of marked degranulation as well as the eosinophil count should therefore be considered in the process of deciding whether urgent investigation is indicated.

Barbara J. Bain, F.R.A.C.P.
St. Mary's Hospital, London W2 1NY, United Kingdom

4 References

1. 1

   Chusid ML, Dale DC, West BC, Wolff SM. The hypereosinophilic syndrome: analysis of fourteen cases with review of the literature. Medicine 1975;54:1-27
   CrossRef | Web of Science | Medline

2. 2

   Angelis M, Yu M, Takanishi D, Hasaniya NW, Brown MR. Eosinophilia as a marker of adrenal insufficiency in the surgical intensive care unit. J Am Coll Surg 1996;183:589-596
   Web of Science | Medline

3. 3

   Beishuizen A, Vermes I, Hylkema BS, Haanen C. Relative eosinophilia and functional adrenal insufficiency in critically ill patients. Lancet 1999;353:1675-1676
   CrossRef | Web of Science | Medline

4. 4

   Spry CJF. Eosinophils: guide to the scientific and medical literature. New York: Oxford University Press, 1988.