Continuation with clozapine after eosinophilia: a case report

Abstract

BackgroundClozapine-induced eosinophilia had been reported in several studies about blood dyscrasias in clozapine-treated patient. The largest study with 2404 patients in Italy found the incidence of 2.2% by criteria of more than 0.4 × 109/l. Associated cases of pancreatitis, hepatitis, colitis, nephritis, and myocarditis were reported. Interestingly, incidence of myocarditis is high in Australia, but low in the rest of the world. In the following, we will present a case of clozapine-induced eosinophilia which spontaneous resolution was noted under continuation of clozapine.Case presentation“Mr. L” was a 54-year-old single, jobless man. He had treatment-resistant chronic schizophrenia with onset at age 28. He had received electroconvulsive therapy twice prior to this admission. After admission, a trial of clozapine was started with an initial dose of 100 mg/day, and gradually titrated to 200 mg/day. He experienced notable improvement after 2 weeks with decreased auditory hallucinations and no more self-harm behaviors, but he also developed eosinophilia. A medical workup was performed and showed no signs of end-organ inflammation. We continued clozapine use and closely monitored complete blood count with a differential test to track his eosinophil count by the recommendation of the hematology service. His eosinophil count decreased then and remained within normal limits 3 weeks later. The dosage of clozapine was gradually raised as high as 400 mg/day. His psychotic symptoms got partial remission and continued to show no signs of end-organ inflammation at the time of discharge.ConclusionsThe pathophysiology of clozapine-induced eosinophilia is still unknown, but resolution of eosinophilia despite ongoing clozapine treatment suggests the possibility of an acute allergic reaction. Signs or symptoms of organ inflammation are important for management of eosinophilia. In this case report, we demonstrated that if eosinophilia occurred without signs or symptoms of organ inflammation, it may be justified to continue clozapine use under careful monitoring.

Unravelling cases of clozapine-related Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) in patients reported otherwise: A systematic review

“…Our findings, however, may imply that clinicians should not automatically classify eosinophilia as benign in the context of clozapine treatment. Moreover, eosinophilia in patients with long-term clozapine treatment might have a completely different meaning (Ho and Lin, 2017), as associations with other inflammatory processes have been described in this patient population (Fong et al, 2005;Frankenburg and Kando, 1992;Garlipp et al, 2002;Kang and Lee, 2013).…”

Clozapine-induced eosinophilia: A case report

“…The pathophysiology of clozapine-induced eosinophilia is not yet well understood, but proposed mechanisms include a type I hypersensitivity reaction, 19 , 33 and a direct toxic effect on the bone marrow. 10 , 33 It is also possible that both mechanisms might co-exist or that other different mechanisms might also be involved.…”

Clozapine‐associated severe eosinophilia following lithium rebound neutropenia: A case report

“…The most recent studies reported that approximately one‐tenth (N = 33; 9.9%) of patients developed eosinophilia (absolute eosinophil count >600 cells/mm 3 ) 8 . In addition, cases of pancreatitis, hepatitis, colitis, nephritis, and myocarditis‐associated eosinophilia have been reported 9 . Drug reaction with eosinophilia and systemic symptoms (DRESS syndrome) is an uncommon side effect of certain medications 6 .…”

“…8 In addition, cases of pancreatitis, hepatitis, colitis, nephritis, and myocarditis-associated eosinophilia have been reported. 9 Drug reaction with eosinophilia and systemic symptoms (DRESS syndrome) is an uncommon side effect of certain medications. 6 The incidence is 0.4 cases per 1,000,000 in the general population, and the mortality rate is as high as 10%.…”

“…6 The incidence is 0.4 cases per 1,000,000 in the general population, and the mortality rate is as high as 10%. In cases in which eosinophilia is accompanied by the involvement of major organs, 9,10 clozapine should be discontinued immediately. Because a rash was not observed, our patient did not meet the DRESS criteria, although other symptoms developed in our patient.…”