Abstract
Diana McKay, East Wing, Manly Hospital, Sydney, New South Wales, Australia:
Southall and Fernando reported a case of clozapine-induced parotitis in New Zealand, noting its rarity [1]. I recently was involved in the management of a similar problem, with a less fortunate outcome than that of their patient.
F is a 42-year-old man with an 18-year history of schizophrenia. He was admitted for a trial of clozapine, having previously responded poorly to both typical and other atypical antipsychotics. F had a dysphoric mood and recently had been on an anti-depressant, with some benefit. On admission, F was taking 22.5 mg olanzapine per night and 100 mg sertraline daily. Results of baseline examination and investigations were normal, including a full blood count (white cell count = 4.2 × 109/L, neutrophils = 2.8 × 109/L, platelets = 191 × 109/L). A decision was made to introduce clozapine, and olanzapine was tapered. By day three olanzapine was ceased and F was on 50 mg clozapine per day. Sertraline was continued. His inpatient stay of 5 d was uneventful and he was discharged for outpatient follow up.
I first assessed F at an outpatient visit (day nine). He had developed marked bilateral parotid enlargement on 150 mg clozapine. He described this as painful, but the swelling itself was non-tender. He was afebrile and normotensive, with a pulse rate of 100 beats per minute. F had hypersalivation but was otherwise tolerating clozapine well. His blood count was normal (white cells = 5.7 × 109/L, neutrophils = 4.3 × 109/L, platelets = 189 × 109/L). A brief review of the literature suggested that the enlargement was secondary to clozapine, and that a short trial of 2 mg per day benztropine was warranted [2],[3]. F was reviewed urgently 5 d later as he had become systemically unwell, with hypersalivation, diaphoresis and headache. His blood count was now abnormal, with a mild drop in his white cell and neutrophil count (3.7 × 109/L and 2.8 × 109/L, respectively) and a more dramatic drop in his platelet and lymphocyte count (platelets = 129 × 109/L, lymphocytes = 0.5 × 109/L). Electrolytes and liver function were normal; amylase was not measured. Clozapine was ceased at this point. F recovered quickly, with parotid enlargement and systemic symptoms settling within a week. Similarly, his blood count returned to normal and he was recommenced on olanzapine at this point. Viral serology done earlier was consistent with a previous – but not recent – mumps infection.
Parotid enlargement during clozapine treatment has now been described in a number of case reports and series [1–7]. It has occurred in both men and women of ages ranging from 19 to 67 years. Swelling has occurred both early [1],[4],[6],[7] and late in treatment [2],[3],[5],[7], with most cases resolving either spontaneously or on treatment with benztropine. Unlike F, no other case was associated with thromobocytopaenia or lymphopaenia. The only common thread between the cases is that many were being treated concurrently with other psychotropic medication at the time the enlargement occurred. These include selective serotonin re-uptake inhibitors antidepressants [2],[7], benzodiazepines [5], mood stabilisers [3],[7] and antipsychotics [3],[4]. Interestingly, after writing this report a colleague discussed a similar case with me: perhaps parotid enlargement is not so rare?