Clozapine is the gold-standard antipsychotic medication for treatment-refractory schizophrenia (TRS). However, one potentially lethal side effect of clozapine, as with other antipsychotics, is neuroleptic malignant syndrome (NMS) which could present differently in clozapine therapy. ‘Atypical NMS’ is a recognised variant of NMS with less rigidity and delayed elevation of creatine kinase; this variant is associated with clozapine.

A case from the author’s clinical practice was reviewed.

A 67-year-old man with TRS was treated with clozapine. Unfortunately, his physical condition deteriorated and he presented with atypical NMS, which initially was treated as presumable urinary tract infection.

Atypical NMS is associated with clozapine. This case exposes the potential difficulties in diagnosis, and highlights the importance of considering less common diagnoses in acutely unwell psychiatric patients.