Neuroleptic malignant syndrome developing after acute overdose with olanzapine and chlorpromazine

Abstract

Neuroleptic malignant syndrome (NMS) is a relatively uncommon side effect that may develop after a recent increase in the therapeutic dose of an antipsychotic medication or the addition of a new agent in therapeutic doses.Case Report: We report a case of NMS developing in a 36-year-old female patient 2 days following deliberate self-poisoning with 30 ϫ10-mg olanzapine tablets, 7 ϫ100-mg chlorpromazine tablets and an unknown amount of escitalopram. These were the patient's own medications. She had not been taking these for several weeks. The patient initially presented with sedation from her overdose which resolved over the next 24 hours. Following this, over the subsequent 24 hours, she became progressively confused, ataxic, hypertonic, ferbrile and tachycardic, with marked lead pipe rigidity of the limbs. Head CT, lumbar puncture and septic screen were all negative. She was treated with intravenous midazolam infusion, nasogastrically administered bromocriptine, external cooling and was mechanically ventilated. She gradually improved over a period of 10 days, with residual confusion lasting another week, and was discharged well with no deterioration from her premorbid neurologic state.Conclusion: To our knowledge, although there are numerous cases reported with therapeutic use, NMS has not been reported to develop following acute olanzapine overdose. Clinicians should be aware that this may be an uncommon side effect of antipsychotic medication.

Regional Differences in the Action of Antipsychotic Drugs: Implications for Cognitive Effects in Schizophrenic Patients

“…However, recent studies found no significant difference between typical and atypical APDs in the emergence of TD (Miller et al 2008;Correll and Schenk 2008). Similarly, there is increasing evidence that treatment with atypical APDs may also result in NMS (El-Gaaly et al 2009;Morris et al 2009;Trollor et al 2009). …”

Endocopic approaches to the skull base

“…In NMS (and parkinsonism‐hyperpyrexia syndrome), a majority of cases do not ever develop the degree of hyperthermia usually associated with morbidity (i.e., 39.5°C or greater), even with only conservative treatment. Also, deterioration of clinical status and morbidity and mortality occur in the absence of a degree of hyperthermia that is injurious: deterioration of renal, mental, neurological, and respiratory function, despite a maximum temperature of less than 39°C, is documented in many reports 5, 83, 102, 121. To regard NMS as a primarily hyperthermic syndrome is an inadequate explanatory model and may lead to underestimation of clinical severity or exclusion of NMS because the patient is not hyperthermic.…”

“…Since activation of 5‐HT2A receptors worsens, and antagonism reduces, the consequences of most forms of hyperthermia,78–80 5‐HT2A agonism is a undesirable property. There is disagreement concerning bromocriptine's efficacy, and some evidence supports the notion that it could worsen NMS 81–83. Apomorphine is the only clinically available DA agonist that is also a 5‐HT2A antagonist and, therefore, may be preferable to bromocriptine 84, 85.…”

Olanzapine-Induced Malignant Neuroleptic Syndrome

“…The syndrome is initiated by the addition of a new drug to pre-existing treatment or by increasing the dosage of the used drug. Clinical findings include fever, tachycardia, muscular rigidity (leadpipe type) and increased muscle tone, altered mental status, leucocytosis and increased serum creatinine phosphokinase (CPK) levels (1). NMS should be suspected in case there is autonomic instability, neuromuscular or central nervous system dysfunction in patients.…”