Medication—induced movement disorders are included in Section II because of their frequent importance in 1) the management by medication of mental disorders or oth- er medical conditions and 2) the differential diagnosis of mental disorders (e.g., anxiety malignant syndrome). Although these movement disorders are labeled “medication in- duced,” it is often difficult to establish the causal relationship between medication expo- sure and the development of the movement disorder, especially because some of these movement disorders also occur in the absence of medication exposure. The conditions and problems listed in this chapter are not mental disorders.
The term neuroleptic is becoming outdated because it highlights the propensity of an- tipsychotic medications to cause abnormal movements, and it is being replaced with the term antipsychotic in many contexts. Nevertheless, the term neuroleptic remains appropri- ate in this context. Although newer antipsychotic medications may be less likely to cause some medication-induced movement disorders, those disorders still occur. Neuroleptic medications include so-called conventional, ”typical,” or first-generation antipsychotic agents (e.g., chlorpromazine, haloperidol, ﬂuphenazine); ”atypical” or second-generation antipsychotic agents (e.g., clozapine, risperidone, olanzapine, quetiapine); certain dopa- mine receptor—blocking drugs used in the treatment of symptoms such as nausea and gas- troparesis (e.g., prochlorperazine, promethazine, trimethobenzamide, thiethylperazine, metoclopramide); and amoxapine, which is marketed as an antidepressant.
332.1 (G21.11) Neuroleptic-Induced Parkinsonism 332.1 (621.19) Other Medication-Induced Parkinsonism
Parkinsonian tremor, muscular rigidity, akinesia (i.e., loss of movement or difficulty ini- tiating movement), or bradykinesia (i.e., slowing movement) developing within a few weeks of starting or raising the dosage of a medication (e.g., a neuroleptic) or after reduc- ing the dosage of a medication used to treat extrapyramidal symptoms.
333.92 (G21.0) Neuroleptic Malignant Syndrome
Although neuroleptic malignant syndrome is easily recognized in its classic full-blown form, it is often heterogeneous in onset, presentation, progression, and outcome. The clin- ical features described below are those considered most important in making the diagno- sis of neuroleptic malignant syndrome based on consensus recommendations.