| Severe catatonia |
Severe rigidity accompanied by psychosis, severe affective disorder, stupor |
| Heat stroke |
Extreme dehydration, exercise or stress in hot, humid environments particularly in patients taking diuretics |
| Central nervous system infection |
General malaise, neurological deterioration, meningeal irritation |
| Tetanus |
Trismus, muscle spasm starting from the neck down, profuse sweating, spasticity intensified by stimuli |
| Thyrotoxicosis |
Tachycardia, tremor and hypertension |
| Phaeochromocytoma |
Tachycardia, hypertension and tremor, diaphoresis, agitation |
