Characteristics of<unk>  include: *fever *tachycardia *hypertension *tachypnea *hyperhidrosis or diaphoresis *dystonic posturing *pupillary dilation *flushing In cases where PSH episodes develop post-injury, specifically traumatic brain injury, symptoms typically develop quickly, usually within a week. Symptom onset has been seen to average 5.9 days post-injury. Episodes vary in duration and occurrence. Episodes can last as little as a few minutes or as long as ten hours, and they can occur multiple times a day. Episode duration has been seen to average 30.8 minutes and occur five to six times a day. Episodes can occur naturally or arise from external triggers. Common triggers include pain or stimulation, body turning or movements, and bladder distention. Bladder distention has been observed in patients being treated in intensive care units with the concurrent use of catheters. Symptoms of PSH can last from weeks to years following initial onset. As episodes persist over time, they have been found to become less frequent in occurrence but last for prolonged periods.
Paroxysmal sympathetic hyperactivity
Cholinergic crisis
Parasympathetic rebound
Postural orthostatic tachycardia syndrome
False awakening
Postanesthetic shivering
Heat syncope
Thalamocortical dysrhythmia