Paroxysmal sympathetic hyperactivity (PSH) is a condition mainly described in patients after traumatic brain injury and it is also known under the terms "autonomic storm" and "dysautonomia". It affects between 8-10% of patients after traumatic brain injury and can also affect patients after other neurological diseases, such as anoxic brain injury, stroke, tumors or infections. PSH manifests with six main symptoms: tachycardia, tachypnea, hypertension, hyperthermia, hyperhidrosis and increased muscle tonus. It is of outmost importance to exclude other causes for the symptoms and there are diagnostic criteria established to identify and diagnose PSH. The treatment is pharmacological and non-pharmacological and often multimodal. PSH is probably underdiagnosed and increased awareness is needed.