Guillain-Barre syndrome
Medication side effects
Severe head trauma and other brain injuries
Subarachnoid hemorrhage (a form of brain bleeding)
Use of illegal stimulant drugs such as cocaine and amphetamines
The following conditions share many symptoms with autonomic hyperreflexia, but have a different cause:
Carcinoid syndrome
Neuroleptic malignant syndrome (a condition caused by some medicines that leads to muscle stiffness, high fever, and drowsiness)
Serotonin syndrome
Thyroid storm [6]