Autonomic dysfunction refers to disruption of the autonomic nervous system, which controls involuntary body functions including heart rate, blood pressure, breathing, digestion, and temperature regulation. Following cardiac arrest and hypoxic brain injury, autonomic dysfunction can arise as part of the wider neurological sequelae.
Symptoms may include postural hypotension (dizziness or lightheadedness on standing), abnormal sweating, temperature dysregulation, gastrointestinal problems, bladder difficulties, and persistent fatigue. These symptoms can overlap with post-cardiac arrest syndrome and psychological sequelae, making diagnosis complex.
Assessment may involve blood pressure measurement lying and standing, a tilt table test, and heart rate variability analysis. Management typically includes lifestyle adjustments such as increased fluid and salt intake, compression stockings, paced physical activity, and in some cases medication to support blood pressure regulation. Survivors experiencing these symptoms should discuss them with their cardiologist or GP, as autonomic dysfunction is under-recognised in post-cardiac arrest care.
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