Autonomic dysfunction syndromes after acute brain injury

Handb Clin Neurol, 2015 · DOI: 10.1016/B978-0-444-63521-1.00034-0 · Published: January 1, 2015

Simple Explanation

Severe traumatic brain injury can damage cortical and subcortical control mechanisms of the autonomic nervous system (ANS), leading to autonomic dysfunction. The hypothalamus serves as the main control center of the ANS, receiving input from higher cortical centers and transmitting information to the brainstem and spinal cord. Paroxysmal sympathetic hyperactivity (PSH) is a clinical example of CAN dysfunction, characterized by exaggerated vital signs and often dystonic posturing.

Study Duration

Not specified

Participants

Not specified

Evidence Level

Not specified

Key Findings

1
Ischemic strokes, especially insular strokes, may cause cardiac autonomic dysregulation, potentially leading to subendocardial hemorrhages and myocardial infarction.
2
In subarachnoid hemorrhage (SAH) patients, inappropriate catecholamine release can produce a hyperadrenergic state, possibly due to elevated intracranial pressure injuring the hypothalamus.
3
Hyperthermia following acute brain injury can result from direct hypothalamic injury or irritation, leading to increased neuronal excitotoxicity and potentially worsened outcomes.

Research Summary

Autonomic dysfunction can occur after traumatic brain injury due to damage to the central autonomic network (CAN), affecting the balance of excitatory and inhibitory inputs to ANS effector organs. Ischemic stroke data serves as a model for how focal injuries can produce autonomic dysregulation, while non-TBI-related SAH exemplifies a disease process causing hyperadrenergic activity. Paroxysmal sympathetic hyperactivity (PSH) is a common clinical outcome of excessive sympathetic hyperactivity from various causes and is discussed in terms of diagnosis and management.

Practical Implications

Telemetry monitoring

Telemetry monitoring should be strongly considered for ischemic stroke patients to identify abnormal heart rhythms and expedite treatments.

Medication review

Clinicians should carefully consider alternatives when prescribing medications that may prolong QT intervals in ischemic stroke patients.

Cardiac support

Once cardiac dysfunction is identified in SAH patients, treatment with cardiac support agents like milrinone and dobutamine is often suitable to ensure systemic perfusion.

Study Limitations

1
Lack of good preventive or therapeutic interventions for cardiac complications in ischemic stroke patients.
2
Pathophysiology of cardiac dysfunction in SAH patients is not well defined.
3
Limited level III research available to guide PSH management.

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