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Catecholamine and thyroid hormones in traumatic injury.
M G Ziegler1, E C Morrissey, L F Marshall
1Department of Medicine, University of California San Diego Medical Center 92103.
Critical Care Medicine
|March 1, 1990
Summary
Severely injured patients show an inverse relationship between norepinephrine and triiodothyronine levels. This connection, vital for thyroid hormone regulation, is disrupted by head injury and barbiturates, indicating the CNS
Area of Science:
- Endocrinology
- Neuroscience
- Trauma Medicine
Background:
- Thyroid hormones and norepinephrine (NE) often exhibit an inverse relationship in conditions like hyperthyroidism, hypothyroidism, and severe stress.
- This relationship's integrity in critical illness states, particularly those involving central nervous system (CNS) injury, requires further investigation.
Purpose of the Study:
- To evaluate the relationship between plasma norepinephrine and thyroid hormones in severely burned patients, patients with combined brain and body injury, patients with head injury, and patients receiving high-dose barbiturates for head injury.
- To determine the influence of CNS integrity on the NE-thyroid hormone axis during severe physiological stress.
Main Methods:
- Assessed plasma norepinephrine levels and thyroid hormone concentrations (thyroxine [T4], triiodothyronine [T3], reverse T3) in distinct patient cohorts.
- Correlational analyses were performed to quantify the relationship between NE and T3 levels.
- Compared these relationships across patient groups with varying degrees of injury and medical interventions.
Main Results:
- Severely burned patients demonstrated a strong negative correlation between NE and T3 (r = -0.88, p < 0.001).
- Patients with combined brain and body injury showed a weaker negative correlation (r = -0.5, p = 0.06).
- Head-injured patients exhibited no significant correlation between NE and T3, with altered thyroid hormone profiles (low T4, low T3, high reverse T3).
- High-dose barbiturate administration for head injury also disrupted the NE-T3 relationship.
Conclusions:
- A close inverse relationship exists between elevated NE and depressed T3 levels in severely injured patients.
- The integrity of the central nervous system is crucial for maintaining this inverse NE-T3 relationship.
- Head injury and barbiturate sedation significantly disrupt this neuroendocrine interaction, highlighting the impact of CNS compromise on thyroid hormone regulation.