Findings in the Magnetic Resonance of Paroxysmal Sympathetic Hyperactivity

The correlation between the severity of paroxysmal sympathetic hyperactivity and plasma catecholamine levels in patients with severe traumatic brain injury

BACKGROUND

There is limited literature investigating the catecholamine levels in patients with paroxysmal sympathetic hyperactivity (PSH) after traumatic brain injury (TBI). The primary objective of this study was to correlate the severity of PSH (assessed using the PSH-Assessment measure [AM]) with plasma catecholamine levels at a resting state.

METHODS

In this prospective case-control study, blood samples for epinephrine and norepinephrine estimation were obtained at rest on three consecutive days, only for 'cases' of PSH after severe TBI (s-TBI) and for control patients (matched for age, gender, and Glasgow coma scale [GCS].

RESULTS

Twenty-seven patients with PSH and 16 controls were recruited. The median PSH-AM score was 20 and 9 in cases and controls, respectively. The epinephrine and norepinephrine levels at rest did not correlate with the severity of PSH assessed during PSH paroxysms (p = 0.949 and 0.975). Norepinephrine levels increased in PSH patients over the 3 consecutive days, once PSH was diagnosed (p = 0.022). The length of hospital stay was longer and the motor-GCS score was lower in PSH patients, with no differences in other outcomes between the groups.

CONCLUSION

Catecholamine levels in the inter-paroxysmal interval cannot be correlated with PSH severity assessed during the paroxysms. However, the results of the study need to be confirmed by a larger sample size as the study is underpowered.

Incidence of Paroxysmal Sympathetic Hyperactivity after Traumatic Brain Injury in a Tertiary Care ICU: A Retrospective Cohort Study

Background Paroxysmal sympathetic hyperactivity (PSH) is an understudied complication of traumatic brain injury (TBI). PSH usually presents with transient rise in sympathetic outflow, leading to increased blood pressure, heart rate, temperature, respiratory rate, sweating, and posturing activity. We retrospectively analyzed the incidence of PSH in TBI using PSH-assessment measure (PSH-AM) scale.

Methods This single-center retrospective cohort study was conducted in traumatic head injury patients admitted in the intensive care unit from January 1, 2016 to December 31, 2019 in a tertiary care center. The data was collected from the hospital database after obtaining approval from the hospital ethics committee.

Results A total of 287 patients (18–65 years of age) were admitted to intensive care unit (ICU) with TBI out of which 227 patients were analyzed who had ICU stay for more than 14 days. PSH was diagnosed in 70 (30.8%) patients. Mean age of PSH positive patients was 40 ± 18 and 49 ± 11 years for PSH negative patients (p < 0.001). The age group between 40 and 50 years had a higher incidence of PSH. The age and Glasgow coma score (GCS) were significantly associated with the occurrence of PSH. The GCS score demonstrated good accuracy for predicting the occurrence of PSH with AUC 0.83, 95% CI of 0.775 to 0.886, and a p-value of 0.001.

Conclusion We observed that the incidence of PSH was 30.8% in the patients with TBI. Age and GCS were found to have a significant association for predicting the occurrence of PSH. The patients who developed PSH had a longer length of hospital stay in ICU.

Paroxysmal Sympathetic Hyperactivity

Paroxysmal sympathetic hyperactivity (PSH) is a relatively common, but often unrecognized, complication of acute diffuse or multifocal brain diseases, most frequently encountered in young comatose patients with severe traumatic brain injury. It is presumed to be caused by loss of cortical inhibitory modulation of diencephalic and brain stem centers and possible additional maladaptive changes in the spinal cord that combine to produce exaggerated sympathetic responses to stimulation. The syndrome consists of repeated sudden episodes of tachycardia, tachypnea, hypertension, sweating, and sometimes fever and dystonic posturing. The diagnosis is clinical. Treatment includes reducing any external stimulation that can trigger the episodes, and starting abortive (e.g., intravenous morphine) and preventive medications (e.g., gabapentin, propranolol, clonidine). Prompt and adequate treatment of PSH may reduce the likelihood of secondary complications, such as dehydration, weight loss and malnutrition, and muscle contractures.

Autonomic dysfunction syndromes after acute brain injury

The central autonomic nervous system (CAN) is a multifaceted, richly connected neural network incorporating the hypothalamus, its descending tracts through the brainstem, the insular cortex and down into the spinal cord. All levels of the CAN are susceptible to injury following traumatic brain injury (TBI), whether from focal or diffuse injury. Focal injuries would be expected to produce localized damage to CAN control centers, whereas the effects of diffuse injuries are presumed to be more diverse and/or widely distributed. As the combination of focal and diffuse injury following TBI can vary widely from one individual to the next, the impact of focal injuries is best understood with reference to the focal ischemic stroke literature. Subarachnoid hemorrhage (SAH), a common complication following TBI, also has predictable effects on autonomic control that can be understood with reference to spontaneous SAH literature. Finally, paroxysmal sympathetic hyperactivity (PSH), a syndrome incorporating episodes of heightened sympathetic drive and motor overactivity following minor stimulation, is discussed as an example of what happens when central inhibitory control of spinal cord autonomics is impaired.