Fatal hyperthermia in a quadriplegic man. Possible evidence for a peripheral action of haloperidol in neuroleptic malignant syndrome

An altered Bioheat model for persons with cervical spinal cord injury

The objective of this work is to develop a Bioheat model to predict the thermal responses of people with tetraplegia (TP) under hot, cold and neutral ambient conditions as well as different physical activities suitable for their level of injury. The focus is on TP with impairment or loss of motor and/or sensory function in C1 to C7 segments of the spinal cord due to damage of neural elements within the spinal canal. Starting from transient multi-segmented Bioheat model of able-bodied (AB) people, specific modifications were performed reflecting the changes in physiology due to the injury affecting the blood circulation system, energy expenditure, and thermoregulatory functions in the body. The TP Bioheat model predicts the TP thermal responses under steady and transient thermal conditions, and different activity levels that are appropriate for the level of injury. The model was validated with published experimental data reporting physiological and thermal data measurements on cases of people with complete and incomplete tetraplegia under controlled environmental conditions and activity levels. In both transient and steady state environmental conditions, the predicted core and mean skin temperature values were compared against the experimental data with maximum error of 0.86 °C and 0.9 °C respectively. The TP Bioheat model can be used as a tool to propose appropriate personal cooling strategies for TP.

Reprint of "Drawing breath without the command of effectors: the control of respiration following spinal cord injury"

The maintenance of blood gas and pH homeostasis is essential to life. As such breathing, and the mechanisms which control ventilation, must be tightly regulated yet highly plastic and dynamic. However, injury to the spinal cord prevents the medullary areas which control respiration from connecting to respiratory effectors and feedback mechanisms below the level of the lesion. This trauma typically leads to severe and permanent functional deficits in the respiratory motor system. However, endogenous mechanisms of plasticity occur following spinal cord injury to facilitate respiration and help recover pulmonary ventilation. These mechanisms include the activation of spared or latent pathways, endogenous sprouting or synaptogenesis, and the possible formation of new respiratory control centres. Acting in combination, these processes provide a means to facilitate respiratory support following spinal cord trauma. However, they are by no means sufficient to return pulmonary function to pre-injury levels. A major challenge in the study of spinal cord injury is to understand and enhance the systems of endogenous plasticity which arise to facilitate respiration to mediate effective treatments for pulmonary dysfunction.

Hemorrhagic shock and encephalopathy syndrome in a quadriplegic child: an argument for the triggering role of impaired thermoregulatory response

STUDY DESIGN

A case presentation of hemorrhagic shock and encephalopathy syndrome (HSES).

OBJECTIVE

To describe an unusual complication of uncontrolled fever in a tetraplegic child and to discuss possible pathophysiological mechanisms in these circumstances.

SUMMARY OF BACKGROUND DATA

HSES is a rare and dramatic disorder of unknown origin occurring mainly in infants and young children. Clinical features of HSES associate hyperpyrexia, acute diarrhea, circulatory collapse, coma, convulsions, and multiple organ failure (MOF). Altered physiologic thermoregulatory response in infants exposed to abruptly increased core temperature or altered thermal environment, and links with heat stroke, have been mentioned in previous publications.

METHODS

We report a case of HSES occurring in a 6-year-old girl with post-traumatic C4 quadriplegia. She eventually experienced hyperpyrexia, deep shock, watery diarrhea, and severe MOF developed rapidly. Despite rapidly resolving MOF, severe brain lesions consistent with HSES were observed and resulted in permanent neurologic impairment.

RESULTS

Negative bacterial and viral screening eliminated a septic origin. In this child, impaired thermoregulatory response to acute hyperpyrexia resulting from complete quadriplegia could be the necessary condition for the development of HSES in the presence of acute hyperpyrexia of unknown origin.

CONCLUSION

Quadriplegic patients, especially young children, could be considered at increased risk of developing severe MOF and acute central nervous system impairment consistent with HSES, when exposed to heat stress and should be treated promptly.

Effect of spinal cord injury on the respiratory system: basic research and current clinical treatment options

Spinal cord injury (SCI) often leads to an impairment of the respiratory system. The more rostral the level of injury, the more likely the injury will affect ventilation. In fact, respiratory insufficiency is the number one cause of mortality and morbidity after SCI. This review highlights the progress that has been made in basic and clinical research, while noting the gaps in our knowledge. Basic research has focused on a hemisection injury model to examine methods aimed at improving respiratory function after SCI, but contusion injury models have also been used. Increasing synaptic plasticity, strengthening spared axonal pathways, and the disinhibition of phrenic motor neurons all result in the activation of a latent respiratory motor pathway that restores function to a previously paralyzed hemidiaphragm in animal models. Human clinical studies have revealed that respiratory function is negatively impacted by SCI. Respiratory muscle training regimens may improve inspiratory function after SCI, but more thorough and carefully designed studies are needed to adequately address this issue. Phrenic nerve and diaphragm pacing are options available to wean patients from standard mechanical ventilation. The techniques aimed at improving respiratory function in humans with SCI have both pros and cons, but having more options available to the clinician allows for more individualized treatment, resulting in better patient care. Despite significant progress in both basic and clinical research, there is still a significant gap in our understanding of the effect of SCI on the respiratory system.

Autonomic Nervous System Dysfunction After Spinal Cord Injury

The autonomic nervous system (ANS) plays a key role in the regulation of many physiologic processes, mediated by supraspinal control from centers in the central nervous system. The role of autonomic dysfunction in persons with spinal cord injuries is crucial to understand because many aspects of the altered physiology seen in these individuals are directly caused by ANS dysregulation.

Clustered lipid droplets in the endomyocardial biopsies from a patient with neuroleptic malignant syndrome

Neuroleptic malignant syndrome is caused by serious adverse effects of antipsychotic agents and occurs only rarely. Endomyocardial biopsies documented unique clustered lipid droplets in a Japanese man with this disease. After administration of haloperidol, he had symptoms of high fever, respiratory dysfunction, and cardiogenic shock, and subsequently suffered from multiple organ failure. Fortunately, he was completely cured with intensive therapy. In the convulsant stage, left ventricular endomyocardial biopsies were performed that yielded the interesting discovery of unique clustered lipid droplets among the myofibrils. It was suggested that although the pathomechanism of neuroleptic malignant syndrome is unknown, this disease may be characterized by a lipid metabolic disorder of the cardiac muscle cell.