Neurogenic fever due to injury of the hypothalamus in a stroke patient: Case report

Decreased levels of hydrogen sulfide in the hypothalamic paraventricular nucleus contribute to sympathetic hyperactivity induced by cerebral infarction

Paroxysmal sympathetic hyperactivity (PSH) is a common clinical feature secondary to ischemic stroke (IS), but its mechanism is poorly understood. We aimed to investigate the role of H2S in the pathogenesis of PSH. IS patients were divided into malignant (MCI) and non-malignant cerebral infarction (NMCI) group. IS in rats was induced by the right middle cerebral artery occlusion (MCAO). H2S donor (NaHS) or inhibitor (aminooxy-acetic acid, AOAA) were microinjected into the hypothalamic paraventricular nucleus (PVN). Compared with the NMCI group, patients in the MCI group showed PSH, including tachycardia, hypertension, and more plasma norepinephrine (NE) that was positively correlated with levels of creatine kinase, glutamate transaminase, and creatinine respectively. The 1-year survival rate of patients with high plasma NE levels was lower. The hypothalamus of rats with MCAO showed increased activity, especially in the PVN region. The levels of H2S in PVN of the rats with MCAO were reduced, while the blood pressure and renal sympathetic discharge were increased, which could be ameliorated by NaHS and exacerbated by AOAA. NaHS completely reduced the disulfide bond of NMDAR1 in PC12 cells. The inhibition of NMDAR by MK-801 microinjected in PVN of rats with MCAO also could lower blood pressure and renal sympathetic discharge. In conclusion, PSH may be associated with disease progression and survival in patients with IS. Decreased levels of H2S in PVN were involved in regulating sympathetic efferent activity after cerebral infarction. Our results might provide a new strategy and target for the prevention and treatment of PSH.

Autonomic dysfunction and treatment strategies in intracerebral hemorrhage

AIMS

Autonomic dysfunction with central autonomic network (CAN) damage occurs frequently after intracerebral hemorrhage (ICH) and contributes to a series of adverse outcomes. This review aims to provide insight and convenience for future clinical practice and research on autonomic dysfunction in ICH patients.

DISCUSSION

We summarize the autonomic dysfunction in ICH from the aspects of potential mechanisms, clinical significance, assessment, and treatment strategies. The CAN structures mainly include insular cortex, anterior cingulate cortex, amygdala, hypothalamus, nucleus of the solitary tract, ventrolateral medulla, dorsal motor nucleus of the vagus, nucleus ambiguus, parabrachial nucleus, and periaqueductal gray. Autonomic dysfunction after ICH is closely associated with neurological functional outcomes, cardiac complications, blood pressure fluctuation, immunosuppression and infection, thermoregulatory dysfunction, hyperglycemia, digestive dysfunction, and urogenital disturbances. Heart rate variability, baroreflex sensitivity, skin sympathetic nerve activity, sympathetic skin response, and plasma catecholamine concentration can be used to assess the autonomic functional activities after ICH. Risk stratification of patients according to autonomic functional activities, and development of intervention approaches based on the restoration of sympathetic-parasympathetic balance, would potentially improve clinical outcomes in ICH patients.

CONCLUSION

The review systematically summarizes the evidence of autonomic dysfunction and its association with clinical outcomes in ICH patients, proposing that targeting autonomic dysfunction could be potentially investigated to improve the clinical outcomes.

Hypothalamic Injury and Clinical Outcomes in Patients with Post-Traumatic Hyponatremia: A Diffusion Tensor Imaging Case-Control Study

BACKGROUND Diffusion tensor imaging (DTI) is an advanced magnetic resonance imaging (MRI) method used to identify changes in microstructures in the brain's white matter. Severe brain injuries after trauma are associated with disorders of consciousness (DOC) and may result in hyponatremia due to damage to the hypothalamus. This case-control study aimed to use DTI to evaluate the hypothalamus in 36 patients with hyponatremia and DOC due to severe brain injuries. MATERIAL AND METHODS Thirty-six patients with DOC after traumatic brain injury (TBI) and 36 healthy control subjects were enrolled in this study. The diagnosis of DOC was based on the coma recovery scale-revised (CRS-R). The 36 patients were divided into 2 groups: Group A (18 with hyponatremia, serum sodium level <135 mmol/L) and group B (18 without hyponatremia). The DTI scans were conducted using a 6-channel head coil on a 1.5T Philips Gyroscan Intera scanner. Among the DTI data, fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) of the hypothalamus were analyzed. RESULTS Patient group A had a lower FA value (P=0.044) and higher ADC value (P=0.004) of the hypothalamus and showed a longer length of hospital stay (P=0.03), lower CRS-R score at discharge (P=0.01), and less change in CRS-R score (P=0.004) compared to patient group B. The improvements in the CRS-R score revealed a moderate negative correlation (r=-0.467) with the severity of the hyponatremia (P=0.004). CONCLUSIONS Post-traumatic hyponatremia was associated with hypothalamic injury and the presence and severity of hyponatremia were associated with poor clinical outcomes in DOC patients.

Relationship between hyperhidrosis and hypothalamic injury in patients with mild traumatic brain injury

Hyperhidrosis is clinical symptom of various diseases and is an important clinical feature of paroxysmal sympathetic hyperactivity (PSH). Traumatic brain injury (TBI) is known to be most common condition associated with PSH, and PSH has been mainly reported in moderate and severe TBI. However, very little has been reported on PSH or hyperhidrosis in mild TBI patients. In this study, we used diffusion tensor imaging (DTI) to investigate the relationship between hyperhidrosis and hypothalamic injury in patients with mild TBI. Seven patients with hyperhidrosis after mild TBI and 21 healthy control subjects were recruited for this study. The Hyperhidrosis Disease Severity Scale was used for evaluation of sweating at the time of DTI scanning. The fractional anisotropy and apparent diffusion coefficient DTI parameters were measured in the hypothalamus. In the patient group, the fractional anisotropy values for both sides of the hypothalamus were significantly lower than those of the control group (P < .05). By contrast, the apparent diffusion coefficient values for both sides of the hypothalamus were significantly higher in the patient group than in the control group (P < .05). In conclusion, we detected hypothalamic injuries in patients who showed hyperhidrosis after mild TBI. Based on the results, it appears that hyperhidrosis in patients with mild TBI is related to hypothalamic injury.

Paroxysmal sympathetic hyperactivity concurrent with hypothalamic injury in a patient with intracerebral hemorrhage: A case report

BACKGROUND

Paroxysmal sympathetic hyperactivity (PSH) is characterized by exacerbated sympathetic discharge following severe brain injury. Here, we reports a patient diagnosed with PSH after ICH concurrent with hypothalamic injury, as demonstrated by diffusion tensor imaging (DTI).

METHODS

A 27-year-old man patient was diagnosed with spontaneous intraventricular hemorrhage and intracerebral hemorrhage in both frontal lobes. Two months after onset, brain magnetic resonance imaging of the brain revealed a leukomalactic lesion in the hypothalamus. Three months after the onset, he presented with intermittent high fever, tachycardia, tachypnea, systolic hypertension, diaphoresis, and aggravated rigidity. Infection was ruled out by a physical examination, laboratory tests, and radiological studies. After administrating morphine and bromocriptine, the clinical manifestations improved dramatically.

RESULTS

PSH after intracranial hemorrhage concurrent with the hypothalamic injury. Fractional anisotropy and mean diffusivity values of DTI were obtained in the hypothalamus. No significant difference in fractional anisotropy value was observed between the patient and control group (10 age-matched healthy male subjects) (P > .05). On the other hand, the mean diffusivity value was higher in the patient group than in the control group (P < .05), indicating hypothalamic injury.

CONCLUSION

PSH concurrent with hypothalamic injury was observed in a patient with stroke. This study suggests that DTI can be a useful imaging method for evaluating the hypothalamic state of patients presenting with PSH after brain injury.