The Trigeminocardiac Reflex — An Example of Reflexive Heart Rhythm Change

The trigeminocardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnoea or gastric hyper-motility during mechanical/thermal stimulation of any of the sensory branches of the trigeminal nerve. The risk factors that are already known for increasing the prevalence of the TCR include anatomical location, hypercapnia, hypoxemia, light general anaesthesia, age (more pronounced in children), the nature of the provoking stimulus (stimulus strength and duration) and different drugs. Already different potential confounders are also identified. This discussion about risk factors has its importance because of the substantial consequences for functional outcome after intraoperative TCR occurrence. But there remains still a substantial lack of thorough understanding of the TCR, the current treatment options for patients with TCR include a mostly empirical approach: (i) risk factor identification and modification; (ii) prophylactic measures of vital signs and (iii) administration of vagolytic agents or sympathomimetics. In this context, we have now created different thinking models so that we can preoperatively plan a skull base surgery procedure safely in relation to a potential occurrence of the TCR episodes. This chapter provides an overview of this unique reflex that presents a unique interaction between heart and brain. In addition, this also illustrates the mechanism of various cardiac rhythm changes related to the TCR

Molecular imaging of potential bone metastasis from differentiated thyroid cancer: a case report

<p>Abstract</p> <p>Introduction</p> <p>Molecular imaging of the spine is a rarely used diagnostic method for which only a few case reports exist in the literature. Here, to the best of our knowledge we present the first case of a combination of molecular imaging by single photon emission computer tomography and positron emission tomography used in post-operative spinal diagnostic assessment.</p> <p>Case presentation</p> <p>We present the case of a 50-year-old Caucasian woman experiencing progressive spinal cord compression caused by a vertebral metastasis of a less well differentiated thyroid cancer. Following tumor resection and vertebral stabilization, total thyroidectomy was performed revealing follicular thyroid carcinoma pT2 pNxM1 (lung, bone). During follow-up our patient underwent five radioiodine therapy procedures (5.3 to 5.7 GBq each) over a two-year period. Post-therapeutic I-131 scans showed decreasing uptake in multiple Pulmonary metastases. However, following an initial decrease, stimulated thyroglobulin remained at pathologically increased levels, indicating further neoplastic activity. F18 Fludeoxyglucose positron emission tomography, which was performed in parallel, showed remaining hypermetabolism in the lungs but no hypermetabolism of the spinal lesions correlating with the stable neurological examinations. While on single photon emission computer tomography images Pulmonary hyperfixation of I-131 disappeared (most likely indicating dedifferentiation), there was persistent spinal hyperfixation at the operated level and even higher fixation at the spinal process of L3. Based on the negative results of the spinal F18 fludeoxyglucose positron emission tomography, a decision was made not to operate again on the spine since our patient was completely asymptomatic and the neurological risk seemed to be too high. During further follow-up our patient remained neurologically stable.</p> <p>Conclusions</p> <p>Molecular imaging by F18 fludeoxyglucose positron emission tomography helps to exclude metabolically active spinal metastases and to spare further risky surgery.</p

Management of the trigeminocardiac reflex: Facts and own experience

The trigeminocardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hyper-motility during stimulation of any of the sensory branches of the trigeminal nerve. The proposed mechanism for the development of TCR is-the sensory nerve endings of the trigeminal nerve send neuronal signals via the Gasserian ganglion to the sensory nucleus of the trigeminal nerve, forming the afferent pathway of the reflex arc. It has been demonstrated that the TCR may occur with mechanical stimulation of all the branches of the trigeminal nerve anywhere along its course (central or peripheral). The reaction subsides with cessation of the stimulus. But, some patients may develop severe bradycardia, asystole, and arterial hypotension which require intervention. The risk factors already known to increase the incidence of TCR include: Hypercapnia; hypoxemia; light general anesthesia; age (more pronounced in children); the nature of the provoking stimulus (stimulus strength and duration); and drugs: Potent narcotic agents (sufentanil and alfentanil); beta-blockers; and calcium channel blockers. Because of the lack of full understanding of the TCR physiology, the current treatment options for patients with TCR include: (i) risk factor identification and modification; (ii) prophylactic measures; and (iii) administration of vagolytic agents or sympathomimetics

A new predisposing factor for trigemino-cardiac reflex during subdural empyema drainage: a case report

Abstract Introduction The trigemino-cardiac reflex is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve. Clinically, trigemino-cardiac reflex has been reported to occur during neurosurgical skull-base surgery. Apart from the few clinical reports, the physiological function of this brainstem reflex has not yet been fully explored. Little is known regarding any predisposing factors related to the intraoperative occurrence of this reflex. Case presentation We report the case of a 70-year-old Caucasian man who demonstrated a clearly expressed form of trigemino-cardiac reflex with severe bradycardia requiring intervention that was recorded during surgical removal of a large subdural empyema. Conclusion To the best of our knowledge, this is the first report of an intracranial infection leading to perioperative trigemino-cardiac reflex. We therefore add a new predisposing factor for trigemino-cardiac reflex to the existing literature. Possible mechanisms are discussed in the light of the relevant literature.</p

Ischemic tolerance in stroke treatment

Although outcome after stroke treatment has significantly improved over the last 30 years, there has been no revolutionary breakthrough. Among different combined approaches, systemic thrombolysis in combination with neuroprotection became a favorite research target. Recent studies suggest that transient ischemic attacks may represent a clinical model of such ischemic tolerance; thus, a new focus on this research has emerged. In this review, we show the parallels between ischemia and neuroprotection and discuss the potential therapeutic options that may be opened by this new molecular knowledge

The trigemino-cardiac reflex in adults: own experience

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