Effect of magnesium sulphate on urinary catecholamine excretion in severe tetanus

Urinary catecholamine excretion, cardiovascular variability, and outcomes in tetanus

Severe tetanus is characterized by muscle spasm and cardiovascular system disturbance. The pathophysiology of muscle spasm is relatively well understood and involves inhibition of central inhibitory synapses by tetanus toxin. That of cardiovascular disturbance is less clear, but is believed to relate to disinhibition of the autonomic nervous system. The clinical syndrome of autonomic nervous system dysfunction (ANSD) seen in severe tetanus is characterized principally by changes in heart rate and blood pressure which have been linked to increased circulating catecholamines. Previous studies have described varying relationships between catecholamines and signs of ANSD in tetanus, but are limited by confounders and assays used. In this study, we aimed to perform detailed characterization of the relationship between catecholamines (adrenaline and noradrenaline), cardiovascular parameters (heart rate and blood pressure) and clinical outcomes (ANSD, mechanical ventilation required, and length of intensive care unit stay) in adults with tetanus, as well as examine whether intrathecal antitoxin administration affected subsequent catecholamine excretion. Noradrenaline and adrenaline were measured by ELISA from 24-h urine collections taken on day 5 of hospitalization in 272 patients enrolled in a 2 × 2 factorial-blinded randomized controlled trial in a Vietnamese hospital. Catecholamine results measured from 263 patients were available for analysis. After adjustment for potential confounders (i.e., age, sex, intervention treatment, and medications), there were indications of non-linear relationships between urinary catecholamines and heart rate. Adrenaline and noradrenaline were associated with subsequent development of ANSD, and length of ICU stay.

Heart Rate Variability as an Indicator of Autonomic Nervous System Disturbance in Tetanus

Autonomic nervous system dysfunction (ANSD) is a significant cause of mortality in tetanus. Currently, diagnosis relies on nonspecific clinical signs. Heart rate variability (HRV) may indicate underlying autonomic nervous system activity and represents a potentially valuable noninvasive tool for ANSD diagnosis in tetanus. HRV was measured from three 5-minute electrocardiogram recordings during a 24-hour period in a cohort of patients with severe tetanus, all receiving mechanical ventilation. HRV measurements from all subjects—five with ANSD (Ablett Grade 4) and four patients without ANSD (Ablett Grade 3)—showed HRV was lower than reported ranges for healthy individuals. Comparing different severities of tetanus, raw data for both time and frequency measurements of HRV were reduced in those with ANSD compared with those without. Differences were statistically significant in all except root mean square SD, indicating HRV may be a valuable tool in ANSD diagnosis.

Assessing the efficacy and safety of magnesium sulfate for management of autonomic nervous system dysregulation in Vietnamese children with severe hand foot and mouth disease

Background

Brainstem encephalitis is a serious complication of hand foot and mouth disease (HFMD) in children. Autonomic nervous system (ANS) dysregulation and hypertension may occur, sometimes progressing to cardiopulmonary failure and death. Vietnamese national guidelines recommend use of milrinone if ANS dysregulation with Stage 2 hypertension develops. We wished to investigate whether magnesium sulfate (MgSO₄) improved outcomes in children with HFMD if used earlier in the evolution of the ANS dysregulation (Stage 1 hypertension).

Methods

During a regional epidemic we conducted a randomized, double-blind, placebo-controlled trial of MgSO₄ in children with HFMD, ANS dysregulation and Stage 1 hypertension, at the Hospital for Tropical Diseases in Ho Chi Minh city. Study participants received an infusion of MgSO₄ or matched placebo for 72 h. We also reviewed data from non-trial HFMD patients in whom milrinone failed to control hypertension, some of whom received MgSO₄ as second line therapy. The primary outcome for both analyses was a composite of disease progression within 72 h - addition of milrinone (trial participants only), need for ventilation, shock, or death.

Results

Between June 2014 and September 2016, 14 and 12 participants received MgSO₄ or placebo respectively, before the trial was stopped due to futility. Among 45 non-trial cases with poorly controlled hypertension despite high-dose milrinone, 33 received MgSO₄ while 12 did not. There were no statistically significant differences in the composite outcome between the MgSO₄ and the placebo/control groups in either study (adjusted relative risk (95%CI) of [6/14 (43%) vs. 6/12 (50%)], 0.84 (0.37, 1.92), p = 0.682 in the trial and [1/33 (3%) vs. 2/12 (17%)], 0.16 (0.01, 1.79), p = 0.132 in the observational cohort). The incidence of adverse events was similar between the groups. Potentially toxic magnesium levels occurred very rarely with the infusion regime used.

Conclusion

Although we could not demonstrate efficacy in these studies, there were no safety signals associated with use of 30-50 mg/kg/hr. MgSO₄ in severe HFMD. Intermittent outbreaks of HFMD are likely to continue across the region, and an adequately powered trial is still needed to evaluate use of MgSO₄ in controlling hypertension in severe HFMD, potentially involving a higher dose regimen.

Trial registration

ClinicalTrials.gov Identifier: NCT01940250 (Registered 22 AUG 2013).

Trial sponsor: University of Oxford

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4356-x) contains supplementary material, which is available to authorized users.

Autonomic dysfunction in the neurological intensive care unit

Autonomic dysfunction is common in neuro-critical care patients and may compromise the function of various organs. Among the many diseases causing or being associated with autonomic dysfunction are traumatic brain injury, cerebrovascular diseases, epilepsy, Guillain-Barré syndrome (GBS), alcohol withdrawal syndrome, botulism and tetanus, among many others. Autonomic dysfunction may afflict various organs and may involve hyper- or hypo-activity of the sympathetic or parasympathetic system. In this short overview, we address only a small number of neuro-intensive care diseases with autonomic dysfunction. In GBS, autonomic dysfunction is frequent and may account for increased mortality rates; rapid changes between sympathetic and parasympathetic hypo- or hyper-activity may cause life-threatening cardiovascular complications. Paroxysmal sympathetic hyperactivity occurs after brain injury, hypoxia and cerebrovascular and other events, causes paroxysmal tachycardia, hypertension, tachypnoea and hyperthermia and is associated with a poorer prognosis and prolonged intensive care treatment. Other, at times life-threatening autonomic complications with exaggerated sympathetic activity and compromised baroreflex sensitivity arise during the alcohol withdrawal syndrome triggered by abrupt cessation of alcohol consumption. Botulism and tetanus are examples of life-threatening autonomic dysfunction caused by bacterial neurotoxins. Common neurological diseases, such as epilepsy, stroke or subarachnoid haemorrhage, are also associated with autonomic dysfunction that can on occasion cause critical deterioration of disease severity and prognosis.

The Importance of Magnesium in Clinical Healthcare

The scientific literature provides extensive evidence of widespread magnesium deficiency and the potential need for magnesium repletion in diverse medical conditions. Magnesium is an essential element required as a cofactor for over 300 enzymatic reactions and is thus necessary for the biochemical functioning of numerous metabolic pathways. Inadequate magnesium status may impair biochemical processes dependent on sufficiency of this element. Emerging evidence confirms that nearly two-thirds of the population in the western world is not achieving the recommended daily allowance for magnesium, a deficiency problem contributing to various health conditions. This review assesses available medical and scientific literature on health issues related to magnesium. A traditional integrated review format was utilized for this study. Level I evidence supports the use of magnesium in the prevention and treatment of many common health conditions including migraine headache, metabolic syndrome, diabetes, hyperlipidemia, asthma, premenstrual syndrome, preeclampsia, and various cardiac arrhythmias. Magnesium may also be considered for prevention of renal calculi and cataract formation, as an adjunct or treatment for depression, and as a therapeutic intervention for many other health-related disorders. In clinical practice, optimizing magnesium status through diet and supplementation appears to be a safe, useful, and well-documented therapy for several medical conditions.

Intravenous magnesium sulfate for the management of severe hand, foot, and mouth disease with autonomic nervous system dysregulation in Vietnamese children: study protocol for a randomized controlled trial

BACKGROUND

Over the last 15 years, hand, foot, and mouth disease (HFMD) has emerged as a major public health burden across the Asia-Pacific region. A small proportion of HFMD patients, typically those infected with enterovirus 71 (EV71), develop brainstem encephalitis with autonomic nervous system (ANS) dysregulation and may progress rapidly to cardiopulmonary failure and death. Although milrinone has been reported to control hypertension and support myocardial function in two small studies, in practice, a number of children still deteriorate despite this treatment. Magnesium sulfate (MgSO4) is a cheap, safe, and readily available medication that is effective in managing tetanus-associated ANS dysregulation and has shown promise when used empirically in EV71-confirmed severe HFMD cases.

METHODS/DESIGN

We describe the protocol for a randomized, placebo-controlled, double-blind trial of intravenous MgSO4 in Vietnamese children diagnosed clinically with HFMD plus ANS dysregulation with systemic hypertension. A loading dose of MgSO4 or identical placebo is given over 20 min followed by a maintenance infusion for 72 h according to response, aiming for Mg levels two to three times the normal level in the treatment arm. The primary endpoint is a composite of disease progression within 72 h defined as follows: development of pre-specified blood pressure criteria necessitating the addition of milrinone, the need for ventilation, shock, or death. Secondary endpoints comprise these parameters singly, plus other clinical endpoints including the following: requirement for other inotropic agents; duration of hospitalization; presence of neurological sequelae at discharge in survivors; and neurodevelopmental status assessed 6 months after discharge. The number and severity of adverse events observed in the two treatment arms will also be compared. Based on preliminary data from a case series, and allowing for some losses, 190 patients (95 in each arm) will allow detection of a 50 % reduction in disease progression with 90 % power at a two-sided 5 % significance level.

DISCUSSION

Given the large numbers of HFMD cases currently being seen in hospitals in Asia, if MgSO4 is shown to be effective in controlling ANS dysregulation and preventing severe HFMD complications, this finding would be important to pediatric care throughout the region.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01940250 (Registered 22 August 2013).

Pharmacological management of tetanus: an evidence-based review

Tetanus is becoming rarer in both industrialized and developing nations due to an effective vaccination program. In 2010, the World Health Organization estimated there was a 93% reduction in newborns dying from tetanus worldwide, compared to the situation in the late 1980s. Due to its rarity, many diagnostic delays occur as physicians may not consider the diagnosis until the manifestations become overt. Without timely diagnosis and proper treatment, severe tetanus is fatal (mortality is also influenced by the comorbidities of the patient). The principles of treating tetanus are: reducing muscle spasms, rigidity and autonomic instability (with ventilatory support when necessary); neutralization of tetanus toxin with human antitetanus immunoglobulin or equine antitetanus sera; wound debridement; and administration of antibiotics to eradicate locally proliferating bacteria at the wound site. It is difficult to conduct trials on different treatment modalities in tetanus due to both logistical and ethical reasons. However, it is imperative that physicians are aware of the best evidence-based treatment strategies currently available to improve the outcome of patients. This review concentrates on analyzing the current evidence on the pharmacological management of tetanus.

Tetanus: pathophysiology, treatment, and the possibility of using botulinum toxin against tetanus-induced rigidity and spasms

Tetanus toxin, the product of Clostridium tetani, is the cause of tetanus symptoms. Tetanus toxin is taken up into terminals of lower motor neurons and transported axonally to the spinal cord and/or brainstem. Here the toxin moves trans-synaptically into inhibitory nerve terminals, where vesicular release of inhibitory neurotransmitters becomes blocked, leading to disinhibition of lower motor neurons. Muscle rigidity and spasms ensue, often manifesting as trismus/lockjaw, dysphagia, opistotonus, or rigidity and spasms of respiratory, laryngeal, and abdominal muscles, which may cause respiratory failure. Botulinum toxin, in contrast, largely remains in lower motor neuron terminals, inhibiting acetylcholine release and muscle activity. Therefore, botulinum toxin may reduce tetanus symptoms. Trismus may be treated with botulinum toxin injections into the masseter and temporalis muscles. This should probably be done early in the course of tetanus to reduce the risk of pulmonary aspiration, involuntary tongue biting, anorexia and dental caries. Other muscle groups are also amenable to botulinum toxin treatment. Six tetanus patients have been successfully treated with botulinum toxin A. This review discusses the use of botulinum toxin for tetanus in the context of the pathophysiology, symptomatology, and medical treatment of Clostridium tetani infection.

Magnesium sulfate as an adjunct therapy in the management of severe generalized tetanus in a dog

OBJECTIVE

To describe the use of magnesium sulfate in a case of generalized tetanus in a dog.

CASE SUMMARY

A 1.5-year-old golden retriever was presented for a digital wound on the right thoracic limb and clinical signs associated with generalized tetanus. Initial case management consisted of wound debridement, treatment with metronidazole, tetanus immunoglobulin, methocarbamol, airway management via tracheostomy, and nursing care. Sedation to control severe muscle spasms became insufficient despite increasing doses of benzodiazepine, methocarbamol, and barbiturate continuous rate infusions. A magnesium sulfate continuous rate infusion was instituted on day 7 and muscle rigidity improved within 16 hours allowing discontinuation of sedative infusions over the subsequent 2 days. Clinical improvement continued and the dog was discharged on day 14.

NEW OR UNIQUE INFORMATION PROVIDED

This case demonstrates the use of supraphysiologic magnesium in the treatment of severe generalized tetanus with a positive outcome. No clinical signs associated with magnesium toxicity were noted during the course of therapy. Magnesium sulfate should be considered as a potential adjunct therapy in the management of spastic paralysis caused by severe tetanus in dogs.

Comparative study of intravenously administered clonidine and magnesium sulfate on hemodynamic responses during laparoscopic cholecystectomy

Background:

Both magnesium and clonidine are known to inhibit catecholamine and vasopressin release and attenuate hemodynamic response to pneumoperitoneum. This randomized, double blinded, placebo controlled study has been designed to assess which agent attenuates hemodynamic stress response to pneumoperitoneum better.

Materials and Methods:

120 patients undergoing elective laparoscopic cholecystectomy were randomized into 4 groups of 30 each. Group K patients received 50 ml normal saline over a period of 15 min after induction and before pneumoperitoneum, group M patients received 50 mg/kg of magnesium sulfate in normal saline (total volume 50 ml) over same time duration. Similarly group C1 patients received 1 μg/kg clonidine and group C2 1.5 μg/kg clonidine respectively in normal saline (total volume 50 ml). Blood pressure and heart rate were recorded before induction (baseline value), at the end of infusions and every 5 min after pneumoperitoneum.

Statistical Analysis:

Paired t test was used for intra-group comparison and ANOVA for inter-group comparison.

Results:

Systolic blood pressure was significantly higher in control group as compared to all other groups during pneumoperitoneum. On comparing patients in group M and group C1, no significant difference in systolic BP was found at any time interval. Patients in group C2 showed best control of systolic BP. As compared to group M and group C1, BP was significantly lower at 10, 30 and 40 min post pneumoperitoneum. No significant episodes of hypotension were found in any of the groups. Extubation time and time to response to verbal command like eye opening was significantly longer in group M as compared to other groups.

Conclusion:

Administration of magnesium sulfate or clonidine attenuates hemodynamic response to pneumoperitoneum. Although magnesium sulfate 50 mg/kg produces hemodynamic stability comparable to clonidine 1 μg/kg, clonidine in doses of 1.5μg/kg blunts the hemodynamic response to pneumoperitoneum more effectively.

Magnesium sulphate attenuates arterial pressure increase during laparoscopic cholecystectomy

BACKGROUND

Magnesium is well known to inhibit catecholamine release and attenuate vasopressin-stimulated vasoconstriction. We investigated whether i.v. magnesium sulphate attenuates the haemodynamic stress responses to pneumoperitoneum by changing neurohumoral responses during laparoscopic cholecystectomy.

METHODS

Thirty-two patients undergoing laparoscopic cholecystectomy were randomly assigned to two groups; a control group was given saline, and a magnesium group received magnesium sulphate 50 mg kg(-1) immediately before pneumoperitoneum. Arterial pressure, heart rate, serum magnesium, plasma renin activity (PRA), and catecholamine, cortisol, and vasopressin levels were measured.

RESULTS

Systolic and diastolic arterial pressures were greater in the control group (P<0.05) than in the magnesium group at 10, 20, and 30 min post-pneumoperitoneum. Norepinephrine or epinephrine levels [pg ml(-1), mean (SD)] were higher in the control group than in the magnesium group at 5 [211 (37) vs 138 (18)] or 10 min [59 (19) vs 39 (9)] post-pneumoperitoneum, respectively (P<0.05). In the control group, vasopressin levels [pg ml(-1), mean (SD)] were higher compared with the magnesium group at 5 [64 (18) vs 35 (9), P<0.01] and 10 min [65 (18) vs 47 (11), P<0.05] post-pneumoperitoneum. There were no significant differences between the groups in PRA and cortisol levels.

CONCLUSIONS

I.V. magnesium sulphate before pneumoperitoneum attenuates arterial pressure increases during laparoscopic cholecystectomy. This attenuation is apparently related to reductions in the release of catecholamine, vasopressin, or both.