Medical complications of head injury

Triphasic response of pituitary stalk injury following TBI: a relevant yet uncommonly recognised endocrine phenomenon

The triphasic response of pituitary stalk injury has previously been described in a minority of patients following intracranial surgery, however, this phenomenon can also occur after traumatic brain injury. We present the case of a 20-year-old male who experienced the triphasic response of pituitary stalk injury (central diabetes insipidus, syndrome of inappropriate antidiuretic hormone and central diabetes insipidus again) after striking his head on a concrete curb. His history and presentation highlight the importance of recognising the distinctive symptoms of each individual stage of pituitary stalk injury, and using the appropriate diagnostic tools and therapies to guide further management.

MANAGEMENT OF ENDOCRINE DISEASE: Neuroendocrine surveillance and management of neurosurgical patients

Advances in the management of traumatic brain injury, subarachnoid haemorrhage and intracranial tumours have led to improved survival rates and an increased focus on quality of life of survivors. Endocrine sequelae of the acute brain insult and subsequent neurosurgery, peri-operative fluid administration and/or cranial irradiation are now well described. Unrecognised acute hypopituitarism, particularly ACTH/cortisol deficiency and diabetes insipidus, can be life threatening. Although hypopituitarism may be transient, up to 30% of survivors of TBI have chronic hypopituitarism, which can diminish quality of life and hamper rehabilitation. Patients who survive SAH may also develop hypopituitarism, though it is less common than after TBI. The growth hormone axis is most frequently affected. There is also accumulating evidence that survivors of intracranial malignancy, who have required cranial irradiation, may develop hypopituitarism. The time course of the development of hormone deficits is varied, and predictors of pituitary dysfunction are unreliable. Furthermore, diagnosis of GH and ACTH deficiency require dynamic testing that can be resource intensive. Thus the surveillance and management of neuroendocrine dysfunction in neurosurgical patients poses significant logistic challenges to endocrine services. However, diagnosis and management of pituitary dysfunction can be rewarding. Appropriate hormone replacement can improve quality of life, prevent complications such as muscle atrophy, infection and osteoporosis and improve engagement with physiotherapy and rehabilitation.

Diagnosis and Management of Combined Central Diabetes Insipidus and Cerebral Salt Wasting Syndrome After Traumatic Brain Injury

BACKGROUND

Combined central diabetes insipidus and cerebral salt wasting syndrome after traumatic brain injury (TBI) is rare, is characterized by massive polyuria leading to severe water and electrolyte disturbances, and usually is associated with very high mortality mainly as a result of delayed diagnosis and improper management.

METHODS

We retrospectively reviewed the clinical presentation, management, and outcomes of 11 patients who developed combined central diabetes insipidus and cerebral salt wasting syndrome after traumatic brain injury to define distinctive features for timely diagnosis and proper management.

RESULTS

The most typical clinical presentation was massive polyuria (10,000 mL/24 hours or >1000 mL/hour) refractory to vasopressin alone but responsive to vasopressin plus cortisone acetate. Other characteristic presentations included low central venous pressure, high brain natriuretic peptide precursor level without cardiac dysfunction, high 24-hour urine sodium excretion and hypovolemia, and much higher urine than serum osmolarity; normal serum sodium level and urine specific gravity can also be present. Timely and adequate infusion of sodium chloride was key in treatment. Of 11 patients, 5 had a good prognosis 3 months later (Extended Glasgow Outcome Scale score ≥6), 1 had an Extended Glasgow Outcome Scale score of 4, 2 died in the hospital of brain hernia, and 3 developed a vegetative state.

CONCLUSIONS

For combined diabetes insipidus and cerebral salt wasting syndrome after traumatic brain injury, massive polyuria is a major typical presentation, and intensive monitoring of fluid and sodium status is key for timely diagnosis. To achieve a favorable outcome, proper sodium chloride supplementation and cortisone acetate and vasopressin coadministration are key.

Propofol-related urine discoloration in a patient with fatal atypical intracerebral hemorrhage treated with hypothermia

Introduction

Mild therapeutic hypothermia is an increasingly recognised treatment option to reduce perihemorrhagic edema in severe intracerebral hemorrhage.

Case description

We report the case of a 77-year old woman with atypical intracerebral hemorrhage that was treated with mild hypothermia in addition to osmotic therapy. The patient’s urine subsequently showed a green discoloration. Urine discoloration was completely reversible upon discontinuation of propofol.

Discussion and evaluation

Propofol-related urine discoloration may have been provoked by hypothermia. Due to the benign nature of this side effect, propofol should be stopped and gastrointestinal function should be supported.

Conclusion

More studies are needed to show a causal role of hypothermia and related decreased enzymatic function.

Sports-related chronic repetitive head trauma as a cause of pituitary dysfunction

Traumatic brain injury (TBI) is recognized as a cause of hypopituitarism even after mild TBI. Although over the past decade, a growing body of research has detailed neuroendocrine changes induced by TBI, the mechanisms and risk factors responsible for this pituitary dysfunction are still unclear. Around the world, sports-especially combative sports-are very popular. However, sports are not generally considered as a cause of TBI in most epidemiological studies, and the link between sports-related head trauma and hypopituitarism has not been investigated until recently. Thus, there is a paucity of data regarding this important concern. Because of the large number of young sports participants with near-normal life expectancy, the implications of undiagnosed or untreated postconcussion pituitary dysfunction can be dramatic. Understanding the pathophysiological mechanisms and risk factors of hypopituitarism caused by sports injuries is thus an important issue that concerns both medical staff and sponsors of sports. The aim of this paper was to summarize the best evidence for understanding the pathophysiological mechanisms and to discuss the current data and recommendations on sports-related head trauma as a cause of hypopituitarism.

The atrial natriuretic peptide does not serve osmoregulation but predicts outcome following brain injury

Atrial natriuretic peptide (ANP) plays an important role in body fluid homeostasis. ANP has been established as a marker of cardiac dysfunction and may play a role in brain edema development after traumatic brain injury (TBI). In order to identify its specific assignment following TBI, we related clinical data and treatment variables in 63 patients to longitudinal midregional (MR) proatrail natriuretic peptide (ANP) measurements. ANP correlated significantly to age (p < 0.0001) and vasopressin release (p < 0.001). Following TBI, ANP was increased initially and on day 3 (cut-off 100 pg/L) in 22% of the patients, in 31% on day 7, and was normalized at follow-up examination. The group comparison revealed that ANP levels did not significantly differ with regard to injury severity, but that high ANP levels predicted a worse Glasgow Outcome Score at 6 months (p < 0.05). While the initially intact osmoregulation - a correlation of urine volume and high serum sodium (r = 0.536, p = 0.003) or low urine osmolality (r = -0.556, p = 0.009) - got lost post-injury, the ANP release was triggered by volume load (p < 0.005). High ANP levels correlated with the neuroendocrine stress response, i.e., high cortisol (p = 0.05) and prolactin (p < 0.001) levels. We conclude that MR-proANP measurements reveal a significant predictive function for the prognosis of TBI.

[Physiologic effects of hypothermia]

Therapeutic use of hypothermia has come to the frontline in the past decade again in the prevention and in mitigation of neurologic impairment. The application of hypothermia is considered as a successful therapeutic measure not just in neuro- or cardiac surgery, but also in states causing brain injury or damage. According to our present knowledge this is the only proven therapeutic tool, which improves the neurologic outcome after cardiac arrest, decreasing the oxygen demand of the brain. Besides influencing the nervous system, hypothermia influences the function of the whole organ system. Beside its beneficial effects, it has many side-effects, which may be harmful to the patient. Before using it for a therapeutic purpose, it is very important to be familiar with the physiology and complications of hypothermia, to know, how to prevent and treat its side-effects. The purpose of this article is to summarize the physiologic and pathophysiologic effects of hypothermia.

Permanent central diabetes insipidus after mild traumatic brain injury

AIM

The patients in the permanent diabetes insipidus (DI) group are more likely to have more severe TBI, which is defined by a post-resuscitational and pre-sedational Glasgow Coma Scale (GCS) score of 8/15 or less. This study presents a case of permanent, central DI following mild traumatic brain injury with post-resuscitation GCS 13/15.

CASE REPORT

A 17-year-old boy suffered from mild brain injury and experienced permanent DI without any anatomical changes on image in the early stage of traumatic brain injury. However, 1 year later, magnetic resonance imaging (MRI) of the brain in this patient has revealed some sequel of contusion. Moreover, the patient still has DI after treatment with diamino-8-D-arginine vasopressin (DDAVP).

CONCLUSION

This patient had a rare clinical presentation of permanent, central DI, following a mild traumatic brain injury. Identification of head trauma as the aetiology of hypopituitarism may be overlooked if there is a long delay in onset after trauma. Since anterior hypopituitarism can develop decades after the episode of head trauma, monitoring for endocrine dysfunction during follow-up of these patients is important.

Induced hypothermia for trauma: current research and practice

Induction of hypothermia with the goal of providing therapeutic benefit has been accepted for use in the clinical setting of adult cardiac arrest and neonatal hypoxic-ischemic encephalopathy (HIE). However, its potential as a treatment in trauma is not as well defined. This review discusses potential benefits and complications of induced hypothermia (IH) with emphasis on the current state of knowledge and practice in various types of trauma. There is excellent preclinical research showing that in cases of penetrating trauma with cardiac arrest, inducing hypothermia to 10 degrees C using cardiopulmonary bypass (CPB) could possibly save those otherwise likely to die without causing neurologic sequelae. A human trial of this intervention is about to get underway. Preclinical studies suggest that inducing hypothermia may be useful to delay cardiac arrest in penetrating trauma victims who are hypotensive. There is potential for IH to be used in cases of blunt trauma, but it has not been well studied. In the case of traumatic brain injury (TBI), clinical trials have shown conflicting results, despite almost uniform efficacy seen in preclinical experiments. Major studies are analyzed and ways to standardize its use and optimize future clinical trials are discussed. More preclinical and clinical research is needed to better define whether there could be a role for IH in the case of spinal cord injuries.

The relation between the incidence of hypernatremia and mortality in patients with severe traumatic brain injury

Introduction

The study was aimed at verifying whether the occurrence of hypernatremia during the intensive care unit (ICU) stay increases the risk of death in patients with severe traumatic brain injury (TBI). We performed a retrospective study on a prospectively collected database including all patients consecutively admitted over a 3-year period with a diagnosis of TBI (post-resuscitation Glasgow Coma Score ≤ 8) to a general/neurotrauma ICU of a university hospital, providing critical care services in a catchment area of about 1,200,000 inhabitants.

Methods

Demographic, clinical, and ICU laboratory data were prospectively collected; serum sodium was assessed an average of three times per day. Hypernatremia was defined as two daily values of serum sodium above 145 mmol/l. The major outcome was death in the ICU after 14 days. Cox proportional-hazards regression models were used, with time-dependent variates designed to reflect exposure over time during the ICU stay: hypernatremia, desmopressin acetate (DDAVP) administration as a surrogate marker for the presence of central diabetes insipidus, and urinary output. The same models were adjusted for potential confounding factors.

Results

We included in the study 130 TBI patients (mean age 52 years (standard deviation 23); males 74%; median Glasgow Coma Score 3 (range 3 to 8); mean Simplified Acute Physiology Score II 50 (standard deviation 15)); all were mechanically ventilated; 35 (26.9%) died within 14 days after ICU admission. Hypernatremia was detected in 51.5% of the patients and in 15.9% of the 1,103 patient-day ICU follow-up. In most instances hypernatremia was mild (mean 150 mmol/l, interquartile range 148 to 152). The occurrence of hypernatremia was highest (P = 0.003) in patients with suspected central diabetes insipidus (25/130, 19.2%), a condition that was associated with increased severity of brain injury and ICU mortality. After adjustment for the baseline risk, the incidence of hypernatremia over the course of the ICU stay was significantly related with increased mortality (hazard ratio 3.00 (95% confidence interval: 1.34 to 6.51; P = 0.003)). However, DDAVP use modified this relation (P = 0.06), hypernatremia providing no additional prognostic information in the instances of suspected central diabetes insipidus.

Conclusions

Mild hypernatremia is associated with an increased risk of death in patients with severe TBI. In a proportion of the patients the association between hypernatremia and death is accounted for by the presence of central diabetes insipidus.

Vasopressin serum levels and disorders of sodium and water balance in patients with severe brain injury

BACKGROUND

Disorders of water and sodium balance are frequently seen in patients with severe brain injury (SBI), and may worsen their prognosis.

PURPOSE

To evaluate vasopressin (AVP) serum levels and sodium and water balance disorders during the first week post-injury in patients with SBI.

METHOD

Thirty-six adult patients with SBI (admission Glasgow Coma Scale score < or= 8) and an estimated time of injury <or= 72 hours were prospectively studied. Clinical and laboratory data were recorded and AVP was measured in venous blood samples collected on the 1st, 2nd, 3rd and 5th days following inclusion.

RESULTS

AVP serum levels remained within the normal range in SBI patients (either traumatic or non-traumatic), although tended to be greater in non-survivor than in survivor patients (p=0.025 at 3rd day). In-hospital mortality was 43% (15/36), and serum sodium and plasma osmolality variabilities were greater in non-survivor than in survivor patients during the observation period (p<0.001).

CONCLUSION

AVP serum levels remained within the normal range values in these SBI patients, but those who died have shown higher incidence of abnormal sodium and water balance during the first week post-injury.

Coagulation disorders after traumatic brain injury

BACKGROUND

Over the past decade new insights in our understanding of coagulation have identified the prominent role of tissue factor. The brain is rich in tissue factor, and injury to the brain may initiate disturbances in local and systemic coagulation. We aimed to review the current knowledge on the pathophysiology, incidence, nature, prognosis and treatment of coagulation disorders following traumatic brain injury (TBI).

METHODS

We performed a MEDLINE search from 1966 to April 2007 with various MESH headings, focusing on head trauma and coagulopathy. We identified 441 eligible English language studies. These were reviewed for relevance by two independent investigators. A meta-analysis was performed to calculate the frequencies of coagulopathy after TBI and to determine the association of coagulopathy and outcome, expressed as odds ratios.

RESULTS

Eighty-two studies were relevant for the purpose of this review. Meta-analysis of 34 studies reporting the frequencies of coagulopathy after TBI, showed an overall prevalence of 32.7%. The presence of coagulopathy after TBI was related both to mortality (OR 9.0; 95%CI: 7.3-11.6) and unfavourable outcome (OR 36.3; 95%CI: 18.7-70.5).

CONCLUSIONS

We conclude that coagulopathy following traumatic brain injury is an important independent risk factor related to prognosis. Routine determination of the coagulation status should therefore be performed in all patients with traumatic brain injury. These data may have important implications in patient management. Well-performed prospective clinical trials should be undertaken as a priority to determine the beneficial effects of early treatment of coagulopathy.

Rehabilitation outcome after traumatic brain injury

Rehabilitation goals after traumatic brain injury are improving function, increasing the level of independence as high as possible, preventing complications and providing an acceptable environment to the patient. Several complications can be encountered during the rehabilitation period which lead to physical, cognitive and neurobehavioral impairments that cause major delay in functional improvement. This prospective study was designed in order to investigate the complications and their relations with functional recovery in patients that were included in the acute phase of a rehabilitation program. Thirty traumatic brain injured patients admitted to the Intensive Care Units of Uludag University School of Medicine were included in the study. Rehabilitation program consisted in appropriate positioning, range of motion exercises, postural drainage and respiratory exercises. Complications that were encountered during intensive care rehabilitation program were recorded. All patients were evaluated by Functional Independence Measure, Disability Rating Scale and Ranchos Los Amigos Levels of Cognitive Function Scale at admission and discharge. Improvement was observed in patients in terms of functional outcome and disability levels. Pneumonia, athelectasis, anemia and meningitis were the most frequent complications. Deterioration in functional outcome and disability levels was noted as the number of these complications increased. In conclusion, rehabilitation has an important role in the management of traumatic brain injured patients. Reduction of frequency of complications and improvement in functional outcome and disability levels can be achieved through rehabilitation programs. Long-term controlled studies with large number of patients are needed in order to obtain accurate data on factors associated with rehabilitation outcomes.

[Controlled mild-to-moderate hypothermia in the intensive care unit]

Controlled hypothermia is used as a therapeutic intervention to provide neuroprotection and (more recently) cardioprotection. The growing insight into the underlying pathophysiology of apoptosis and destructive processes at the cellular level, and the mechanisms underlying the protective effects of hypothermia, have led to improved application and to a widening of the range of potential indications. In many centres hypothermia has now become part of the standard therapy for post-anoxic coma in certain patients, but for other indications its use still remains controversial. The negative findings of some studies may be partly explained by inadequate protocols for the application of hypothermia and insufficient attention to the prevention of potential side effects. This review deals with some of the concepts underlying hypothermia-associated neuroprotection and cardioprotection, and discusses some potential clinical indications as well as reasons why some clinical trials may have produced conflicting results. Practical aspects such as methods to induce hypothermia, as well as the side effects of cooling are also discussed.

Coronary Artery Disease and Risk Factors in People With Posttraumatic Vision Loss

OBJECTIVE

To examine the prevalence of coronary artery disease (CAD) and its risk factors in people with posttraumatic vision loss (PTVL).

DESIGN

Cross-sectional, controlled study.

SETTING

The general community.

PARTICIPANTS

Study groups included 82 subjects with PTVL, 49 siblings, 58 blind subjects with retinitis pigmentosa (RP), and the general population in Israel.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Sociodemographic and biomedical data collected by using a structured questionnaire and medical records.

RESULTS

The prevalence of CAD among subjects with PTVL (24%) was 2 to 3 times higher than the control groups ( P <.001). However, the prevalence of the CAD risk factors in these subjects was similar to or lower than those in the control groups. For example, significantly fewer subjects with PTVL were physically inactive (16%) than patients with RP (55%, P <.01). The only variable that was significantly associated with CAD prevalence was the cause of blindness-that is, trauma versus disease; the odds of having CAD after traumatic vision loss was 3.75 times higher than after RP.

CONCLUSIONS

People with PTVL exhibit elevated rates of risk for CAD similar to those of other groups with physical disability. The traumatic injury that caused vision loss might be an important factor underlying that risk.

Chronic trauma in sports as a cause of hypopituitarism

TBI is one of the most important public health problems in the world. Although the relationship between TBI and hypopituitarism has been known for a long time, neuroendocrine changes were investigated in detail recently. The prevalence of neuroendocrine abnormalities in patients with TBI is very high. Gonadotropin and GH deficiencies appear to be the most common defects. Although combative sports are very popular around the world, trauma due to sports is not generally considered as a cause of TBI in most of the epidemiological studies. All the studies regarding TBI in sports published so far in the literature based on neuropshycological or radiological assessment and no neuroendocrine changes were investigated. In a recent study, pituitary functions in amateur boxers have been investigated and it has been reported that boxing is a cause of TBI and isolated GH deficiency is very common among amateur boxers. It seems that acute or chronic head trauma in sports is a possible cause of hypopituitarism. In this review, current data regarding TBI in sports are discussed.

Diabetes Insipidus in the Head-Injured Patient

Diabetes insipidus (DI) is an uncommon but important complication in the head-injured population. A retrospective review of all trauma patients admitted to the intensive care unit (ICU) during a 4-year period who developed DI was undertaken. The incidence of DI was 1.3 per cent in ICU trauma admissions and 2.9 per cent in traumatic head injuries admitted to the ICU. The overall mortality was 69 per cent (18/26). The mean onset time of DI in nonsurvivors (1.5 ± 0.7 days) was shorter compared to survivors (8.9 ± 10.2 days) ( P < 0.001). All patients who died developed DI within the first 3 days of hospitalization. Patients who develop DI early in their course have a higher mortality than those who develop DI later in their hospital course. The development of diabetes insipidus after head injury carries a 69 per cent mortality rate, and if the onset is within the first 3 days after injury, mortality rate rises to 86 per cent.

Neuroendocrine dysfunction in the acute phase of traumatic brain injury

BACKGROUND

Pituitary hormone abnormalities have been reported in up to 50% of survivors of traumatic brain injury (TBI) who were investigated several months or longer following the event. The frequency of pituitary dysfunction in the early post-TBI period is unknown.

AIM

To evaluate the prevalence of anterior and posterior pituitary dysfunction in the early phase following TBI.

SUBJECTS

Fifty consecutive patients admitted to the neurosurgical unit with severe or moderate TBI [initial Glasgow Coma Scale (GCS) score 3-13], and 31 matched healthy control volunteers were studied.

METHODS

The glucagon stimulation test (GST) was performed at a median of 12 days (range 7-20) following TBI. Baseline thyroid function, PRL, IGF-1, gonadotrophins, testosterone or oestradiol, plasma sodium, plasma and urine osmolalities or the standard observed water deprivation test were performed. The control subjects underwent the GST for GH and cortisol responses; other parameters were compared to locally derived reference ranges.

RESULTS

Control data indicated that peak serum GH of > 5 ng/ml and cortisol > 450 nmol/l following glucagon stimulation should be taken as normal. Nine TBI patients (18%) had GH response < 5 ng/ml (12 mU/l). Eight patients (16%) had peak cortisol responses < 450 nmol/l. Compared to controls, basal cortisol values were significantly lower in patients with subnormal cortisol responses to glucagon and significantly higher in patients with normal cortisol responses (P < 0.05). GH and cortisol deficiencies were unrelated to patient age, BMI, initial GCS or IGF-1 values (P > 0.05). Forty patients (80%) had gonadotrophin deficiency, with low sex steroid concentrations, which was unrelated to the presence of hyperprolactinaemia. In males there was a positive correlation between serum testosterone concentration and GCS (r = 0.32, P = 0.04). One patient had TSH deficiency. Hyperprolactinaemia was present in 26 patients (52%) and serum PRL levels correlated negatively with the GCS score (r =-0.36, P = 0.011). Thirteen patients (26%) had cranial diabetes insipidus (DI) and seven (14%) had syndrome of inappropriate ADH secretion.

CONCLUSION

Our data show that post-traumatic neuroendocrine abnormalities occur early and with high frequency, which may have significant implications for recovery and rehabilitation of TBI patients.

Application of therapeutic hypothermia in the intensive care unit. Opportunities and pitfalls of a promising treatment modality--Part 2: Practical aspects and side effects

Induced hypothermia can be used to protect the brain from post-ischemic and traumatic neurological injury. Potential clinical applications and the available evidence are discussed in a separate paper. This review focuses on the practical aspects of cooling and physiological changes induced by hypothermia, as well as the potential side effects that may develop. These side effects can be serious and, if not properly dealt with, may negate some or all of hypothermia's potential benefits. However, many of these side effects can be prevented or modified by high-quality intensive care treatment, which should include careful monitoring of fluid balance, tight control of metabolic aspects such as glucose and electrolyte levels, prevention of infectious complications and various other interventions. The speed and duration of cooling and rate of re-warming are key factors in determining whether hypothermia will be effective; however, the risk of side effects also increases with longer duration. Realizing hypothermia's full therapeutic potential will therefore require meticulous attention to the prevention and/or early treatment of side effects, as well as a basic knowledge and understanding of the underlying physiological and pathophysiological mechanisms. These and other, related issues are dealt with in this review.

Systemic complications of neurologic diseases

The systemic complications associated with neurologic disease constitute an extensive topic, because the central nervous system controls many of the functions of the other organ systems in the body and because the brain cannot live in isolation of these systems. The precise mechanisms of many of these systemic alterations are poorly understood, but they appear to depend on the location and the severity of the initial central nervous system pathologic lesion.

Hypophosphatemia and hypomagnesemia induced by cooling in patients with severe head injury

OBJECT

Induced hypothermia in patients with severe head injury may prevent additional brain injury and improve outcome. However, this treatment is associated with severe side effects, including life-threatening cardiac tachyarrhythmias. The authors hypothesized that these arrhythmias might be caused by electrolyte disorders and therefore studied the effects of induced hypothermia on urine production and electrolyte levels in patients with severe head injury.

METHODS

Urine production, urine electrolyte excretion, and plasma levels of Mg, phosphate, K, Ca, and Na were measured in 41 patients with severe head injury. Twenty-one patients (Group I, study group) were treated using induced hypothermia and pentobarbital administration, and 20 patients (Group 2, controls) were treated with pentobarbital administration alone. In Group 1, Mg levels decreased from 0.98+/-0.15 to 0.58+/-0.13 mmol/L (mean +/- standard deviation; p < 0.01), phosphate levels from 1.09+/-0.19 to 0.51+/-0.18 mmol/L (p < 0.01), Ca levels from 2.13+/-0.25 to 1.94+/-0.14 mmol/L (p < 0.01), and K levels from 4.2+/-0.59 to 3.6+/-0.7 mmol/L (p < 0.01) during the first 6 hours of cooling. Electrolyte levels in the control Group 2 remained unchanged. Electrolyte depletion in Group I occurred despite the fact that moderate and, in some cases, substantial doses of electrolyte supplementation were given to many patients, and supplementation doses were often increased during the cooling period. Average urine production increased during the cooling period, from 219+/-70 to 485+/-209 ml/hour. When the targeted core temperature of 32 micro C was reached, urine production returned to levels that approximated precooling levels (241+/-102 ml/hour). Electrolyte levels rose in response to high-dose supplementation. In the control group, urine production and electrolyte excretion remained unchanged throughout the study period.

CONCLUSIONS

Induced hypothermia is associated with severe electrolyte depletion, which is at least partly due to increased urinary excretion through hypothermia-induced polyuria. This may be the mechanism through which induced hypothermia can lead to arrhythmias. When using this promising new treatment in patients with severe head injury, stroke, or postanoxic coma following cardiopulmonary resuscitation, prophylactic electrolyte supplementation should be considered and electrolyte levels should be monitored frequently.

General pediatric emergencies. Acute pulmonary edema

This article focuses on three types of acute pulmonary edema in children: negative-pressure pulmonary edema, neurogenic pulmonary edema, and cardiogenic pulmonary edema.

Hypopituitarism following closed head injury

We describe four young patients (age 19-34 years) with hypopituitarism following closed head injury. The diagnosis was made by demonstration of low basal pituitary hormone levels and dynamic tests showing low pituitary reserve. The time interval between the injury and diagnosis of hypopituitarism was between three weeks and two months demonstrating the difficulty and complexity of making this diagnosis. Three of our patients (all patients suffering from anterior pituitary hormone deficiency) had ACTH deficiency, a condition which may be life threatening if left undiagnosed; these patients also demonstrated central hypothyroidism. Hypogonadotrophic hypogonadism occurred in three of the patients and was treated with hormonal replacement. Diabetes insipidus was the only insult in one of our patients, accompanied other hormonal deficits in two, and did not appear at all in another patient. Information about skull damage was available for three of the patients, and included skull base and facial bone fractures, probably reflecting the extent of injury necessary to cause hypopituitarism. All patients regained normal lives with adequate hormonal replacement therapy.

The early assessment and intensive care unit management of patients with severe traumatic brain and spinal cord injuries

The assessment and management of neurotrauma have progressed significantly over the past several years. Improved understanding of the physiology of injured neural tissue and advances in technology have refined the approach to the care of patients suffering neurologic injury. Evidence-based clinical management guidelines, such as those developed by the Brain Trauma Foundation and the American Association of Neurological Surgeons, for the management of traumatic brain injury have been introduced to standardize certain aspects of care. The ongoing evolution of critical care also has had a significant impact on the care of patients suffering from neurotrauma. This article reviews some current issues related to the diagnosis and management of traumatic brain injury and spinal cord injury as we head into the next millennium.

Assessment of endocrine functions in children following severe head trauma

The goal of the present study was to assess endocrine functions in children following severe head trauma. Subjects included 21 children between the ages of 3 years and 18 years 6 months, referred to the Pediatric Rehabilitation Unit at Sheba Medical Center, Israel, between 1984 and 1995. Each was examined 4 months to 11 years following the first admission, undergoing a complete physical examination, including neurologic assessment, biochemical and baseline endocrine profiles, and bone age determination. A GnRH stimulation test was performed in prepubescent children who had advanced bone age. Sixteen children had experienced the head trauma before, or at onset of puberty, according to their chronologic ages. Two children had completed puberty before the head trauma. A 12-year-old male who sustained head trauma at 10 years 6 months of age was found to have Tanner grade 3 pubertal stage and advanced bone age. In addition, 3 prepubescent children also had advanced bone age with no other signs of precocious puberty and a normal GnRH test. For all children studied, the biochemical and hormonal laboratory measurements were in the normal range. Endocrine abnormalities were not found in children examined 4 months or more following severe head trauma. We conclude that clinical monitoring of endocrine status after severe head trauma is sufficient; specific hormonal measurements are not required unless warranted by abnormal physical signs.

Changes of sympatho-adrenal and hypothalamo-pituitary-adrenocortical system in patients with head injury

To determine the role of the sympatho-adrenal (SAS) and hypothalamo-pituitary-adrenocortical system (HPAS) after head injury, the relationship between venous blood epinephrine (E), norepinephrine (NE), adrenocorticotropic hormone (ACTH), cortisol levels, and clinical condition was examined in 55 patients. These observations suggest that head injury causes mainly activation of the above-mentioned systems depending on the severity of trauma. An inverse correlation between the levels of E, NE and Glasgow Coma Scale score, indicating the severity of head injury was revealed. ACTH and cortisol were similarly related to the clinical condition, although the observed correlation was less expressed. The changes in hormonal levels were present during the whole research period (1 week), although a certain shift to normalization was observed. However, catecholamines and ACTH levels in plasma were relatively low in severely head-injured patients whose CT scans revealed serious alterations in the mesencephalic-diencephalic area. At the same time their cortisol levels obtained maximal values and their chance to survive was diminutive. The results of this study indicate that investigation of hormones of SAS and HPAS might be useful as an additional method in the complex of ordinary examinations in establishing early prognosis in patients with brain injury.

Psychogenic polydipsia after traumatic brain injury. A case report

Electrolyte abnormalities are common medical complications of traumatic brain injury (TBI). Hyponatremia is the most common of these disorders. The syndrome of inappropriate antidiuretic hormone and cerebral salt-wasting are the most well known causes of hyponatremia following TBI. In the presence of polydipsia and polyuria, psychogenic polydipsia should be included in the differential diagnosis. It is important to distinguish among these entities because treatment differs to such an extent that improper diagnosis may lead to a worsening of the patient's condition. We present a patient who presented with a new onset of polyuria and polydipsia after sustaining a TBI. Evaluation, including monitoring of fluid intake and output, serum and urine sodium and osmolarity, as well as a fluid deprivation test revealed the cause to be psychogenic polydipsia. The patient's symptoms improved after institution of a behavioral program and fluid restriction. Various models of drinking behavior have been used to identify the site of dysregulation. Dopaminergic, cholinergic, and hippocampal etiologies have been implicated in this abnormality of fluid homeostasis. If disorders of these systems can lead to psychogenic polydipsia, it is reasonable to believe that a person who has sustained a TBI would be at higher risk of developing psychogenic polydipsia.

Head trauma

No definitive, clinically proven drug therapy currently exists for reversal or amelioration of the injurious cellular events initiated by head trauma. The patient's physiologic status should therefore be monitored and managed as best as possible bearing in mind all the factors that can aggravate intracranial abnormalities. All treatment options have positive and negative aspects that should be considered and balanced on an individual patient basis. A major concern in the management of head-injured patients is the avoidance or treatment of intracranial hypertension. This may be achieved largely through medical means and accurate efforts can only be made if intracranial pressure and the variables that influence it are monitored directly. A definite place exists for surgery in the management of head-injured patients, though such a decision is best guided by objective evaluation of the intracranial vault.

Posterior pituitary hematoma in a case of posttraumatic diabetes insipidus. Case report

A 28-year-old man presented with diabetes insipidus (DI) 10 days after basilar skull fracture without brain injury. Magnetic resonance (MR) imaging revealed a hematoma in the posterior lobe of the pituitary gland but no lesions in the hypothalamus or pituitary stalk. The patient's DI continued for 2 months at which time transsphenoidal surgery was performed to decompress the cystic hematoma with persistent mass effect. The DI attenuated shortly after the surgery and the patient became completely free from DI 5 months later. Although hemorrhage into the posterior lobe is one of the frequent pathological changes in fatal head-injury victims and secondary DI in these cases has usually been thought to be acute and transient, the true incidence and natural course of the posterior pituitary hemorrhage and subsequent DI in nonfatal head-injury patients are totally unknown. In this article, the authors present the first demonstration on MR imaging of a posterior pituitary hematoma in a patient with head injury. The authors propose that serial MR imaging is an important diagnostic tool in patients with posttraumatic DI because some of them may harbor pituitary hematoma and because decompression surgery may prevent transition to permanent DI, especially in cases when the mass effect is persistent due to a cystic change in the hematoma.

Effects of hypotensive treatment with alpha 2-agonist and beta 1-antagonist on cerebral haemodynamics in severely head injured patients

Therapy of post-traumatic brain oedema often includes preservation of high arterial blood pressure to avoid secondary ischaemic injuries to the brain. This practice can be questioned since high arterial blood pressure may aggravate brain oedema through raised hydrostatic capillary pressure, causing fluid filtration across the damaged blood-brain barrier. This latter view is in agreement with our clinical experience and therefore hypotensive therapy with an alpha 2-adrenergic agonist (clonidine) and a beta 1-adrenergic antagonist (metoprolol) has become part of our treatment protocol for severely head injured patients to decrease the post-traumatic brain oedema. The present study is an attempt to analyse whether there are any direct local cerebrovascular effects of the hypotensive agents used, which also might influence intracranial pressure. Severely head injured patients were investigated. Heart rate, mean arterial blood pressure, intracranial pressure, cerebral blood flow and arteriovenous difference in oxygen content were measured before and after a bolus dose of clonidine (six patients) and metoprolol (nine patients). Clonidine decreased mean arterial blood pressure and cerebrovascular resistance without affecting other parameters measured. Metoprolol decreased heart rate and mean arterial pressure, but had no effect on the cerebrovascular parameters. The results show that clonidine and metoprolol have no, or only minor, direct influence on local cerebral haemodynamics in severely brain injured patients. This implies that if there is an intracranial pressure reducing effect of these drugs, as suggested, this must be due to other mechanisms, namely a reduction in capillary hydrostatic pressure secondary to decreased arterial blood pressure and heart rate.

Thalamic neuron theory: theoretical basis for the role played by the central nervous system (CNS) in the causes and cures of all diseases

The Thalamic Neuron Theory (TNT) postulates that the central nervous system (CNS) is involved in all disease processes, as the CNS not only processes incoming physical and chemical information from the periphery, it also sends out physiological commands to the periphery in order to maintain homeostasis for the entire body. Inherent in its capacity to learn and adapt (i.e. to habituate) is the CNS' ability to learn to be sick (pathological habituation) by looking in certain deranged central neural circuitries, leading to chronic disease states. These pathologically habituated states can be reversed by dehabituation through manipulation or modulation of the abnormal neural circuits by physical means (physical neuromodulation) like acupuncture, or chemical means (chemoneuromodulation) such as Chinese medicine, homeopathy or other modern medical techniques in a repetitious manner to mimic the habituation process. Chemoneuromodulation can also be achieved by delivery of minute amounts of pharmacological agents to specific sites in the periphery such as the acupuncture loci. It is hypothesized that humoral and neurotrophic factors and cytokines could be highly effective neuromodulating agents. TNT assumes the blue print for embryological development is embodied in the phylogenetically ancient part of the brain. This primordial master plan, organized in the form of a homunculus, possibly encased in a small nucleus, retains control over the subsequently evolved parts of the brain so that the entire CNS functions like a composite homunculus which controls the physiological functions of the entire body. TNT further postulates that the master homunculus takes the shape of a curled up embryo with its large head buried close to its pelvic region, with its large feet and hands crossed over to the contralateral sides. Neuronal clusters along a neuronal chain in the homunculus represent acupuncture points in the periphery. The neuronal chain itself represents a meridian and Chi is nothing more than the phenomenon of neurotransmissions. Certain new theoretical concepts such as the principles of Adynamic Stat and Bilaterality are also presented. Many difficult to explain clinical observations in modern medicine, Chinese herbal medicine, acupuncture and homeopathy can now be adequately explained using TNT. Based on this model, new therapeutic techniques can be launched to combat a whole host of intractable diseases.