Hyponatremic emergencies

Seizures and epilepsy associated with central nervous system tuberculosis

Central nervous system (CNS) tuberculosis is a life-threatening condition that usually presents with seizures, particularly in children and HIV-infected patients. Tuberculous meningitis (TBM) and tuberculomas are the two forms of CNS tuberculosis that can present with seizures. Seizures usually resolve after successful treatment of the underlying infection. However, the success of the treatment is usually based on an early diagnosis. Delay in the treatment of CNS tuberculosis increases the risk of its associated complications, such as stroke. This would lead to the development of epilepsy. Early seizures may be related to meningeal irritation and cerebral edema, whereas late seizures are often associated with structural brain lesions that generally require more advanced and prolonged treatment. Risk factors associated with the development of epilepsy include young age, refractory seizures, tuberculoma, cortical involvement, epileptiform discharges, and residual lesions. Treatment of CNS tuberculosis is based on early initiation of appropriate anti-tuberculous drugs, antiseizure medications, and correction of associated predisposing factors. Finally, further research into the mechanisms of seizures and the development of epilepsy in CNS tuberculosis could help improve management of these conditions.

Mechanism, spectrum, consequences and management of hyponatremia in tuberculous meningitis

Hyponatremia is the commonest electrolyte abnormality in hospitalized patients and is associated with poor outcome. Hyponatremia is categorized on the basis of serum sodium into severe (< 120 mEq/L), moderate (120-129 mEq/L) and mild (130-134mEq/L) groups. Serum sodium has an important role in maintaining serum osmolality, which is maintained by the action of antidiuretic hormone (ADH) secreted from the posterior pituitary, and natriuretic peptides such as atrial natriuretic peptide and brain natriuretic peptide. These peptides act on kidney tubules via the renin angiotensin aldosterone system. Hyponatremia <120mEq/L or a rapid decline in serum sodium can result in neurological manifestations, ranging from confusion to coma and seizure. Cerebral salt wasting (CSW) and syndrome of inappropriate secretion of ADH (SIADH) are important causes of hyponatremia in tuberculosis meningitis (TBM). CSW is more common than SIADH. The differentiation between CSW and SIADH is important because treatment of one may be detrimental for the other; evidence of hypovolemia in CSW and euvolemia or hypervolemia in SIADH is used for differentiation. In addition, evidence of dehydration, polyuria, negative fluid balance as assessed by intake output chart, weight loss, laboratory evidence and sometimes central venous pressure are helpful in the diagnosis of these disorders. Volume contraction in CSW may be more protracted than hyponatremia and may contribute to border zone infarctions in TBM. Hyponatremia should be promptly and carefully treated by saline and oral salt, while 3% saline should be used in severe hyponatremia with coma and seizure. In refractory patients with hyponatremia, fludrocortisone helps in early normalization of serum sodium without affecting polyuria or functional outcome. In SIADH, V2 receptor antagonist conivaptan or tolvaptan may be used if the patient is not responding to fluid restriction. Fluid restriction in SIADH has not been found to be beneficial in TBM and should be avoided.

Mechanism, spectrum, consequences and management of hyponatremia in tuberculous meningitis

Hyponatremia is the commonest electrolyte abnormality in hospitalized patients and is associated with poor outcome. Hyponatremia is categorized on the basis of serum sodium into severe (< 120 mEq/L), moderate (120-129 mEq/L) and mild (130-134mEq/L) groups. Serum sodium has an important role in maintaining serum osmolality, which is maintained by the action of antidiuretic hormone (ADH) secreted from the posterior pituitary, and natriuretic peptides such as atrial natriuretic peptide and brain natriuretic peptide. These peptides act on kidney tubules via the renin angiotensin aldosterone system. Hyponatremia <120mEq/L or a rapid decline in serum sodium can result in neurological manifestations, ranging from confusion to coma and seizure. Cerebral salt wasting (CSW) and syndrome of inappropriate secretion of ADH (SIADH) are important causes of hyponatremia in tuberculosis meningitis (TBM). CSW is more common than SIADH. The differentiation between CSW and SIADH is important because treatment of one may be detrimental for the other; evidence of hypovolemia in CSW and euvolemia or hypervolemia in SIADH is used for differentiation. In addition, evidence of dehydration, polyuria, negative fluid balance as assessed by intake output chart, weight loss, laboratory evidence and sometimes central venous pressure are helpful in the diagnosis of these disorders. Volume contraction in CSW may be more protracted than hyponatremia and may contribute to border zone infarctions in TBM. Hyponatremia should be promptly and carefully treated by saline and oral salt, while 3% saline should be used in severe hyponatremia with coma and seizure. In refractory patients with hyponatremia, fludrocortisone helps in early normalization of serum sodium without affecting polyuria or functional outcome. In SIADH, V2 receptor antagonist conivaptan or tolvaptan may be used if the patient is not responding to fluid restriction. Fluid restriction in SIADH has not been found to be beneficial in TBM and should be avoided.

Clinical Profile of Patients Admitted with Hyponatremia in the Medical Intensive Care Unit

Background and Aims

Hyponatremia is the predominant electrolyte abnormality with an incidence rate of approximately 22%. It is the leading cause of morbidity and mortality with scarce data in Indian intensive care settings. The aim of this study is to evaluate the clinical features and etiology of hyponatremia in patients admitted to an Intensive Care Unit (ICU) of a tertiary care hospital.

Materials and Methods

A 1-year prospective cross-sectional observational study was conducted, including 100 adult patients with moderate-to-severe hyponatremia admitted to the Medical ICU. Patients underwent investigations such as serum creatinine, blood urea nitrogen, serum osmolality, serum sodium, urine sodium, and urine osmolality, sputum culture, cerebrospinal fluid analysis, and neuroimaging. Data were analyzed using independent sample t-test, Chi-square test, and Fisher's exact test.

Results

Vomiting (28) followed by confusion (26) was the most common complaint. Syndrome of inappropriate antidiuretic hormone secretion (SIADH) (46) was the most common etiology for hyponatremia, and euvolemic hypoosmolar hyponatremia (50) was the most common type of hyponatremia. Confusion was significantly high in patients with severe hyponatremia as compared to patients with moderate hyponatremia (22 vs. 4, P < 0.001). In majority of the patients (46), SIADH was the main cause of euvolemic type of hyponatremia (P < 0.001). Increased urine sodium levels were observed in patients with SIADH (46), renal dysfunction (12), and drug-induced etiology (8, P < 0.001).

Conclusion

Patients with hyponatremia secondary to an infectious cause should be meticulously screened for tuberculosis. The timely and effective treatment of hyponatremia is determined by the effective understanding of pathophysiology and associated risk factors of hyponatremia.

Special medical conditions associated with catatonia in the internal medicine setting: hyponatremia-inducing psychosis and subsequent catatonia

Diagnosis and treatment of catatonia in the psychiatry consultation service is not infrequent. Usually, the patient either presents to the Emergency Department or develops catatonia on the medical floor. This condition manifests with significant behavioral changes (from mildly decreased speech output to complete mutism) that interfere with the ability to communicate. After structural brain disorders are excluded, one of the diagnoses that always should be considered is catatonia. However, the causes of catatonia are numerous, ranging from psychiatric causes to a plethora of medical illnesses. Therefore, it is not surprising that there are many proposed underlying mechanisms of catatonia and that controversy persists about the etiology of specific cases.There are only 6 reports of hyponatremia-induced catatonia and psychosis in the literature. Here, we present the case of a 30-year-old woman with catatonia and psychosis induced by hyponatremia, and we use this report to exemplify the multitude of biologic causes of catatonia and to propose a new way to look at the neuroanatomical basis of processing, particularly the vertical processing systems we believe are involved in catatonia.

Prevalence of hyponatremia in intensive care unit patients with brain injury in kashan shahid-beheshti hospital in 2012

Background

Hyponatremia is a common disorder in patients with brain injury. It can result in acute and chronic complications providing this electrolytic disorder is not diagnosed and treated in due time.

Objectives

The aim of this study was to evaluate the prevalence of hyponatremia in 95 brain injury patients hospitalized in the intensive care unit (ICU) in Kashan Shahid-Veheshti hospital.

Patients and Methods

This trans-sectional study was conducted on brain injury patients (brain traumas, brain hemorrhage, meningitis and brain tumors) during their six-month stay in the ICU in Kashan Shahid-Beheshti hospital. Data were analyzed after excluding cases of pseudohyponatremia.

Results

Ninety-five patients with brain injury (69.5% male and 30.5% female ( had a mean age of 42.85 ± 22.59 years, while the hyponatremic patients had a mean age of 48.37 ± 24.03 years. Prevalence and occurrence of hyponatremia were 31.6% and 9.29 ± 6.8 days, respectively. This study revealed no meaningful differences between age, sex, underlying disease and the prevalence of hyponatremia.

Conclusions

Our study showed an elevated frequency of hyponatremia in patients with brain injuries in ICU which demands the effective approaches for an accurate and timely diagnosis of this electrolyte disorder.

Neurologic complications of electrolyte disturbances and acid-base balance

Electrolyte and acid-base disturbances are common occurrences in daily clinical practice. Although these abnormalities can be readily ascertained from routine laboratory findings, only specific clinical correlates may attest as to their significance. Among a wide phenotypic spectrum, acute electrolyte and acid-base disturbances may affect the peripheral nervous system as arreflexic weakness (hypermagnesemia, hyperkalemia, and hypophosphatemia), the central nervous system as epileptic encephalopathies (hypomagnesemia, dysnatremias, and hypocalcemia), or both as a mixture of encephalopathy and weakness or paresthesias (hypocalcemia, alkalosis). Disabling complications may develop not only when these derangements are overlooked and left untreated (e.g., visual loss from intracranial hypertension in respiratory or metabolic acidosis; quadriplegia with respiratory insufficiency in hypermagnesemia) but also when they are inappropriately managed (e.g., central pontine myelinolisis when rapidly correcting hyponatremia; cardiac arrhythmias when aggressively correcting hypo- or hyperkalemia). Therefore prompt identification of the specific neurometabolic syndromes is critical to correct the causative electrolyte or acid-base disturbances and prevent permanent central or peripheral nervous system injury. This chapter reviews the pathophysiology, clinical investigations, clinical phenotypes, and current management strategies in disorders resulting from alterations in the plasma concentration of sodium, potassium, calcium, magnesium, and phosphorus as well as from acidemia and alkalemia.

Neurologic presentations of acid-base imbalance, electrolyte abnormalities, and endocrine emergencies

Accurate identification of nervous system dysfunction is vital in the assessment of any multisystem disorder. The neurologic manifestations of acid-base disturbances, abnormal electrolyte concentrations, and acute endocrinopathies are protean and typically determined by the acuity of the underlying derangement. Detailed history and physical examination may guide appropriate laboratory testing and lead to prompt and accurate diagnosis. Neurologic manifestations of primary and secondary systemic disorders are frequently encountered in all subspecialties of medicine. This article focuses on key neurologic presentations of respiratory and metabolic acid-base derangements and potentially life-threatening endocrinopathies.

Vasopressin-receptor antagonist therapy in patients with hyponatraemia

Hyponatraemia often complicates the treatment of underlying conditions in patients who are seriously ill. Arginine vasopressin receptor antagonists block the action of arginine vasopressin and correct sodium and water imbalance in patients with euvolaemic or hypervolaemic hyponatraemia.

Evaluation and management of hyponatremia: an emerging role for vasopressin receptor antagonists

Vasopressin-2 receptor antagonists, collectively known as the 'vaptans', provide a new approach to the treatment of hyponatremia; therefore, an updated Review of the pathophysiology of hyponatremia is particularly timely. After briefly defining hyponatremia and introducing its clinical aspects and complications, we present an approach to the diagnosis and evaluation of hyponatremia that is based primarily on the often-underused concept of free water clearance and, more specifically, the electrolyte-free water clearance. Then we review the use of vasopressin receptor antagonists in the management of hyponatremia from the standpoint of their pharmacology, their mechanism of action, and available efficacy data from clinical trials.

Hyponatremia in the neurosurgical patient: epidemiology, pathophysiology, diagnosis, and management

OBJECTIVE

Hyponatremia is an important and common electrolyte disorder in critically ill neurosurgical patients that has been reported in association with a number of different primary diagnoses. The correct diagnosis of the pathophysiological cause is vital because it dramatically alters the treatment approach.

METHODS

We review the epidemiology and presentation of patients with hyponatremia, the pathophysiology of the disorder with respect to sodium and fluid balance, and the diagnostic procedures for determining the correct cause.

RESULTS

We then present the various treatment options, including discussion of one of the newest groups of agents, the arginine vasopressin receptor antagonists, currently under study for the treatment of hyponatremia in neurosurgical patients.

CONCLUSION

Hyponatremia is a serious comorbidity in neurosurgical patients that requires particular attention as its treatment varies by cause and its consequences can affect neurological outcome.

Hyponatremia in neurologic patients: consequences and approaches to treatment

BACKGROUND

Hyponatremia is a common fluid-electrolyte disturbance, particularly in patients with neurologic disorders, in part because of the major role the central nervous system (CNS) plays in the regulation of sodium and water homeostasis.

REVIEW SUMMARY

The classification of hyponatremia is based on an assessment of serum sodium concentration ([Na+]), serum and urine osmolality, and body volume status. In most cases, hyponatremia is associated with hypotonicity, which causes water to move into the brain. Adaptive responses limit the impact of cerebral edema in chronic hyponatremia, but CNS symptoms and death may occur in response to rapid or large decreases in serum [Na+]. The prompt correction of serum [Na+] is mandatory in symptomatic patients, but overly rapid correction must be avoided to limit the risk of myelinolysis. In neurologic disorders, euvolemic hyponatremia (usually caused by the syndrome of inappropriate secretion of antidiuretic hormone) must be distinguished from hypovolemic states such as cerebral salt wasting because the treatment of the 2 conditions differs. Vasopressin antagonists represent a new approach to the treatment of euvolemic and hypervolemic hyponatremia secondary to arginine vasopressin dysregulation.

CONCLUSION

The optimal treatment of hyponatremia is controversial, but appropriate treatment must be determined according to the osmolality and volume status of the patient. If left untreated, serious CNS complications and adverse outcomes, including an increased risk of death, can occur.

Hyponatremia in critically ill neurological patients

BACKGROUND

Hyponatremia is the most common and important electrolyte disorder encountered in the neurologic intensive care unit (NICU). Advances in our knowledge of the pathophysiological mechanisms at play in patients with acute neurologic disease have improved our understanding of this derangement.

REVIEW SUMMARY

Evaluation of hyponatremia requires a structured approach beginning with the measurement of serum and urine osmolalities. Most cases of hyponatremia in the NICU are associated with serum hypotonicity. Iatrogenic causes, most conspicuously inadequate tonicity of intravenous fluids, should be promptly identified and removed when possible. Two main mechanisms are responsible for most non-iatrogenic cases of hyponatremia in patients with neurologic or neurosurgical disease: inappropriate secretion of antidiuretic hormone (SIADH) and cerebral salt wasting syndrome (CSW). Distinction between these two syndromes may be difficult and must be based on an accurate assessment of the patient's volume status. SIADH is associated with normal or slightly expanded volume status and should be treated with fluid restriction. Patients with CSW are hypovolemic and require adequate fluid and sodium replacement. Correction of hyponatremia should not exceed 8 to 10 mmol/L over any 24-hour period to avoid the risk of osmotic demyelination.

CONCLUSIONS

Hyponatremia may complicate the clinical course of many acute neurologic and neurosurgical disorders. It is most often iatrogenic causes, CSW, or SIADH. Physicians working with critically ill neurologic patients should be familiar with management strategies addressing these underlying pathophysiological mechanisms.

Heat cramps: fluid and electrolyte challenges during tennis in the heat

Sweat losses during tennis can be considerable. And while most players make a genuine effort to stay well hydrated to maintain performance and reduce the risk of heat illness, regular and copious water intake is often not enough. Besides an extraordinary water loss, extensive sweating can lead to a concomitant large electrolyte deficit too--particularly for sodium. Although a variety of other mineral deficiencies and physiological conditions are purported to cause muscle cramps, evidence suggests that, when a tennis player cramps in warm to hot weather, extensive and repeated sweating during the current and previous matches and a consequent sodium deficit are usually the primary contributing factors. Heat cramps often begin as subtle "twitches" or fasciculations in one or more voluntary muscles and, unless treated, can rapidly progress to widespread debilitating muscle spasms that leave an afflicted player on the court writhing in pain. If sufficient preventive measures are taken well before and during play, such cramping is avoidable in most cases. Appropriate and sufficient salt and fluid intake will enhance rehydration and fluid distribution throughout a player's body, so that heat cramps can be completely averted, even during long matches in the most challenging environments.

Syndrome of inappropriate antidiuretic hormone-induced hyponatremia associated with amiodarone

The syndrome of inappropriate antidiuretic hormone (SIADH), the most common cause of euvolemic hyponatremia, is due to nonphysiologic release of arginine vasopressin from the posterior pituitary. Hyponatremia induced by SIADH can be caused by several conditions, such as central nervous system disorders, malignancies, various nonmalignant lung diseases, hypoadrenalism, and hypothyroidism. A 67-year-old man developed hyponatremia consistent with SIADH. Although common comorbid conditions associated with SIADH were excluded as possible causes, his medical history and drug regimen were extensive. However, he had been taking spironolactone, amiodarone, and simvastatin for less than 3 months. Amiodarone was discontinued based on a case report suggesting that this drug can cause SIADH-induced hyponatremia. The patient's serum sodium level began to rise within 3 days of discontinuation and returned to normal within 1 month. Although SIADH-induced hyponatremia occurs only rarely, it should be recognized as a possible adverse effect of amiodarone.

Response to a fluid load in athletes with a history of exercise induced hyponatremia

PURPOSE

To determine whether athletes who had previously developed hyponatremia during an ultradistance triathlon show an impaired ability to excrete a large fluid load compared with athletes who had completed the same race without developing hyponatremia.

METHODS

Six athletes who had developed hyponatremia ([Na] < 135 mmol x L(-1)) in the 1997 Ironman Triathlon (study cases) were compared with six athletes who completed the same race without hyponatremia (controls). All participants consumed 3.4 L of water over 2 h at rest. Weight, urine output, urine electrolytes, serum [Na(+)], hemoglobin, and hematocrit were measured every 30 min. Changes in plasma volume and residual fluid volume in the gut were estimated from these data.

RESULTS

There were no significant differences between cases and controls in any parameters measured. Maximal rates of urine production (+/- SD) (1043 +/- 331 mL x h(-1) for cases, 878 +/- 168 mL x h(-1) for controls) were substantially behind the rate of fluid intake (1500 mL x h(-1)). Consequent to fluid retention, serum [Na(+)] fell progressively in both groups. Five cases and four controls developed hyponatremia. There was an inverse correlation between change in body weight and change in [Na(+)] (r = -0.67). Estimated changes in the intra- and extra-cellular fluid volumes could account for all the retained fluid, and there was little evidence for fluid accumulation in the bowel.

CONCLUSION

When evaluated at rest, there does not appear to be any unique pathophysiological characteristic that explains why some athletes develop hyponatremia in response to fluid overload during prolonged exercise. Rather, hyponatremia was induced with equal effect in both cases and controls, consequent to progressive fluid overload of all the body fluid compartments and without evidence for fluid retention in the small bowel.

Hyponatremia and hypernatremia. A systematic approach to causes and their correction

Disorders of sodium and water metabolism can be approached by following a few basic steps: Thorough history taking and physical examination that focuses on volume assessment and laboratory evaluation that includes serum osmolality, urine osmolality, and urine sodium concentration are usually all that are required for diagnosis. Results of these findings are helpful in guiding therapy. Monitoring serum sodium concentration often to ensure adequate treatment and to avoid potential complications is required in management of both hyponatremia and hypernatremia.

Hyponatremia and seizures in an ultradistance triathlete

Hyponatremia is being increasingly recognized as a complication of participation in ultra-endurance sports. Reported is the case of an Ironman triathlete who collapsed at the end of the race, having gained 5% in body weight. His serum sodium concentration at the finish was 116 mmol/L. After an Intensive Care Unit course complicated by recurrent seizures, he eventually made a complete neurologic recovery. The pathogenesis of hyponatremia and its management in such cases is discussed.

Endocrinologic and metabolic complications in the intensive care unit

Critical illness provides major stresses on all body systems, including those serving important regulatory functions. Endocrinologic and metabolic abnormalities are common on presentation and during hospitalization in the intensive care unit. Some of these abnormalities are the focus of this article. The authors review abnormalities of the adrenal and thyroid glands and in the metabolism of glucose, and include a brief review of abnormalities of sodium and calcium metabolism.

Rectus abdominis rhabdomyolysis after sit ups: unexpected detection by bone scan

Uptake of technetium-99m methylene diphosphonate by the rectus abdominis muscle was unexpectedly found in a 29 year old man who had started to perform 30 to 40 sit ups a day for five days before the bone scan. After a week of rest, serum creatine kinase activity was still abnormal but muscle uptake of technetium-99m methylene diphosphonate had ceased. This specific muscle injury after short term sit ups as well as the resolution of the phenomenon within a week are of interest.

Iatrogenic acute hyponatraemia in a college athlete

Hyponatraemia is one of the most common electrolyte abnormalities, leading to significant morbidity and mortality. In the most basic sense, hyponatraemia can be due to sodium loss or fluid excess. The extracellular fluid status is used to clinically divide hyponatraemia into three categories to help to determine both the cause and treatment required. Hyponatraemic patients can be categorised on the basis of their fluid status as hypovolaemic, euvolaemic, or hypervolaemic. Another distinction to make in evaluating hyponatraemia is whether the onset was acute or chronic in nature. The case presented here is iatrogenic acute hypervolaemic hyponatraemia in a college athlete. The patient presented in respiratory distress with an altered mental status after the administration of hypotonic fluids for treatment of muscle cramps. Treatment included intubation, water restriction, and furosemide, to which he responded favourably. Hyponatraemia should be in the differential diagnosis for patients presenting after intravenous fluid administration.

Acute hyponatremic encephalopathy after a cerebrovascular accident

A 66-year-old hypertensive male with acute intracerebral hemorrhage developed acute hyponatremic coma 3 days after the addition of enalapril and a combination of amiloride and a thiazide diuretic to his hypotensive regimen. The patient recovered consciousness and serum sodium normalized 2 days after fluid restriction and withdrawal of both medications. Three weeks later, upon inadvertent reinstitution of enalapril and indapamide, severe hyponatremic encephalopathy promptly recurred; recovery was again rapid following fluid restriction and withdrawal of both medications. This temporal relationship establishes the thiazide diuretic or the angiotensin converting enzyme inhibitor or both as the cause of the profound symptomatic hyponatremia in this patient. Results of simultaneous serum and urine osmolality assays on several occasions were consistent with a decrease in free water clearance, a result of either increased antidiuretic hormone (ADH) secretion or potentiation of its peripheral action, and thiazide-induced natriuresis. The use of a thiazide diuretic in the presence of either of these aberrations of ADH homeostasis most likely explains the profound and rapid development of hyponatremia. Drug-induced disturbances in serum osmolality are a potentially reversible cause of deterioration of the mental state in a patient with an acute cerebrovascular accident.

Drug-induced syndrome of inappropriate antidiuretic hormone secretion. Causes, diagnosis and management

Hyponatraemia is common among the elderly, and may be caused by physiological changes, disease processes or drugs. About half of elderly patients with hyponatraemia have features typical of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). It is important to establish whether drugs are the cause, as this is easily remediable. The clinical manifestations of SIADH are predominantly attributable to hyponatraemia and serum hypo-osmolality. The severity of the signs and symptoms depends on the degree of hyponatraemia and the rapidity with which the syndrome develops. Although a growing number of drugs have been reported to produce SIADH, most published reports concern vasopressin and its analogues, thiazide and thiazide-like diuretics, chlorpropamide, carbamazepine, antipsychotics, antidepressants and nonsteroidal anti-inflammatory drugs. Old age is a risk factor for SIADH following the use of many of these drugs. The use of these drugs in combination, excessive fluid intake and other underlying conditions that limit free water excretion increase the risk. Drug-induced SIADH usually resolves following cessation of the offending agent(s). Additional measures are required in patients with symptomatic hyponatraemia, including fluid restriction and intravenous sodium chloride and/or furosemide (frusemide) therapy. Careful monitoring is essential, with particular attention paid to the rate and extent of correction of the hyponatraemia.