Hyponatremia and syndrome of inappropriate antidiuretic hormone secretion in adult spinal surgery

Effect of controlled hypotensive hemorrhage on plasma sodium levels in anesthetized pigs: An exploratory study

Perioperative hyponatremia, due to non-osmotic release of the antidiuretic hormone arginine vasopressin, is a serious electrolyte disorder observed in connection with many types of surgery. Since blood loss during surgery contributes to the pathogenesis of hyponatremia, we explored the effect of bleeding on plasma sodium using a controlled hypotensive hemorrhage pig model. After 30-min baseline period, hemorrhage was induced by aspiration of blood during 30 min at mean arterial pressure <50 mmHg. Thereafter, the animals were resuscitated with retransfused blood and a near-isotonic balanced crystalloid solution and monitored for 180 min. Electrolyte and water balances, cardiovascular response, renal hemodynamics, and markers of volume regulation and osmoregulation were investigated. All pigs (n = 10) developed hyponatremia. All animals retained hypotonic fluid, and none could excrete net-free water. Urinary excretion of aquaporin 2, a surrogate marker of collecting duct responsiveness to antidiuretic hormone, was significantly reduced at the end of the study, whereas lysine vasopressin, i.e., the pig antidiuretic hormone remained high. In this animal model, hyponatremia developed due to net positive fluid balance and generation of electrolyte-free water by the kidneys. A decreased urinary aquaporin 2 excretion may indicate an escape from antidiuresis.

Acute and Chronic Hyponatremia

Hyponatremia is the most common electrolyte disorder in clinical practice. Catastrophic complications can occur from severe acute hyponatremia and from inappropriate management of acute and chronic hyponatremia. It is essential to define the hypotonic state associated with hyponatremia in order to plan therapy. Understanding cerebral defense mechanisms to hyponatremia are key factors to its manifestations and classification and subsequently to its management. Hypotonic hyponatremia is differentiated on the basis of urine osmolality, urine electrolytes and volume status and its treatment is decided based on chronicity and the presence or absence of central nervous (CNS) symptoms. Proper knowledge of sodium and water homeostasis is essential in individualizing therapeutic plans and avoid iatrogenic complications while managing this disorder.

Associations Between Preoperative Hyponatremia and 30-Day Perioperative Complications in Lumbar Interbody Spinal Fusion

STUDY DESIGN

Retrospective population database study.

OBJECTIVE

To investigate the relationship of preoperative hyponatremia to postoperative morbidity and mortality in lumbar interbody fusion patients.

SUMMARY OF BACKGROUND DATA

Optimization of preoperative patient selection and perioperative management can improve patient outcomes in spinal surgery. Hyponatremia, incidentally identified in 1.7% of the US population, has previously been tied to poorer postoperative outcomes in both the general surgery and orthopedic surgery populations.

MATERIALS AND METHODS

Using the National Surgical Quality Improvement Program database, the authors identified all lumbar interbody fusion patients treated between 2012 and 2014. Patients were classified as hyponatremic (Na<135 mEq/L) or as having normal sodium levels (135-145 mEq/L) preoperatively. The primary outcome was major morbidity and secondary endpoints were prolonged hospitalization, 30-day readmission, and reoperation. Multivariable linear regression was used to find independent predictors of these outcomes.

RESULTS

Of 10,654 patients, 45.6% were male individuals, 5.5% were hyponatremic, and 4.2% experienced a major postoperative complication. On multivariable analysis, preoperative hyponatremia was independently associated with major morbidity (odds ratio, 1.22; 95% confidence interval, 1.03-1.44; P<0.05) and prolonged hospitalization (odds ratio, 1.14; 95% confidence interval, 1.02-1.27).

CONCLUSIONS

Here the authors provide the first evidence suggesting preoperative hyponatremia is an independent predictor of major morbidity after lumbar interbody fusion. Hyponatremia may represent a modifiable risk factor for improved patient care and preoperative risk counseling.

Preoperative Hyponatremia and Perioperative Complications in Cervical Spinal Fusion

OBJECTIVE

Preoperative patient optimization is increasingly recognized as key to good surgical outcomes. Preoperative hyponatremia is a modifiable risk factor linked to poorer postoperative outcomes in other surgical fields. We provide the first investigation of the association of preoperative hyponatremia with morbidity and mortality in patients undergoing cervical spine surgery.

METHODS

We queried the National Surgical Quality Improvement Program registry for patients who underwent cervical spine fusion. Preoperative serum sodium levels were classified as normal (135-145 mEq/L) or hyponatremic (<135 mEq/L); hypernatremic patients were excluded from the analysis. Multivariable logistic analyses using a multiple imputations methodology were performed to determine significant predictors of major morbidity and mortality (MMM).

RESULTS

We included 20,817 patients, of whom 5.2% were hyponatremic at presentation. Preoperative hyponatremia was a significant predictor of MMM (odds ratio [OR], 1.23; 95% confidence interval [CI], 1.09-1.39), mortality (OR, 1.36; 95% CI, 1.03-1.77), major morbidity (OR, 1.24; 95% CI, 1.10-1.40), and odds of prolonged hospitalization (OR, 1.13; 95% CI, 1.04-1.23). Other significant predictors of MMM included age, undergoing an emergent versus nonemergent operation, having chronic obstructive pulmonary disease, having disseminated malignancy, being functionally dependent, presenting with sepsis or septic shock, and having an American Society of Anesthesiologists status of 3, 4, or 5. Similar results were seen in analyses using only complete cases and in sensitivity analyses.

CONCLUSIONS

Using the National Surgical Quality Improvement Program database, hyponatremia is observed in approximately 1 in every 20 patients undergoing cervical spine fusion. More importantly, it is a predictor of mortality, major morbidity, and prolonged hospitalization. From a systems-level perspective, preoperative hyponatremia may therefore represent a point of intervention for preoperative patient optimization.

Acute kidney injury following spinal instrumentation surgery in children

AIM

To determine acute kidney in jury (AKI) incidence and potential risk factors of AKI in children undergoing spinal instrumentation surgery.

METHODS

AKI incidence in children undergoing spinal instrumentation surgery at British Columbia Children’s Hospital between January 2006 and December 2008 was determined by the Acute Kidney Injury Networ classification using serum creatinine and urine output criteria. During this specific time period, all patients following spinal surgery were monitored in the pediatric intensive care unit and had an indwelling Foley catheter permitting hourly urine output recording. Cases of AKI were identified from our database. From the remaining cohort, we selected group-matched controls that did not satisfy criteria for AKI. The controls were matched for sex, age and underlying diagnosis (idiopathic vs non-idiopathic scoliosis).

RESULTS

Thirty five of 208 patients met criteria for AKI with an incidence of 17% (95%CI: 12%-23%). Of all children who developed AKI, 17 (49%) developed mild AKI (AKI Stage 1), 17 (49%) developed moderate AKI (Stage 2) and 1 patient (3%) met criteria for severe AKI (Stage 3). An inverse relationship was observed with AKI incidence and the amount of fluids received intra-operatively. An inverse relationship was observed with AKI incidence and the amount of fluids received intra-operatively classified by fluid tertiles: 70% incidence in those that received the least amount of fluids vs 29% that received the most fluids (> 7.9, P = 0.02). Patients who developed AKI were more frequently exposed to nephrotoxins (non steroidal anti inflammatory drugs or aminoglycosides) than control patients during their peri-operative course (60% vs 22%, P < 0.001).

CONCLUSION

We observed a high incidence of AKI following spinal instrumentation surgery in children that is potentially related to the frequent use of nephrotoxins and the amount of fluid administered peri-operatively.

Prevalence, Timing, Causes, and Outcomes of Hyponatremia in Hospitalized Orthopaedic Surgery Patients

BACKGROUND

Hyponatremia is common among orthopaedic patients and is associated with adverse clinical outcomes. We examined the prevalence, timing, causes, and outcomes of hyponatremia in adult hospitalized orthopaedic surgery patients.

METHODS

We evaluated the medical records of 1067 consecutive orthopaedic surgery patients admitted to a tertiary academic institution. The medical records were reviewed to investigate hyponatremia (serum sodium <135 mEq/L) that (1) had been present on hospital admission or (2) had developed postoperatively. The primary outcomes were the prevalence and timing of, and risk factors for, presentation with or development of hyponatremia. Secondary outcomes were hospital length of stay, total hospital cost, and discharge disposition. Multivariable logistic regression models were used to assess the variables associated with hyponatremia and the effects of hyponatremia on clinical outcomes.

RESULTS

Of the 1067 patients, seventy-one (7%) had preoperative hyponatremia and 319 (30%) developed hyponatremia postoperatively. Of the latter, 298 (93%) developed hyponatremia within forty-eight hours postoperatively. Compared with patients with normonatremia, those who presented with hyponatremia, on the average, were older (67.2 versus 60.5 years, p < 0.001), had longer hospital stays (4.6 versus 3.3 days, p < 0.001), incurred higher hospital costs ($19,200 versus $17,000, p = 0.006), and were more likely to be discharged to an extended-care facility (odds ratio [OR] = 2.87, p < 0.001). Developing hyponatremia postoperatively resulted, on average, in a longer hospital stay (3.7 versus 3.3 days, p = 0.002) and greater hospital cost ($18,800 versus $17,000, p < 0.001). Age (OR = 1.13 per decade, p = 0.012), spine surgery (OR = 2.76 versus knee, p < 0.001), hip surgery (OR = 1.76 versus knee, p < 0.001), and the amount of lactated Ringer solution used (OR = 1.16, p = 0.002) increased the risk of developing hyponatremia.

CONCLUSIONS

Hyponatremia in orthopaedic patients is associated with longer, costlier hospitalizations. The factors that significantly increased the risk of developing postoperative hyponatremia were an older age, spine fusion, hip arthroplasty, and the amount of lactated Ringer solution used.

Comparison of perioperative complications following staged versus one-day anterior and posterior cervical decompression and fusion crossing the cervico-thoracic junction

INTRODUCTION

Multilevel cervical pathology may be treated via combined anterior cervical decompression and fusion (ACDF) followed by posterior spinal instrumented fusion (PSIF) crossing the cervico-thoracic junction. The purpose of the study was to compare perioperative complication rates following staged versus same day ACDF combined with PSIF crossing the cervico-thoracic junction.

MATERIAL AND METHODS

A retrospective review of consecutive patients undergoing ACDF followed by PSIF crossing the cervico-thoracic junction at a single institution was performed. Patients underwent either same day (group A) or staged with one week interval surgeries (group B). The minimum follow-up was 12 months.

RESULTS

Thirty-five patients (14 females and 21 males) were analyzed. The average age was 60 years (37-82 years). There were 12 patients in group A and 23 in group B. Twenty-eight complications noted in 14 patients (40%) included: dysphagia in 13 (37%), dysphonia in 6 (17%), post-operative reintubation in 4 (11%), vocal cords paralysis, delirium, superficial incisional infection and cerebrospinal fluid leakage each in one case. Significant differences comparing group A vs. B were found in: the number of levels fused posteriorly (5 vs. 7; p=0.002), total amount of intravenous fluids (3233ml vs. 4683ml; p=0.03), length of hospital stay (10 vs. 18 days; p=0.03) and transfusion of blood products (0 vs. 9 patients). Smoking and cervical myelopathy were the most important risk factors for perioperative complications regardless of the group.

CONCLUSIONS

Staging anterior cervical decompression and fusion with posterior cervical instrumented fusion 1 week apart does not decrease the incidence of perioperative complications.

Masking of syndrome of inappropriate antidiuretic hormone secretion: the isonatremic syndrome

OBJECTIVE

To determine whether the administration of isotonic saline in patients undergoing spinal fusion surgery prevents the development of hyponatremia, thus masking the detection of syndrome of inappropriate antidiuretic hormone secretion (SIADH).

STUDY DESIGN

Prospective observational cohort study conducted in pediatric patients undergoing spinal fusion surgery. Using established criteria for diagnosing SIADH with the exception of serum sodium as a criterion, we separated patients into those with and without masked SIADH. Random cortisol levels were measured in the perioperative period to test for adrenal insufficiency to exclude it as a cause for natriuresis and hyponatremia.

RESULTS

Of the 40 patients included in the study, 13 (32%; 95% CI, 19%-49%) met study criteria for masked SIADH. The serum sodium levels between the 2 groups were not different throughout the postoperative period. The antidiuretic hormone levels were increased at 24-48 hours after surgery (20.4 pg/mL in masked SIADH group vs 6.6 pg/mL in no masked SIADH group, P = .04). Subjects with masked SIADH demonstrated a tendency for weight gain (3.9 kg vs 2.5 kg, P = .058), which was maximal on postoperative day 2. Cortisol levels were similar between the groups.

CONCLUSION

Masked SIADH (SIADH-like state without hyponatremia) commonly occurs in the postoperative period in children and young adults undergoing spinal fusion surgery. Early postoperative evaluation and recognition may result in appropriate management of patient's fluid balance.

Central diabetes insipidus after staged spinal surgery

Diabetes insipidus (DI) is described following penetrating spinal cord trauma but rarely following instrumented spinal fusion. More commonly, hyponatremia is seen following spine surgery, which may be iatrogenic, attributed to the syndrome of inappropriate antidiuretic hormone release. The authors present a case of a 57-year-old woman who underwent a planned two-stage operation for scoliotic deformity correction. On the third postoperative day, the patient developed hypernatremia (sodium levels of 157 mmol/L) and polyuria. In conjunction with endocrinology, the patient was diagnosed with central DI. The patient was treated with desmopressin acetate (DDAVP), which led to resolution of her symptoms. DDAVP was temporary and eventually weaned off. Central DI is a possible cause of hypernatremia following significant spine surgery. Correct diagnosis is paramount for rapid and appropriate treatment.

Syndrome of inappropriate secretion of antidiuretic hormone as a leading cause of hyponatremia in children who underwent chemotherapy or stem cell transplantation

BACKGROUND

Hyponatremia is a common metabolic disorder in cancer patients. However, little information is available for patients receiving chemotherapy or stem cell transplantation (SCT). We analyzed the frequency, characteristics, and various causes of hyponatremia including routine use of hypotonic fluids in children following chemotherapy or SCT.

PROCEDURE

We reviewed the clinical and laboratory data of 63 children who received chemotherapy or SCT at the Department of Pediatrics, Hanyang University Medical Center from July 2005 to July 2008.

RESULTS

All 63 patients at admission received routine parenteral fluids of 0.25% or 0.45% NaCl and 82 episodes of hyponatremia were observed in 40 (63.5%) patients. Of these 82 episodes, 50 episodes of hyponatremia developed in 29 children following chemotherapy and 32 episodes in 16 children following SCT. Seventy-six out of 82 episodes (92.7%) of hyponatremia developed in 37 patients receiving hypotonic fluids with NaCl concentrations between 30 and 150 mEq/L. The frequency of SIADH in the SCT setting was more frequent (14/21, 66.6%) than in the chemotherapy setting (18/58, 31.0%) (P = 0.02), even though the leading cause of hyponatremia was SIADH in both settings.

CONCLUSIONS

SIADH is a leading cause of hyponatremia in children following chemotherapy or SCT, and more frequent in SCT settings than in chemotherapy settings. Furthermore, the routine use of hypotonic fluids which could aggravate the development of hyponatremia for these patients should be avoided and then switched to isotonic fluids.

Hyponatremia in neurosurgical patients: clinical guidelines development

OBJECTIVE

Neurosurgical patients have a high risk of hyponatremia and associated complications. We critically evaluated the existing literature to identify the determinants for the development of hyponatremia and which management strategies provided the best outcomes.

METHODS

A multidisciplinary panel in the areas of neurosurgery, nephrology, critical care medicine, endocrinology, pharmacy, and nursing summarized and classified hyponatremia literature scientific studies published in English from 1950 through 2008. The panel's recommendations were used to create an evaluation and treatment protocol for hyponatremia in neurosurgical patients at the University of Florida.

RESULTS

Hyponatremia should be further investigated and treated when the serum sodium level is less than 131 mmol/L (class II). Evaluation of hyponatremia should include a combination of physical examination findings, basic laboratory studies, and invasive monitoring when available (class III). Obtaining levels of hormones such as antidiuretic hormone and natriuretic peptides is not supported by the literature (class III). Treatment of hyponatremia should be based on severity of symptoms (class III). The serum sodium level should not be corrected by more than 10 mmol/L/d (class III). Cerebral salt wasting should be treated with replacement of serum sodium and intravenous fluids (class III). Fludrocortisone may be considered in the treatment of hyponatremia in subarachnoid hemorrhage patients at risk of vasospasm (class I). Hydrocortisone may be used to prevent natriuresis in subarachnoid hemorrhage patients (class I). Hyponatremia in subarachnoid hemorrhage patients at risk of vasospasm should not be treated with fluid restriction (class II). Syndrome of inappropriate antidiuretic hormone may be treated with urea, diuretics, lithium, demeclocycline, and/or fluid restriction (class III).

CONCLUSION

The summarized literature on the evaluation and treatment of hyponatremia was used to develop practice management recommendations for hyponatremia in the neurosurgical population. However, the practice management recommendations relied heavily on expert opinion because of a paucity of class I evidence literature on hyponatremia.

Hyponatremia: clinical diagnosis and management

Hyponatremia is a common clinical problem in hospitalized patients and nursing home residents. It also may occur in healthy athletes after endurance exercise. The majority of patients with hyponatremia are asymptomatic and do not require immediate correction of hyponatremia. Symptomatic hyponatremia is a medical emergency requiring rapid correction to prevent the worsening of brain edema. How fast we should increase the serum sodium levels depends on the onset of hyponatremia and still remains controversial. If the serum sodium levels are corrected too rapidly, patients may develop central pontine myelinolysis, but if they are corrected too slowly, patients may die of brain herniation. We review the epidemiology and mechanisms of hyponatremia, the sensitivity of women to hyponatremic injury, the adaptation and maladaptation of brain cells to hyponatremia and its correction, and the practical ways of managing hyponatremia. Because the majority of hyponatremia is caused by the non-osmotic release of vasopressin, the recent approval of the vasopressin receptor antagonist conivaptan for euvolemic hyponatremia may simplify hyponatremia management. However, physicians should be aware of the risk of rapid correction of hyponatremia, hypotension, and excessive fluid intake.

Medical complications of surgical treatment of adult spinal deformity and how to avoid them

STUDY DESIGN

Review article of medical complications related to adult spinal deformity surgery.

OBJECTIVE

To identify medical complications related to surgery for adult spinal deformity and suggest ways to minimize their occurrence and to avoid them.

SUMMARY OF BACKGROUND DATA

Medical complications are a major consideration in adult spinal deformity surgery. Few studies have been done to identify the medical complication rate in relation to these procedures.

METHODS

We review the literature pertaining to medical complications regarding spinal deformity surgery.

RESULTS

Urinary tract infections are the most frequently seen complication. Additionally, pulmonary complications are the most common life-threatening complication. Medical complications are a frequent occurrence with adult deformity spinal surgery.

CONCLUSIONS

Awareness of the presentation, treatment, and prevention of medical complications of deformity surgery may allow minimization of their occurrence and optimize treatment should they occur.

Complicaciones médicas precoces en el postoperatorio de cirugía de escoliosis

Several medical complications can occur after scoliosis surgery in children and adolescents. New surgical techniques have allowed greater degrees of scoliosis correction but have also increased the possibility of postsurgical deficit due to their greater aggressivity. We analyzed the early postsurgical complications of scoliosis surgery in a pediatric intensive care unit over a 10-year period. Seventy-six surgical procedures were performed. Of these, no complications occurred in 55 (73%). Chest X-ray revealed pulmonary atelectasia in 8 patients (10%) and pleural effusion in 7 patients (9%). Symptoms and signs of infection related to surgery were observed in only 6 children (8%). The absence of severe medical complications may be related to new surgical techniques and an experienced team.

Syndrome of inappropriate secretion of antidiuretic hormone and hyponatremia after spinal surgery

Hyponatremia caused by an inappropriately high level of antidiuretic hormone secretion after spinal surgery is an uncommon and self-limiting phenomenon that resolves within 2 or 3 weeks. During the early postoperative period, the patient's urine output and serum level of sodium should be monitored closely to prevent possible serious complications of the syndrome of inappropriate secretion of antidiuretic hormone. Symptoms vary depending on the severity of the hyponatremia and can range from mild headache, muscle cramps, nausea, and vomiting to convulsions, coma, and death. Treatment options include fluid restriction, oral intake of salt, and hypertonic saline. It is important that spine surgeons recognize this phenomenon early and treat it appropriately and conservatively to prevent possible serious complications.

Diabetes insipidus secondary to penetrating spinal cord trauma: case report and literature review

STUDY DESIGN

Case report.

OBJECTIVE

To present a case of central diabetes insipidus (CDI) that developed after a gunshot injury to the thorax and thoracic spinal cord and to discuss the disease process in light of the relevant literature.

SUMMARY OF BACKGROUND DATA

Antidiuretic hormone (ADH) abnormalities may develop after spinal trauma and/or surgery. Although there are published reports of inappropriate ADH syndrome arising in this clinical picture, CDI is rare.

METHODS

A 33-year-old woman with hemopneumothorax and a gunshot wound to her thoracic spine was treated with chest tube drainage. No surgery was performed for the spinal injury. The patient was paraplegic on admission and rapidly developed excessive urine output. Testing revealed that her serum ADH level was low, consistent with CDI. Desmopressin acetate nasal spray was the prescribed treatment.

RESULTS

The patient responded well to the desmopressin acetate spray.

CONCLUSIONS

CDI is a complicated hormonal disorder characterized by excessive urine output. It is typically linked to an abnormality in the hypothalamohypophyseal axis that markedly reduces ADH production. The most common inciting causes are craniocerebral trauma, brain tumor and/or surgery, and central nervous system infection. Although uncommon, CDI should be considered when a spinal trauma patient develops excessive urine output.

Medical complications in scoliosis surgery

Several medical complications can occur after scoliosis surgery in children and adolescents. They include the syndrome of inappropriate antidiuretic hormone; pancreatitis; cholelithiasis; superior mesenteric artery syndrome; ileus; pnemothorax; hemothorax; chylothorax; and fat embolism. This review focuses on the pathophysiology, diagnosis, and treatment of the various conditions that occur after correction of spinal deformity. Attention is given to recent literature specifically related to scoliosis surgery. Surgical complications like urinary tract infection, wound infection, and hardware failure will not be addressed.

Effects of anesthesia, surgery, and intravenous administration of fluids on plasma antidiuretic hormone concentrations in healthy dogs

OBJECTIVE

To evaluate effects of anesthesia, surgery, and intravenous administration of fluids on plasma concentrations of antidiuretic hormone (ADH), concentration of total solids (TS), PCV, arterial blood pressure (BP), plasma osmolality, and urine output in healthy dogs.

ANIMALS

22 healthy Beagles.

PROCEDURE

11 dogs did not receive fluids, and 11 received 20 ml of lactated Ringer's solution/kg of body weight/h. Plasma ADH adn TS concentrations, PCV, osmolality, and arterial BP were measured before anesthesia (T0) and after administration of preanesthetic agents (T1), induction of anesthesia (T2), and 1 and 2 hours of surgery (T3 and T4, respectively). Urine output was measured at T3 and T4.

RESULTS

ADH concentrations increased at T1, T3, and T4, compared with concentrations at T0. Concentration of TS and PCV decreased at all times after administration of preanesthetic drugs. Plasma ADH concentration was less at T3 in dogs that received fluids, compared with those that did not. Blood pressure did not differ between groups, and osmolality did not increase > 1% from To value at any time. At T4, rate of urine production was less in dogs that did not receive fluids, compared with those that did.

CONCLUSIONS AND CLINICAL RELEVANCE

Plasma ADH concentration increased and PCV and TS concentration decreased in response to anesthesia and surgery. Intravenous administration of fluids resulted in increased urine output but had no effect on ADH concentration or arterial BP. The causes and effects of increased plasma ADH concentrations may affect efficacious administration of fluids during the perioperative period in dogs.

Syndrome of inappropriate antidiuretic hormone secretion in children following spinal fusion

OBJECTIVES

a) To determine if antidiuretic hormone (ADH) is elevated in patients undergoing spinal fusion, especially in those who have clinical evidence of syndrome of inappropriate antidiuretic hormone (SIADH); b) to evaluate the relationship between ADH secretion and the secretion of atrial natriuretic peptide (ANP).

SETTING

Tertiary care pediatric intensive care unit (ICU) in a university hospital.

DESIGN

A prospective cross-sectional, observational study with factorial design.

PATIENTS

Thirty patients > or = 10 yrs of age undergoing spinal fusion admitted to the ICU for postoperative care.

INTERVENTIONS

Patients underwent anterior, posterior, or both anterior/posterior spinal fusion. Blood was collected for serial measurements of ADH, ANP and serum electrolyte levels. Heart rate, blood pressure and central venous pressure were measured.

MEASUREMENTS AND MAIN RESULTS

Thirty children were studied. Nineteen had idiopathic scoliosis, nine had neuromuscular scoliosis, one had Marfan's disease, and one had congenital scoliosis. Ten (33%) children met clinical criteria of SIADH. There was no difference in duration of surgery, blood loss, volume of iv fluid administration pre- and intraoperatively, or type of scoliosis between those who developed SIADH and those who did not. Hemodynamic variables were similar in both groups. ADH levels increased in both groups immediately postoperatively and at 6 hrs after surgery, but were much more elevated in those patients with SIADH. Patients with SIADH also had significantly higher ADH levels preoperatively. In relation to serum osmolality, ADH was considerably higher in those with SIADH compared with those who did not. Although ANP values tended to be higher in the group with SIADH, this did not reach statistical significance.

CONCLUSION

SIADH occurs in a subset of children who undergo spinal fusion. The diagnosis of SIADH can be made easily using clinical parameters which are well-defined. In the face of SIADH, continued volume expansion may be harmful, and should therefore be avoided.

Hyponatremia related to medical anticancer treatment

Hyponatremia is a common potential complication in cancer patients. It can be related to anticancer medical therapy. Vincristine, vinblastine, cisplatin and cyclophosphamide are the chemotherapeutic agents most frequently associated with hyponatremia. More recently, analogs such as carboplatin and ifosfamide have also been incriminated. Hyponatremia is also associated with new immunomodulators (interferon, interleukin-2 and levamisole) and monoclonal antibodies. The mechanism by which all these drugs act on the sodium steady state is only partially known. The syndrome of inappropriate antidiuretic hormone secretion is described secondary to vinca alkaloids and cisplatin and possibly with alkylating agents. Renal salt wasting is described with platinum compounds.

Inappropriate secretion of antidiuretic hormone in postoperative scoliosis patients: the role of fluid management

STUDY DESIGN

The present study examined the hypothesis that hypotonic saline therapy before surgery was a major factor in the development of the syndrome of inappropriate antidiuretic hormone secretion.

OBJECTIVES

The influence of fluid therapy and its relationship to the syndrome of inappropriate antidiuretic hormone secretion was studied by measuring patient electrolyte and osmolar responses at given times after surgery.

SUMMARY OF BACKGROUND DATA

Mild renal dysfunction and increased plasma antidiuretic hormone occurs after surgery. Occurrence of the syndrome of inappropriate secretion of antidiuretic hormone after spine surgery is rare. The development of the syndrome of inappropriate secretion hormone after surgery may be related to hypotonic fluid replacement during and after surgery.

METHODS

Twelve patients undergoing surgery for correction of idiopathic scoliosis were assigned randomly to two groups. The control group (five patients) was given isotonic saline, and the trial group (seven patients) was given hypotonic saline.

RESULTS

The trial group developed syndrome of inappropriate antidiuretic hormone secretion with a significant decrease in serum sodium and osmolarity. The control group did not develop syndrome of inappropriate antidiuretic hormone secretion.

CONCLUSIONS

Hypotonic saline therapy predisposes to the development of syndrome of inappropriate antidiuretic hormone secretion, whereas isotonic saline protects patients from syndrome of inappropriate antidiuretic hormone secretion when undergoing surgery for scoliosis.