Plasma Osmolality Research Articles

Empagliflozin Raises Sodium in SIADH Patient, Enabling Timely Surgery

AbstractEmpagliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, induces osmotic diuresis via glucosuria and may represent a novel therapeutic approach for managing syndrome of inappropriate antidiuretic hormone secretion (SIADH). This case report details the successful use of empagliflozin to correct persistent hyponatremia in a 78-year-old man with SIADH, awaiting elective abdominal surgery for hernia repair over several months. The patient, who had a history of hypertension and multinodular thyroid goiter with normal thyroid function tests, continued to experience low serum sodium levels despite discontinuing enalapril, previously used for hypertension management. An extensive evaluation confirmed a diagnosis of SIADH, with sodium levels initially ranging between 124 and 128 mmol/L. Traditional management, including fluid restriction, failed to normalize his sodium levels, leading to repeated cancellations of his scheduled surgery due to persistent hyponatremia. In October 2023, treatment with empagliflozin was initiated, leading to a gradual increase in sodium levels. Within 3 weeks, his serum sodium had normalized to 134 mmol/L, accompanied by a rise in serum osmolality. As a result, the elective surgery was successfully performed without complications. These findings suggest that empagliflozin, in combination with fluid restriction, offers a promising treatment option for improving sodium levels in patients with SIADH, helping avoid unnecessary delays in elective surgical interventions.

Study on the physiological responses and tolerance mechanisms to subchronic carbonate alkalinity exposure in the gills of Paramisgurnus dabryanus

Given the reduction of freshwater resources, saline-alkaline aquaculture has emerged as an effective approach to expand the fishery's accessible space. High carbonate alkalinity (CA) is a major stressor for aquatic organisms in saline-alkaline environments. Paramisgurnus dabryanus is a potential species for culture in saline-alkaline water, making it an ideal model for investigating the physiological responses and tolerance mechanisms to CA exposure in freshwater fishes. In the current study, P. dabryanus were exposed to 15 and 30mmol/L NaHCO3, combining blood biochemical, gill histological, transcriptomic, and metabolomic methods for conjoint analysis of response mechanisms. After 28-d exposure, the gill ventilation frequency of P. dabryanus decreased significantly, gill lamellae twisted and atrophied, and gill filament epithelial cells proliferated, potentially limiting gas exchange, whereas the accessory air-breathing frequency increased significantly, possibly for greater oxygen uptake. Serum osmolality and blood pH remained relatively steady, while serum ammonia levels rose significantly. A total of 3718 differentially expressed genes (DEGs) and 205 differential metabolites (DMs) were identified between the control group and 30mmol/L NaHCO3 group, involved in ion transport (Na+/K+-ATPase, V-type ATPase, carbonic anhydrase, and ABC transporters), ammonia transport (Rh glycoproteins and Aquaporins), amino acid metabolism, carbohydrate metabolism, and fatty acid metabolism. Furthermore, DEGs were significantly associated with cell-cell/ extracellular matrix interaction and protein synthesis. An integrated multi-omics analysis revealed the activation of carbon metabolism and TCA cycle. These results indicate that in response to CA exposure, P. dabryanus may facilitate carrier-mediated ion and ammonia transport to maintain the internal osmotic equilibrium and lessen the deleterious effects of blocked ammonia excretion. Meanwhile, amino acid metabolism and protein synthesis are disturbed, P. dabryanus can modulate carbohydrate catabolism to maintain energy homeostasis. The above findings provide novel insights into saline-alkaline adaptation in freshwater fishes, paving the way for future research and development of saline-alkaline-tolerant Cobitidae strains.

Heart Failure Related Fatigue and Serum Osmolality: An Exploratory Analysis of the National Health and Nutrition Examination Survey

Heart Failure Related Fatigue and Serum Osmolality: An Exploratory Analysis of the National Health and Nutrition Examination Survey

Comparative transcriptomic analysis reveals osmoregulatory mechanisms of juvenile Lateolabrax maculatus responses to long term hypotonic and hypertonic acclimation

Salinity limits the abundance and distribution of some fishes in a particular ecological niche. The spotted sea bass (Lateolabrax maculatus), an euryhaline species, exhibits remarkable adaptability to various salinity levels. To elucidate the osmoregulation mechanisms of this species, the growth performance, serum biochemical parameters and gill transcriptomic profiles of the juvenile spotted sea bass subjected to long term hypotonic (0 ppt) and hypertonic environment (30 and 45 ppt), with the isotonic environment (12 ppt) as the control, were investigated. During the 30 days' salinity acclimation, the growth performance of the juvenile sea bass was inhibited significantly (P < 0.05) at hypertonic condition of 45 ppt, while no significant differences were observed among those at 0, 12, and 30 ppt. The serum biochemical indicators of plasma osmolality, concentration of Na+, Cl−, glucose, urea, total protein, and ALT and AST activities significantly increased during the hypertonic acclimation. Transcriptome analysis identified 1179, 103, and 443 differentially expressed genes in the 0, 30, and 45 ppt salinity groups, respectively, compared to the isotonic (12 ppt) group. Bioinformatics analysis revealed that signal transduction pathways were promoted during hypotonic acclimation, while energy metabolism pathways were activated during hypertonic acclimation. Protein-protein interaction and WGCNA analysis identified hub genes that may play important functions during acclimation. Among them, protein synthesis related-genes including Rps15, Rps16, Rps9, Rpl4, Rpl15, Rpl30, Rpl31, Rpl13a and Eef2 were down-regulated under hypotonic acclimation, metabolic related-genes including Cs, Idh2, Idh3, Mdh2, Pck1, Pck2, Pdha1 and Ldhb were up-regulated under the hypertonic condition. Rac1 were up-regulated in both conditions. This study provides new insights into the osmoregulatory mechanisms of spotted sea bass in response to long-term hypotonic and hypertonic acclimation.

SIADH secondary to rhino-orbito-cerebral mucormycosis: A case report.

Invasive fungal mucormycosis and its outcome as SIADH and orbital apex syndrome is uncommon. Mucormycosis in paranasal sinuses can even lead to intracranial invasion and its treatment with the use of amphotericin B can cure improve the prognosis of the disease. Early diagnosis and prompt treatment with antifungal, endoscopic surgery, and controlling of diabetes can be beneficial. Mucormycosis is an opportunistic invasive fungal infection which is rare and fatal and can even cause intracranial invasion leading to SIADH. The infrequency with which mucormycosis with SIADH is encountered makes it a formidable diagnostic challenge. 70-year-old women uncontrolled diabetes mellitus presented with bilious vomiting and persistent headache with ptosis, proptosis, absence of extraocular movement, pupillary light reflex, and light perception of left eye. Radiographic investigation, KOH mount, and Biopsy showed mucormycosis in sinus with intracranial extension leading to SIADH. Further investigation revealed hyponatremia, decreased plasma osmolality. Then, when diabetes was controlled and hydrocortisone and amphotericin was given along with Endoscopic sinus debridement, SIADH was well controlled. This case illustrates the potential of mucormycosis in paranasal sinuses can even lead to intracranial invasion and its treatment with the use of amphotericin B can cure improve the prognosis of the disease. Prompt diagnosis through clinical history, radiological investigation, and laboratory parameters are important and its treatment is crucial for the better prognosis.

Long-term Outcome of a Chihuahua With Idiopathic Syndrome of Inappropriate Antidiuretic Hormone Secretion.

An approximately 3 yr old female Chihuahua was presented for evaluation of polyuria and polydipsia noted by the owner after adoption. Serum biochemistry and urinalysis revealed hyponatremia, hypochloremia, hypo-osmolality, and normal fractional excretion of sodium. Serum antidiuretic hormone concentration was 5.54 pg/mL and serum copeptin concentration was 135.40 pg/mL. The antidiuretic hormone value was above the reported range for healthy dogs and was considered inappropriate in light of serum osmolality. Idiopathic syndrome of inappropriate antidiuretic hormone secretion was considered the most likely diagnosis after excluding other potential causes, such as diuretic use, renal disease, adrenal disease, and thyroid dysfunction. The dog remains clinically well 2 yr after diagnosis without specific treatment other than minimal dietary salt supplementation. This case is unique because of the absence of systemic or neurologic signs, good long-term outcome without treatment, and use of novel diagnostic testing.

Suratentorial Tümör Cerrahisinde %20 Mannitol ve %3 Hipertonik Salin Kullanımlarının Beyin Relaksasyonu, Hemodinamik Parametreler, Serum Osmolaritesi ve Elektrolitleri Üzerine Etkilerinin Değerlendirilmesi

Objective: Different drugs or methods can be applied to provide brain relaxation in supratentorial tumor surgery. In our study, we aimed to evaluate effects of 20% Mannitol and 3% Hypertonic Saline (HS) used during supratentorial tumor surgery on brain relaxation, hemodynamic parameters, urine flow, fluid volume, pulse pressure variability (PPV), pleth variability index (PVI), serum osmolarity and electrolytes. Methods: The study included 60 patients aged 18-65 years, ASA I-II class, who were scheduled to undergo supratentorial tumor surgery. General anesthesia was administered with sevoflurane and remifentanil to achieve a state entropy of 40-60. Patients were allocated into two groups, with Group Mannitol receiving 20% mannitol (2.5 mL kg-1) and Group Hypertonic Saline receiving 3% HS (2.5 mL kg-1). In all patients, PPV and PVI values were planned to be ≤13%. After the dura was opened, brain relaxation scores were evaluated. Perioperative hemodynamic variables, blood gases, PVI, PPV values were recorded. Na+, K+ values, urine volume and administered fluid were recorded at 30, 45 and 60 minutes and 2-3 hours after the end of the infusion. Preoperative and postoperative BUN, creatinine and osmolarity values were recorded. Results: No statistical difference was found between demographic characteristics, brain relaxation and hemodynamic data. In HS group, PVI and PPV values were higher than Mannitol group from the beginning of infusion. In mannitol group, urine and administered fluid amounts were higher. Decrease in Na+ values was detected with Mannitol and increase with HS. It was determined that BUN and creatinine values were similar, serum osmolarity did not change at postoperative period in mannitol group and increased HS. Average intensive care and length of hospital stay were similar. Conclusion: In supratentorial tumor surgery, effective brain relaxation was achieved with Mannitol and HS, without affect to hemodynamics. Pulse pressure variability and PVI decreased with Mannitol. Blood gases, Na+, K+, BUN creatinine, osmolarity levels did not show serious changes. It was concluded that HS could be an alternative to mannitol in supratentorial surgery. Keywords: Hypertonic saline,mannitol, serum osmolarity, supratentorial tumor surgery

Serum Osmolality as a Predictor of Renal Function Decline: A Retrospective Cohort Study.

Background and Aims: Dehydration is a prevalent and costly healthcare concern, linked to heightened risks of acute kidney injury and in-hospital mortality. Despite its significance, limited evidence exists regarding its prevalence and correlation with renal function decline in apparently healthy individuals. This retrospective cohort study aimed to investigate the prevalence and association of dehydration with renal function decline and the development or progression of chronic kidney disease (CKD) in the general population. Methods: The medical records of subjects undergoing annual health check-ups from 2016 to 2019 at a single center in Taiwan were analyzed, and those with CKD stage V, insufficient data, or an increased estimated glomerular filtration rate (eGFR) were excluded. Serum osmolality, eGFR, and relevant parameters were measured. Logistic regression and Kaplan-Meier analyses were used to assess associations between osmolality and CKD-related outcomes. Results: Among the 4449 eligible subjects, those in the higher osmolality quartiles had an elevated risk of CKD or CKD progression. Multivariate analyses identified age, systolic blood pressure, serum osmolality, uric acid, proteinuria, and a history of diabetes as independent risk factors, with high-density lipoprotein being protective. Cumulative incidence curves demonstrated a significant increase in the risk of CKD with increasing osmolality levels. Restricted cubic spline analyses confirmed a nonlinear relationship between osmolality and CKD risk. Conclusions: Elevated serum osmolality independently predicted renal function decline and CKD development in apparently healthy individuals, and this effect persisted after adjusting for established risk factors. Our findings underscore the importance of addressing dehydration as a modifiable risk factor for CKD.

Seasonal Variation in Vascular Dehydration Risk: Insights from the KOBE Study

Abstract Objectives Dehydration, a risk factor for ischemic cerebrovascular diseases, is common in summer; however, the incidence of ischemic diseases is not necessarily higher in summer. The phenomenon may be influenced by the differences in the susceptibility to vascular dehydration based on the season. Therefore, this study aimed to distinguish types of dehydration in colder and warmer seasons by analyzing serum osmolarity, hematocrit, and daily non-alcohol drink (NAD) intake. Methods Participants in the Kobe Orthopedic and Biomedical Epidemiologic (KOBE) Study, consisting of healthy individuals, were categorized into two groups based on the examination month: the warmer and colder seasons. Multivariate analyses were conducted to examine disparities in serum osmolarity, hematocrit, and NAD intake between these two groups. Results Participant ratios by age group and the seasons (warmer season/colder season) were as follows: Women under 50 (35/62), 50-60 (77/126), 60-70 (123/170), over 70 (58/52); Men under 50 (14/17), 50-60 (22/36), 60-70 (57/71), over 70 (55/34). The colder season was found to be negatively correlated with serum osmolarity and NAD intake, but positively correlated with hematocrit, even after adjusting for relevant factors. Age was independently associated with serum osmolarity, but not with hematocrit and NAD intake. Conclusions This study highlights that vascular dehydration is more likely in the colder season despite lower serum osmolarity than the warmer season. Age-related increases in serum osmolarity without a corresponding rise in water intake may contribute to this. These findings emphasize the importance of addressing dehydration in the colder season, particularly in older adults. Key messages • The colder season showed a negative correlation with serum osmolarity and NAD intake but a positive correlation with hematocrit. • Raising awareness about the importance of hydration during winter may be essential.

Effects of Salinity and Ca2+: Mg2+ Ratio on Nutrient Profile, Physiological Responses and Clinical Signs of Penaeus vannamei (Boone, 1931) Reared in Inland Saline Ground Water

Background: A 60-day experiment was conducted to evaluate the combined effect of salinity and Ca2+: Mg2+ ratio on the nutrient profile, physiological responses, and clinical signs of Penaeus vannamei reared in inland saline ground water. Methods: The study used three different salinities viz. T1 (5 ppt), T2 (10 ppt) and T3 (15 ppt) with four different levels of Ca2+: Mg2+ ratios such as 1:1, 1:2, 1:3, and 1:4. A total of 720 healthy post larvae of P. vannamei (mean body weight of 3.70±0.02 g) were stocked (20 shrimp/tank) in 36 circular plastic tanks (100 L capacity each). Each treatment was triplicated following the 3 × 4 factorial design. Result: A significant increase of protein and ash contents and decrease of moisture content were noticed with increasing salinity. The study found no significant difference in the carbohydrate and crude lipid content of P. vannamei. A linear relationship between salinity and serum osmolality was observed which indicated significant increase of osmoregulatory capacity with increasing salinity. The treatment groups fortified with deficient level of Ca2+: Mg2+ ratio showed prominent changes such as abdominal white muscle on dorsal side and muscle cramps. Based on the results, it can be concluded that the better physiological adoption of P. vannamei was observed in 10 and 15 ppt salinities of ISGW fortified with Ca2+: Mg2+ ratio 1:3.

The relationship between oropharyngeal dysphagia and dehydration in older adults

BackgroundRelationship between dysphagia and dehydration has not been studied widely. The aim of this study is to determine the frequency of dysphagia and dehydration in geriatric outpatient clinic, to evaluate the relationship between these two conditions.MethodsThe cross-sectional study included 1345 patients. Plasma osmolarity (Posm) was calculated using the following formula: [1.86 x (Na + K) + 1.15 x glucose + urea + 14]. Overt dehydration was defined as a calculated Posm of > 300 mmol/L. Eating Assessment Tool (EAT-10) score of ≥ 3 was accepted as dysphagia. Associations between dehydration and dysphagia was evaluated.ResultsMean age was 78 ± 8 years, and 71% were females. Dysphagia was observed in 27% of patients. Dysphagia was associated with a higher number of drug exposure, dependency on basic activities of daily living and geriatric depression (p < 0.05). Overt dehydration was found in 29% of patients with dysphagia, and 21% of patients with no dysphagia (p = 0.002); and dysphagia was significantly associated with overt dehydration mmol/L (OR 1.49, 95% CI 1.13–1.96, p = 0.005) after adjustments for age and sex. In another model, EAT-10 score was found as one of the independent predictors of overt dehydration (OR1.03, 95% CI 1.00-1.06, p = 0.38), along with diabetes mellitus (OR 2.32, 95% CI 1.72–3.15, p < 0.001), chronic kidney disease (OR 3.05, 95% CI 2.24–4.15, p < 0.001), and MNA score (OR 0.97, 95% CI 0.94-1.00, p = 0.031).ConclusionEAT-10 scale was independently associated with overt dehydration among older adults, as MNA score was. Correction of both dysphagia and malnutrition might improve overt dehydration to a better extent than correction either of these factors alone. Future studies are needed to test cause and effect relationships.

Plasma and serum volume remain unchanged following a 12-h fast from food and drink despite changes in blood and urinary hydration markers.

The effect of mild dehydration on plasma and serum volume has not been well established. Furthermore, the ability of urinary and blood biomarkers to monitor small hydration changes have not been solidified. There were two objectives of this research: 1. Determine if mild dehydration affects plasma and serum volume; 2. Determine if mild dehydration can be detected better by urinary or blood biomarkers. 47 subjects were recruited; 10 subjects were removed from the study and 37 subjects (27% male) completed the study. This was a crossover study design such that each subject underwent all protocols in a counterbalanced order. Protocols consisted of 12-h dehydration, 12-h hydration, and control. Neither plasma volume (p = 0.914), plasma volume status (p = 0.649), nor serum volume (p = 0.273) were different among protocols. Body mass (p < 0.001) was lower following the dehydration protocol. Urine color (p < 0.001), urine osmolality (p < 0.001), urine specific gravity (p < 0.001), serum osmolality (p < 0.001), and plasma osmolality (p < 0.001) were all lower following the hydration protocol. Hematocrit (p = 0.842) and hemoglobin concentration (p = 0.558) were not different among protocols. Dehydration did not affect plasma or serum volume. Therefore, a 12-h fast from food and water as done in this study will not likely affect laboratory test results of biomarker concentration. All 3 urinary measures were able to detect changes in hydration status, whereas only 2 blood measures were able to detect changes in hydration status. This may indicate that urinary measures are best at detecting small changes in hydration status.

Associations Between Hydration Status and Executive Function in Middle-Aged and Older Adults: Findings from the Nationally Representative Health and Retirement Study

The purpose of the current study is to examine the association between hydration status and cognitive function in middle-aged and older adults, drawing from a large, nationally representative sample in the United States and using a comprehensive set of executive function performance measures. We utilized data from the Health and Retirement Study to conduct twelve, three-stage hierarchical regressions on hydration status and executive function performance of older adults. Cognitive performance scores on the Trail Making A, Symbol Digit Modalities, and Letter Cancellation tests significantly differed by hydration status, and these outcomes follow a curvilinear pattern, such that performance scores are lower for those who are hyper-hydrated or dehydrated relative to those who are euhydrated or near-dehydration. Our study’s findings are consistent with prior studies examining the impact of serum osmolarity on cognitive performance. Specifically, a curvilinear pattern was associated with speed of processing tests of executive function. Overall, hydration status is associated with curvilinear patterns of performance on executive function measures, specifically Trail Making A, Symbol Digit Modalities, and Letter Cancellation Tests.

Evaluation of Plasma-Lyte Versus Lactated Ringer's in Surgical Intensive Care Unit Trauma Patients as Fluid Resuscitation.

In critically ill patients, fluid resuscitation with balanced crystalloids close to plasma osmolarity have a lower risk of electrolyte imbalances and demonstrated better clinical outcomes compared to normal saline (NS). While lactated ringer's (LR) has shown benefit over NS, plasma-lyte (PL) with a higher osmolarity and different electrolyte formulation is hypothesized to be superior. We performed a retrospective observational cohort study over 37 months at a tertiary hospital. Inclusion criteria were hospitalization in the surgical intensive care unit (SICU), trauma indication, ≥18 years old, and received either PL or LR. All PL administrations and every fifth patient with LR as resuscitation were included in order to match the sample size in each group. Primary outcomes were SICU length of stay (LOS), hospital LOS, and mortality. Secondary outcomes were biomarker changes from baseline. There were 113 patients in both PL and LR groups. The PL arm had higher APACHE II scores (16 vs 13, P = .033) and were more likely ventilated (39.3% vs 20.4%, P = .002) compared to LR. Median hospital LOS (12.0 vs 8.0, P < .001) and SICU LOS (6.0 vs 3.0, P < .001) are significantly longer in PL group compared to the LR group. However, there was no difference in in-hospital mortality (5.3% vs 3.5% P = .519) and SICU mortality (9.7% vs 5.3%, P > .208) between PL and LR. Overall, PL use was associated with prolonged hospital and SICU LOS. PL use did not demonstrate mortality benefit. However, patients were more critically ill in PL group based on higher APACHE II scores and higher rates of mechanical ventilation, which could be contributing to these unfavorable outcomes.

Physiological adaptations of red blood cells during aestivation in the south American lungfish Lepidosiren paradoxa

The South American lungfish Lepidosiren paradoxa inhabits areas with variable pluvial regimes. During aestivation (dormancy state observed in some species during dry seasons), the prolonged period of dryness imposes osmotic stress. We aimed to investigate the physiological and morphological adaptations of RBCs in Lepidosiren paradoxa during aestivation. Here, the lungfish were subjected to aestivation for 20 and 40 days and compared to a control group in an active period. The osmotic fragility, blood osmolality, and pH were measured. Blood smears were performed to assess morphological changes in the RBCs. Lepidosiren paradoxa presented lower hemolysis when compared with a teleost fish and tegu lizard. Hemolysis increased when the lungfish was subjected to 40 days of aestivation (from 6.04 % to 16.51 %; control vs 40-day aestivation). Hematocrit rose in both aestivation groups compared to the control (26.36 %, 41.36 % and 41 %, control, 20 and 40 days, respectively; p < 0.05) indicating changes in RBC volume and hydration status. Moreover, the results revealed increased osmolality in the 40-day aestivation group (244.4 vs 372.1 mmol/Kg; control vs 40-day aestivation). 40 days of aestivation led to a decrease in blood pH when compared to the control and 20-day aestivation groups. Both aestivation durations resulted in a reduction in the perimeter and cell diameters in at least one direction of the RBCs (24 % mean reduction in size from control to 40 days aestivation). These findings suggest that South American lungfish possess remarkable physiological and morphological adaptations in their RBCs during aestivation.

Arginine vasopressin deficiency (central diabetes insipidus) with partial empty sella: a case report

BackgroundArginine vasopressin deficiency (central diabetes insipidus) is defined as a reduction in the release of arginine vasopressin (AVP) resulting in a variable degree of polyuria. Partial empty sella refers to an enlarged sella turcica that is not completely filled by pituitary gland. It can be either primary or secondary and its manifestation ranges from asymptomatic cases to isolated posterior pituitary, isolated anterior pituitary or both anterior and posterior pituitary dysfunctions. Diabetes insipidus caused by a partially empty sella is rare.Case presentationThe patient, an 18-year-old Ethiopian woman who presented with long standing headache, increased urination, increased thirst, absence of menses and weight loss. Urine and serum osmolality was done and suggested diabetes insipidus. On further workup, brain magnetic resonant imaging was done and partially empty sella was diagnosed.ConclusionDiabetes insipidus secondary to partially empty sella is uncommon. In patients presenting with headache and anterior or posterior pituitary dysfunction, empty sella should be considered, whether partial or complete.

Acute freshwater CO2 exposure does not impair seawater transfer in three different sizes of Atlantic salmon (Salmo salar) subjected to different photoperiod manipulations.

There is a growing interest in Atlantic salmon (Salmo salar) aquaculture to extend the time fish are reared in freshwater (FW) recirculating aquaculture systems (RAS), producing larger FW salmon that can then be induced to undergo smoltification before transfer into marine net pens for grow-out and harvest. Smolts can be produced by photoperiod (PT) manipulation in RASs, but little is known about how delaying smoltification to larger body sizes affects susceptibility to elevated CO2 levels (hypercapnia), which can occur at high stocking densities in FW RAS or during transport from FW RAS rearing facilities to marine net pens. To address this, Atlantic salmon were reared from hatch to one of three different sizes (~230, ~580, or ~1300 g) in FW (3 ppt) under continuous light (24:0, light:dark). Once fish reached the desired sizes, a group of salmon were maintained on continuous light 24L:0D to serve as a control salmon. A second group of salmon were exposed to 8 weeks of 12L:12D and then to 4 weeks of 24L:0D to serve as PT treatment salmon, which is the PT manipulation commonly used in Atlantic salmon aquaculture to induce smoltification. At the end of PT manipulation, both control and PT treatment salmon were exposed to 0% or 1.5% CO2 (30 mg/L) for 96 h in FW and then transferred to air-equilibrated seawater (SW, 35 ppt, normocapnia). Salmon were sampled at the end of the 96-h FW CO2 exposure and at 24 h and 7 days in SW for measurements of blood ion/acid-base status, muscle water content (MWC), and gill and kidney Na+/K+ ATPase (NKA) activity. Exposure to 96 h of CO2 in FW resulted in acid-base disturbances in fish from all three size classes, with decreases in blood pH and increases in blood PCO2 and plasma [HCO3 -] but no mortality. Despite these large acid-base disturbances in FW, after transfer to normocapnic SW, there were no significant effects of CO2 exposure on extracellular blood pH, intracellular red blood cell pH, or plasma osmoregulatory status for all three sizes of post-smolt salmon. In general, SW transfer was associated with significant increases in plasma ions and osmolality, as well as gill and kidney NKA activity after 24 h and 1 week in SW with no significant impacts between different sizes of salmon. Thus, exposure to 30 mg CO2/L that mimics levels experienced during transport from FW RAS to an SW transfer site may have minimal effects on Atlantic salmon smolts up to 1300 g.

7418 Xanthoma Disseminatum - A Rare cause of Diabetes Insipidus

Abstract Disclosure: P. Balasubramanian: None. J. Cohen: None. Z. Corbin: None. G. Panse: None. S.E. Inzucchi: None. Background: Xanthoma disseminatum is a rare non-Langerhans cell-derived benign histiocytosis of unknown etiology, characterized by mucocutaneous xanthomatosis. Systemic involvement occurs in a subset of patients, the most common manifestation being central diabetes insipidus in the setting of hypothalamic-pituitary- infundibulum infiltration, occurring in about 30-50% of the patients. We present the case of a man with biopsy proven cutaneous xanthoma disseminatum who developed central diabetes insipidus due to pituitary stalk involvement. Case Presentation: A 69-year-old male presented with a 2-year history of symmetrically distributed, erythematous to hyperpigmented macules and papules in the axillae and inguinal folds. He did not have any mucosal lesions. Skin biopsy revealed histiocytic infiltrate consistent with non-Langerhans cell histiocytosis, likely xanthoma disseminatum. He developed symptoms of polyuria and nocturia around the same time of the eruption, resulting in a large daily fluid intake of 100-120 ounces/day for several months. Laboratory evaluation revealed normal electrolytes. After an overnight water deprivation test, serum osmolality was 299mOsm/kg, serum sodium was 144mmol/L and urine osmolality was 280mOsm/kg, consistent with partial central diabetes insipidus. MRI pituitary with and without IV contrast showed thickening and hyperenhancement of the pituitary stalk. Anterior pituitary function was intact except for mild hypogonadotropic hypogonadism. He was started on DDAVP with good response and resolution of symptoms. Conclusion: Xanthoma disseminatum is characterized by extensive mucocutaneous xanthomatosis with occasional systemic involvement. The natural history of xanthoma disseminatum is usually benign, indolent, and slowly progressive with spontaneous regression described in a few cases. Hypothalamic and pituitary involvement may cause hyperprolactinemia, central diabetes insipidus, and variable degrees of hypopituitarism. Diabetes insipidus is often mild and sometimes transient. Occasionally, central diabetes insipidus can precede the skin lesions. Prognosis is generally good. Central nervous system involvement outside the hypothalamus/pituitary carries a poor prognosis. Presentation: 6/2/2024

12431 14-year-old Presenting With Thrombocytopenia-Associated Multi-Organ Failure In The Setting Of Diabetic Ketoacidosis/Hyperosmolar Hyperglycemic Syndrome

Abstract Disclosure: N.C. Gunaratne-Breaux: None. D. Deplewski: None. Title: 14-Year-Old Presenting with Thrombocytopenia Associated Multi-Organ Failure in the setting of Diabetic Ketoacidosis/Hyperosmolar Hyperglycemic Syndrome Background: Coagulation complications are rare in hyperglycemia emergencies in children and adolescents. In patients presenting with severe and atypical hyperglycemia emergencies, special considerations need to be made to rule out life-threatening coagulopathy. Clinical Case: A 14-year-old male with history of Type 1 Diabetes presented in severe Diabetic Ketoacidosis/Hyperosmolar Hyperglycemic Syndrome overlap. Initially had severe hypotension and altered mental status concerning for cerebral edema. Initial venous blood gas showed pH of 6.82, pCO2 17.1, and HCO3 2.8, serum glucose was 1375 mg/dL, serum ketones &amp;gt;7.00 mmol/L, and serum osmolality was 384 mOsm/kg. Once insulin drip was started, glucose, ketones, and serum osmolality improved, but patient continued to be encephalopathic and had worsening tachypnea and desaturations. Patient was eventually intubated. After intubation, patient’s acidosis improved, but patient developed kidney failure (prompting initiation of dialysis), liver injury, decreased cardiac function, and high inflammatory state. A comprehensive multi-specialty team including pediatric intensive care, infectious diseases, rheumatology, neurology, and cardiology were involved in the care. On day three of admission, patient had multiple areas of ischemia on fingertips and ear and clotting of multiple IV and dialysis catheters, prompting a coagulopathy evaluation. Labs showed microcytic anemia (hemoglobin 10.0 g/dL; mean corpuscular volume 75fL), thrombocytopenia (platelet count 17 10e3/uL), coagulopathy (prothrombin time 16.8 sec, INR 1.3, prolonged thrombin time 48.8 sec), and elevated ferritin (507 ng/mL). Given labs and multi-organ involvement, determined by hematology to be Thrombocytopenia Associated Multi-Organ Failure (TAMOF). Patient was started on plasmapheresis and had dramatic improvement – was eventually extubated and returned to neurologic baseline without any notable deficits. Multi-specialty team ruled out all other possible causes of TAMOF; determination that the TAMOF developed secondary to DKA/HHS. Conclusion: Hyperglycemia emergencies can lead to a hyperinflammatory state that can lead to disruption of the coagulation cascade, including disseminated intravascular coagulopathy or thrombotic thrombocytopenia purpura. There have been rare reports of thrombocytopenia associated multi-organ failure provoked by DKA, thought secondary to critical illness mediated low ADAMST13 levels. This is a novel case of TAMOF caused by DKA/HHS overlap syndrome. It is important to screen for coagulopathy in cases of patients with DKA or DKA/HHS who do not show clinical improvement with resolution of ketosis and hyperosmolarity. Presentation: 6/2/2024

8155 Isolated Hypothalamic-Pituitary Langerhans' Cell Histiocytosis in Adult Patients

Abstract Disclosure: A. Vu: None. M. Aguilera: None. J. Shakil: None. R. Al-Ward: None. Introduction: Langerhans cell histiocytosis (LCH) is an infiltrative disease due to clonal proliferation of immature dendritic cells mainly affecting children and seen in adults in less than 30% of cases. It can present as localized or with systemic manifestations, with isolated hypothalamic-pituitary lesions being exceptionally rare. Our report adds to the limited published literature by presenting two cases of isolated hypothalamic-pituitary LCH diagnosed in adults. Furthermore, one of the cases reveals a rare association with papillary thyroid cancer (PTC). Case 1: 35-year-old woman with no past medical history presented with 4 year history of amenorrhea and weight gain and more recently, polyuria and polydipsia. Further investigations showed hypogonadotropic hypogonadism, central hypothyroidism, and mildly elevated prolactin. She couldn’t complete water deprivation test due to extreme thirst. A dedicated pituitary MRI showed marked infundibular enlargement, concerning for hypophysitis. An extensive workup including assessments for autoimmune etiology, sarcoidosis, infections, and low-grade tumors, did not identify a definitive etiology. A PET scan was obtained (to rule out LCH and Erdheim Chester disease), which showed increased uptake in the pituitary stalk. Due to otherwise negative workup, transsphenoidal biopsy of the pituitary lesion was done. Post-procedure, diabetes insipidus (DI) was diagnosed due to elevated sodium while fasting for the procedure. Tissue examination revealed increased histiocytes and lymphocytes, and a positive BRAF V600E mutation confirming LCH as the underlying diagnosis. Case 2: 26-year-old male with history of LCH limited to the skull, in remission for 8 years after chemotherapy, presented with 4-week history of polyuria, polydipsia and weight loss. A 24-hour urine collection resulted in 6.5L of urine. During water deprivation test, there was notable increase in serum sodium, serum osmolarity, and urine osmolarity. Initial pituitary MRI was normal, but subsequent imaging revealed the loss of the posterior pituitary bright spot. PET scan showed focal FDG avidity in the right lower thyroid lobe, confirmed on fine needle aspiration as PTC with BRAF mutation. He underwent total thyroidectomy and is currently receiving chemotherapy for LCH recurrence. Discussion: LCH is infrequent in adults, presenting with variable manifestations based on affected organs. In the multifocal form, the hypothalamic-pituitary axis is involved in 5-50% of cases. Our report describes two unique cases with only four other reported cases of isolated hypothalamic-pituitary axis LCH in adults. Central diabetes insipidus can be seen before the diagnosis or as the disease progresses. Pituitary biopsy, although invasive, should be considered when the diagnosis is not clear. The association of PTC with a BRAF mutation is extremely rare and has been reported. Presentation: 6/2/2024