Pseudohyponatremia in a patient with HIV and hepatitis C coinfection

Evidence-based hyponatremia management in liver disease

Hyponatremia is primarily a water balance disorder associated with high morbidity and mortality. The pathophysiological mechanisms behind hyponatremia are multifactorial, and diagnosing and treating this disorder remains challenging. In this review, the classification, pathogenesis, and step-by-step management approaches for hyponatremia in patients with liver disease are described based on recent evidence. We summarize the five sequential steps of the traditional diagnostic approach: 1) confirm true hypotonic hyponatremia, 2) assess the severity of hyponatremia symptoms, 3) measure urine osmolality, 4) classify hyponatremia based on the urine sodium concentration and extracellular fluid status, and 5) rule out any coexisting endocrine disorder and renal failure. Distinct treatment strategies for hyponatremia in liver disease should be applied according to the symptoms, duration, and etiology of disease. Symptomatic hyponatremia requires immediate correction with 3% saline. Asymptomatic chronic hyponatremia in liver disease is prevalent and treatment plans should be individualized based on diagnosis. Treatment options for correcting hyponatremia in advanced liver disease may include water restriction; hypokalemia correction; and administration of vasopressin antagonists, albumin, and 3% saline. Safety concerns for patients with liver disease include a higher risk of osmotic demyelination syndrome.

Pseudohyponatremia: Mechanism, Diagnosis, Clinical Associations and Management

Pseudohyponatremia remains a problem for clinical laboratories. In this study, we analyzed the mechanisms, diagnosis, clinical consequences, and conditions associated with pseudohyponatremia, and future developments for its elimination. The two methods involved assess the serum sodium concentration ([Na]_S) using sodium ion-specific electrodes: (a) a direct ion-specific electrode (ISE), and (b) an indirect ISE. A direct ISE does not require dilution of a sample prior to its measurement, whereas an indirect ISE needs pre-measurement sample dilution. [Na]_S measurements using an indirect ISE are influenced by abnormal concentrations of serum proteins or lipids. Pseudohyponatremia occurs when the [Na]_S is measured with an indirect ISE and the serum solid content concentrations are elevated, resulting in reciprocal depressions in serum water and [Na]_S values. Pseudonormonatremia or pseudohypernatremia are encountered in hypoproteinemic patients who have a decreased plasma solids content. Three mechanisms are responsible for pseudohyponatremia: (a) a reduction in the [Na]_S due to lower serum water and sodium concentrations, the electrolyte exclusion effect; (b) an increase in the measured sample's water concentration post-dilution to a greater extent when compared to normal serum, lowering the [Na] in this sample; (c) when serum hyperviscosity reduces serum delivery to the device that apportions serum and diluent. Patients with pseudohyponatremia and a normal [Na]_S do not develop water movement across cell membranes and clinical manifestations of hypotonic hyponatremia. Pseudohyponatremia does not require treatment to address the [Na]_S, making any inadvertent correction treatment potentially detrimental.

Pseudohyponatraemia caused by acute pancreatitis-derived hypertriglyceridaemia

We report a case of pseudohyponatraemia due to severe hypertriglyceridaemia-induced acute pancreatitis, stemming from unknown diabetes. A woman in her late 30s was admitted to the local hospital by her general practitioner due to severe hyponatraemia (116 mmol/L) and upper abdominal pain. At admission to the hospital, there was a discrepancy of 19 mmol/L between arterial and venous sodium, along with severe hypertriglyceridaemia and hypercholesterolaemia. Pancreatitis was diagnosed using a CT scan. The patient received plasmapheresis which significantly reduced triglycerides, and venous plasma sodium was normalised indicating pseudohyponatraemia at admission. Finally, a haemoglobin A1c of 83 mmol/mol was found. Diabetes was diagnosed, and insulin was initiated.

Hyponatremia in kidney transplant patients: its pathophysiologic mechanisms

Kidney transplant patients (KTPs), and particularly those with advanced chronic kidney rejection, may be affected by opportunistic infections, metabolic alterations and vascular and oncologic diseases that promote clinical conditions that require a variety of treatments, the combinations of which may predispose them to hyponatremia. Salt and water imbalance can induce abnormalities in volemia and/or serum sodium depending on the nature of this alteration (increase or decrease), its absolute magnitude (mild or severe) and its relative magnitude (body sodium:water ratio). Hyponatremia appears when the body sodium:water ratio is reduced due to an increase in body water or a reduction in body sodium. Additionally, hyponatremia is classified as normotonic, hypertonic and hypotonic and while hypotonic hyponatremia is classified in hyponatremia with normal, high or low extracellular fluid. The main causes of hyponatremia in KTPs are hypotonic hyponatremia secondary to water and salt contraction with oral hydration (gastroenteritis, sepsis), free water retention (severe renal failure, syndrome of inappropriate antidiuretic hormone release, hypothyroidism), chronic hypokalemia (rapamycin, malnutrition), sodium loss (tubular dysfunction secondary to nephrocalcinosis, acute tubular necrosis, tubulitis/rejection, interstitial nephritis, adrenal insufficiency, aldosterone resistance, pancreatic drainage, kidney–pancreas transplant) and hyponatremia induced by medication (opioids, cyclophosphamide, psychoactive, potent diuretics and calcineurinic inhibitors). In conclusion, KTPs are predisposed to develop hyponatremia since they are exposed to immunologic, infectious, pharmacologic and oncologic disorders, the combinations of which alter their salt and water homeostatic capacity.

Hyponatremia is a marker of disease severity in HIV-infected patients: a retrospective cohort study

Background

Hyponatremia is a frequent electrolyte disorder in HIV-infected patients with a prevalence of up to 56% in the pre-cART era. Several studies have demonstrated that patients with hyponatremia are at an increased risk of death. We aimed to investigate the prevalence of hyponatremia in the recent cART-era and evaluate its association with mortality.

Methods

Single-center retrospective cohort study. A total of 1196 newly diagnosed and cART-naïve HIV patients followed at the AIDS Reference Center, St Pierre University Hospital in Brussels, Belgium, between 1 January 1998 and 31 December 2013 were included. Hyponatremia was defined as a baseline natremia lower than 135 mmol/l. The outcome of interest was the occurrence of death.

Results

In this study 177 (14.8%) patients had hyponatremia at baseline with a median natremia of 132.0 mmol/l [interquartile range (IQR) 130.0-134.0 mmol/l]. Hyponatremic patients had a lower CD4 cell count (207.5 ± 197.7/μl vs 400.4 ± 277.0/μl; P < 0.0001) and a higher prevalence of AIDS (50.3% vs 12.4%; P < 0.0001) compared to normonatremic patients. A significantly higher proportion of patients with hyponatremia were hospitalized at first contact (72.3% vs 20.0%; P < 0.0001). During the follow-up hyponatremic patients had a shorter median time to a first hospitalization (2.0 IQR [0.0-12.0] months vs 13.0 IQR [2.0-29.0] months; P = 0.001) and an increased incident hospitalization rate (785/1000 patient-years, 95% CI 725–845 vs 370/1000 patient-years, 95% CI 352–388; P < 0.0001]. The incident mortality rate was 28.3/1000 patient-years (95% CI 18.15-42.16) in patients with hyponatremia compared to 9.33/1000 patient-years (95% CI 6.63-12.75) in normonatremic patients (P < 0.0001). Three-year cumulative survival rates were 85.8% ± 3.0% in hyponatremic patients and 96.3% ± 0.7% in normonatremic patients (log-rank P < 0.0001). However, in a multivariate Cox model adjusting for other risk factors such as AIDS, CD4 count < 350/μl and hepatitis C, hyponatremia was no longer a predictor for patient death (hazard ratio: 1.03, 95% CI 0.54-1.97; P = 0.935).

Conclusions

Hyponatremia is a marker of severity of HIV-disease but not an independent risk factor for mortality. HIV-patients with a low serum sodium at baseline might benefit from a close follow-up to improve outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2191-5) contains supplementary material, which is available to authorized users.

Accidental Diagnosis of Multiple Myeloma in a 44-Year-Old White Woman due to Erroneous Results via Chemical Analyzers

PATIENT

44-year-old white woman.

CHIEF COMPLAINTS

Cramping, nausea, shortness of breath, visual disturbances ("seeing yellow dots").

MEDICAL HISTORY

Status asthmticus, tobacco use, hypertension, migraines.

PRINCIPLE LABORATORY FINDINGS

TABLES 1-7, FIGURES 1-4: .

Water, electrolytes, and acid-base alterations in human immunodeficiency virus infected patients

The clinical spectrum of human immunodeficiency virus (HIV) infection associated disease has changed significantly over the past decade, mainly due to the wide availability and improvement of combination antiretroviral therapy regiments. Serious complications associated with profound immunodeficiency are nowadays fortunately rare in patients with adequate access to care and treatment. However, HIV infected patients, and particularly those with acquired immune deficiency syndrome, are predisposed to a host of different water, electrolyte, and acid-base disorders (sometimes with opposite characteristics), since they have a modified renal physiology (reduced free water clearance, and relatively increased fractional excretion of calcium and magnesium) and they are also exposed to infectious, inflammatory, endocrinological, oncological variables which promote clinical conditions (such as fever, tachypnea, vomiting, diarrhea, polyuria, and delirium), and may require a variety of medical interventions (antiviral medication, antibiotics, antineoplastic agents), whose combination predispose them to undermine their homeostatic capability. As many of these disturbances may remain clinically silent until reaching an advanced condition, high awareness is advisable, particularly in patients with late diagnosis, concomitant inflammatory conditions and opportunistic diseases. These disorders contribute to both morbidity and mortality in HIV infected patients.

Spurious electrolyte disorders: a diagnostic challenge for clinicians

Spurious electrolyte disorders refer to an artifactually elevated or decreased serum electrolyte values that do not correspond to their actual systemic levels. When a clinician is confronted with a case of electrolyte disturbance, the first question should be whether it is an artifact. Spurious electrolyte disorders (pseudohyponatremia, pseudohypernatremia, pseudohypokalemia, pseudohyperkalemia, pseudohypomagnesemia, pseudohypophosphatemia, pseudohyperphosphatemia, pseudohypocalcemia and pseudohypercalcemia) are not infrequently observed in clinical practice. The recognition that an electrolyte disturbance may be an artifact may prevent inappropriate therapeutic interventions that could potentially have unfavorable outcomes. Clinicians must be alert to the possibility of spurious laboratory abnormalities when faced with conflicting laboratory values or measurements that are discordant with the clinical presentation. Moreover, in the presence of conditions that predispose to spurious electrolyte disorders, the normal measured electrolyte levels should raise the suspicion that true electrolyte disorders may be present.

Hyponatremia in patients with infectious diseases

Hyponatremia is a common electrolyte disturbance associated with considerable morbidity and mortality. Hyponatremia may not infrequently be present during the course of an infection, does not cause specific symptoms and may be overlooked by clinicians. Nonetheless, it may reflect the severity of the underlying process. This review focuses on the clinical and pathophysiological aspects of hyponatremia associated with infectious diseases. In the majority of cases, the fall in serum sodium concentration is of multifactorial origin owing to increased secretion of the anti-diuretic hormone either appropriately or inappropriately. Inadvertent administration of fluids may worsen hyponatremia and prolong morbidity.