Pseudohyponatremia Leading to a Fatal Outcome in a Patient With Familial Hypertriglyceridemia

Abstract

Serum sodium assay is a commonly performed laboratory test in a clinical setting and the results are taken for granted without being aware of the actual methods involved. In conditions like hyperlipidemia and hyperproteinemia, excessive lipids in serum dilute the water component of the serum. Since sodium is dissolved only in the aqueous phase of serum, the sodium content per unit volume of plasma is reduced. Currently, most of the laboratories use the indirect ion-selective electrode method (ISE), where the plasma sample is diluted before the measurement. Indirect ISE may not give accurate results in conditions with higher serum lipid and protein levels. Overcorrection of the serum sodium levels in pseudohyponatremia may cause serious complications. We report a case of a 26-year-old Asian male with a past medical history of chronic pancreatitis, familial hypertriglyceridemia, and fatty liver who presented to the emergency department with acute pancreatitis. Initially, the patient was found to have hyponatremia and he was started on hypertonic saline for one day. Later the patient’s condition deteriorated and then it was determined that serum sodium results were a measurement artifact since the patient had extremely high levels of triglycerides. After realizing that it was a measurement artifact, the saline infusion was stopped and he was started on desmopressin. However, the patient deteriorated neurologically and expired later. As this patient had normal sodium levels, administration of hypertonic saline led to a fatal outcome.

Pseudohyponatremia: Mechanism, Diagnosis, Clinical Associations and Management

“…The risk of iatrogenic complications accompanies pseudohyponatremia if this is not diagnosed promptly and is mismanaged. Both restriction of fluid intake [ 98 ] and saline infusion [ 19 , 92 , 108 , 160 ] have been inadvertently used to treat misdiagnosed pseudohyponatremia. Severe neurological manifestations [ 19 ] and deaths [ 91 , 160 ] have been reported following hypertonic saline infusion, leading to a rapid rise in the [Na] SW to extreme levels in patients with pseudohyponatremia.…”

“…Both restriction of fluid intake [ 98 ] and saline infusion [ 19 , 92 , 108 , 160 ] have been inadvertently used to treat misdiagnosed pseudohyponatremia. Severe neurological manifestations [ 19 ] and deaths [ 91 , 160 ] have been reported following hypertonic saline infusion, leading to a rapid rise in the [Na] SW to extreme levels in patients with pseudohyponatremia. The magnitude of the spurious measurement and the subsequent risk of inappropriate treatment increase in parallel with the magnitude of the difference in serum solids from normal values ( Table 1 and Table 2 ).…”

Demystifying hyponatremia: A clinical guide to evaluation and management

“…16,19 SPECIAL CONSIDERATIONS Pseudohyponatremia Isotonic hyponatremia should raise suspicion of pseudohyponatremia, which can be encountered owing to paraproteinemia or hyperlipidemia. The term pseudohyponatremia refers to a falsely low measurement of serum sodium levels due to expansion of the solid phase of the plasma by a high protein level (in paraproteinemia) or lipid level (in hypertriglyceridemia and hypercholesterolemia), 20,21 as is demonstrated in Figure 3. The traditional method of measurement of serum sodium in the laboratory uses indirect potentiometry with ion-specific electrodes.…”

Familial chylomicronemia syndrome: importance of diagnostic vigilance

“…Unfortunately, these symptoms are often either disregarded as a common viral or childhood illness or worse, misdiagnosed as an acute abdomen, prompting unnecessary exploratory procedures. To make matters more complicated, artifactual laboratory abnormalities due to HTG or chylomicronemia such as pseudohyponatremia ( 6 ) and abnormal coagulation studies due to the plasma turbidity via optical analyzer ( 7 ) as described in the case report, may prompt extraneous workups, and cause a delay in arriving at the correct diagnosis.…”