Pseudohyponatremia

What is Pseudohyponatremia?

Pseudohyponatremia is a rare lab mistake that shows a low sodium level in your blood test results, even when the sodium concentration is actually normal. If we compare this with true hyponatremia, where there is genuinely less sodium in your system, it’s crucial to understand that true hyponatremia can be a serious condition requiring immediate medical attention and more detailed tests.

Pseudohyponatremia is not a true disease but an mistake that occurs when the blood sample is processed for checking sodium content. If it’s not identified immediately, it could lead to serious misdiagnoses and improper treatments. Certain conditions or substances, such as mannitol or high blood sugar, can contribute to pseudohyponatremia. An extreme degree of high cholesterol is, however, the main cause of this lab mistake

Being aware of these false results is crucial to avoid mistaking pseudohyponatremia for other types of hyponatremia. Sometimes, substances present in your bloodstream can cause actual decreases in sodium concentration. That’s why the category of hyponatremia related to these substances should not be confused with pseudohyponatremia.

Correctly interpreting sodium levels in the blood can reveal pseudohyponatremia, which is helpful in distinguishing it from other forms of sodium deficiency. The main way to manage pseudohyponatremia is by accurately interpreting blood sodium measurements. This, in turn, allows us to identify and treat the cause behind high cholesterol levels, which is often the root of the issue. In some cases, you might need to consult with a kidney specialist (nephrologist) to accurately differentiate the root causes.

What Causes Pseudohyponatremia?

Pseudohyponatremia is a condition that can be caused by a number of diseases or health issues. More often, it is due to extremely high cholesterol levels. If you have an extraordinarily high amount of triglycerides – a type of fat in your blood, it can make your blood look thicker or change color. However, even if excess cholesterol is dissolved in the blood, it might not change the way your blood looks.

This condition can happen when there’s an increase in cholesterol-related substances in your body. Some of these causes include: hypertriglyceridemia (high triglycerides), hyperlipidemia (high fat levels), the buildup of lipoprotein X (often because of blockage in the bile ducts or a condition called primary biliary cirrhosis), and related to a genetic condition called familial hypercholesterolemia.

Pseudohyponatremia can also result from excessively high protein levels in the body, caused by things such as native or externally added immunoglobulins – aka antibodies, which are proteins that your immune system uses to fight off harmful substances. Various conditions can contribute to the increase of protein, including long-term infectious diseases like hepatitis C or HIV, blood disorders like multiple myeloma, POEMS syndrome, and Waldenstrom macroglobulinemia, cancers particularly those related to the lymph system, conditions affecting blood cell production like myelodysplastic syndromes, diseases related to heavy- or light chains – types of antibodies which are overly produced in certain diseases, immune system disorders like amyloidosis – a condition where an abnormal protein builds up in your organs, and even therapy involving intravenous immunoglobulin – a treatment where antibodies are put into your bloodstream to boost your immune system.

Risk Factors and Frequency for Pseudohyponatremia

Evidence of incorrect low readings of sodium levels in the blood because of too much fat in the blood has been found dating back to the 1950s. Though it’s not certain how often this condition, known as pseudohyponatremia, happens, it seems to be more common in people with certain health conditions. These include high levels of fat in the blood, abnormal plasma cells, cancers, and long-term infections such as Hepatitis C and HIV.

Signs and Symptoms of Pseudohyponatremia

If you’re suspected of having pseudohyponatremia, a condition where sodium levels in your blood appear falsely low, it’s critical that your doctor takes a detailed health history and conducts a thorough physical exam. They’ll ask about your symptoms and past health conditions that might cause this sodium discrepancy. True hyponatremia, which is a real low sodium level, has symptoms like fatigue, muscle cramps, changes in thinking, headaches, and seizures. Your doctor will make sure those aren’t present before diagnosing pseudohyponatremia. They’ll also review all the medications you’re taking to make sure none of them could mess with your normal sodium balance.

What’s interesting about pseudohyponatremia is that it’s really a mistaken result from lab technology rather than a condition with physical signs you can feel or your doctor can see during an exam. However, your doctor will still perform certain exams to rule out true hyponatremia, which can be dangerous if not identified and treated. Expect a full checkup of your brain and mental health and potentially your heart and lungs as well all to establish a health baseline for future visits.

Pseudohyponatremia itself doesn’t show any unique physical signs. That said, whether you get more tests may depend on the findings that suggest an underlying problem:

Hypercholesterolemia: Signs may include obesity, peripheral arterial disease, heart disease, and yellowish fatty deposits under your skin (xanthomas).
Hyperproteinemia/hypergammaglobulinemia: If you have a history of cancer, signs of cancer spread, bone lesions, abnormal electrolyte or blood tests, pain, and signs of weakened immunity, more tests might be needed.
Lipoprotein X accumulation: If you experience symptoms like abdominal pain, pancreatitis, itching, yellowing of the skin (jaundice), and xanthomas, this might be the cause.

Testing for Pseudohyponatremia

When doctors suspect a low sodium level condition named pseudohyponatremia, the first step they take is to rule out the possibility of true hyponatremia – an actual low sodium level that can lead to serious health complications and even death if not correctly identified.

To evaluate hyponatremia, your doctor will conduct a detailed examination, noting your current and past health conditions, medicines you’re taking, and checking your overall fluid levels. They’ll also test your blood’s osmolality – a measure of the concentration of particles in your blood. If the osmolality is less than 280 mOsm/kg, it is more likely you have true hyponatremia.

Your doctor will also calculate your blood’s osmolality. If there’s a significant difference between your actual and calculated osmolality, it suggests there may be factors complicating the diagnosis. Once pseudohyponatremia is confirmed, your doctor will explore the possible causes to determine the next stage of the diagnosis and treatment.

In most cases, a specific test called direct ion-selective electrode potentiometry isn’t necessary to confirm pseudohyponatremia. This test might only be considered if it can significantly alter the treatment plan or provide essential diagnostic information.

Direct ion-selective electrode potentiometry could be crucial when multiple complicating factors are involved, which can confuse the diagnosis. Some doctors might also suggest this test if the blood sample looks abnormally fatty, the measured and calculated osmolality values don’t match, or if a person with diabetes shows signs of hyponatremia along with elevated blood sugar levels.

Treatment Options for Pseudohyponatremia

Pseudohyponatremia is a medical condition where a person’s sodium levels look lower than they actually are on lab tests, often as a result of something else going on in the body. Treatments for pseudohyponatremia are focused on addressing the underlying cause:

– Hypercholesterolemia: This means having high levels of cholesterol in your blood. To lower these high cholesterol levels, you might need to change your lifestyle (like modifying your diet or increasing exercise) and/or take certain medications. These changes can usually be gradually implemented and monitored over time while you continue your regular activities.

– Hyperproteinemias and hypergammaglobulinemias: Hyperproteinemia is a condition where there is too much protein in the blood, and hypergammaglobulinemia is a specific type of that where your blood has too many immunoglobulin proteins (these are part of your immune response). The exact protein or antibody that’s causing the issue will determine the appropriate treatment. Additional specialist advice may be needed to manage these conditions properly.

– Lipoprotein X: It’s very rare, but sometimes pseudohyponatremia can result from the build-up of a substance called lipoprotein X in the blood. Nearly all cases of this occur with a condition called cholestasis, which is where your liver struggles to move bile (a liquid produced by the liver that helps to digest fats). So, the management of this condition mainly involves resolving the underlying cholestasis.

– Graft-versus-host disease: This is a complication that can occur after a bone marrow or stem cell transplant, where the donor cells attack the recipient’s body. If pseudohyponatremia appears, it’s usually connected to cholestasis and related high cholesterol levels that can follow certain digestive issues resulting from this disease. The treatment plan often involves managing the immune response, which could include steroid therapy and/or a medication called octreotide. Specialist consultation is typically recommended in these cases.

When a doctor is trying to diagnose pseudohyponatremia, they need to also consider other diseases that are related to low sodium levels in the blood. This is important because sometimes lab mistakes can mask other problems with sodium balance in the body. Also, diagnosing pseudohyponatremia doesn’t mean that other sodium-related disorders are not present.

When exploring low levels of sodium as a diagnosis, the doctor should consider the following conditions:

Hypertonic or isotonic hyponatremia that could be caused by the infusion of substances like mannitol, glucose, glycine, sorbitol, or ethanol.
Hypertonic hyponatremia because of high blood sugar.
Hypovolemic hypotonic hyponatremia that could be due to loss of free water from your digestive system, kidneys, or skin.
Hypovolemic hypotonic hyponatremia due to reduced function of the adrenal glands.
Euvolemic hypotonic hyponatremia can be caused by drinking too much water (psychogenic polydipsia), kidney disease, chronic blockages in the urinary system, an underactive thyroid (hypothyroidism), excessive alcohol consumption without enough food (beer potomania), too much pain or too much diuretic hormone (SIADH).
Hypervolemic hypotonic hyponatremia can be caused by chronic kidney disease, heart failure, or liver disease.
Inherited or developed imbalances of sodium like renal tubular acidosis, Liddle syndrome, Bartter syndrome, Gitelman syndrome, and pseudohypoaldosteronism.

Once other causes of hyponatremia are ruled out, pseudohyponatremia could be related to conditions like high cholesterol, high protein in the blood, excess of the protein “gamma globulin”, and cholestasis which is a condition where the normal flow of bile from the liver is slowed or stopped, leading to the accumulation of a specific lipoprotein (lipoprotein X).

What to expect with Pseudohyponatremia

The results or “outcomes” of a condition called pseudohyponatremia largely depend on what caused it in the first place. If you’re dealing with pseudohyponatremia, doctors generally recommend learning more about the ailment that led to it. This is because understanding the root cause can provide valuable insight into what to expect or “prognosis” of pseudohyponatremia.

Possible Complications When Diagnosed with Pseudohyponatremia

Managing a condition known as hyponatremia, which involves an imbalance of fluid and sodium in the body, can be quite complex. If medical practitioners do not accurately identify and diagnose a subset of this condition known as pseudohyponatremia, it can result in severe health problems, and potentially even death. Therefore, doctors are encouraged to keep an open mind when dealing with hyponatremia, using a patient’s serum osmolality (a measure of the concentration of substances in their blood) to help confirm or rule out pseudohyponatremia.

Furthermore, doing an in-depth review of a patient’s medical records, lab results and past health history can also help identify any factors potentially linked to pseudohyponatremia. In other words, patience and diligence are key to the diagnosis process.

Important Steps and Considerations when dealing with Hyponatremia:

Recognize and accurately diagnose pseudohyponatremia
Maintain a broad perspective when approaching hyponatremia
Use serum osmolality to confirm or rule out pseudohyponatremia
Do a thorough review of the patient’s medical record
Perform a detailed laboratory workup
Take into account the patient’s past medical history

Preventing Pseudohyponatremia

If you’re a patient, it’s crucial to know what your diagnosis means and what it could mean for your health. For those admitted to the hospital, the hospital staff should plan for regular check-ins before you are discharged. This helps everyone stay connected in managing your health care. It’s also smart to double-check your sodium levels in your blood, along with other tests relating to the cause of your illness, to make sure things are resolved or getting better.

You should also know that pseudohyponatremia (a condition where your sodium levels seem too low, but it’s actually due to other factors) does not seem to increase your chances of getting sicker or dying. However, any future treatments should address the health problems that give the false impression of low sodium in your test results.

Frequently asked questions

Pseudohyponatremia is a rare lab mistake that shows a low sodium level in blood test results, even when the sodium concentration is actually normal.

It is not certain how often pseudohyponatremia happens.

Pseudohyponatremia itself does not show any unique physical signs. However, it is important to rule out true hyponatremia, which has symptoms such as fatigue, muscle cramps, changes in thinking, headaches, and seizures. These symptoms will be assessed by your doctor to ensure that pseudohyponatremia is the correct diagnosis. Additionally, if there are findings that suggest an underlying problem, further tests may be needed. These findings and associated signs and symptoms include: - Hypercholesterolemia: Signs may include obesity, peripheral arterial disease, heart disease, and yellowish fatty deposits under the skin (xanthomas). - Hyperproteinemia/hypergammaglobulinemia: If you have a history of cancer, signs of cancer spread, bone lesions, abnormal electrolyte or blood tests, pain, and signs of weakened immunity, more tests might be required. - Lipoprotein X accumulation: Symptoms such as abdominal pain, pancreatitis, itching, yellowing of the skin (jaundice), and xanthomas may indicate this as the cause of pseudohyponatremia. It is important to note that these signs and symptoms are not specific to pseudohyponatremia alone, but rather indicate potential underlying conditions that may be associated with it.

Pseudohyponatremia can be caused by a number of diseases or health issues, including high cholesterol levels, high triglycerides, high fat levels, the buildup of lipoprotein X, familial hypercholesterolemia, high protein levels, long-term infectious diseases, blood disorders, cancers, conditions affecting blood cell production, diseases related to heavy- or light chains, immune system disorders, and therapy involving intravenous immunoglobulin.

The doctor needs to rule out the following conditions when diagnosing Pseudohyponatremia: 1. Hypertonic or isotonic hyponatremia caused by the infusion of substances like mannitol, glucose, glycine, sorbitol, or ethanol. 2. Hypertonic hyponatremia due to high blood sugar. 3. Hypovolemic hypotonic hyponatremia caused by loss of free water from the digestive system, kidneys, or skin. 4. Hypovolemic hypotonic hyponatremia due to reduced function of the adrenal glands. 5. Euvolemic hypotonic hyponatremia caused by drinking too much water (psychogenic polydipsia), kidney disease, chronic blockages in the urinary system, underactive thyroid (hypothyroidism), excessive alcohol consumption without enough food (beer potomania), too much pain or too much diuretic hormone (SIADH). 6. Hypervolemic hypotonic hyponatremia caused by chronic kidney disease, heart failure, or liver disease. 7. Inherited or developed imbalances of sodium like renal tubular acidosis, Liddle syndrome, Bartter syndrome, Gitelman syndrome, and pseudohypoaldosteronism. 8. Conditions like high cholesterol, high protein in the blood, excess of the protein "gamma globulin", and cholestasis.

To properly diagnose Pseudohyponatremia, a doctor may order the following tests: 1. Blood osmolality test: This measures the concentration of particles in the blood. If the osmolality is less than 280 mOsm/kg, it suggests true hyponatremia. 2. Calculated osmolality test: This calculates the blood's osmolality. If there is a significant difference between the actual and calculated osmolality, it suggests complicating factors in the diagnosis. 3. Direct ion-selective electrode potentiometry: This test may be considered if there are multiple complicating factors, if the blood sample looks abnormally fatty, if the measured and calculated osmolality values don't match, or if a person with diabetes shows signs of hyponatremia along with elevated blood sugar levels. This test can provide essential diagnostic information. It's important to note that the direct ion-selective electrode potentiometry test is not necessary in most cases and is only considered if it can significantly alter the treatment plan or provide essential diagnostic information.

Pseudohyponatremia is treated by addressing the underlying cause. The specific treatments depend on the underlying condition causing pseudohyponatremia. For hypercholesterolemia, lifestyle changes such as modifying the diet and increasing exercise, along with medications, may be necessary. Hyperproteinemias and hypergammaglobulinemias require specialist advice to determine the appropriate treatment based on the specific protein or antibody causing the issue. In cases where pseudohyponatremia is caused by the build-up of lipoprotein X, resolving the underlying cholestasis is the main focus of management. If pseudohyponatremia is connected to graft-versus-host disease, the treatment plan often involves managing the immune response with steroid therapy and/or the medication octreotide. Specialist consultation is typically recommended for these cases.

The prognosis for pseudohyponatremia largely depends on the underlying cause. Understanding the root cause can provide valuable insight into what to expect or the prognosis of pseudohyponatremia. It is recommended to learn more about the ailment that led to pseudohyponatremia in order to have a better understanding of the prognosis.

A kidney specialist (nephrologist).

Hormones and Body Chemistry Hyperglycemia Hyperlipidemia Hyperproteinemia/Hypergammaglobulinemia Normal Serum Osmolality