Improper Diagnosis Or Treatment of Hyponatremia

Low sodium, or hyponatremia, is one of the most common electrolyte problems treated in U.S. hospitals. In most patients, hyponatremia is found on bloodwork and easily treated with IV fluids. But when doctors or hospital staff fail to follow the standard of care for correcting sodium, patients can suffer devastating and permanent injury.

This article focuses on the worst-case outcome related to improper diagnosis or treatment of hyponatremia, a condition known as Locked-In Syndrome (LIS).  To help you understand Locked-In Syndrome, we start with the underlying disease process which leads to LIS – Osmotic Demyelination Syndrome (ODS). 

When a Correctable Problem Becomes a Permanent Injury

Who is at risk? Low sodium often develops slowly and quietly. A typical patient might be an older adult on a diuretic for blood pressure, somebody recovering from prolonged vomiting or diarrhea, a patient with heart failure, kidney disease, or liver disease, or somebody taking certain antidepressants or seizure medications. In many cases, the sodium level drifts down over days or weeks without obvious symptoms. By the time the patient arrives at the hospital, often for an unrelated complaint like a fall, confusion, or weakness, the body has already adapted to the lower sodium level. This is what doctors call chronic hyponatremia, and it requires a well-controlled, slow correction with careful monitoring.

What causes ODS? When a doctor sees the abnormal lab result, the instinct is to fix it. The doctor orders hypertonic saline, a solution of sodium chloride (NaCl) in water to be administered to the patient by IV infusion. But the patient’s brain has spent days adjusting to the lower sodium level.  When this happens, the brain cannot keep pace with a fast correction through IV sodium chloride. If the sodium is raised too quickly, the body’s chemistry shifts faster than the brain can tolerate. That is when ODS occurs.

What does ODS do to the brain? The rapid shift in blood sodium damages the protective coating around nerve cells, disrupting how the brain communicates with the body. ODS ranges in severity. Some patients are left with weakness or cognitive problems but retain a meaningful level of independence. Locked-In Syndrome (LIS) describes patients who suffer the worst outcomes from ODS.

In LIS, the patient’s mind works normally. They are awake, aware, and able to think and feel. But they cannot move, speak, or swallow, and many cannot breathe on their own. They are fully conscious inside a body that no longer responds to them.

The Red Flag Timeline: The Biphasic Course

One of the worst features of this injury is its timing. ODS does not show up at the time medical providers are correcting a patient’s blood sodium levels. It shows up days later, after the patient appears to be improving.

This pattern is called the biphasic course, meaning ODS develops over two separate phases. Negligence usually occurs when doctors fail to recognize this pattern and treat the patient within the window of opportunity.

Phase One: The False Recovery. After sodium is corrected, the patient looks better. Confusion clears. Lab values normalize. They eat, talk, and interact with family. The chart shows a patient on the mend. The hospital may start planning to discharge the patient. This phase usually lasts two to three days. During this time, the clinical team often relaxes its monitoring after assuming the patient’s hyponatremic episode is over.

Phase Two: The Crash. Between day two and day six after correction, subtle symptoms appear including:

• Slurred speech.
• Hand tremors;
• Trouble swallowing, even a sip of water;
• A change in facial expression.

These signs are often dismissed as fatigue, medication side effects, or normal hospital fog.

From there, the decline moves fast. Within hours to a day or two, the patient can progress to severe weakness, loss of speech, loss of swallowing, and finally complete paralysis with full awareness. That is when Locked-In Syndrome occurs.

By the time the patient is clearly in crisis, the damage is done and largely permanent. The window to intervene by reintroducing free water and reversing the overcorrection of hyponatremia exists during the period when the patient looks like they are getting better. The negligence almost always lies in what staff failed to notice, report, and act on during that window.

Systemic Hospital Failures

Severe ODS rarely results from a single bad decision by a single provider. It results from a chain of system failures. Each failure on its own might be survivable. Together, they cause permanent injury.

The “Set It and Forget It” Error

A doctor identifies low sodium and orders saline, sometimes hypertonic saline, to correct it. The order is entered in the EMR and the infusion begins. But the order is incomplete. There is no ceiling, meaning no instruction limiting correction to 8 mEq/L in 24 hours, or 10 mEq/L in severe cases. There are no standing orders for blood draws to obtain sodium checks every two to four hours during active correction. There is no automatic stop or review trigger within the hospital’s electronic systems.

The saline runs and the patient’s sodium level climbs. The correction of the blood sodium level overshoots before anyone draws a lab to catch it. In such a situation, a doctor who fails to specify a target blood sodium level and a rate limit for saline, or fails order the lab monitoring needed to enforce that limit, has unnecessarily exposed their patient to an increased risk of ODS and LIS.

The Communication Breakdown

In real-life hospital settings, a critical blood sodium lab result may be resulted for hours without being seen or acted upon. The lab may fail to flag the result and call it to the floor nurse responsible for the patient.  Or despite the lab calling with the critical result, the floor becomes so busy with other patients that nobody acts upon the sharp rise in blood sodium. The patient’s sodium keeps climbing, or has already climbed past the safe threshold without anyone noticing.

A critical lab value that no nurse or doctor reviews or reacts to is, in practice, a lab value that was never drawn. This is often due to a system failure and it reflects the hospital’s failure to put communication protocols in place that match the severity of the harm which can result from ODS.

The Nursing Failure

During the 48 hours after sodium correction, bedside nurses are the front line of neurological monitoring. They see the patient every hour. They are the ones positioned to notice the small change in speech, the new tremor, or the trouble with a sip of water. The standard of care requires them to document these findings and report them to the doctor in real time.

Suppose a nurse notes that a patient’s speech is “a little off” but does not call the doctor. A family member tells the nurse “Mom isn’t herself today,” and the comment goes into a note but is never reported up the chain. Or, a subtle decline in the patient’s level of responsiveness gets attributed to sedation or fatigue without a neurological reassessment. If nursing staff do not appreciate these sometimes subtle changes in the patient, reintroduction of free water to reverse the effects of ODS may come too late.

What Should Be Done When Overcorrection of Sodium Levels Is Recognized

When a doctor realizes that sodium has been corrected too quickly, there is a window of time, typically the first 24 to 48 hours, during which the injury can often be prevented or reduced.

The standard response includes several steps:

Stop the saline. Any ongoing infusion that is raising the sodium is stopped immediately.

Give free water. This is usually done with an IV solution called D5W, which acts as free water in the body. The goal is to dilute the blood and bring the sodium back into the safe range.

Consider desmopressin (DDAVP). This medication signals the kidneys to hold onto water instead of flushing it out. In patients recovering from low sodium, the kidneys often start dumping water on their own, which drives the sodium up even faster. Desmopressin stops that runaway correction.

Check sodium frequently. Labs are typically drawn every two hours so the team can confirm the relowering is working and adjust the plan in real time.

Watch for neurological changes. Bedside checks for slurred speech, tremors, swallowing difficulty, or new weakness continue for several days, because symptoms of ODS can appear well after the correction itself.

If medical providers recognize the problem in time and respond appropriately, ODS can often be prevented or at the very least, severe injury avoided. Once Locked-In Syndrome has developed, symptoms are often entirely irreversible.

This is why the timeline matters so much in these cases. Negligence may begin with the original overcorrection of blood sodium levels. But more troubling is the failure to recognize and respond to the overcorrection during the window when intervention could still have made a difference.

The Human Cost of Locked-In Syndrome

Many Locked-In patients need a ventilator for the rest of their lives because the muscles that control breathing no longer respond. They are fed through a surgically placed feeding tube because they cannot swallow. They cannot speak, so they communicate through eye-tracking devices that read pupil movement to spell words on a screen, one letter at a time. A single sentence can take minutes to produce.

Patients with LIS may need 24-hour skilled nursing, specialized beds to prevent pressure sores, ongoing respiratory care, management of bladder and bowel function, and constant monitoring for the infections that come with total immobility. Lifetime care costs routinely run into tens of millions of dollars. None of that captures what cannot be priced: the loss of every ordinary interaction with friends, family and the world around you, the inability to work and support loved ones, and the inability to enjoy the activities, hobbies, and daily pleasures which make life worth living.

Families bear this with their loved ones. They become full-time caregivers, advocates, and interpreters. Marriages strain. Siblings take on primary care. Children grow up visiting a parent who can see them but cannot hold them.

Proving the Case

Medical malpractice cases involving ODS and Locked-In Syndrome are not won with a general sense of when and how things went wrong. They are won by reconstructing exactly what happened in the hospital, minute by minute during the critical window, and then showing where the standard of care was breached.

This work requires lawyers who understand both the medicine and the systems hospitals are expected to employ to prevent patients from developing ODS and LIS. That means knowing how to read sodium correction curves against EMR audit logs, knowing what to ask nursing supervisors and hospitalists, and knowing how to bring in the right neurology, nephrology, and critical care experts to explain to a jury how a preventable error caused a permanent injury.

If This Has Happened to Your Family

If a loved one developed Osmotic Demyelination Syndrome or Locked-In Syndrome after hospital treatment for low sodium, you should not delay your search for  experienced medical malpractice lawyers who can request medical records, apply their knowledge of ODS to uncover evidence showing improper treatment of hyponatremia, and consult the medical experts necessary to support a case.