Why Is Multiple Sclerosis Misdiagnosis So Common?

The signs and symptoms of multiple sclerosis (MS) overlap with many other conditions. This makes misdiagnosis common.

Further, MS isn't fully understood, which makes differential diagnosis (a way of ruling out or confirming other, similar conditions) a complicated and time-consuming process. Getting an MS diagnosis involves verifying the presence of MS lesions that show up as white spots on MRI (magnetic resonance imaging) scans. Unfortunately, getting an accurate MS diagnosis often takes a long time.

This article discusses the challenges of diagnosing MS and why misdiagnosis can occur.

MS Diagnosis

Diagnosing MS is complex. There isn't a singular, definitive test for multiple sclerosis diagnosis. So, getting an MS diagnosis involves a multifaceted diagnostic process that includes:

• Medical history review
• Neurological exam
• Differential diagnosis
• Lumbar puncture (spinal tap)
• McDonald criteria
• MRI
• Evoked potential tests (VEP or SEP)

MS diagnosis typically requires ruling out other conditions that might be causing symptoms through a process called differential diagnosis. For example, there isn't a blood test for MS, but extensive blood work results help rule out or confirm MS mimics, which include many autoimmune and chronic inflammatory diseases with similar symptoms.

In 2017, the McDonald criteria, which is a tool that's considered the gold standard for diagnosing multiple sclerosis using MRI, was updated. This update is expected to reduce misdiagnosis and speed up the diagnostic process, which will give MS patients access to the right treatment options sooner.

According to the McDonald criteria, the key requirement for an MS diagnosis remains evidence of damage to the CNS. More specifically, CNS damage needs to demonstrate dissemination in time (DIT) and dissemination in space (DIS), which means that damage occurred on different dates at least 30 days apart and affected at least two different parts of the CNS. Together, DIT and DIS distinguish MS from other neurological conditions.

Challenges to MS Diagnosis

Because a specific disease biomarker for MS doesn't exist, confirming an MS diagnosis usually isn't a straightforward process. The signs and symptoms of MS manifest in different and unpredictable ways that vary from patient to patient.

A 2016 study found that leading factors contributing to MS misdiagnosis include being thrown off by symptoms caused by other diseases affecting the myelin sheath and misidentifying white spots on the brain in MRIs that look like MS lesions but aren't.

MS isn't the only condition that causes white spots to show up on MRIs, making accurate diagnosis incredibly challenging. For example, migraines can be a cause of non-MS white spots on MRIs.

Copycat Conditions

Many diseases and disorders share symptoms with multiple sclerosis. These MS mimics need to be ruled out during differential diagnosis. Some of these conditions include:

• Chronic inflammatory disease, including vasculitis, lupus, and Sjögren's syndrome
• Infections of the central nervous system, including Lyme disease and syphilis
• Hereditary disorders
• Brain tumors
• Vitamin B12 deficiency
  
• Migraines
• Neuromyelitis optica spectrum disorder (NMOSD)
• Acute disseminated encephalomyelitis (ADEM)
• Other damage to the brain or spinal cord

Early Signs of MS

Although every individual experiences the early signs of MS uniquely, and no two people are likely to experience the exact same symptoms, there are some common early warning signs of MS, including:

• Fatigue and weakness
• Blurry or foggy vision or other vision problems, including jerking or uncoordinated eye movements and double vision
• Numbness and tingling
• Muscle spasms (spasticity)
• Tremor
• Neuropathic pain
• Bladder dysfunction
• Bowel problems (constipation, fecal incontinence)
• Cognitive problems
• Dizziness or balance problems
  

The term "clinically isolated syndrome" (CIS) refers to the first time someone experiences a neurological episode caused by inflammation and damage to their nerves' myelin sheath. CIS is typically followed by a period of recovery when an early warning sign temporarily goes away. MS can only be officially diagnosed after someone has experienced more than one CIS episode.

When to See a Healthcare Provider

You should always see a healthcare provider if you're experiencing new MS symptoms. Although acute MS symptoms are distressing and can be painful, they're rarely life-threatening. During MS flare-ups or pseudo-exacerbation, it typically takes over 24 hours to know if you're actually having an MS attack.

You may need to visit the emergency room during an MS attack if you suddenly experience any of the following severe symptoms:

• Intense pain
• Vision loss in one or both eyes
• Suddenly can't walk, use your limbs, or eat
• High-grade fever (usually 103 degrees Fahrenheit or higher)

Summary

MS misdiagnosis is surprisingly common. This is because there is no single test to diagnose MS, and MS can present similarly to other central nervous system conditions. Often, differential diagnosis is needed to rule out other conditions that may be causing symptoms. Updated diagnostic criteria and a new MRI technique that looks at a patient's central vein sign profile show promise for reducing the rate of MS misdiagnosis.

A Word From Verywell

Misdiagnosing MS can have harmful effects. A person may be started on an unnecessary treatment course with possibly detrimental side effects. That's why it's so important to work with your healthcare team to accurately diagnose MS and rule out every other possible reason for your symptoms. Patience is key when getting an accurate MS diagnosis and avoiding misdiagnosis.