Researchers found that nearly 1 in 5 people who had received a diagnosis of multiple sclerosis had other unrelated conditions.

Multiple Sclerosis

Multiple sclerosis (MS) is a widespread disabling neurological condition.  In MS the immune system attacks and destroys the tissue (myelin) that surrounds the nerves. This leads to nerve damage, which affects communication between the nerves and the brain.  People with MS may experience symptoms, including numbness or weakness in the limbs, tremors, and lack of coordination. However, some of the symptoms have similarities to other conditions, including stroke and migraine.

MS and conditions such as stroke are very different conditions, but they both harm the brain. Some of the symptoms they share include attention issues, dizziness, numbness in the limbs, slurring, visual impairment, and difficulty in walking.  MS and migraine attacks also have some symptoms in common, including dizziness and vision impairment. The symptoms of MS are so similar to the symptoms of some other conditions that it can be difficult at times for physicians to make the right diagnosis. Moreover, the results of MRI testing results can look like other conditions, such as stroke, migraines, and vitamin B12 deficiency.

Identifying traits in misdiagnosed people

A recent study combined data from multiple studies on people who had received an MS diagnosis in error.  The goal of the study was to determining how many people received a misdiagnosis of MS, and better understand common characteristics that lead to a misdiagnosis of MS.  The study analyzed the cases of 241 people who had received an MS diagnosis.

The analysis found that, of the 241 patients reviewed, 110 were misdiagnosed.  Of the misdiagnosed patients, 51 (46%) were classified as “definite” and 59 (54%) “probable” misdiagnoses according to study definitions.  

For most of the misdiagnosed cases the researchers were able to identify alternate diagnoses that included:

The study also found that the average duration of misdiagnosis was 10 years or longer in 36 (33%) of the cases and an earlier opportunity to make a correct diagnosis was identified for 79 patients (72%).  Seventy-seven (70%) of the misdiagnosed cases received disease-modifying therapy (a drug to treat MS) and 34 (31%) experienced unnecessary health issues because of misdiagnosis.  Four (4%) of the mis-diagnosed patients had participated in a research study of an MS therapy. 

The primary factors leading to a misdiagnosis were:

• Not considering symptoms that were not typical for MS
• Lack of objective evidence of brain injury that is indicative criteria for MS attacks, and
• Ooverreliance on MRI abnormalities in patients with nonspecific neurologic symptoms.

The researchers identified that the condition most often correctly diagnosed was migraine, followed by radiologically isolated syndrome — a condition where the results of MRI scans determined that the people had MS, despite them not experiencing any other symptoms linked to MS.

Risks and costs of incorrect diagnoses

Among people who received a wrong diagnosis, 72 percent had received treatment for MS, and of those, 48 percent had received treatments that can lead to a serious adverse effect (progressive multifocal leukoencephalopathy – PML – a rare viral infection that targets nerve cells and damages the white matter in the brain).

The researchers also found that of the people misdiagnosed with MS, many received MS treatment for 4 years before receiving the right diagnosis.  The researchers concluded that the estimated costs of unnecessary treatments that they identified in just this study reached almost $10 million.

The cost of mis-diagnosed MS to the patient is huge — medically, psychologically, financially.  The researchers hope that their findings, along with recently funded research, will help to prevent MS misdiagnoses in the future and help improve diagnosis and treatments for people with the disease.