These diseases are commonly misdiagnosed

By Naveed Saleh, MD, MS
Published July 1, 2021

Key Takeaways

Diagnostic error is a major source of preventable harm, according to a study published in Diagnosis. According to the authors, diagnostic errors are the most frequent, catastrophic, and costly medical errors underlying closed malpractice claims.

They discovered that “nearly three-fourths of serious misdiagnosis-related harms are attributable to diseases in just three major categories—vascular events, infections, and cancers (the 'Big Three'). Perhaps more importantly, we found that nearly half of the serious harms from diagnostic error are attributable to one of just 15 disease states (aggregating the top five diseases from each category)."

Almost half of the high-severity harms involved death and the other half represented serious, permanent disability. “Failures in clinical judgment were, by far, the leading identified cause of serious misdiagnosis-related harms,” the authors wrote.

Fortunately, not all cases of misdiagnosis result in death or disability. However, many misdiagnoses can pose serious harm. Here’s a look at five commonly misdiagnosed conditions.


Unlike unipolar depression, patients with bipolar depression often cycle between manic and depressed states. Because depressive states are diagnosed the same in both conditions, confusion can arise.

According to the authors of a review published in the International Journal of Bipolar Disorders, “The range of symptoms seen in unipolar and bipolar depression do not differ, consistent with our classification systems that use the same diagnostic criteria for both syndromes. Some symptoms are more common in bipolar depression, including hypersomnia, hyperphagia/weight gain, psychomotor retardation and psychotic symptoms. However, no single symptom or group of symptoms reliably distinguishes unipolar from bipolar depression.”

Problems can arise when physicians prescribe antidepressants instead of mood stabilizers for patients with bipolar depression. (Prescription of antidepressants to those with bipolar disorder is a highly controversial topic in the field of psychiatry.) In those with bipolar depression, antidepressants can induce a manic/hypomanic state or trigger rapid cycling.

Click here to read about the top 10 medication errors and hazards at MDLinx.   


Although there is no cure for lupus, treatment effectively reduces the number of disease flare-ups. The problem, however, is that lupus is notoriously difficult to diagnose, and has been called the “great imitator.”

According to the CDC, “Lupus can be hard to diagnose because it has many symptoms that are often mistaken for symptoms of other diseases. Many people have lupus for a while before they find out they have it.” 

Lupus can affect nearly any organ system. Among its many manifestations are rash, anemia, muscle/joint pain, kidney problems, heart disease, eye disease, and clotting issues. For instance, one patient with lupus may present with swollen knees and fever while another presents with fatigue and kidney problems.

Diagnosing lupus includes medical history, family history of lupus or other autoimmune diseases, physical exam, blood/urine tests (eg, positive ANA), and skin/kidney biopsy.


When patients present with an infection, they often expect that they will receive a drug to treat it. The problem is that viral infections shouldn’t be treated with antibiotics. Nevertheless, physicians ostensibly continue to confuse the two treatments, according to an oft-cited article published in JAMA in 2016.

The investigators found that overall, per 1,000 population, 506 antibiotics were prescribed between 2010 and 2011, whereas only 353 prescriptions were appropriate and met guidelines. With respect to acute respiratory infections, 221 were prescribed, whereas only 111 were needed.

Antibiotics are not benign and can pose health risks, such as allergic reactions and Clostridium difficile infection. Moreover, overprescription contributes to increasing rates of antibiotic resistance, which is a burden on society as a whole.

According to the authors, “Effective interventions to reduce inappropriate prescribing, such as clinician and patient education, audit-and-feedback, academic detailing, communication training, rapid diagnostics, clinical decision support, and delayed prescriptions, can be used in ambulatory care settings to improve appropriate antibiotic use.”

Multiple sclerosis

This is another condition that is often confused with other autoimmune diseases (eg, lupus, myasthenia gravis, sarcoidosis); infectious disease (Lyme); and vascular disease (stroke). Of note, common symptoms of multiple sclerosis are visual (diplopia, optic neuritis); facial sensory loss; cerebellar (nystagmus, ataxia); and motor loss.

“Misdiagnosis of multiple sclerosis (MS) (the incorrect assignment of a diagnosis of MS) remains a problem in contemporary clinical practice. Studies indicate that misdiagnosed patients are often exposed to prolonged unnecessary health care risks and morbidity,” according to the authors of an article published in Neurology.

“The recently published 2017 revision of the McDonald criteria for the diagnosis of MS provides an opportunity to consider the effect of these revisions on the problem of MS misdiagnosis. The 2017 McDonald criteria include several new recommendations to reduce the potential for misdiagnoses. The criteria should be used for the types of patients in which validation studies were performed, specifically those patients who present with typical demyelinating syndromes. MRI lesion characteristics were defined for which McDonald criteria would be expected to perform with accuracy,” they added.

Lyme disease

The bacteria that result in Lyme disease are difficult to detect with modern lab tests. Patients often test positive for Lyme disease despite their illness having a different bacterial nidus.

“People may test positive because they were infected with the Lyme disease bacteria at some point during their lives, but the infection may not be active and may not cause any illness,” according to Michigan Medicine. “People may test negative when they actually have been infected.”

Chronic Lyme disease can present similarly to other chronic illnesses, including juvenile idiopathic arthritis, fibromyalgia, and myalgic encephalomyelitis/chronic fatigue syndrome, as well as multiple sclerosis and arthritis.

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