Wednesday, March 29, 2023
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Diagnostic errors are a major concern of both patients and physicians.[1] In a recent survey, more than one half of patients said they were very concerned about being diagnosed properly when they see a physician in an outpatient setting.[2] In addition, physicians consistently report encountering diagnostic errors. Moreover, compared with all safety concerns inherent to patient care, physicians worry that diagnostic errors are most likely to cause serious harm or death.[3,4] Malpractice claims bear these findings out: A failure to diagnose properly or a delay in diagnosis are the most common complaints in these claims.[5]
Misdiagnosis in patients with neurologic symptoms may result in ineffective and potentially toxic treatment. For example, misdiagnosis of multiple sclerosis (MS) subjects patients to the adverse effects of disease-modifying agents with no chance of benefit. Misdiagnosis of epilepsy exposes patients to the risks of antiepileptic drugs, as well as loss of a driving license and perhaps even their job.[6] In addition, misdiagnosis fails to address symptoms, delays appropriate therapy, and may engender a worse prognosis. Finally, misdiagnosis results in unnecessary dollar costs to patients and the healthcare system.
In this article, five common misdiagnoses in neurology are discussed. The following patient scenarios are not ranked in any order of importance, frequency, or potential harm.
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A 33-year-old woman has blurry vision, muscle ache, and excessive fatigue. Her left hand goes numb every time she has a headache. She is convinced that she has MS because her sister's friend has the same symptoms. Her primary care doctor ordered an MRI. The radiologist's differential diagnosis of several small T2 lesions included "demyelinating disease," which confirmed her fears. She is referred to neurology clinic for treatment of MS.
Why is this a medical diagnostic error?
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Misdiagnosis of MS is common. In a recent study based on input from neurologists at four academic centers, the most common diagnoses mistaken for MS were migraine with or without other diagnoses (22%), fibromyalgia (15%), nonspecific or nonlocalizing neurologic symptoms with abnormal MRI (12%), conversion or psychogenic disorders (11%), and neuromyelitis optica spectrum disorder (6%).[7] Misdiagnosis resulted in inappropriate treatment for MS with disease-modifying therapy (70%) and even inclusion in an MS research study (4%).
Overreliance on MRI abnormalities in patients with nonspecific neurologic symptoms, as in this case, was one of the leading factors contributing to misdiagnosis.[8] Diabetes, high cholesterol, hypertension, migraine, and smoking, as well as demyelinating disease, may cause T2 hyperintensities on MRI.[8]
MS is a clinical diagnosis that relies on history, symptoms, physical findings, and specific radiographic criteria.[9] An update on the role of MRI in the diagnosis of MS was recently published.[10] Diagnosis of MS can be difficult. In the study by Solomon and colleagues,[7] 24% of the misdiagnoses were made by MS specialists. If there is any uncertainty, patients should be referred to an MS center.
See this article for a more in-depth discussion of MS.
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A 48-year-old woman attended a crowded music festival and suddenly felt like she had to lie down. Her head tingled, and her face and arms went numb. She felt hot and had palpitations, her body shook, and she lost consciousness. Her emergency department evaluation was unrevealing, and she was referred to cardiology and neurology clinics. The cardiology workup was negative.
The patient told the neurologist that over the course of the past several years, she had had other spells where her body suddenly twitched and her head turned to the left. EEG revealed small sharp spikes that were widespread over the temporal regions. She was diagnosed with partial seizures, often called "little seizures" by patients.
Why is this a medical diagnostic error?
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Misdiagnosis of epilepsy is common. In one retrospective study of patients referred to an epilepsy center, nearly 25% had received a misdiagnosis.[11] The most common conditions mistaken for epilepsy are syncope and nonepileptic seizures.[6] Other causes, such as migraine, sleep disorders, and paroxysmal movement disorders, may also be mistaken for epilepsy.[11]
The patient described above had a benign syncopal event, one of the most common reasons for misdiagnosis of epilepsy. When her "little seizures" occurred during a neurologic examination, it was apparent that they were motor tics, not partial seizures.
The main reasons for misdiagnosis of epilepsy are an incomplete history and overinterpretation of the EEG.[6] Multiple normal variants, as well as electrode artifacts, may be mistaken for epileptic discharges.[12] In a retrospective study of patients with nonepileptic seizures initially misdiagnosed as epilepsy, benign variants, such as wicket spikes, hypnagogic hypersynchrony, hyperventilation-induced slowing, and normal variations of background alpha activity, were misinterpreted as epileptic.[11]
A misread EEG may be the sole reason for the misdiagnosis of epilepsy.[13] Because EEGs are often "overread," it has been recommended that all EEGs be interpreted by a specialist in EEG.[14] [Editor's note: The image above depicts an epileptic seizure on EEG.]
See this article for a more in-depth discussion of tic disorders.
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A 65-year-old woman with hypertension, obesity, and a smoking history presented to the emergency department for evaluation of possible stroke. The night before, she noted that her eyes were weeping, and the next morning her face was "crooked." She called her daughter, who said that her mother's words sounded slurred. A stroke code was called, and she was evaluated by the neurologist.
On neurologic exam in the emergency department, the patient was alert and cooperative, with a right facial droop and tearing from her right eye. She could not completely close her right eye. When she tried to close it, her eye rolled upward (palpebral oculogyric reflex, or Bell phenomenon). Apart from right peripheral seventh nerve palsy, her neurologic examination was normal. The neurologist reassured her that this was not a stroke and prescribed prednisone, valacyclovir, lubricating eye drops, and an eye patch. No neuroimaging was ordered.
Why were her symptoms initially diagnosed as a stroke?
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It is no surprise that Bell palsy is sometimes confused with stroke. Public awareness campaigns, such as the National Stroke Association's Act FAST (face, arms, speech, time), highlight facial droop and dysarthria as reasons to rush a patient to the hospital for treatment with tissue plasminogen activator (tPA).[15] Bell palsy is characterized by unilateral facial droop that, if severe enough, may cause difficulty speaking.[16]
However, facial weakness from Bell palsy is due to lower motor neuron dysfunction, whereas facial weakness from a stroke usually stems from upper motor neuron impairment. (In rare cases, a brainstem stroke may cause lower motor neuron involvement.) Paralysis of the forehead muscles suggests lower motor neuron weakness and Bell palsy, whereas preservation of the forehead muscles reflects an upper motor neuron lesion and a stroke. In addition, most strokes that cause facial weakness have other symptoms and signs, such as arm numbness or weakness on the same side.
The time-dependent nature of successful stroke treatment with tPA puts pressure on clinicians to arrive at a rapid diagnosis and predisposes to diagnostic errors. In this case, after the neurologist took the time to complete a thorough examination, the correct diagnosis of Bell palsy was made. The decision not to order any imaging studies was the correct one.
Follow this link for more in-depth discussion on Bell palsy.
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A 77-year-old divorced woman was hospitalized several months ago for pneumonia and new-onset atrial fibrillation. Since discharge, she has trouble keeping track of appointments, misplaces objects in the house, can no longer do crossword puzzles, has difficulty finding words, and sometimes forgets what she is going to say. She has trouble sleeping some nights, and other nights can't sleep at all. She falls asleep while checking her email on the computer, which she never used to do.
The patient was diagnosed with early dementia by her primary care doctor and referred for neurologic workup. After giving details of her symptoms and medical history, she added that it was difficult living alone with so many of her friends dying or sick, and 2 weeks ago, she had to put her dog down. Then, she burst into tears.
Her neurologic exam was normal, as was her MRI. Her scores on the Patient Health Questionnaire 9-item screen for depression and the Generalized Anxiety Disorder 7-item screen were both elevated. Formal neuropsychological testing did not reveal any cognitive deficits.
Why was this patient initially diagnosed with dementia?
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Late-life depression associated with cognitive impairment is often termed "pseudodementia." It may be difficult to distinguish from early dementia due to neurodegenerative disease. Social isolation and chronic physical illness are risk factors for depression. Late-life depression is also a risk factor for dementia.[17] To further complicate matters, neurodegenerative disorders, such as Alzheimer disease, increase the risk for depressive symptoms.
Major depression occurs in more than 10% of patients with Alzheimer disease, and even more often in patients with Lewy body and vascular dementia.[17] (Robin Williams' suicide has been attributed to Lewy body disease.[18]) Because late-life depression and dementia are common, patients may have both syndromes simultaneously. Differentiating major depression from depression secondary to dementia is challenging but can be facilitated by clinical context, neurologic examination, neuroimaging, and neuropsychological testing.[17]
Follow this link for more news regarding the link between depression and dementia.
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The patient is a 35-year-old man with a 10-year history of headaches, which have become more frequent and severe over the past few months. He reports that the headaches are sometimes accompanied by tearing or rhinorrhea. When seen by his general practitioner, his neurologic exam was normal, but his MRI was notable for left frontal sinusitis. He was prescribed antibiotics and a decongestant, and referred to the otolaryngology service. After learning that the patient's headaches were hemicranial; pounding; and associated with photophobia, phonophobia, and nausea and vomiting, the otolaryngologist referred him to the neurology service.
Why is this a medical diagnostic error?
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The most frequent misdiagnosis made in patients with migraine is sinusitis.[18] Autonomic features of migraine may result in tearing or rhinorrhea, causing confusion with sinusitis.[19] Contrary to popular belief, headaches are rarely caused by sinusitis.[20] Sinusitis on CT or MRI is a common finding, and is often clinically irrelevant.[21] However, purulent nasal discharge suggests sinusitis. Inappropriate medical and surgical treatment for sinusitis may delay migraine diagnosis and result in the development of medication overuse headache. Accurate diagnosis of migraine is important because there are proven medications for both prophylactic[22] and abortive[23] therapy.
Clinical characteristics that differentiate migraine from other headache types, including rhinosinusitis, are listed in the comprehensive International Classification of Headache Disorders.[24] A careful history is usually all that is needed to properly classify a patient's headache. However, in the case of worsening headache or change in character of the usual headache pattern, imaging may still be necessary.[25]
Follow this link for more in-depth discussion of assessment of patients with facial pain and headache.
Follow the author at: @drwilner
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