A "Reflexive" Diagnosis in Primary Care
- Appreciate that primary care doctors may be caring for an increasing number of patients with neurologic conditions.
- Describe the need to differentiate between upper motor neuron and lower motor neuron disease.
- State that spinal cord injuries are common and often misdiagnosed.
- Appreciate the value of a high-yield screening neurologic exam in primary care.
- State the need in primary care to have a low threshold to refer for neurologic consultation.
A 54-year-old man with no significant past medical history presented to a new primary care physician complaining of 2 years of progressive bilateral hand and foot paresthesias, pain, and weakness. Due to these symptoms, he had multiple falls and an inability to grasp simple objects. At the time, the primary care doctor documented 4/5 weakness in all extremities and a loss of sensation in his hands and feet bilaterally. Based on this, the patient was diagnosed with a peripheral neuropathy (a loss of sensation that typically begins in the hands and feet) and referred to see a neurologist sometime in the next 3 months.
Over the next 10 weeks, the patient returned 2 more times to the same clinic with worsening symptoms, including more frequent falls and new back pain. He saw two different providers who did not order any additional diagnostic testing and treated him supportively, assuming his symptoms were due to the previously diagnosed peripheral neuropathy.
When he was finally seen in the neurology clinic, the exam revealed hyperreflexia and increased tone in all extremities. This was most consistent with a spinal cord process and not a peripheral neuropathy. The neurologist ordered an urgent magnetic resonance imaging (MRI) of the spinal cord, which revealed critical cervical (neck) cord compression, so tight that it placed the patient at risk for permanent paralysis. He was admitted to the hospital and underwent urgent neurosurgical decompression.
Unfortunately, likely due to the delay in making the diagnosis and surgery, the patient still has some weakness in his legs and persistent nerve pain.
A root cause analysis of the case revealed that none of the doctors who had seen the patient had performed an exam of the reflexes or assessed for overall muscle tone. The safety committee felt if these components of the exam had been performed, the providers may have arrived at the diagnosis earlier or may have made a more urgent referral to neurology.
From 1990–2020, the share of total global burden of disease from neuropsychiatric disorders is estimated to rise from 10.5% to 14.7%.(1) By 2020, both cerebrovascular disease and dementia are projected to be among the top 10 leading causes of disease burden for developed regions.(1) This large prevalence of neurologic disease coupled with an increasing emphasis on primary care-focused medical homes implies that primary care providers are likely to be increasingly managing neurologic conditions.
Limited data exist to suggest how often patients with neurologic conditions present to their primary care provider (PCP) or what the most common neurologic complaints might be. Yet, we know that neurologic complaints are frequent in the general population. The estimated 1-year prevalence of migraine, epilepsy, and multiple sclerosis per 1000 people is 121, 7.1, and 0.9 respectively.(2) Among the elderly, the prevalence of Alzheimer dementia is 67/1000 and Parkinson disease is 9.5/1000.(2) More germane to this case, the annual incidence of spinal cord injury is 4.5/100,000.(2) These figures translate to millions of people in the United States living with these relatively common neurologic disorders. A survey of family or general practitioners found that neurologic issues were addressed in approximately 9% of patient visits; the most frequently encountered neurologic disorders were pain (including back pain), headache, peripheral neuropathy, dizziness/vertigo/tinnitus, cerebrovascular disorders, epilepsy, dementia, and Parkinson disease.(3) A second study examining both rural and urban primary care settings found that 10.7% of patients presented with neurologic symptoms.(4)
Disorders of the spinal cord, as in this case, remain a common problem encountered by PCPs and neurologists alike. A prospective study demonstrated that cervical spondylotic myelopathy (spinal cord dysfunction from direct impingement of the cord resulting from age-related degenerative changes of the spinal discs and facet joints) was the most frequently diagnosed etiology for nontraumatic spastic paraparesis and tetraparesis.(5) A magnetic resonance imaging-based study of the cervical spine found that 57% of asymptomatic patients older than 40 years, as many as 86% of asymptomatic men, and 89% of women older than 60 years had evidence of degenerative disk disease.(6) A study of 3781 patients newly referred to a neurologist found that spinal disorders were the 7th most common diagnosis made by the neurologist, after only headache, psychological/functional, epilepsy, peripheral nerve/neuromuscular, miscellaneous neurological, and multiple sclerosis/demyelinating.(7)
This case illustrates a common error in diagnosis and neurologic localization, which in our experience is one of the more typical errors seen with neurologic conditions. Generally speaking, diagnostic errors throughout medicine are quite prevalent, with an overall incidence ranging from 10%–20%, resulting in 40,000–80,000 deaths per year and countless more injuries.(8) In a study of 100 diagnostic errors involving internists, cognitive factors played a role in 74%. The researchers found premature closure, "the failure to continue considering reasonable alternatives after an initial diagnosis was reached," to be the most common cognitive error.(9) A separate survey study of diagnostic errors revealed that mistakes occur most frequently in the testing and assessment phases (during the initial evaluation of complaints where there is a failure to consider alternative or competing diagnoses).(10) Delays in appropriate referral or consultation were the second most common phase where mistakes were made.(10)
Based on the information available for the present case, there appears to have been a delay in diagnosis of a spinal cord injury. There may have been a cognitive error of premature closure around the diagnosis of peripheral neuropathy. In addition, peripheral neuropathy is quite common in the primary care setting, so there may also have been an availability bias that contributed to this error. Last, the second pair of providers who saw the patient did not seem to consider alternative diagnoses, which may have been an anchoring error.
Solutions to premature closure and other cognitive biases and diagnostic errors are not straightforward and are difficult to solve with systems changes. Instead, experts advocate for more focused educational efforts and harnessing information technology.(11) A full discussion of preventing cognitive or diagnostic errors is beyond the scope of this commentary, but more information is available in other AHRQ WebM&M articles.(12-14)
Regarding enhanced education for PCPs, training programs should identify which neurologic diseases commonly present to general medicine clinics so that student and resident education can focus on these conditions. One challenge is that, like many neurologic conditions, spinal cord compression can present in a variety of ways, underscoring the importance of formulating a broad differential diagnosis. A recent study of diagnostic errors in primary care settings found that a differential diagnosis was not present in 81.1% of index visits and that practitioners copied and pasted prior notes in 7.4% of cases.(15) In that same study, spinal cord compression was the most frequently missed neurologic condition. PCPs and specialists need to be vigilant about improving communication, specifically seeking out and providing feedback once a patient has been evaluated in a specialty clinic.
This missed diagnosis stemmed from performing an incomplete screening neurologic exam and overlooking a few important "red flags." In any patient presenting with muscle weakness, the first critical step is to use the history and examination to distinguish between an upper motor neuron lesion resulting from brain or spinal cord injury and a lower motor neuron injury from peripheral neuropathy (Table 1). Determining upper motor neuron versus lower motor neuron weakness early on can be essential as many of the causes of upper motor neuron weakness are more serious or urgent conditions (as in this case). The key findings of hyperreflexia and spasticity (described in a later exam) would strongly argue in favor of an upper motor neuron process and should have prompted imaging of the central nervous system.
Peripheral neuropathy, on the other hand, tends to present as a length-dependent neuropathy, often resulting in hyporeflexia (decreased reflexes) in the distal limbs. The two most common etiologies for peripheral neuropathy in the US are diabetes and alcohol use. These two conditions tend to cause a symmetric, length-dependent sensory neuropathy, and the finding of diffuse weakness in all extremities argues against a pure sensory neuropathy. Regarding red flags, the fact that the patient returned with new back pain should have been very concerning, as this can point to a spinal cord localization for weakness. Incorporating this new symptom into a revised differential diagnosis may have helped to overcome the potential anchoring. Though not specifically mentioned in this case, an additional red flag to inquire about is bowel/bladder dysfunction (e.g., incontinence, urinary retention), as these symptoms can be an important clue to a spinal cord process.
In addition to highlighting the need to determine upper versus lower motor neuron weakness and recognizing red flags, the case also highlights the importance of a high-yield screening neurologic exam. Busy PCPs who may only have 15 minutes for a visit cannot be expected to complete a detailed neurologic examination. Yet, a brief, focused, high-yield exam can be performed in 5 minutes and help avoid missing key diagnoses. Components of a high-yield neurologic screening exam are listed in Table 2 and should be performed on all patients with neurologic complaints. If focal abnormalities are noted on the screening exam, a more detailed examination can be performed in that particular area.
Many neurologic conditions can be managed by a PCP (e.g., early peripheral neuropathy), but some patients will need to be referred to see a neurologist. It is challenging to create clear concrete guidelines for when a PCP should refer to a neurologist given the myriad neurologic conditions and their varied presentations. Overall, PCPs should have a low threshold to refer a patient for neurologic consultation especially when symptoms worsen and a satisfactory diagnosis remains elusive. Studies examining referral patterns have demonstrated disagreement between PCPs and neurologists over the extent of specialty involvement, with neurologists favoring more specialty involvement for common neurologic conditions.(16,17) Although patients with common neurologic conditions such as Parkinson disease tend to have fewer complications and hospitalizations when treated by a specialist (18,19), the upcoming shortage of neurologists in the US is likely to mean that PCPs will be asked to take a larger role in caring for neurologic conditions. This potential shortage of neurologists may also provide opportunities for novel methods of care delivery. A recent report from the American Academy of Neurology Telemedicine Work Group discusses potential opportunities for telemedicine particularly in remote or underserved populations.(20)
In this case, a delay in correct diagnosis and referral to a specialist are likely responsible for the patient's permanent neurologic symptoms. This case illustrates several key points in the management of common neurologic disease in a primary care setting.
- The burden of neurologic diseases is increasing and thus PCPs may be responsible for caring for a significant proportion of patients with neurologic conditions.
- Incorporating an efficient yet thorough screening neurologic exam into primary care visits is critical in avoiding diagnostic errors.
- The distinction between an upper and lower motor neuron lesion is crucial in forming a differential diagnosis and guiding diagnostic and therapeutic strategies.
- Tailoring primary care training towards the neurologic diseases commonly encountered in general medicine clinics may help to overcome errors in diagnosis.
- PCPs should have a relatively low threshold to refer to a neurologist and improved communication and feedback between the two parties is vital to preventing future errors.
John Betjemann, MD
Assistant Professor of Neurology
University of California, San Francisco
S. Andrew Josephson, MD
Associate Professor and Vice Chairman
Department of Neurology
University of California, San Francisco
Faculty Disclosure: Drs. Betjemann and Josephson have declared that neither they, nor any immediate member of their families, have a financial arrangement or other relationship with the manufacturers of any commercial products discussed in this continuing medical education activity. In addition, the commentary does not include information regarding investigational or off-label use of pharmaceutical products or medical devices.
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Table 1. Upper motor neuron versus lower motor neuron exam findings. Note that all signs in each column need not be present.
Upper Motor Neuron Signs
Lower Motor Neuron Signs
Increased tone (spasticity)
Normal or decreased tone
Absence of fasciculations
Mild or no atrophy
More profound atrophy
Weakness in pyramidal pattern
• Arms: Extensors weaker than flexors
• Legs: Flexors weaker than extensors
Variable patterns of weakness
High-Yield Screening Neurologic Exam
• Orientation: date and location
• Attention: digit span
• Language: naming repetition and comprehension
• Pupillary responses
• Visual fields
• Extraocular movements
• Facial symmetry
• Assess bulk and tone
• Pronator drift
• Finger and foot taps
• Extensors in the arms and flexors in the legs
• Biceps, brachioradialis
• Knees, Achilles
• Assess for patterns of sensory loss (distal>proximal, sensory level, etc.)
• Observe casual gait (stride length, arm swing, posture, turning)
• Tandem gait