upper and lower mn....................ppt

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1. Spotlight
A Reflexive Diagnosis in
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Primary Care

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•This presentation is based on the April 2014
AHRQ WebM&M Spotlight Case
–See the full article at http://webmm.ahrq.gov
–CME credit is available
•Commentary by: John Betjemann, MD, and S.
Andrew Josephson, MD, University of California,
San Francisco
–Editor, AHRQ WebM&M: Robert Wachter, MD
–Spotlight Editor: Bradley A. Sharpe, MD
–Managing Editor: Erin Hartman, MS
Source and Credits

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Objectives
At the conclusion of this educational activity, participants should
be able to:
•Appreciate that primary care doctors (PCPs) 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
•Discuss the need in primary care to have a low threshold to
refer for neurologic consultation

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Case: Reflexive Diagnosis
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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.

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Case: Reflexive Diagnosis (2)
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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 MRI study 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.

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Case: Reflexive Diagnosis (3)
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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 might have
arrived at the diagnosis earlier or made a more urgent referral
to neurology.

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Background
•The global burden of neuropsychiatric disease is increasing
–By 2020, cerebrovascular disease (e.g., stroke) and dementia are
projected to be among the top 10 leading causes of disease in
developed regions
•Given this rise and the increasing focus on primary care, PCPs are
likely to be increasingly managing neurologic conditions
•Limited data exist to suggest how often patients with neurologic
conditions present to their PCP or what the most common
neurologic complaints might be
•Neurologic complaints are common in the general population
–Estimated 1-year prevalence of migraine, epilepsy, and multiple
sclerosis per 1,000 people is 121, 7.1, and 0.9, respectively
–Annual incidence of spinal cord injury is 4.5/100,000

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Background (2)
•A survey of family or general
practitioners found that neurologic
issues were addressed in
approximately 9% of patient visits
•The most commonly encountered
neurologic disorders were pain
(including back pain), headache,
peripheral neuropathy,
dizziness/vertigo/tinnitus,
cerebrovascular disorders, epilepsy,
dementia, and Parkinson disease

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Spinal Cord Disease
•Disorders of the spinal cord, as in this case, remain a
common problem encountered by primary care
physicians and neurologists
•An MRI-based study of the cervical spine found that
more than 80% of asymptomatic men and women older
than 60 had evidence of degenerative disk disease of
the spine
•A study of 3781 patients newly referred to a neurologist
found that spinal disorders were the 7th most common
diagnosis made by the neurologist

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Diagnostic Errors
•This case illustrates a common error in diagnosis and
neurologic localization, one of the more common errors
seen with neurologic conditions
•In general, diagnostic errors are common, with
incidence ranging from 10%−20%
•Premature closure (the failure to continue considering
reasonable alternatives after an initial diagnosis was
reached) may be the most common cognitive error
•In another study, delays in appropriate referral or
consultation were the second most common phase
where mistakes were made

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Diagnostic Error in This Case
•Based on the information available, 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
•Peripheral neuropathy is common in the primary care setting,
so there may also have been an availability bias (assuming
that the first possibility that comes to mind is the most likely
possibility) that contributed to this error
•Lastly, the second pair of providers who saw the patient did
not seem to consider alternative diagnoses, which may have
been an anchoring bias (the tendency to hold on to the initial
diagnosis, even in the face of disconfirming evidence)

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Solutions to Diagnostic Errors
•Solutions to 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
•More information is available in other AHRQ WebM&M
articles (see notes)

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Enhanced Education
•Training programs for primary care providers should
identify which neurologic conditions commonly present
to general medicine clinics
–This may allow for better recognition of spinal cord injury
•In one study, spinal cord compression was the most
frequently missed neurologic condition

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Screening Neurologic Exam
•The missed diagnosis in this case stemmed from
performing an incomplete screening neurologic exam
•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 (from
brain or spinal cord injury) and a lower motor neuron
injury (peripheral neuropathy)

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Upper vs. Lower Motor Neuron
Upper Motor Neuron Signs Lower Motor Neuron Signs
Hyperreflexia Hyporeflexia
Increased tone (spasticity)Normal or decreased tone
Absence of fasciculationsFasciculations
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

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Upper vs. Lower Motor Neuron (2)
•Determining upper vs. lower motor neuron weakness
early can be essential
•Many of the causes of upper motor neuron weakness
are more serious or urgent (as in this case)
•In this case, the findings of hyperreflexia and spasticity
(described in a later exam) would strongly suggest an
upper motor neuron process
•This finding should have prompted imaging of the
central nervous system

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Peripheral Neuropathy
•The two most common causes of peripheral neuropathy
in the United States are diabetes and alcohol use
•Peripheral neuropathy usually presents with length-
dependent (i.e., legs first) distal sensory changes and
hyporeflexia
•Diffuse weakness in all extremities argues against a
pure sensory neuropathy

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Red Flags in Neurology
•The case also highlights the need to recognize red flags
in neurology
•New back pain in a patient with neurologic complaints
should be very concerning
•A key additional red flag to inquire about is bowel or
bladder dysfunction (e.g., incontinence, urinary
retention)
–These may indicate a spinal cord process

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High-Yield Screening Exam in Neurology
•Busy providers who may only have 15 minutes for a visit
cannot be expected to complete a detailed neurologic
examination
•A brief, focused, high-yield exam can be performed in
minutes (see next 2 slides)
•If focal abnormalities are noted on the screening exam,
a more detailed examination can be performed in that
particular area

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Elements of High-Yield Screening Neurologic Exam
•Mental Status
–Orientation: date and location
–Attention: digit span
–Language: naming repetition and comprehension
•Cranial Nerves
–Pupillary responses
–Visual fields
–Extraocular movements
–Facial symmetry
•Motor
–Assess bulk and tone
–Pronator drift
–Finger and foot taps
–Extensors in the arms and flexors in the legs

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Elements of High-Yield Screening Neurologic Exam (2)
•Reflexes
–Biceps, brachioradialis
–Knees, Achilles
•Sensory
–Assess for patterns of sensory loss (distal>proximal, sensory
level, etc.)
•Coordination
–Finger-nose-finger
–Heel-knee-shin
•Gait
–Observe casual gait (stride length, arm swing, posture, turning)
–Tandem gait

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Referral to Neurology
•Creating clear guidelines for when a PCP should refer to a
neurologist given the myriad neurologic conditions and their
varied presentations is challenging
•PCPs should have a low threshold to refer patients to
neurology
–Should be considered when symptoms worsen and a satisfactory
diagnosis remains elusive
•A possible future shortage of neurologists may prompt
opportunities for novel methods of care delivery
•A recent report from American Academy of Neurology
Telemedicine Work Group discusses potential opportunities
for telemedicine particularly in remote or underserved
populations

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Take-Home Points
•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 avoiding future errors