Modified Rankin Scale Score: mRS 1
This patient should be assigned a Modified Rankin Scale score of 1 (Symptomatic but Nondisabled), as she has fully recovered from all stroke symptoms and can carry out all usual duties and activities, despite having pre-existing left leg numbness from a lumbar disc herniation that predates the stroke. 1
Rationale for mRS 1 Assignment
The key principle in mRS scoring is that the scale measures disability attributable to the stroke, not pre-existing conditions. According to the 2021 STAIR XI consensus guidelines, mRS 1 is defined as a patient who can "do work/leisure/school activities fulltime" but "has symptoms" 1. The standardized health state term for this level is "Symptomatic but Nondisabled" 1.
Critical Distinction: Stroke-Related vs. Pre-Existing Disability
- The patient has no residual stroke symptoms (complete stroke recovery)
- The left leg numbness is from a pre-existing lumbar disc herniation that occurred one year before the stroke
- Pre-stroke mRS should be evaluated separately from post-stroke mRS 2
- The mRS is designed to measure post-stroke recovery, not aggregate all medical conditions 2
Why Not mRS 0?
mRS 0 requires "No symptoms" at all 1. Since this patient has ongoing left leg numbness (even though it's not stroke-related), she technically has symptoms. However, the critical question is whether these symptoms prevent her from carrying out all usual duties and activities.
Why Not mRS 2?
mRS 2 ("Disabled but Independent") is defined as a patient who "can't do work/leisure/school activities fulltime" but can "live alone for >1 wk" 1. The question explicitly states she "recovered from all the stroke symptoms," implying she can perform her usual activities.
Common Pitfall to Avoid
Do not conflate pre-existing disability with stroke-related disability. The mRS should reflect the patient's functional status as it relates to the stroke event. If the lumbar disc herniation was causing significant functional impairment before the stroke, that would be captured in a pre-stroke mRS assessment, but the post-stroke mRS should reflect recovery from the stroke itself 2, 3.
Practical Application
When assessing this patient:
- Ask specifically: "Can you do all the work, leisure, and daily activities you were doing before the stroke?"
- If yes → mRS 1 (she has symptoms but is functionally nondisabled from the stroke)
- The pre-existing numbness does not change this assessment unless it independently prevents her from performing these activities
The 2021 consensus guidelines emphasize that mRS 1 patients are "able to carry out all usual duties and activities" despite having symptoms 1, which precisely describes this clinical scenario.