Diagnosing Neuropathy
Clinical Pearls
Sir William Osler (1849 – 1919), Canadian physician
Presentation
Referral "neuropathy," self-dx googling numbness/tingling
-hard numbness≠tingling≠weakness
-true negative sx (loss) are more specific
>unable to feel floor T°
>unable to sense sand/cold surfaces
-positive sx (gain) are nonspecific
>dd: CVI, MSK, compression, positional
Localizing
P.neuropathy patterns
-stocking-glove distribution
>1st stocking knee level → 2nd hands: likely DM
-dist → prox progression in limbs
-symmetric sensory loss
Ddx patterns
-only the legs, not feet → unlikely neuropathy
-nocturnal hand numbness relieved by shaking → CTS
-lat thigh numbness in obese/tight clothing → meralgia paresthetica
-shooting pain into arm → cervical radiculopathy
Constant vs Intermittent
Constant → more likely neuropathy
Intermittent → more likely non-neuropathic
Clinical pearl:
Ask patients to close their eyes, focus internally, and report any abnormal sensation in their feet
>If they report nothing, neuropathy becomes less likely
Pain
Neuropathy pain: burn, electric/shock, stab
Less likely neuropathy
-isolated focal spot pain
-predominantly aching pain (usually MSK)
> foot palpation/press (plantar fasciitis)
> flat-foot (arthritis)
Neuropathic pain typically
-worsens at night
-worsens with walking/standing
If pain improves by walking at night → consider RLS
Review of systems
-always ask autonomic, bulbar, fever, weight, and skin changes
-autonomix sx
Orthostatic lightheadedness/syncope
Gastroparesis (early satiety, bloating, vomiting)
Abnormal sweating
Urinary retention
Bowel dysfunction
Autonomic sx
Auto sx are SN but not SP of true auto dysfx (AD)
Ex dry mouth/eyes (medications, Sjögren’s, etc.)
-complain w/o ask → ⬆️ SP
High SP clues:
True OH symptoms require stabilization
Severe early satiety with minimal intake
PE
Gait
Walk normal, heels (dorsiflex), toes (plantarflex), tandem, Romberg
*Normal gait & toe/heel walk usually no severe neuropathy
Motor ex
Focus on strong msc
-tibialis ant (dorsiflex)
-gastrocnemius (plantarflex)
Not able to break in a nml pt
-toe strength is too easy to overpower
Sensory ex
If no TF
-cotton/kleenex for light touch
*cotton → finger → press
*monofilament more SN for % of ulcer
-pin/ pinprick
*compare toe → ankle → knee for gradient
Ask: “do these feel the same?” (not “is this normal?”)
*if toe is 100%, how much is knee? >80% → normal
*if ask to repeat → normal
*if not feel pin, do dull part; if not feeling both → absent pinprick
Temperature
-ice pack/ metal can is more objective
Proprioception & vibration
Subjective
Vibration is more objective
test toe → ankle → knee
Reflexes
Absent ankle reflex support neuropathy
If ankle reflex are present, neuropathy is usually not severe
Other PE clues
Foot ulcers → severe neuropathy; often DM or hereditary
-ulcer is sensory & autonomic (heal impair)
-ulcer is sensory & autonomic (heal impair)
-avoid nerve bx → wound not heal
High arches + hammertoes → possible CMT
Marked leg atrophy → chronic neuropathy
Initial lab workup
CBC, BMP, LFTs, A1C, lipid panel, Vit B12, folate, B1, Cu & Zn, B6
Avoid ordering initially unless referring
SPEP/ UPEP
When EMG
Do NOT order EMG/NCS
-obvious cause (malnutrition, uncontrolled DM)
-check baseline
Order EMG/NCS
-motor weakness
-gait impair
-rapid progression
-phenotype is unclear
-refer to neuro
U&L limb testing prevents mislabeling severity
*if upper nml → no severe
Small fiber neuropathy
True isolated SFN is rare
Criteria:
-normal EMG
-abnormal exam (temp/pinprick)
-abnormal confirmatory test (QST, skin biopsy)
*biopsy abnormal in high% of population
SFN vs fibromyalgia; exam findings are key
Time as a diagnostic tool
Following the patient over 2–3 months helps differentiate
-static sx → less likely serious
-progressive sx → refer & evaluate urgently
Patients often misjudge onset; serial exams are invaluable