DISCLOSURES. UCSF Continuing Medical Education Neuropathy Pearls. Overview. Neuropathy terminology. Topics to be covered:

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1 UCSF Continuing Medical Education DISCLOSURES Nothing to Disclose Laura K. Rosow, MD Overview Topics to be covered: Neuropathy definitions, terminology Evaluation of the patient with neuropathy History Red flags Examination Management of neuropathy When do to additional testing (labs, EMG/NCS, biopsy) Symptomatic management When to refer Clinical cases (throughout) Neuropathy terminology Mononeuropathy - Compressive (e.g., median nerve at wrist) - Infiltrative (e.g., amyloidosis) - Inflammatory Polyneuropathy - Sensory, motor, or mixed Small or large fiber - Different patterns Distal symmetric (DSPN, length-dependent ) Generalized/diffuse Multifocal 3 4

2 Case #1: My feet hurt Case #1: My feet hurt 68 yo woman with longstanding T2DM, intermittently well controlled - Most recent HbA1c 8.0% 10 years ago, started to notice sensory symptoms - Painful tingling/numbness in toes, now to mid-shin, symmetric - Allodynia: difficulty tolerating bedsheets, shoes Neurological examination: - Sensory: pinprick to distal shin bilaterally vibratory sensation reduced in big toes - Motor: Diminished muscle bulk in feet, mild weakness of toe flexion bilaterally New balance difficulties: - Recently fell while walking on uneven ground - Prefers to sit on bench in the shower - Reflexes: 2+ patellar, absent ankle reflexes Case #1 diagnosis: Diabetic distal sensorimotor polyneuropathy Taking a neuropathy history Goal #1: Localize symptoms, narrow differential dx Diabetic PN = most common neuropathy in western world - Risk factors: duration of illness, poor control ( HbA1c) - Up to 50% of patients have neuropathy after 25y of disease - Neuropathy can be the presenting sign of DM Sensory: - Small sensory nerve fibers pain/temperature Neuropathic pain, allodynia - Large sensory nerve fibers vibration, proprioception Multiple forms, including: - Distal sensory (large and/or small fiber) +/- motor Imbalance: worse with vision (shower, dark room), uneven ground Reduced manual dexterity (fastening buttons) - Autonomic - Compressive mononeuropathies (e.g., carpal tunnel, ulnar) Motor: Tendency to trip Treatment: glycemic control slows/halts progression, may improve sx slightly Autonomic: Dry mouth/eyes, GU sx (difficulty voiding, ED), orthostatic intolerance, GI upset 7 8

3 Taking a neuropathy history High yield neuropathy examination Goal #2: identify potential secondary causes of neuropathy* Motor: PMH: - Toxic med exposures? - Risk factors for nutritional deficiency? (e.g., gastric bypass, IBD) Review of systems: - Systemic symptoms: rash, weight loss, fevers - Examine muscle bulk in feet and hands - Test a couple of proximal and distal muscle groups E.g., deltoids, finger abduction, hip flexion, ankle dorsiflexion, toe extensors/flexors Sensory: Social history: - Dietary veganism, excessive fish consumption - Small fiber: safety pin (temperature often unreliable) - Large fiber: tuning fork or joint position sensation; Romberg - Etoh consumption - Occupational exposures - Infectious risk: travel hx, sexual hx, IVDU Reflexes: - At least knees and ankles, add biceps if these are absent *Up to 50% of neuropathies are idiopathic Gait: Heel and toe walk, tandem gait 9 10 Laboratory workup for DSPN Which labs should I obtain? AAN practice parameters: Standard (level C possibly useful/predictive): - Extensive lit review, panelists determine strength of evidence - Blood glucose - Exist for diagnosis/mgmt of several neurological conditions - B12 and MMA (+/- homocysteine) - Serum protein immunofixation electrophoresis Question: What is the yield of screening laboratory tests in evaluating DSPN? If indicated by history (data inadequate or conflicting): Answer: Screening labs are probably useful in identifying the cause of DSPN, though yield depends on the particular test Screening labs may be considered in all patients with DSPN - 2h GTT (especially if painful neuropathy)* - HIV - ESR, SSA/SSB, ANA - TSH - Hepatitis serologies - 24h urine heavy metals 11 Presentation Title 12 *Sumner et al., The spectrum of neuropathy in diabetes and impaired glucose tolerance, Neurology January 14, 2003; 60 (1)

4 13 What can EMG/NCS tell me? Confirm localization/severity of large fiber (sensory, motor, mixed) polyneuropathies. - N.B.: Small fiber neuropathies cannot be diagnosed by EMG/NCS. Establish whether axonal, demyelinating, or mixed - This may change DDx (e.g. monoclonal gammopathies more often associated with demyelination) Identify concomitant radiculopathies, compressive neuropathies Exclude unusual features that may prompt further workup - E.g., diffuse demyelination, asymmetries When should I order EMG/NCS? Usually not indicated when: - Symptoms/signs are mild, slowly progressive - Cause is obvious (e.g., DM, alcohol abuse, chemotherapy) Consider when: - No obvious cause - Rapidly progressive, unusual pattern (asymmetric, diffuse, motorpredominant) - Considering biopsy (e.g., concern for vasculitis, amyloidosis) - Counsel patient regarding procedure. Pain relief/anxiolytics are okay, so long as patient can participate in testing. - Refer to a physician who is specially trained in EMG/NCS 14 Should I get a skin biopsy? Case #2: My hands tingle Biopsy allows quantitative assessment of epidermal nerve fiber density - Can help solidify dx of small fiber neuropathy when EMG/NCS is normal - Simple procedure (3mm punch biopsy), usually well-tolerated - However, rarely helps identify etiology or guide treatment - Dx can often be made on clinical grounds alone 45 year-old RH woman with no known PMH presents with intermittent numbness/tingling in both hands - Worse when driving, talking on cell phone - Wakes from sleep, improves with shaking hands out - Sometimes feels manual dexterity is worse - No neck or arm pain Focused neuro exam: Skin bx with normal ENFD - Motor: normal muscle bulk and strength - Sensory: mild reduction in pinprick sensation over lateral palm and 3 digits bilaterally, +Tinel s at both wrists

5 17 Case #2 diagnosis: carpal tunnel syndrome Would you refer to hand surgery? Anatomic compression of median nerve within carpal tunnel nerve ischemia Risk factors: hypothyroidism, DM, rheumatoid arthritis, pregnancy, edema, mechanical/occupational stressors A. Yes B. No C. Only after failing wrist splints 36% 61% Can present with: Intermittent numbness/tingling of hands (occasionally more proximal) Often exacerbated by manual tasks (driving, typing) May awaken from sleep, improve with shaking hands Progresses to more fixed numbness, manual dexterity, may develop atrophy/weakness of abductor pollicis brevis Yes 4% No Only after failing wrist sp Management of CTS Case #3: I ve always had weird feet Wrist splinting +/- glucocorticoid injections Mild = intermittent sx, no fixed sensory impairment Moderate = fixed sensory impairment, sx may wake from sleep Severe = fixed sensory and motor impairment, difficulty with ADLs UpToDate - 30 yo F presents for annual physical On exam: high arches (pes cavus), thick calluses on feet, hammertoe deformities. Patient states these are chronic abnormalities. Admits she has always been clumsy, prone to tripping FHx: - Father and paternal grandmother have high arches. - Father walks with a cane, and grandmother uses a walker. - Neurological exam: Motor: Thinning of distal shins, 4-/5 ankle dorsiflexion, 3/5 toe flexion and extension Sensory: Mild vibratory deficits in big toes Reflexes: Diminished in arms, absent at knees and ankles 19 20

6 21 Case #3 continued Case #3 diagnosis: heredofamilial neuropathy Charcot Marie Tooth disease refers to a wide variety of hereditary polyneuropathies with different phenotypes. Can be distinguished by inheritance, EMG/NCS, symptoms. Often very slowly progressive, delayed dx orthoinfo.aaos.org EMG/NCS can help target genetic testing (if desired). 22 Neuropathy red flags Case #4: I woke up like this 50 yo woman with history of cutaneous polyarteritis nodosa, not on medications, presents with bilateral foot drop. - 6 weeks prior, recurrent rash consistent with PAN - 4 week prior, woke up with left foot drop Also tingling and burning pain over the dorsum of the left foot and left lateral calf - 1 week prior, woke up with similar symptoms on the right - In past 2 days, has noticed burning discomfort in right lateral hand PMH: Cutaneous PAN, HTN, HLD, poorly controlled migraines Saw her PCP, who referred urgently to neurology 23 24

7 25 Neuropathy red flags Case #4: continued Tempo: Examination: - Rapidly progressive (weeks-to-months) - Sudden, stepwise changes - Derm: Livedo reticularis over legs - Neuro: E.g., wakes up with a foot drop Pattern: - Generalized/non-length-dependent - Patchy, multifocal - Asymmetric Associated symptoms: weight loss, severe pain, rash Motor: Bilateral foot drop R>>L Sensory: pinprick over bilateral feet and shins and in right hand over radial and median distributions Distribution: - Multiple peripheral nerves - Asymmetric, patchy 26 Case #4: continued Vasculitic Neuropathy EMG/NCS: Multifocal, asymmetric, axonal sensorimotor polyneuropathy Sural nerve biopsy: Vasculitic neuropathy with severe (greater than 75%) active axonal loss. Initially will often present as mononeuropathy or multiple mononeuropathies, usually w/ neuropathic pain - Stepwise progression with acute changes - Over time, can become more confluent, may appear similar to length-dependent neuropathy Amato AA, Russell JA. Neuromuscular Disorders. First edition. Boston, Massachusetts: McGraw-Hill Education Medical; Vasculitis may be primary or secondary to other systemic disease Useful labs: CBC w/ diff (eosinophilia), ANA, ANCAs, ESR, CRP, RF, cryos, hep serologies, UA Merits URGENT REFERRAL to neurology or rheumatology 27 28

8 A. Gabapentin How would you treat this patient s pain? B. Tricyclic antidepressant -e.g., nortriptyline, amitryptline C. Pregabalin D. Topical treatment -e.g., lidocaine ointment, capsaicin cream E. SNRI F. Tramadol -e.g., duloxetine, venlafaxine Gabapentin 83% Tricyclic antidepressant... 3% Pregabalin 10% Topical treatment -e.g., lido... 0% SNRI -e.g., duloxetine, venl... 3% 0% Tramadol Neuropathic pain management First line agents: - Gabapentin, pregabalin - Tricyclics (e.g., nortriptyline) - SNRIs (duloxetine, venlafaxine) - Adjunctive topicals (e.g., 1% lido) Narcotics generally less effective Choose med/dosing based on comorbidities, timing of worst pain. - Tramadol can be acceptible second line agent for breakthrough Maximize dosing of one agent before adding another/switching Low threshold for Pain Mgmt referral if not responding to 1 st line agents Case #5: Not doing as well at the gym Neuropathy red flags 55 year-old man with no significant PMH - Baseline excellent strength, normal sensation. Goes to the gym 3-4x per week for cardio, weights - In past 8 weeks, gradual performance on leg press machine and when lifting free weights Tempo: - Rapidly progressive (weeks-to-months) - Sudden, stepwise changes E.g., wakes up with a foot drop - Also notices numbness/tingling in feet to ankles and in fingertips Pattern: Examination: - Motor: Mild weakness of deltoids, intrinsic hand muscles, hip flexors, ankle dorsiflexion - Sensory: Vibratory sensation absent to MTP joint, reduced in fingertips - Generalized/non-length-dependent - Patchy, multifocal - Asymmetric No associated symptoms/signs sensory motor From: Approach to Neuropathy, by Dr. Thomas Cochrane - Reflexes: Absent throughout 31 32

9 33 Case #5: continued When to refer neuropathy to neurology Workup: - EMG/NCS: Generalized, primarily demyelinating motorpredominant polyneuropathy with features of acquired demyelination - LP: 1 WBC, 1 RBC, 65 glucose, 175 protein Need assistance with/confirmation of diagnosis - E.g., in patients with complicated/multifocal symptoms Concerns about associated symptoms that may indicate more extensive neurological disorder Diagnosis: Chronic inflammatory demyelinating polyneuropathy (CIDP) Help with supportive care - E.g., disease-appropriate rehab Treatment: Either steroids or IVIG, may require long term treatment prognosis usually good if caught early. Any red flag symptoms urgent referral - If cannot get patient in quickly enough, start with urgent EMG/NCS or consider inpatient admission 34 We have discussed today: Neuropathy definitions, terminology Evaluation of the patient with neuropathy History Red flags Examination Questions? Management of neuropathy When do to additional testing (labs, electrodiagnostic, biopsy) Symptomatic management When to refer 35 36

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