Polineuropatias

Question 1

Qual a definição e como investigar uma mononeuropatia multiplex?

Answer 1

Defi nition: Involvement of multiple separate peripheral nerves.

#Dx: Labs: Chem10, CBC, ESR, rheumatological markers (ANA, ESR, RF, c- & p-ANCA, anti-Ro & La, ACE), hepatitis panel, cryoglobulins, SPEP/ UPEP, fasting blood sugar, Lyme titer, HIV. EMG/NCS: Biopsy: Sural nerve or superfi cial peroneal nerve/peroneus brevis muscle biopsy depending on clinical exam & EMG/NCS results. 
# Causes: Primary or systemic, including Leprosy, DM, SLE, vasculitis, sarcoidosis, RA, PAN, amyloidosis, Sjogren syndrome, Wegener granulomatosis, HIV, CMV, Hepatitis B & C.

Question 2

Como fazer a avaliação inicial de uma neuropatia?

Answer 2

Obtain a careful history: Ask about motor, sensory, or autonomic disturbances, obtain time course & distribution of sx, h/o toxic or infectious exposures, family history, meds, vitamins, sx of systemic diseases.

Detailed physical exam: Determine anatomic pattern & localization: Mononeuropathy, mononeuropathy multiplex, polyneuropathy, predominant motor or sensory & to which modalities, autonomic sx. Evaluate for lymphadenopathy, organomegaly, musculoskeletal/ joint abnormalities, rash. Examine hair, skin, & nails; evaluate oropharynx (tonsils, palate movement); palpate peripheral nerves; evaluate for pes cavus & hammertoes.

EMG/NCS: Helpful to confi rm neuropathy; provide localization of lesions; distinguish between axonal vs. demyelinating neuropathy.

Nerve biopsy: Most useful for suspected vasculitis & amyloid neuropathy. Also may be helpful to evaluate for infection (e.g., leprosy) & occasionally infl ammatory disorders (e.g., sarcoid); typically sural nerve since sensory defi cit is restricted to a small area over the heel & dorsolateral foot. Superfi cial peroneal is useful when vasculitis is suspected since the underlying peroneus brevis muscle can be biopsied at the same time; 15% complication rate such as minor wound infections, wound dehiscence, stump neuromas. 1/3 report unpleasant sensory sx.

Labs for w/u of peripheral polyneuropathy: Chem10, CBC, ESR, TSH, B12, SPEP & UPEP w/ IFE, ANA, anti-Ro & La. Fasting glucose & HbA1c; if normal, do 2 h glucose tolerance test. Screen for monoclonal proteins in pts w/ chronic neuropathy, especially if age > 60.

Question 3

Quais os sintomas e sinais da síndrome de Guillain-Barre, a principal polineuropatia aguda em PS?

Answer 3

Si/Sx: Ascending, predominantly motor paralysis; may progress to respiratory failure; evolves over days–weeks; pain in hips, thigh, & back; reduced vibratory & position sensation; reduced tendon refl exes; facial diplegia may occur; autonomic instability; may be preceded by Campylobacter, EBV, CMV, Mycoplasma; paresthesias in toes & fi ngers. Variants

Question 4

Quais os subtipos da SGB?

Answer 4

Variants: (1) Acute infl ammatory demyelinating polyneuropathy (AIDP; classical demyelinating form). (2) Descending form (facial/brachial onset). (3) Miller Fisher syndrome: Ophthalmoplegia w/ ataxia & arefl exia. (4) Acute motor & sensory axonal neuropathy or “Axonal GBS”: Worse prognosis & slower recovery. (5) Acute motor axonal neuropathy.

Question 5

Quais os exames diagnósticos na SGB?

Answer 5

# LP: High protein, few cells (<50), albuminocytological dissociation. If increased cell count, consider GBS in setting of alternative dx such as Lyme disease, HIV, neurosarcoidosis, CNS lymphoma or leukemia w/ nerve infi ltration. 
# EMG/ NCS: Demyelination except in axonal variant. MRI: Gadolinium enhancement of cauda equina roots.  
# Antibodies: Anti-GM1 (AIDP), anti-GQ1b (Miller— Fisher variant). 
# Labs: May be abnormalities in LFTs, EKG, hyponatremia secondary to SIADH.

Question 6

Qual o manejo da SGB?

Answer 6

Rx: Close VS monitoring, NIFs, FVCs. If NIF < −20, FVC < 1.5 L or downward trend, consider intubation; monitor electrolytes. Consider plasmapheresis or IVIg → Plasmapheresis: Exchange 200–250 mL/kg of plasma in four to six treatments qod; IVIg: 0.4 g/kg/day × 5 days. Adverse effects: Rarely ARF, proteinuria, aseptic meningitis, anaphylaxis if IgA defi cient, headache, rash, thromboembolic events (Ann Neurol 2001;49:694)

Question 7

Quando a polineuropatia desmielinizante tem fraqueza em progressão por > 8 semanas, chamamos de CIDP e não mais SGB. Qual a investigação de CIDP?

Answer 7

x: Labs/x-ray: Chem10, CBC, LFTs, ESR, HIV, SPEP, UPEP, immunofi xation, skeletal bone survey for evaluation of underlying systemic disorder. EMG/NCS: Multifocal demyelination & partial conduction block. CSF: High protein w/ normal cells. Nerve biopsy: May reveal demyelinating or axonal changes. Usually not necessary. MRI: lumbosacral roots may reveal gadolinium enhancement.

Question 8

Qual o tratamento da CIDP?

Answer 8

Rx: IVIg 2 g/kg over 2–5 days monthly for 3 mo. If sx improve, may continue IVIg 1 g/kg at intervals depending on disease response, generally every 1–2 mo. Prednisone started at 60–80 mg for 2–3 mo followed by a slow taper as tolerated (5–10 mg/mo or the lowest possible dose that controls the neuropathy). May add a second line steroid-sparing immunosuppressive agent (e.g., azathioprine, mycophenolate mofetil, methotrexate). Plasma exchange biweekly initially & then individualized (Ann Neurol 1994;36:838; Ann Neurol 2001;50:195).

Question 9

Como são os exames na neuropatia motora multifocal?

Answer 9

Dx: EMG/NCS: Persistent focal motor conduction block or other features of demyelination. Multifocal motor demyelination. CSF: Protein usually normal but may be slightly increased. Antibodies: IgM anti-GM1 antibodies in 80% of patients.

Question 10

Como é o tratamento da neuropatia motora multifocal?

Answer 10

IVIg per rx of CIDP (Neurology 2000;55:1256). Rituximab 750 mg/m2 (up to 1 g) IV w/ repeat dose in 2 wk. Repeat rituximab on an individualized basis (every 6–12 mo in most cases). Cyclophosphamide 1 g/m2 IV qmo × 6–8 mo for nonresponders to IVIg.