Neuropatia periférica Flashcards
Quais as sete perguntas a serem feitas nas neuropatias periféricas?
- What systems are involved? – Motor, sensory, autonomic, or combinations
- What is the distribution of weakness? – Only distal versus proximal and distal – Focal/asymmetric versus symmetric
- What is the nature of the sensory involvement? – Temperature loss or burning or stabbing pain (e.g., small fiber) – Vibratory or proprioceptive loss (e.g., large fiber)
- Is there evidence of upper motor neuron involvement? – Without sensory loss – With sensory loss
- What is the temporal evolution? – Acute (days to 4 weeks) – Subacute (4 to 8 weeks) – Chronic (>8 weeks)
- Is there evidence for a hereditary neuropathy? – Family history of neuropathy – Lack of sensory symptoms despite sensory signs
- Are there any associated medical conditions? – Cancer, diabetes mellitus, connective tissue disease or other autoimmune diseases, infection (e.g., HIV, Lyme disease, leprosy) – Medications including over-the-counter drugs that may cause a toxic neuropathy – Preceding events, drugs, toxins
Como diferenciar neuropatia axonal e desmielinizante na eletroneuromiografia?
(1) Motor Nerve Conduction Studies: Axonal/Desmyelination
CMAP amplitude Decreased/Normal (except with CB) Distal latency Normal/Prolonged
Conduction velocity Normal/Slow
Conduction block Absent/Present
Temporal dispersion Absent/Present
F wave Normal or absent/Prolonged or absent
H reflex Normal or absent/Prolonged or absent
(2) Sensory Nerve Conduction Studies
SNAP amplitude Decreased/ Normal
Distal latency Normal/Prolonged
Conduction velocity Normal/Slow
(3) Needle EMG
Spontaneous activity Fibrillations Present/Absent Fasciculations Present/Absent
Motor unit potentials
Recruitment Decreased/Decreased
Morphology Long duration-polyphasic/Normal
Como fazer o diagnóstico de AIDP (SCB mais comum)?
I. Required for Diagnosis
- Progressive weakness of variable degree from mild paresis to complete paralysis
- Generalized hypo- or areflexia
II. Supportive of Diagnosis
- Clinical Features
a. Symptom progression: Motor weakness rapidly progresses initially but ceases by 4 weeks. Nadir attained by 2 weeks in 50%, 3 weeks 80%, and 90% by 4 weeks.
b. Demonstration of relative limb symmetry regarding paresis.
c. Mild to moderate sensory signs.
d. Frequent cranial nerve involvement: Facial (cranial nerve VII) 50% and typically bilateral but asymmetric; occasional involvement of cranial nerves XII, X, and occasionally III, IV, and VI as well as XI. e. Recovery typically begins 2–4 weeks following plateau phase.
f. Autonomic dysfunction can include tachycardia, other arrhythmias, postural hypotension, hypertension, other vasomotor symptoms.
g. A preceding gastrointestinal illness (e.g., diarrhea) or upper respiratory tract infection is common. - Cerebrospinal Fluid Features Supporting Diagnosis a. Elevated or serial elevation of CSF protein.
b. CSF cell counts are <10 mononuclear cell/mm3. - Electrodiagnostic Medicine Findings Supportive of Diagnosis
a. 80% of patients have evidence of NCV slowing/ conduction block at some time during disease process. b. Patchy reduction in NCV attaining values less than 60% of normal.
c. Distal motor latency increase may reach 3 times normal values.
d. F-waves indicate proximal NCV slowing.
e. About 15–20% of patients have normal NCV findings.
f. No abnormalities on nerve conduction studies may be seen for several weeks.
III. Findings Reducing Possibility of Diagnosis
- Asymmetric weakness
- Failure of bowel/bladder symptoms to resolve
- Severe bowel/bladder dysfunction at initiation of disease
- Greater than 50 mononuclear cells/mm3 in CSF
- Well-demarcated sensory level
IV. Exclusionary Criteria
- Diagnosis of other causes of acute neuromuscular weakness (e.g., myasthenia gravis, botulism, poliomyelitis, toxic neuropathy).
- Abnormal CSF cytology suggesting carcinomatous invasion of the nerve roots
Qual o tratamento da SGB?
(1) Either high-dose intravenous immune globulin (IVIg) or plasmapheresis can be initiated, as they are equally effective for typical GBS. A combination of the two therapies is not significantly better than either alone. IVIg is often the initial therapy chosen because of its ease of administration and good safety record. Anecdotal data has also suggested that IVIg may be preferable to PE for the AMAN and MFS variants of GBS. IVIg is administered as five daily infusions for a total dose of 2 g/kg body weight. There is some evidence that GBS autoantibodies are neutralized by anti-idiotypic antibodies present in IVIg preparations, perhaps accounting for the therapeutic effect. A course of plasmapheresis usually consists of ∼40–50 mL/kg plasma exchange (PE) four to five times over a week. Meta-analysis of randomized clinical trials indicates that treatment reduces the need for mechanical ventilation by nearly half (from 27% to 14% with PE) and increases the likelihood of full recovery at 1 year (from 55% to 68%). Functionally significant improvement may occur toward the end of the first week of treatment, or may be delayed for several weeks. The lack of noticeable improvement following a course of IVIg or PE is not an indication to treat with the alternate treatment. However, there are occasional patients who are treated early in the course of GBS and improve, who then relapse within a month. Brief retreatment with the original therapy is usually effective in such cases. Glucocorticoids have not been found to be effective in GBS
(2) In the worsening phase of GBS, most patients require monitoring in a critical care setting, with particular attention to vital capacity, heart rhythm, blood pressure, nutrition, deep vein thrombosis prophylaxis, cardiovascular status, early consideration (after 2 weeks of intubation) of tracheotomy, and chest physiotherapy. As noted, ∼30% of patients with GBS require ventilatory assistance, sometimes for prolonged periods of time (several weeks or longer). Frequent turning and assiduous skin care are important, as are daily range-of-motion exercises to avoid joint contractures and daily reassurance as to the generally good outlook for recovery.
Qual o prognostico da SGB?
Approximately 85% of patients with GBS achieve a full functional recovery within several months to a year, although minor findings on examination (such as areflexia) may persist and patients often complain of continued symptoms, including fatigue. The mortality rate is <5% in optimal settings; death usually results from secondary pulmonary complications. The outlook is worst in patients with severe proximal motor and sensory axonal damage. Such axonal damage may be either primary or secondary in nature, but in either case successful regeneration cannot occur. Other factors that worsen the outlook for recovery are advanced age, a fulminant or severe attack, and a delay in the onset of treatment. Between 5 and 10% of patients with typical GBS have one or more late relapses; such cases are then classified as chronic inflammatory demyelinating polyneuropathy (CIDP).
Quais os exames a serem solicitados na CIDP?
Serum protein electrophoresis with immunofixation is indicated to search for monoclonal gammopathy and associated conditions. In all patients with presumptive CIDP, it is also reasonable to exclude vasculitis, collagen vascular disease (especially SLE), chronic hepatitis, HIV infection, amyloidosis, and diabetes mellitus. Other associated conditions include inflammatory bowel disease and lymphoma
Qual o tratamento da CIDP?
(1) Controlled studies have shown that high-dose IVIg, PE, and glucocorticoids are all more effective than placebo. Initial therapy is usually with IVIg, administered as 2.0 g/kg body weight given in divided doses over 2–5 days; three monthly courses are generally recommended before concluding a patient is a treatment failure. If the patient responds, the infusion intervals can be gradually increased or the dosage decreased (e.g., 1 g/kg per month). PE, which appears to be as effective as IVIg, is initiated at two to three treatments per week for 6 weeks; periodic re-treatment may also be required. Treatment with glucocorticoids is another option (60–80 mg prednisone PO daily for 1–2 months, followed by a gradual dose reduction of 10 mg per month as tolerated), but long-term adverse effects including bone demineralization, gastrointestinal bleeding, and cushingoid changes are problematic. As many as one-third of patients with CIDP fail to respond adequately to the initial therapy chosen; a different treatment should then be tried. Patients who fail therapy with IVIg, PE, and glucocorticoids may benefit from treatment with immunosuppressive agents such as azathioprine, methotrexate, cyclosporine, and cyclophosphamide, either alone or as adjunctive therapy. Early experience with anti-CD20 (rituximab) has also shown promise. Use of these therapies requires periodic reassessment of their risks and benefits.
(2) In patients with a CIDP-like neuropathy who fail to respond to treatment it is important to evaluate for POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes)
Qual o prognostico da CIDP?
(1) CIDP tends to ameliorate over time with treatment; the result is that many years after onset, nearly 75% of patients have reasonable functional status.
(2) Death from CIDP is uncommon.
Quais os três objetivos ao avaliar uma neuropatia?
(1) identify where the lesion is, (2) identify the cause, and (3) determine the proper treatment. The first goal is accomplished by obtaining a thorough history, neurologic examination, and electrodiagnostic and other laboratory studies. Despite an extensive evaluation, in approximately half of patients no etiology is ever found; these patients typically have a predominately sensory polyneuropathy and have been labeled as having idiopathic or cryptogenic sensory polyneuropathy (CSPN).
Cmo caracterizar o padrão da neuropatia motora?
Delineating the pattern of weakness, if present, is essential for diagnosis, and in this regard two additional questions should be answered: (1) Does the weakness only involve the distal extremity or is it both proximal and distal? and (2) Is the weakness focal and asymmetric or is it symmetric? Symmetric proximal and distal weakness is the hallmark of acquired immune demyelinating polyneuropathies, both the acute form (acute inflammatory demyelinating polyneuropathy [AIDP] also known as Guillain-Barré syndrome [GBS]) and the chronic form (chronic inflammatory demyelinating polyneuropathy [CIDP]). The importance of finding symmetric proximal and distal weakness in a patient who presents with both motor and sensory symptoms cannot be overemphasized because this identifies the important subset of patients who may have a treatable acquired demyelinating neuropathic disorder (i.e., AIDP or CIDP).
Qual a tetrade da doença de Refsum?
Refsum disease can manifest in infancy to early adulthood with the classic tetrad of (1) peripheral neuropathy, (2) retinitis pigmentosa, (3) cerebellar ataxia, and (4) elevated CSF protein concentration. Most affected individuals develop progressive distal sensory loss and weakness in the legs leading to footdrop by their 20s. Subsequently, the proximal leg and arm muscles may become weak. Patients may also develop sensorineural hearing loss, cardiac conduction abnormalities, ichthyosis, and anosmia
Quais os achados da doença de Tangier?
Tangier disease is a rare autosomal recessive disorder that can present as (1) asymmetric multiple mononeuropathies, (2) a slowly progressive symmetric polyneuropathy predominantly in the legs, or (3) a pseudosyringomyelia pattern with dissociated sensory loss (i.e., abnormal pain/temperature perception but preserved position/vibration in the arms) The tonsils may appear swollen and yellowish-orange in color, while there may also be splenomegaly and lymphadenopathy.
Como é a apresentação da neuropatia associada ao HIV?
The major presentations of peripheral neuropathy associated with HIV infection include (1) distal symmetric polyneuropathy (DSP), (2) inflammatory demyelinating polyneuropathy (including both GBS and CIDP), (3) multiple mononeuropathies (e.g., vasculitis, CMV-related), (4) polyradiculopathy (usually CMV-related), (5) autonomic neuropathy, and (6) sensory ganglionitis.
Quais os mecanismos de neuropatías associadas a malignidade?
Patients with malignancy can develop neuropathies due to (1) a direct effect of the cancer by invasion or compression of the nerves, (2) remote or paraneoplastic effect, (3) a toxic effect of treatment, or (4) as a consequence of immune compromise caused by immunosuppressive medications. The most common associated malignancy is lung cancer, but neuropathies also complicate carcinoma of the breast, ovaries, stomach, colon, rectum, and other organs, including the lymphoproliferative system.
Como são as características da neuropatia associada as monopatias monoclonais?
These neuropathies, which may also occur with solitary plasmacytoma, are distinct because they (1) are usually demyelinating in nature and resemble CIDP; (2) often respond to radiation therapy or removal of the primary lesion; (3) are associated with different monoclonal proteins and light chains (almost always lambda as opposed to primarily kappa in the lytic type of multiple myeloma); (4) are typically refractory to standard treatments of CIDP; and (5) may occur in association with other systemic findings including thickening of the skin, hyperpigmentation, hypertrichosis, organomegaly, endocrinopathy, anasarca, and clubbing of fingers. These are features of the POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes).
