Ebook Neuromuscular disorders (2/E): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Neuromuscular disorders (2/E): Part 2
Ebook Neuromuscular disorders (2/E): Part 2
CHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neur Ebook Neuromuscular disorders (2/E): Part 2ropathies due to chemotherapeutic agents arc discussed in Chapter 19. Hie associated neuropathy for most of these is an axonal, length dependent predominantly sen sory neuropathy. Ihe history of exposure and sometimes the involvement of other organ systems help to suggest the correct diagnosis. Alth Ebook Neuromuscular disorders (2/E): Part 2ough we mention features that have been reported on nerve biopsy, this is not typically part of the workup as in most cases the abnormalities are nonsEbook Neuromuscular disorders (2/E): Part 2
pecific.► TOXIC NEUROPATHIES ASSOCIATEDWITH MEDICATIONSMETRONIDAZOLEClinical FeaturesMetronidazole is used to treat a variety of protozoan infections CHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neur Ebook Neuromuscular disorders (2/E): Part 2ndent pattern. Autonomic dysfunction may develop as well. Motor strength is typically normal. The cumulative dose at which neuropathy occurs is wide, ranging from 3.6 to 228 g. Although there is no clear dose effect, neuropathy appears to occur more frequently in patients receiving greater than 1.5 Ebook Neuromuscular disorders (2/E): Part 2g daily of metronidazole for 30 or more days The neuropathic symptoms usually improve upon discontinuation of the drug, but there can be a coasting efEbook Neuromuscular disorders (2/E): Part 2
fect such that the symptoms may continue to worsen for several weeks. Some patients are left with residual sensory symptoms.Laboratory FeaturesNerve cCHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neur Ebook Neuromuscular disorders (2/E): Part 2(SNAPs) in the legs worse than in the arms. Motor conduction studies are usually normal.HistopathologyNerve biopsies are not routinely performed for this but have demonstrated loss of myelinates! nerve fibers.PathogenesisThe pathogenic basis of the neuropathy is not known. Some have found that metro Ebook Neuromuscular disorders (2/E): Part 2nidazole binds to DNA and/or RNA, which could lead to breaks and impair transcription or trans lation to normal proteins.7* Others have speculated thaEbook Neuromuscular disorders (2/E): Part 2
t toxic ily may arise from the production of nitro radical anions that bind and disrupt normal protcin/cnzyme function.11 Furthermore. the histologicaCHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neur Ebook Neuromuscular disorders (2/E): Part 2 thiamine (vitamin Bl) deficiency. Il has been postulated dial there may lie enzymatic conversion of metronidazole to an analog of thiamine, which may act as a Bl antagonist. ‘MISONIDAZOLEClinical FeaturesMisonidazolc is used as an adjuvant agent in the treatment of various malignancies.10 I? As wit Ebook Neuromuscular disorders (2/E): Part 2h metronidazole, misonidazole is a member of the nilroimklazolc group. Some patients have developed painful paresthesias and sometimes distal weaknessEbook Neuromuscular disorders (2/E): Part 2
in a length dependent pattern after approximately 3-5 weeks of therapeutic drug administration (total dose greater than 18 g). Vibratory and temperatCHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neur Ebook Neuromuscular disorders (2/E): Part 2aboratory FeaturesSensory NCS reveal reduced amplitudes or unobtainable responses in the legs more than the arms. Motor conduction studies are typically normal.HistopathologyA reduction in the large myelinated fibers with axonal degeneration and segmental demyelination and remyelination has been fou Ebook Neuromuscular disorders (2/E): Part 2nd on sural nerve biopsies. Accumulation of neu-rolilaments with axonal swellings can be found on electron microscopy (EM).PathogenesisThe pathogenicEbook Neuromuscular disorders (2/E): Part 2
basis of the neuropathy is not known, but may be similar to metronidazole.CHAPTER 20 I0XK. NtUROPAI Hits 449► TABLE 20-1. TOXIC NEUROPATHIESDrugMechanCHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neur Ebook Neuromuscular disorders (2/E): Part 2ies, and sometimes distal weakness in lengthdependent patternAxonal degeneration of large myelinated fibers; axonal swellings; segmental demyelinationLow amplitude or unobtainable SNAPs with normal or only slightly reduced CMAP amplitudesMetronidazoleUnknownPainful paresthesias, loss of large and sm Ebook Neuromuscular disorders (2/E): Part 2all fiber sensory modalities, and sometimes distal weakness in lengthdependent patternAxonal degenerationLow amplitude or unobtainable SNAPs with normEbook Neuromuscular disorders (2/E): Part 2
al CMAPChloroquine andAmphiphileLoss of large and smallAxonal degenerationLow amplitude or unobtainablehydroxychlo-properties mayfiber sensory modalitCHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neur Ebook Neuromuscular disorders (2/E): Part 2tal weakness in length-dependent pattern; superimposed myopathy may lead to proximal weaknessvacuoles in nerves as well as muscle fibersreduced CMAP amplitudes; distal denervation on LMG; irritability and myopathic appearing MUAPs proximally in patients with superimposed toxic myopathyAmiodaroneAmph Ebook Neuromuscular disorders (2/E): Part 2iphilic properties rnay lead to drug lipid complexes that are indigestible and result in accumulation of autophagic vacuolesParesthesia and pain withEbook Neuromuscular disorders (2/E): Part 2
loss of large and small fiber sensory modalities and distal weakness in length-dependent pattern; superimposed myopathy may lead to proximal weaknessACHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neur Ebook Neuromuscular disorders (2/E): Part 2educed CMAP amplitudes; can also have prominent slowing of CVs; distal denervation on FMG; irritability and myopathic appearing MUAPs proximally in patients with superimposed toxic myopathyColchicineInhibits polymerization of tubulin in microtubules and impairs axoplasmic flowNumbness and paresthesi Ebook Neuromuscular disorders (2/E): Part 2a with loss of large fiber modalities in a length dependent fashion; superimposed myopathy may lead to proximal in addition to distal weaknessNerve biEbook Neuromuscular disorders (2/E): Part 2
opsies demonstrate axonal degeneration; muscle biopsies reveal fibers with vacuoles1 ow-amplitude or unobtainable SNAPs with normal or reduced CMAP amCHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neur Ebook Neuromuscular disorders (2/E): Part 2rs axoplasmic flowSensory loss, tingling, muscle weakness, and diminished muscle stretch reflexes in length-dependent pattern; autonomic neuropathyAxonal degenerationLow amplitude or unobtainable SNAPs with normal or reduced CMAP amplitudesĩhalidomideUnknownNumbness, tingling, burning pain, and weak Ebook Neuromuscular disorders (2/E): Part 2ness in a lengthdependent patternAxonal degeneration; Autopsy studies reveal degeneration of dorsal root gangliaLow amplitude or unobtainable SNAPs wiEbook Neuromuscular disorders (2/E): Part 2
th normal or reduced CMAP amplitudesDisulfiramAccumulation of neurofilaments and impaired axoplasmic flowNumbness, tingling, and burning pain in a lenCHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neur Ebook Neuromuscular disorders (2/E): Part 2P amplitudesDapsoneUnknownDistal weakness that may progress to proximal muscles; sensory lossAxonal degeneration and segmental demyelinationLow-amplitude or unobtainable CMAPs with normal or reduced SNAP amplitudes Ebook Neuromuscular disorders (2/E): Part 2CHAPTER 20Toxic NeuropathiesThis chapter reviews neuropathies associated with various drugs and other environmental exposures (Table 2Q I). Toxic neurGọi ngay
Chat zalo
Facebook