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Disorders of SomaticSensation

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CONTENTS

Approach to diagnosis, 200

Functional anatom of the somatic sensor path! "as, 20#

$istor, 20#

Sensor e%amination, 202Sensor changes & their sig! ni'cance, 20(

Distinction of organic & ps! chogenic sensor distur! )ances, 20*

+eripheral nere lesions, 20-

+olneuropathies, 2#2

.diopathic in/ammator neuropathies, 2#2

eta)olic & nutritional neu! ropathies, 2#( .nfectie & granulomatous neuropathies, 2#1 Neuropathies in asculitis & collagen ascular disease, 2#6

Neoplastic & paraproteine! mic neuropathies, 2#* Drug!induced & to%ic neu! ropathies, 2#- $ereditar neuropathies, 2#Entrapment neuropathies, 22# Entrapment sndromes of upper lim)s, 22# Entrapment sndromes of lo"er lim)s, 222

3oot & ple%us lesions, 22( Compressie & traumatic lesions, 22( Ta)es dorsalis, 22( 4me disease, 225elopathies, 225 Sringomelia, 225

Su)acute com)ined degen! eration itamin 7#2 de'! cienc8, 221Cere)ral disease, 221+ain sndromes, 221 +eripheral nere pain, 221 3adicular pain, 226 Thalamic pain, 226 7ac9 & nec9 pain, 226

:E; CONCE+TS

The distri)ution of sensor smptoms and signsoften suggests their site of origin in the neura%is,and their temporal pro'le ma suggest theircausemaoccur "ith lesions of the central or peripheralnerous sstemand times to signif an sensor impairment= its memust )e clari'ed "heneer the "ord is used< .n o)taining a histor of sensor complaints, important to determine the location of the smpthe mode of onset and progression of the smp"hether the smptoms are constant or episodicture= "hether an factors speci'call produce,enhance,

or reliee smptoms= and "hether there are anaccom!paning smptomsas occurs, for e%ample, in ta)esdorsalis< Apositie test is indicatie of grossl impaired @oiposi!tion sense in the legsthere is characteristicall a loss of pain andtemperature appreciation "ith sparing of othermodali!ties< This loss is due to the interruption of ')ers con!eing pain and temperature that cross from one side

ofthe cord to the spinothalamic tract on the other< Suchaloss is usuall )ilateral, ma )e asmmetric, and in!oles onl the ')ers of the inoled segments< .tma)e accompanied ) lo"er motor neuron "ea9ness inthe muscles supplied ) the aGected segments andsometimes ) a pramidal and posterior columnde'cit)elo" the lesion Figure 6B18particularl in acute idiopathic polneuro?uillain!7arrL sndrome8, chronic in/ammatormelinating polneuropath, and diphtheriticneuropa!th>and preparations must )e made to assistentila!tion if the ital capacit falls )elo" a)out # 4< .npatients "ith seere dsesthesia, a cradle inemetal )ar frame8 can )e used to 9eep the )edclfrom touching sensitie areas of the s9in< Treatm"ith phentoin, (00 mgd, car)amaepine, up t

#200mgd, or me%iletine, 600B00 mgd is sometimehelp!ful in relieing the lancinating pain of certain neropathies< .f the pain is more constant, )urning,dsesthetic, amitriptline 21B#00 mg at )edtimten helpful as are other tricclic agents< ?a)ape(00 mg three times dail, "ith su)seHuentincrementsdepending on response and tolerance8 is eGectitreating arious neuropathic pain disorders= pairelief

ma similarl occur "ith lamotrigine, topiramatsodium alproate, )ut this has )een documente"ell and in some clinical studies these medicati

.n ta)es dorsalis, there is often a histor ofsphiliticinfection, and e%amination reeals other stigmas ofsphilis< .n addition, tactile sensation is presered< 3adiculopathies are distinguished from peripheralneuropathies ) the distri)ution of motor or sensorde'cits see Figure 6B5A, 78< The presence of nec9 or)ac9 pain that radiates to the e%tremities in a

radiculardistri)ution also suggests a root lesion

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2#2 C$A+TE3 6

E%tremities "ith sensor loss must )e protectedfrom repeated minor trauma, such as thermal in@ur,that can destro tissues< The temperature of hot sur!faces should )e chec9ed "ith a part of the )od in"hich sensation is presered, and the setting of"ater

heaters must )e reduced to preent scalding< Thes9inand nails must )e cared for meticulousl< Dsautonomic smptoms ma )e trou)lesome, es!peciall in dia)etic or alcoholic polneuropathor maoc!cur "ithout o)ious precipitants< Clinical andepidemi!ologic eidence suggests an association "ithprecedingCamplo)acter @e@uni infection< .ts precise cause isun!clear, )ut it appears to hae an immunologic )asisare preferentialoled< nli9e most polneuropathies, that causlepros tends to spare the tendon re/e%esand increased )elo"Sco!liosis is a common accompaniment of cord caitCaitation commonl occurs in the cerical regithiscan cause a capeli9e distri)ution of sensor lossone or )oth shoulders, diGuse pain in the nec9, radicular pain in the arms= inolement of the Tment freHuentl leads to ipsilateral $orner snd

.f the caitation inoles the lo"er )rainstem sringo)ul)ia8, there ma also )e ipsilateral tongu"ast!ing, palatal "ea9ness, ocal cord paralsis,dissociatedtrigeminal sensor loss, and other eidence of )stem inolement< Communicating sringomelia is often assoc"ith deelopmental anomalies of the )rainstemforamen magnum region such as Arnold!Chiariformation= see Chapter (8 or "ith chronicarachnoiditis

of the )asal cisterns< Arnold!Chiari malformatiolead to hdrocephalus, cere)ellar ata%ia, pramandsensor de'cits in the lim)s, and a)normalities lo"er cranial neres, alone or in an com)inatioelograph, magnetic resonance imaging 3computed tomographic CT8 scanning of the formagnum region con'rms the diagnosis< Treatmesurgical< Noncommunicating sringomelia is often dutrauma, intramedullar tumors, or spinalarachnoiditisor lifting heo)!@ects "ithout adeHuate )racing of the spine>cacausemusculos9eletal pain that impro es ith rest C

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D.SO3DE3S OF SOAT.C SENSAT.ON 22*

e%amination commonl reeals spasm of the lum)armuscles and restricted spinal moementssometimes accompanied ) ness or radicular sensor distur)ances in the lethatoccurs "ith actiit or "ith certain postures andlieed ) rest< .n such circumstances, spinaldecompres!sion is indicated