Clinical Approach to Neurologic Disorders Surgical Approaches • Ablative – thalamotomy • G ENERAL S YMPTOMS AND S IGNS – Pallidotomy Anatomic • Electrical stimulation (DBS) Pathophysiologic – VIM thalamus, globus pallidus internus, sub-thalamic nucleus Phenomenologic • Transplant • T REATMENT – autologous adrenal, human fetal, xenotransplants, genetically Symptomatic engineered transplants Protective Curative Surgical Medtronic DBS system 1
Disease Classification Physical Exam Congenit al In neurology, asymmetric or focal findings are typically most important Genet ic Demyelinat ing Vascular Immunologic Neoplast ic/ Para-neoplasti c • Vital signs Toxic/ Nut riti ve • Appearance Met abolic • Emotional state Mit ocho ndrial/ Sub-cellular s yste ms Infe ct ious/ Post -infect ious General medical Brief comments on relevant pulmonary, Traumati c cardiovascular (murmurs, bruits), musculo-skeletal (deformities, Degenerat ive asymmetries) and skin (rashes, other Idiopath ic markings). Iatr ogenic Physical Exam Physical Exam Neurologic Motor exam Strength e.g. MRC 5/5 point scale Ment al st atu s orient at ion, level of a lert ness, speech, m emory, Muscle mass cognit ive st at e (m ini-me nt al exam is helpful). Tone Reflexes deep tendon (can be elicited in the jaw) Cranial nerves I import ant r eally if as ymmet ric, part icularly with a cutaneous (Babinski, abdominals) change in personalit y or su spect ed front al lobe disease. Rapid alternating movements II - fundu s exam, visual acuit y (should be doc ument ed), speed, decrement rhythm visual fields, and relat ive afferent pupillary d efect Involuntary movements (RAPD). tremor III, IV and VI - pupil and e ye movement s, opto kinet ic myoclonus chorea nyst agmus (OKN), oth er forms of nyst agmus and athetosis relate d findings. tics V sensory: cornea, skin to vert ex of h ead, not angle dystonia of mandible. ballismus moto r: muscles of mast icat ion (c hewing). dyskinesia VII should clarify peripheral vs cent ral issues. Motor apraxias VIII import ant in hearing, b alance. dressing, combing hair, brushing teeth IX - XII - speech qualit y, sw allowing, t ongue movements, t ongue atrop hy. Physical Exam Physical Exam Coördination Usually, but not always, tests for cerebellar dysfunction Sensory exam Targeted voluntary movements finger-to-nose heel-shin Cranial divisions of V Rapid alternating movements Other head and neck Angle of jaw fine hand, finger control Spinal levels Nerve or root Gait and posture Primary modalities Light touch Stride, stance Two point discrimination truncal sway, arm swing Pain Vibration Posture Position sense stooped, falling forward, backward Higher cortical modalities Freezing Graphesthesia in doors Stereognosis on or off medication at start of walking 2
Disorders of muscle tone Disorders of muscle tone I. H YPERTONICITY a. Upper m ot or n euron syndro me 1. Loss o f str ength - paresis or p aralysis II. H YPOTONICITY 2. Loss o f fine dist al movements a. Cerebellar disease - acut e 3. Spasti cit y b. Deep coma clasp-knife ( velocit y-dependent ) t one increased (velocit y-dependent ) deep t endon III. G EGENHALTEN reflexes Resist ance t o pa ssive manipulat ion, unable to r elax, con fusion, 4. Release of flexor r eflex afferents, eg Babinski sign front al lobe disease b. Ext rapyramidal rigidit y 1. Plast ic, lead-pipe, equally increased t one t hroughout 2. Normal deep t endon reflexes 3. No paralysis of movement Basal ganglia disease Basal Ganglia N EGATIVE sympto ms a. Primary f unct ional deficit s - 1. Akinesia or b radykinesia underact ivit y or po vert y of m ovement (hyp okinesia) • Subcortical forebrain structures 2. Loss of post ural ref lexes connected to sensorimotor and failure to m ake small adjust ments wa lking, st anding up, etc limbic systems 3. Difficulty with rapid alt ernat ing movements P OSITIVE sympto ms • Crucial part of the “control b. Secondary effect s - circuitry” that allows for the 1. Lead pipe rigidit y smooth execution of voluntary increased to ne movement 2. Involunt ary movement s (hyp erkinet ic disorders or dy skinesias) tr emor dyst onia chorea ath eto sis ballism akat hisia Normal Parkinson’s disease Cerebral cortex Cerebral cortex Basal Ganglia Glu + Glu + Striatum Striatum D2 D1 D2 D1 Glu + Glu + • Multiple cortico-basal ganglia-thalamo-cortical circuits - - + + GABA GABA GABA GABA DA DA SP SP Enk - - Enk - - Dyn Dyn • Help program and carry out motor plans SNc SNc • Scale the amplitude and effort of the execution of Ventral Ventral GPe GPe thalamus thalamus tasks with relation to requirements GABA - GABA - GABA - GABA - • Incorporate motivation and emotional drives STN STN GPi/SNr GPi/SNr Glu + Glu + GABA - GABA - Brainstem/spinal cord Brainstem/spinal cord 3
Normal Huntington’s disease Basal ganglia disease Cerebral cortex Cerebral cortex Glu + Glu + Tremor Striatum Striatum ♦ Rhyth mic oscillat ion about a joint D2 D1 D2 D1 Glu + Glu + 1. Physiologic and exaggerat ed physiologic - + - + 2. Rest (parkinsonian) GABA GABA GABA GABA DA DA Enk SP - Enk SP - 3. Kinet ic or act ion - - Dyn Dyn SNc SNc 4. Postu ral 5. Int ent ion (cerebellar) Ventral Ventral 6. Task-relat ed: writ ing tr emor, ortho st at ic tr emor GPe GPe thalamus thalamus Dystonia GABA - GABA - ♦ Sust ained and/ or semi-rhyth mic muscle spasms, oft en worse with a GABA - GABA - STN STN part icular t ask or po stur e ♦ Persist ent att itud e in ext remes of po sit ion, e g hyp er-flexed or hyper- GPi/SNr GPi/SNr Glu + Glu + ext ended GABA - GABA - ♦ Irregular tr emors ♦ “ Occupat ional” cramps (w rit er’s c ramps, musician’ cramps, et c) Brainstem/spinal cord Brainstem/spinal cord ♦ Meige’s syndro me: blepharospasm and o ro-facial dyskinesias/ dysto nia. Basal ganglia disease Chorea ♦ Rapid, arrhyth mic, jerky, equal dist ally and pro ximally Athet osis ♦ Slow, sinuous movement s ♦ Movement s fr om o ne postu re t o anot her ♦ Inability t o keep limb in one posit ion Ballism ♦ Wild, flinging movement s of limbs ♦ Associat ed with lesions o f th e subth alamic nucleus Photo by James Parkinson from his paper "An Essay on the Shaking Palsy” 1817 Normal PD Basal ganglia disease Neurologic Issues Relevant to Dentistry Myoclonus Bell’s palsy ♦ Shock-like fast muscle jerks - fast er t han chorea, less sinuous t han t remor ♦ Irregular Inflammat ion of th e facial (VII) n erve - weakness of a ll parts o f t he ♦ May have sensory relat ionship face – t he forehead movement s , eye closure, mouth movements . ♦ Cort ical, sub-corti cal, spinal ♦ Unusual variant s: pa lat al myoclonus Oft en is mist aken f or a “ st roke” with slurred speech except th at language and cognit ive funct ions are p reserved. Tics ♦ Stereoty ped movements Never results in double vision, can affect t ast e on on e side of th e ♦ Simple, eg eye blinking, or co mplex involving many body r egions to ngue, can oc cur a t any age, and can be p receded by p ain in or ♦ Associat ed with “inner feeling” to r elease t ension arou nd t he ear. ♦ May be vocal, eg b arking, s niffing ♦ Gilles de la Tour ett e syndrome Akathisia ♦ restl essness ♦ unable to s it for m ore t han a few second s 4
Neurologic Issues Relevant to Dentistry Bell’s palsy Disorders affecting the face, jaw, mouth and neck • Trigeminal neuralgia • Temporo-mandibular joint disorders • Other facial pains • Jaw tremors • Bruxism • Tardive dyskinesia • Meige’s syndrome • Other oro-buccal facial dystonias • Torticollis Initial presentation After 6 months Other Neurologic Issues Relevant to Dentistry Malignant Hyperthermia Sudden onset of high fever , muscle rigidit y and auton omic signs. Complications of anesthesia ♦ Temperat ure rise → 42 -4 3° C ♦ Tachypnea, t achycardia ♦ Coma ♦ Loss of brainst em reflexes ♦ Malignant h yperth ermia ♦ Circulat ory collapse ♦ Rigidit y in all muscles → high CK and myoglobinuria ♦ Jaw c lenching - unexpect ed aft er relaxat ion from anesth esia ♦ Anesth et ic agent s haloth ane succinylcholine eth er Malignant Hyperthermia Patho genesis: a. anesth esia lead t o increase in O2 consumpt ion b. deplet ion of ATP c. muscles unable t o relax (muscles require energy t o r elax) Treat ment: D/C anest hesia at first sign IV dant rolene - inhibits Ca++ release Cooling, hydrat ion, sodium bicarbonat e Suscept ible pat ient s: Family hist ory of anesth et ic-relate d problems Musculo-skelet al abnor malit ies Short s t at ure, pto sis, hi gh arched palat e 5
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