神经病学教学ppt课件：Peripheral neuropathy.ppt

Peripheral neuropathy,The peripheral nervous system (PNS) includes all neural structures lying outside the pial membrane of the spinal cord and brain stem. Not include the optic nerves and olfactory bulbsComposed of Cranial nerves (10 pairs) and Spinal nerves (31 pairs),Myelinated fibers: coated with the membrane of one Schwann cell every 250 to 1000m in concentric way, forming the insulated myelin (a multilayer sheath). Each segment is called node of Ranvier, permitting the conduction of the nerve impulse saltatory and therefore rapidlyInjury of the myelin causes the destruction of node of Ranvier leading the slow down of nerve conducting velocityUnmyelinated fibers: bundles of fibers is capsulated by a single Schwann cell. No sheath slow propagation of electric flow of nerve impulse.,Etiology,NEUROPATHY,Segmental demyelination: Focal degeneration of the myelin sheath with sparing of the axon,Wallerian degeneration: the nerve degenerates from the point of axonal damage outwards,Axonal degeneration: the axon degenerates from the distal-most site to the proximal site (both axon and myelin),Neuropathy: Secondary degeneration due to neuron necrosis,Clinical symptoms,Impairment of motor functionLMN paralysisStimulus symptoms: fasciculationSensory impairment anaesthesia, paraesthesia and painAutonomic dysfunction: Anhidrosis and orthostatic hypotension,Clinical patterns,Mononeuropathy: weakness and sensory loss in the territory of a single peripheral nerveMutiple mononeuropathy: more than one peripheral nerve are involvedPolyneuropathy: symmetric weakness of limbs and areflexia, symmetric loss of sensory, autonomic dysfunction in the affected area,Auxiliary examination,NCV and EMG are helpful to the diagnosis of the peripheral nerve disease. Discover the preclinical nerve impairmentFind out whether the disease is caused by the axon degeneration or demyelinationDistinguish muscle disease from neuropathy,Idiopathic Trigeminal Neuralgia,Trigeminal neuralgia is a disease characterized with transient and recurrent severe pain within the distribution of trigeminal nerve.,Etiological factor and Pathology,Usually idiopathic. Some may be due to the compression of tortuous blood vessel.,Clinical manifestation,Women: men=3:2. Much higher in elderly;Paroxysmal in natureUnilateral and limited to one or two divisions (mandibular and maxillary branches are more involved) of trigeminal nerve territoryIntensity to make patients grimace or ticPresence of initiating or trigger pointLack of demonstrable sensory or motor decit.,Diagnosis and differential diagnosis,According to the location and nature of the pain , trigger point and without positive signs of nerve system examinations.Symptomatic trigeminal neuralgia;Dental neuralgia;,Treatment,Anticonvulsant drugs GabapentinPregabalinCarbamazepinePhenitoinValproic acid Tricyclic AntidepressantsVitamin B12 and Vitamin B1PimozideNerve blocking therapyStereotactically controlled thermocoagulation of the trigeminal rootsVascular decompression,Idiopathic facial paralysis,idiopathic facial paralysis is also called facial neuritis or Bell palsy, which is peripheral facial paralysis due to the non special inflammation of facial nerve.,Etiology and Pathology,The cause is still unclear. Maybe is related with virus infection, especially herpes zoster. Compression from the osseous facial canal after the edema formation also participates pathologic process.The first pathological change of cranial nerve is the edema of nerve and demyelination, in serious condition axonal degeneration occurs.,Scheme of facial nerve,Clinical manifestation,The disorder affects men and women more or less equally and occurs at all ages and all times of the year.The onset is acutePain behind the ear may precede the paralysis by a day or two. Symptoms according the lesion positionStylomastoid foramenparalysis of muscles of facial expressionJunction of the chorda tympani bers to geniculate ganglia Impairment of taste.Nerve to the stapedius muscle hyperacusis or distortion of sound in the ipsilateral ear(paralysis of the stapedius muscle)Above geniculate gangliareduction of lacrimation and salivation.,Treatment,Prednisone: 40-60mg/dayMedication of vitamin B12 and vitamin B1Antiviral therapyProtection of the eye during sleepPhysical therapySurgery Anastomosis,Prognosis,Fully 80 percent of patients recover within a month or two. Good prognostic signs: Recovery of taste in the rst week; Early recovery of some motor function in the rst 5 to 7 daysBad prognostic sign: Denervation after 10 days in electromyography,Guillain-Barre syndrome (GBS),Guillain-Barre syndrome (GBS) is an autoimmune-related polyneuropathy. Its classic pathological characteristic is the segment demyelination of peripheral nerves and the nerve roots and the infiltration of the lymphocyte and the macrophage around the small vessels.,Pathogenesis,Presumed to be immuno-related cross reaction between antibody to virus and components of nerve Mild respiratory or gastrointestinal infection in 60% of cases 1-3weeks before GBS. Presence of antibody of campylobacter jejuni (enteric organism) in some casesVaccination-related: influenza, rabies,Epidemiology,The incidence rate of GBS is 0.61.9/100,000 per year. The rate for men is a slightly lower than that for women. It occurs at all ages.,Clinical Manifestations,Antecedent infection symptoms or the history of vaccination Acute or subacute onsetThe paraesthesia of limbs and the symptoms of nerve root stimulationMajor symptom: limb weakness and hypo/areflexia5% of cases respiratory musclesPain in muscles ( thigh, hip, back)Involvement of cranial nerve: facial nerve, ocularmotor nerve, glossopharyngeal nerve, accessory nerve The symptoms of autonomic system Monophase course of disease,Variants of GBS,Fisher syndrome: ophthalmoplegia with ataxia and areexiaAcute motor axonal neuropathyAcute sensory-motor axonal neuropathy Pandysautonomia: prominent autonomic symptoms without sensory-motor symptomsAcute inflammatory demyelinating polyneuropathy(AIDP),investigative examination,CSFcell account- normal elevation of protein after several days; peaks around 3weeksElectromyographic abnormalityDemyelination- slow conduction velocityAxon degenerationreduction of amplitude of potential Prolonged or absent F-responses (indicating involvement of proximal parts of nerves and roots),Diagnosis and differential diagnosis,diagnosis according to:the infection history one to four weeks before onset, acute or subacuteSymmetric flaccid paralysis of four limbs Glove stocking like paresthesia, anesthesia Involvement of cranial nerve.,Differential Diagnosis,Periodic paralysis: caused by hypokalemia, transient paralysis without sensory deficitsAcute transverse myelitis: sensory/motor level, prolonged urinary impairment. UMN paralysis after spinal shock,Treatment,ImmunoglobulinPlasmapheresis Ventilatory supportPhysical treatment,Headache,Cranial structures sensitive to pain,skin, subcutaneous tissue, muscles, extra-cranial arteries, and periosteum of the skullDelicate structures of the eye, ear, nasal cavities, and paranasal sinusesIntracranial venous sinuses and their large tributaries, especially pericavernous structuresParts of the dura at the base of the brain and the arteries within the dura and pia-arachnoid, particularly the proximal parts of the anterior and middle cerebral arteries and the intracranial segment of the internal carotid arteryThe middle meningeal and supercial temporal arteries The trigeminal, glossopharyngeal, vagus, and rst three cervical nerves.,Migraine,Periodic, commonly unilateral, often pulsatile headaches Begin in childhood, adolescence, or early adult life Recur with diminishing frequency during advancing years,Mechanism,Vascular hypothesisA reduction in blood ow in occipital cortex spreading forward Seritonin over-secretion during the ischemic stage and depletion thereafter leading the dilution of vessels Spreading cortical depressionTrigeminovascular complex involvementThe involved vessels, both extracranial and intracranial, are innervated by small unmyelinated bers that are derived from the trigeminal nerve and subserve both pain and autonomic functionsActivation of the fibers release substance P, calcitonin gene-related peptide (CGRP) and dilute the vessels,Classic Migraine (Migraine with Aura),Preceding nervous disturbance symptoms: often visual( abruptly onset, unformed ashes of white, or silver lights (photopsia), followed by an enlarging blind spot with a shimmering edge (scintillating scotoma), or formations of dazzling zigzag.)Hemicranial and throbbing headache (one-third of cases bilateral headache) occurs in a few minutes Accompanied symptoms: nausea, vomiting, sensitivity to light and noise, intensification by head movementDuration: hours to one or two days,Common Migraine (Migraine without Aura),No preceding symptoms,Factors influence the attacks,Certain dietary items chocolate, cheese, fatty foods, oranges, tomatoes, and onions-Rich in tyramineAlcoholMenstrual migraine: perimenstrullyStressLack of sleep,Differential diagnosis,Tension-type headache :Most common; pain is often described as a constant pressure, as if the head were being squeezed in a vise. The pain is frequently bilateral and gets severe later in the day . Tension-type headache pain is typically mild to moderate.Cluster headacheAn immense pain locating behind the eye or in the temple, lasting from15min to several hours. the regularity of its timing in that both the individual attacks and the clusters themselves redness of the conjunctiva, runny nose, facial blushing Low-pressure headache steady occipital and frontal pain occures after arising from a recumbent position and is relieved by lying down.,Treatment during attacks,Non-steroidal anti-inammatory drugSelective agonists of serotonin (5HT) receptors: triptansErgotamine: an alpha-adrenergic agonist with strong 5HT receptor afnity and vasoconstrictive actionOral corticosteroids,Prophylactic Treatment,BetablockersCertain anticonvulsantsanti-depressantsCalcium channel blockersAntagonist of 5-HT receptor: pizotifan,Thanks,