PEDIAT.CNS
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CENTRAL NERVEOUS SYSTEM [CNS], PERIPHERAL NERVEOUS SYSTEM AND NEUROMUSCULA-JUNCTION [NMJ] EXAMINATION - The central nervous system [CNS], peripheral nervous system [PNS] and neuromuscular-junction [NMJ] examination is one of the major part of the art of physical examination. Supplementary history from relatives or others who witnessed any state of impaired level of consciousness [LOC] or higher CNC function or abnormal movement is helpful. LOCALIZATION OF THE CNS AND PERIPHERAL LEISON BY THE SIGNS AND/OR THE SYMPTOMS - The diagnosis of children with neurological diseases depends entirely on the history. Patient with black out or headache may have no physical findings. Even, the localization of the lesion may be identified from properly taken history. The major symptoms which should be enquired about during history taking are listed in the table below; SERIAL PART OF CNS OR PNS 1 MENTAL STATE SYMPTOM - - Level of consciousness [LOC]. Orientation [time, place and person]. Speech. General knowledge. Memory. Retention and recall. Reasoning and judgment. Reading, writing and calculation. Object recognition. Praxis. Perception. Mood and affect. Normal gait. Heel to toe walking. Romberg Test. First (I) [olfactory nerve] 4 - Second (II) [optic nerve] 5 - Third (III), fourth (IV) and - 2 GAIT AND STATION 3 CRANIAL NERVES REMARKS - Smell [olfactaion]. - Visual acuity. - Visual field. - Color vision. - Fundoscopy. - External eye - 6 - - sixth (VI) nerve. The 3d CN is the oculomotor nerve, the 4th CN is the trochlear nerve and the 6th CN is the abducent nerve. Fifth (V) cranial nerve (trigeminal nerve) Seventh (VII) CN (facial nerve). Eighth (VIII) CN. It comprises the cochlear nerve and the vestibular nerve. movement. - Nystagmus. - Pupil reaction to light. - Facial and oral sensation. - Masticatory Muscles. - Facial muscles. - Taste. - Tested by whisper in each ear and by tuning fork tests. - Ninth (IIX) CN - It can be tested [Glossopharyngeal nerve]. by noticing the power of the trapeziuus muscle and sternomastoidm uscle. - Tenth (X) CN [Vagus nerve]. - Eleventh (XI) CN[Accessory nerve]. - Twelfth (XII) CN [Hypoglossal nerve]. - Tested by asking the patient to say aaah where the palate should be elevated - Tested by turning the head to left and right and flexing it against resisitance. - Test the patient tongue after opening his mouth and ask him to protrude the tongue. - Look for any deviation of the tongue. - Assess the bulk of the tongue. - Wasting and fasciculation of the tongue indicate LMN lesions. - Be aware that tremor of the tongue may difficult to differentiate from fasciculation. - LMN of the nerve produces ipsilateral wasting and weakness of the tongue. - Only occasionally, acute, severe UMN lesions of the nerve produces deviation of the tongue toward the opposite side. NEUROLOGICAL EXAMINATION - Neurological examination can be done quickly and efficiently if a routine is adhered to. Most of the information can be gathered by observation. So, spend more time watching and playing with infants, toddlers and young children. Have a look at the child from head to the toes while you are entering the room. The CNC and the PNC examination of neonates and infants differs from that of the adult neurological examination. The site of the CNS lesion may be identified by the presence or the absence of certain symptoms and/or signs as shown in the table below; SERIAL LEVEL OF THE LEISON SIGNS AND OR SYMTOMS 1 CORTEX 2 CORONA RADIATA 3 INTERNAL CAPSULE [IC] 4 MID-BRAIN Monopleg ia. Seizure [jacksonian fit] Incomplet e hemiplegia Incomplet e hemianesthesia Complete [dense] hemiplegia Complete hemianesthesia Supranucl ear involvement of the 7thcranial nerve Weber Syndrome [involvement of the 3d cranial nerve [CN]in the same side and hemiplegia on the opposite side]. Benedikt Syndrome [involvement of the 3d CNin REMARKS 5 JUNCTION OF THE MIDBRAIN TO PONS 6 PONS 7 MEUULLA OBLANGATA the in the same side and hemianesthesia and tremor on the opposite side]. Bilateral supra-nuclear 7thCNinvolvem ent. Loss of horizontal conjugate ocular deviation Involveme nt of all or any one of the 5th, 6th, 7th and/or 8th CN of the same side. Hemiplegi a in the opposite side. Pinpoint pupils. Pyrexia. Ptosis. Enophthal mia. Central lesions 8 Slightly lateral lesions 9 Wedge shaped lesions [posteriorinterior cerebellar artery syndrome (Wallen berg syndrome)] Fovilsyndrome is the involvement of 6th and 7thCN in the same side and hemiplegia in the opposite side. Quadreplegia as the pyramidal tracts decussate in this area. 12thCN paralysis in the same side. Hemiplegia in the opposite side. Hemianesthesia in one half of the face in the same side. Horner syndrome in the same side. Loss of the movement of one half of the palate in the same side. Signs and symptoms of cerebellar lesion in the same side. Hemianesthesia in the opposite side. 10 PARAIETAL LOBE 11 SPINAL CORD 13 CAUDA EQUINA Disorienta tion. Apraxia [loss of skilled movement]. Agnosia [inability to recognize the things]. Sensory inattention [allocheiria] Homonym ous hemianopia. Receptive dysphasia. Hemi-section of the cord above C 5 [Brown sequard syndrome] Wasting of leg muscles Parasthet hesia Sphincteri cdisturnanves Anesthesi a around the anus Hemiplegia in the same side. Loss of deep sensation in the same side. Loss of pain and temperature in the opposite side. NOCN involvement. Mainly calf muscles wasting Crossed hemiplegia means hemiplegia in the opposite side and CNsinvolvement in the same side. It indicates brain stem lesion [mid-brain, pons or medulla oblongata] lesions. Uncrossed hemiplegia meansinvolvement CNs and hemiplegia in the same side [opposite side of the leisons]. Uncrossed hemeplegia is caused by lesions in the following 3 areas; 1]- internal capsule [IC], 2]corona radiate, 3]-or cerebral cortex. LEISONS OF THE LOBES OF THE BRAIN - Localized lesions of the different lobes of the brain, often, give readily recognizable clinical syndromes. The most common of these clinical syndromes are tumor or areas of infarction. These clinical syndromes are shown in the table below by the lobe involved; LOBE CLINICAL SYNDROME REMARKS FRONTAL Contralateral hemiparesis Due to the involvement of the motor areas and upper part of the cortico-spinal tract. Due to the involvement of Broca s area. Common. - Intellectual impairement [poor attention span, loss of retention and recall impairment of judgment]. - With periods of euphoria or depression. Expressive aphasia fits Mental changes [common] Mood changes [prominent] PARIETAL Fatuous or frivolous affect Disinhibited behavior. Loss of bowel and bladder control leading to incontinence. Abnormalities of cortical sensation. - There is inappropriate lack of concern Common. Impairment of task involving visiospacial skills. Apraxia. - Common. - Topographagnosis. - Lower homomnymousquadrantanopia. - Common. Leads to serious practical problems, such as inability to perform simple tasks such as dressing, eating and shaving. The difficulty experienced by the patient in finding their way in familiar places [particularly with non dominant parietal lobe lesions]. Due the involvement of TEMPORAL TEMPORAL - optic radiation. Due the involvement of Wernicke area in anterior part of the temporal lobe, Receptive aphasia. Memory impairment. Upper homomnymousquadrantanopia. - Hemianopic visual field defect - Visual agnosia and agnosia of colors. - Due the involvement of visual radiation. Due the involvement of the visual cortex. Due the involvement of more anterior part of occibital lobe, in the visual association area.. Remember, fits are commonest with frontal and temporallobe lesions, less common with parietal lobe lesions and the least with occipital lobe lesions. CRANIAL NERVE EXAMINATION - Most important points inn cranial nerve examination are listed in the table below; CRANIAL NERVE OLFACTORY NERVE (1st CN) EXAMINATION TECHNIQUE - - - OPTIC NERVE (2st CN) - LESION Ask the child to Paralysis affect the close his eyes. movements of Occlude one nostril individual muscles. at a time. Bring the test of smell form the periphery. Ask the child to say yes if he smell anything new and what it is. Do the same for the other nostril. Use, camphor, peppermint, cloves or coffee. Pupil reaction to Wasting of the light, Visual acuity, affected musles. Visual field, fundoscopy are the part of the 4th CN examination REMARKS - Rarely needed. It is essential if ; 1]- the child complain of loss of taste or smell, 2]has visual field defect, 3]- and if the child had frontal lobe trauma or surgery. OCULOMOTO R NERVE (3st CN) - - - - TROCHLEAR NERVE (4st CN) - The 3d ,4th and 6thCNs are examined together. The 3dCN cotntains motor fibers to the extra-occular voluntary muscles except the later rectus and superior obique muscles, afferent proprioceptive fibers from these muscles and motor parasympathatic fibers to the pupils which upon stimulation causes pupillary constriction. The inferior oblique elevates the eyes during adduction]. The motor fibres arise from its nucleus in the midbrain near aqueduct of slvius. - - - - - - ABDUCENT NERVE (6st - - Paralytic divergent squent [eye deviated laterally in the sane side. The pupil in the affected side aybe normal or larger and unreactive. Failure of pupil reaction to light and accommodat ion. Complete ptosis in the same side. Diplopia in all direction of the gase except lateral gase to the side of the lesion. - Compensato ry torticollis. Squint is not obvious. Diplopia occurs when attempting downward gase, causing proplem with going dwnsatis. - Compensato ry torticollis. - - - - The inferior muscles are attached to the eyes behind the equator of the globe. Hus the inferior oblique elevates rather than depresses the eyes during adduction and the superior oblique depresses rather than elevates the eyes during adduction. The muscles of the eylids are supplied by the 3d CN [levator muscles]and by cervicle sympathetic nerve fibers [the Muller muscle. So, any lesion in the superior division of the will cause ptosis. CN) - - MANDIBULAR NERVE (7st CN) - - It has motor and sensory cmponent. The sensory componenet are [opthalmic supplying area around and above the eyes and lateral aspect of fore head in the same side, maxillary sensory component supplies area over the cheek or the maxilla in the same side and mandibular sensory component supplying the area of the lower part of the face over the mandibule [chin] It is only necessary to test the light touch sensation using wisp of cotton wool in the - - Squint is not obvious. Diplopia occurs when attempting downward gaze, causing problem with going downstairs. Failure of downward and lateral gaze due to failure to Ssuperior oblique muscle. LMNs keison, while you are attempting o clos the opened mouth , the mouth deviates toward the weak side in the same side. - - - - - - OCULOVESTIB ULAR NERVE (8st CN) - different three areas of both side of the face [above the eyes, over maxilla and over the chin in both side. Ask the child to close the eye first and to say yes as soon as he feels anything and localizes the part of the face. To examine rhe motor component, inspect the muscles of masticcation for wasting or fasiculation. To test the bower of the muscles of mastication, ask the child to open his/her mouth and t keep it open while you puch against his/her chin to close it. In uncooperative child, ask him to pit in wood spatula [tongue depressor. If e is able to do so with no deviation of the chin, then the power is likely to be normal. It has 2 components [auditory fibres arising from the cochle and vestibular fibers arising from the otolith organs and semi-circular - - - Air conduction is normally more efficient than bone conduction. - - - - - GLOSSOPHAR YNGEAL NERVE (9st CN) - canals. It runs along the facial nerve in the internal auditory meatus and both enter the brain stem at the cerebro-pontine angle. Both may therfore affected by a posterior fossa tumor or in acustic neuroma. The cochlear divison conveys impulses from the inner ear. Before testing hearing, always examine both external auditory meatus for local disease, wax, grommets and perforation of ear drum. If you judge that the hearing is impaired, you must distinguish between sensorneural [perceptive] due to damage to the nerve itself or conductive hearing loss due to lesion of the external auditory canal or drum or middle ear. The 9th and 10th CN are considered together AS they exit the skull togother and run similar course and - - - - - VAGUS NERVE (10st CN) ACCESSORY NERVE (11th CN) both are usually involving in a single lesion. The has 2 component [sensory and motor]. The motor divison supplies te stylopharyngeal muscle, which elevate the upper part of the pahrynx, togother with the palatopharyngeal muscle, which is supplied by the 10th C. This is difficult to test because the child still be able to elevate the palate if the 10th CN is intact. The sensory component function as combined with the 10th CN, except for the taste - It supplies the trapezius and sternomastoid muscles. Function is easily tested by asking the child to shrug their shoulders, turn the head to one side while you are applying force from the other side over the chin. This test the sternomastoid in the opposite side. - - - - - HYPOGLOSSAL NERVE (12st CN) - - - Younger children may not cooperate, however they will obliginbly turn toward a toy or toward their mother voice. Supplies the muscles of the tongue. First inspect the tong lying in the floor of the mouth after asking the child to open his moth. Look for wasting and fasiculation. Then ask the child to protrude his tongue out. A unliateral lesion causes ipsi-lateral atrophy of the tongue and deviation toward the side of the lesion.'UNMLs of the 4th CN is extremely rare except in child with cerebral palsy and leads to small and spastic tongue. - - - Fasiculation in seen in LMNs leison such as spinal muscular atrophy. Do not mistake apparent deviation of the tongue as a result of 7th CN palsy from 12th CN palsy. THE ACTION OF EXTRA-OCCULAR MUSCLES AND THE NERVE INVOLVED - The action of extra-ocular muscles and the nerve involved are shown in the table below; THE MUSCLE THE ACTION THE NERVE SUPPLY - Superior rectus Inferior rectus Medial rectus Lateral rectus Superior oblique Inferior oblique Moves the eyes up and out Moves the eyes down and out Moves the eyes medially Moves the eyes laterally Moves the eyes down and in Moves the eyes up and in 3d CN 3d CN 3d CN 3d CN 6thCN 3d CN - \ MYOTOMES UPPER MOTOR LEISON [UMNs] AND LOWER MOTOR LEISON [UMNs] - The differences between UMNs and LMNs lesions are listed in the table below; UMNs LESIONS LMNs LESIONS Paralysis affect the movements of group of muscles. No wasting of the affected group of muscles. Tone is increased [clasp knife]. No involuntary movements. DTRs are exaggerated. Clonus is present. Trophic changes are absent. Reaction of degeneration is not present. Paralysis affect the movements of individual muscles. Wasting of the affected muscles. Tone is decreased. Involuntary movements present [fasciculation]. DTRs are decreased or absent. No Clonus. Trophic changes are present. Reaction of degeneration is present on electrical stimulation. ANTERIOR HORN CELLS LESIONS VERSUS PERIPHERAL NERVES - LEISONS - The differences between peripheral nerves lesions and anterior horn cells [AHCs] lesions are listed in the table below; AHCs LEISONS PERIPHERAL NERVES LESIONS Disease onset is gradual Fasciculation [by EMG] and fasciculation are present. Involvement of motor system only. Onset is sudden. Fasciculation [by EMG] and fasciculation are absent. Involvement of both the sensory and motor system. No sphencteric disturbances. Sphencteric disturbances are present. PATTERN OF NEUROLOGICAL DEFICITS BY THE LOBE OF BRAIN - The common pattern of neurological deficit by the site of insult are listed in the table below; SITE DIFFUSE CEREBRAL CEREBRAL HEISPHERE EXTRAPYRAMIDAL CEREBELLUM PATTERN OF DEFECT - - Elbow extension - EXPANDING PITUITARY LESIONS Dementia with or without physical signs depending on the location of the lesion. Fit. Gait dyspraxia. Hemiparesis. dysarthria - - Ataxia of the trunk [mid-line lesion]. Ipsi-lateral ataxia of the limbs and nystagmus with cerebellar hemisphere involvement. Dysarthria. Bitemporal visual field loss. Hypituitrism [usually partial]. Optic atrophy [some of the cases]. Ocular movement REMARKS BRAIN-STEM - - - - - - - - - - - palsies [some of the cases]. CR involvement at the level of the lesion. Limbs signs [often bilateral]. Bulbular involvement with medulla involvement. Variable sensory impairment [often contra-lateral spinothalmic [ST] loss. Limbs signs [often bilateral]. Upper motor neurons [UMN] signs below the level of the lesions. - Bulbular involvement include; dysarthria, dysphagia and breathinf difficulties. - - - Bulbular involvement with medulla involvement. Variable sensory impairment [often contra-lateral spinothalmic [ST] loss. Limbs signs [often bilateral]. Variable bladder and bladder involvement. Cerebellar signs [very common]. Impairment in the LOC with acute lesions Hydrocephalus - Usually with ventrally placed lesions. - Due to aqueduct stenosis. SPINAL CORD - - - - - - with mass lesions. There may root signs at the level of the lesions. UMN (pyramidal tract involvement) weakness below the level of the lesions. Extensor planter reflex. Brisk deep tendon reflexes [DTRs] below the lesions Absent or reduced superfacial abdominal reflex. There may be sensory level at the trunk. Sensory loss in the limbs. - This may be at or below the level of the lesions. - May e of dorsal column [DC] or ST type or affects all modalities. Intrinsic cord lesions is most likely to cause ST sensory loss. DC sensory loss is most likely caused by compressive lesions. Common. May be the early major sign. - ANTERIOR HORN CELLS - CAUDA EQUINA - - ROOT PERIPHERAL NERVES - - Bladder and bowel involvement. Muscle weakness. Muscle wasting. Muscle fasciculation. Multiple lumbosacral root lesions. Bladder and bowel involvement. Absent reflexes at the affected root level. - LMN signs and sensory loss in mononeuritis. Asymmetrical, - In motor neuron lesion [MNL], a combination of UMN and LMN signs are present. - Often asymmetrical. - At the distribution of the affected nerve. - Attributable to affection of multiple - - NEUROMUSCULAR JUNCTION [NMJ] MUSCLES - - patchy motor and/or sensory deficit in mononeuritismult eplix. Symmetrical LMN signs and or sensory loss in poly neuropathy. The DTRs are variably absent. Fatigue weakness affecting any muscle. Proximal muscle weakness. Proximal muscle wasting. Reduced or absent DTRs. Plantar flexor response. nerves. - Most marked distally. - Depends on type and extent of the lesions. - If muscle wasting is severe. MYOTOMES - The nerve root involved in joints movement are listed in the table below; SERIAL MOVEMENTTESTED NERVE ROOT 1 2 3 4 5 6 7 8 9 10 11 12 C5/C6 C5/C6 C7/C8 C8 C8/T1 L1 L2 L3 L4 S1 Shoulder abduction Elbow flexion Elbow extension Finger flexion Finger abduction Hip flexion Hip abduction Knee extension Foot dorsiflexion Foot plantar flexion SENSORY SYSTEM REMARKS - - The sensory exam includes testing for; 1]- pain sensation [pin prick], 2]- light touch sensation [brush], 3]- temperature sensation, 4]- vibration sensation, 5]- position [muscles and joint position] sensation, 6]-stereognosia, 7]-graphesthesia, 8]- and extinction. A working knowledge the peripheral nerves and dermatomes anatomy is essential The initial evaluation of the sensory system is completed with the patient lying supine, eyes closed. The light touch is tested with a cotton wool or wisp. The pinprick sensation is tested with disposable pin. For pain and light touch sensation test, you should instruct the patient to say sharp or dull when they feel the respective object. Show the patient each object and allow them to touch the needle and brush prior to beginning to alleviate any fear or anxiety of being hurt during the examination. With the patient eyes closed, alternate touching the patient with the needle and the brush at intervals of roughly 5 seconds. Begin rostrally and work towards the feet in both side [left upper limb, right upper limb, abdomen, back, left lower limb and right lower limb]. Make certain to instruct the patient to tell the physician if they notice a difference in the strength of sensation on each side of their body. Alternating between pinprick and light touch, touch the patient in the 13 places. Touch one body part followed by the corresponding body part on the other side [for example; the right shoulder then the left shoulder] with the same instrument. This allows the patient to compare the sensations and note asymmetry. The corresponding nerve root for each area tested are shown in the table below; . AREA TESTED CORRESPONDING ROOT Posterior aspect of the shouldres Lateral aspect of the upper arms Medial aspect of the lower arms Tip of the thumb Tip of the middle finger Tip of the pinky figure Thorax and nipple level Thorax and umbilical level C4 C5 T1 C6 C7 C8 T5 T10 - Body charts are useful to record the sensory abnormalities. Test position sense by having the patient, eyes closed, report if their large toe is up or down when the examiner manually moves the patient toe in the respective direction. Repeat on the opposite foot and compare. - - Make certain to hold the toe on its sides, because holding the top or bottom provides the patient with pressure cues which make this test invalid. The joint position sensation should be tested initially in the distal inter-phalangeal joints of the fingers and toes. The temperature sensation is tested by tubes filled with hot or cold water. The vibration sensation is tested by tuning fork [120 – 130cycles per second]. The joint position sensation should be tested initially in the distal inter-phalangeal joints of the fingers and toes. Body charts are useful to record the sensory abnormalities.The stereognosis is tested by asking the patient to close their eyes and identify the object you place in their hand. Place a coin or pen in their hand. Repeat this with the other hand using a different object. Astereognosis refers to the inability to recognize objects placed in the hand. Without a corresponding dorsal column system lesion, these abnormalities suggest a lesion in the sensory cortex of the parietal lobe. The graphesthesia is tested by asking the patient to close their eyes and identify the number or letter you will write with the back of a pen on their palm. Repeat on the other hand with a different letter or number. Apraxias are problems with executing movements despite intact strength, coordination, position sense and comprehension. This finding is a defect in higher intellectual functioning and is associated with cortical damage. To test the extinction, have the patient sit on the edge of the examining table and close their eyes. Touch the patient on the trunk or legs in one place and then tell the patient to open their eyes and point to the location where they noted sensation. Repeat this maneuver a second time, touching the patient in two places on opposite sides of their body, simultaneously. Then ask the patient to point to where they felt sensation. Normally they will point to both areas. If not, extinction is present. With lesions of the sensory cortex in the parietal lobe, the patient may only report feeling one finger touch their body, when in fact they were touched twice on opposite sides of their body, simultaneously. With extinction, the stimulus not felt is on the side opposite of the damaged cortex. The sensation not felt is considered extinguished. SENSORY SYSTEM LESIONS - The evaluation of somatic sensation or any sensory modality for that matter, is highly dependent on the ability and the desire of the patient to cooperate. - Sensation belongs to the patient [subjective] and the examiner must therefore depend,, almost entirely on their reliability. - For example, a patient with dementia or a psychotic patient is likely to give only the crudest, if - any, picture of their perception of sensory stimuli. The affected patient usually reports paresthesias [pins and needles sensation] in the hands and feet. Some patients may report dysesthesias [pain] and sensory loss in the affected limbs also. Some patients may report dysesthesias [pain] and sensory loss in the affected limbs also. - For example, a patient with dementia or a psychotic patient is likely to give only the crudest, if - any, picture of their perception of sensory stimuli. - An intelligent, stable patient may refine asymmetries of stimulus intensity to such a degree that insignificant differences in sensation are reported, only confusing the picture. - Suggestion can also modify a subject response to a marked degree [for example; to ask a patient where a stimulus changes suggests that it must change and may therefore create false lines of demarcation in an all too cooperative patient]. - Obviously, the examiner must not waste time and efficiency on detailed sensory testing of the psychotic or demented patient and must warn even the most cooperative patient that minute differences requiring more than a moment to decipher are probably of no significance. - Additionally, the examiner must avoid any hint of predisposition or suggestion. - In neonates, young infant and toddler, sensory system examination may not be done unless specifically asked for. - Even after all precautions are taken, problems with the sensory exam still arise. - Uniformity, in testing is almost impossible and there is considerable variability of response in the same patient. - Fatigue can be an additional confounding variable and is particularly likely to be induced by a long, detailed and tedious sensory examination. - A rapid, efficient exam is the most practical means of diminishing fatigue. - Use of a pressure transducer, such as VonFrey monofilaments, allows more consistent stimulus intensities and therefore more objectivity in the examination; however, this is impractical at the bedside and does not eliminate patient variability. - Sensory changes that are unassociated with any other abnormalities [such as motor, reflex, cranial or hemispheric dysfunctions] must be considered weak evidence of disease unless a pattern of loss in a classical sensory pattern is elicited [for example, in a typical pattern of peripheral nerve or nerve root distribution]. - Therefore, one of the principle goals of the sensory exam is to identify meaningful patterns of sensory loss [see below]. - Bizarre patterns of abnormality, loss, or irritation usually indicate hysteria or simulation of disease. - However, the examiner must be aware of their own personal limitations. - Peripheral nerve distributions vary considerably from individual to individual, and even the classic distributions are hard to keep in mind unless one deals with neurologic problems frequently. - Therefore, it is advisable for the examiner to carry a booklet on peripheral nerve distribution, sensory and motor [such as Aids to the Examination of the Peripheral Nervous System, published by the Medical Council of the UK]. - As in all components of the examination, an efficient screening exam must be developed for sensory testing. - This should be more detailed when abnormalities are suspected or detected or when sensory complaints predominate. - Basic testing should sample the major functional subdivisions of the sensory systems. - The patient eyes should be closed throughout the sensory examination. - The stimuli should routinely be applied lightly and as close to threshold as possible so that minor abnormalities can be detected. - Spino-thalamic [ST] (such as pain, temperature and light touch], dorsal column [DC] (such as vibration, proprioception and touch localization] and hemispheric (such as stereognosis and graphesthesia] sensory functions should be screened. - Pain [using a pin or toothpick], vibration [using a C120 – 128Hertz tuning fork] and light touch should be compared at distal and proximal sites on the extremities and the right side should be compared with the left. - Proprioception should be tested in the fingers and toes and then at larger joints if losses are detected. - Stereognosis [the ability to distinguish objects by feel alone] and graphesthesia[the ability to decipher letters and numbers written on skin by feel alone using back of the pin] should be tested in the hands if deficits in the simpler modalities are minor or absent. - Significant defects in graphesthesia and stereognosis occur with contra-lateral hemispheric disease, particularly in the parietal lobe [since this is the somato-sensory association area that interprets sensation]. - However, any significant deficits in the basic sensory modalities cause dysgraphesthesia and stereognostic difficulties whether the lesion or lesions are peripheral or central. - Therefore, it is difficult or impossible to test cortical sensory function when there are deficits of the primary sensory functions. - It may be surprising that the more basic modalities are usually not greatly affected by cortical lesions. - With acute hemispheric insults [such as cerebral infarction or hemorrhage], an almost complete contra-lateral loss of sensation may occur. - It is relatively short lived, however; perception of pinprick and light touch, as routinely tested, returns to almost normal levels, whereas proprioception and vibration may remain deficient [though considerably improved] in most cases. - This lack of a significant long term deficiency in basic sensation following hemispheric lesions has no completely satisfactory explanation, although some basic sensations probably have considerable bilateral projection to the hemispheres. - Double simultaneous stimulation [DSS] is the presentation of paired sensory stimuli to the two sides simultaneously. - This can be visual, aural or tactile. - Light touch stimuli presented rapidly, simultaneously, and at minimal intensity to homologous areas on the body [distal and proximal samplings on extremities] may pick up very minor threshold differences in sensation. - Additionally, this testing can also detect neglect phenomena due to damage of the association cortex. - Neglect may be hard to distinguish from involvement of the primary sensory systems. However, neglect usually can be demonstrated in multiple sensory systems [visual, auditory and somesthetic], confirming that this is not simply damage to one sensory system. - Association cortex lesions, particularly involvement of the right posterior parietal cortex, may become apparent only on double simultaneous stimulation. - The face hand test is a further modification of DSS. - This test takes advantage of the fact that stimuli delivered to the face dominate over stimulation elsewhere in the body. - This dominance is best illustrated in children and in demented and therefore regressed patients. - Before the age of 10 years, most strikingly earlier than age 5 years, stimuli presented simultaneously to the face and ipsi-lateral or contra-lateral hand are frequently [more than 3 in 10 stimulations] perceived at the face alone. - Perception of the hand, and, if tested, other parts of the body is extinguished. - In an older child or adult, several initial extinctions of the hand may occur, but very quickly both stimuli are correctly perceived. - In the patient with diffuse hemispheric dysfunction [dementia], a regression to consistent bilateral extinction of the hand stimuli is frequently seen. - This test therefore can be doubly useful, first as an indication of diffuse hemispheric function and second by stimulating the face and opposite hand, a means of detecting minor hemisensory defects [such as if the patient consistently extinguishes only the right hand and not the left], a sensory threshold elevation due to primary sensory system or association cortex involvement on the left is suspect. - Since the main goal of the sensory exam is to determine which, if any, components of the sensory system are damaged, it is important to consider the principle patterns of sensory loss resulting from disease of the various levels of the sensory system. - These patterns of loss are based on the functional anatomy and we will also briefly review some of this anatomy. - Peripheral neuropathy, that is, symmetrical damage to peripheral nerves, is a relatively common disorder that has many causes. - Most of these can broadly be classified as toxic, metabolic, inflammatory or infectious. - In this country, the most common causes are diabetes mellitus [DM] and the malnutrition of alcoholism, although other nutritional deficiencies or toxic exposures [either environmental toxins or certain medicines] are occasionally seen. - Infections, such as lyme disease, syphilis or HIV can cause this pattern and there are inflammatory and autoimmune conditions that can also produce this pattern of damage. - Because this is a systemic attack on peripheral nerves, the condition produces symmetrical symptoms. - The initial symptoms are most often sensory and the longest nerves are affected first [the ones that are most exposed to the toxic or metabolic insult]. - The receptors of the feet are considerably farther removed from their cell bodies in the dorsal root ganglia than are the receptors of the hands. - The metabolic demands on these neurons is substantial which accounts for their being the first affected and for the early appearance of sensory loss in the feet in a stocking distribution. - Later on, as the symptoms reach the mid calf, the fingers are involved and a full stocking glove loss of sensation develops. - Even later, when the trunk begins to be involved, sensory loss is noted first along the anterior midline. - Vibration perception is often the earliest affected modality since these are the largest, most heavily myelinated and most metabolically demanding fibers. - Usually the loss of pinprick, temperature and light touch perception follow, with conscious proprioception [joint position sensation] being variably affected. - Despite the fact that proprioception follows many of the same pathways as vibration it is usually not as noticeably affected because the testing procedure [moving the toes or fingers up or down] is quite crude and is not likely to pick up early loss. - The peripheral deep tendon reflexes [DTRs] are depressed early in most cases of peripheral neuropathy, particularly the achilles reflex. - This is because the sensory limb of this reflex depends on large myelinated fibers. - As a rule, symptomatic motor involvement is late and, when it occurs, it affects the intrinsic muscles of the feet first. - Radiculopathy [nerve root damage] is the relatively common result of inter-vertebral disc [IVD] herniation or pressure from narrowing of the inter-vertebral foramina [IVF] due to spondylosis [arthritis of the spine]. - The most common presentation of this is sharp, shooting pain along the course of the nerve root. - Damage to a single nerve root, even when severe, usually does not have any sensory loss because of the striking overlap of dermatomal sensory distribution. - There may be slight loss, often accompanied with paresthesias [tingling or pins and needles] in small areas of the distal limbs where the sensory overlap is not great. - Herpes zoster, which affects individual dorsal roots, nicely demonstrates thedermatomal distribution because, despite the lack of sensory loss [attributable to the overlap], vesicles [shingles] appear at the nerve endings in the skin. - Nerve root damage in the caudaequine [CE] often produces a saddle distribution of sensory loss by affecting the lower sacral nerve roots. - This saddle distribution of sensory loss can also be seen in anterior spinal cord damage, and, in either case, must be taken quite seriously due to the potentially serious sequellae of spinal cord and CE damage. - Nerve root pain is often quite characteristic. - It is often quite sharp and well localized to the dermatomes distribution and may be brought on by stretching of the nerve rootor by maneuvers that load the inter-vertebral discs [IVD] and compress the intervertebral foramina ([IVF]. - However, pain can also refer. - This referred pain is less localized and is often felt in the muscles [myotomal or skeletal structures (sclerotomal)] that are innervated by the nerve root. - The person usually complains of a deep aching sensation. - Myotomes should not be memorized but can be looked up easily by referring to the motor root innervations of muscles, which are essentially the same as their sensory innervations. - Sclero-tomal overlap is so great that localization on their basis is impractical. - Spinal cord damage is characterized by both sensory and motor symptoms, both at the level of involvement, as well as below, by affecting the tracts running through the cord. - Symptoms referable to the level of injury appear in the pattern of dermatomes and myotomes and, when present, are very useful for localizing the level of spinal cord damage. - The symptoms of damage to the long sensory tracts [the dorsal columns and the ST tract] are less helpful in localizing the lesion because it is often impossible to determine the precise level of the sensory loss and also because, particularly in the case of the ST tract, there is considerable dissemination of the signal in the spinal cord before it is relayed up the cord. - Similar difficulties make it difficult to localize the level of spinal cord damage by examining for damage to the descending [cortico-spinal] motor tracts. - Therefore, when long tract damage is identified, one can only be certain that the lesion is above the highest level that is demonstrably affected. - Compression of the spinal cord from the anterior side first involves the ST paths from the sacral region, and a saddle loss of pain and temperature perception is usually the first symptom even with lesions high in the spinal cord. - In this case, as symptoms progress with greater degrees of compression, symptoms progressively ascend the body up toward the level of the actual cord damage. - Intra-medullary lesions of the spinal cord [such as syrinx, ependymoma or central glioma] may present with a very unusual pattern of suspended sensory loss. - This consists of an isolated loss of pain and temperature perception in the region of the expanding lesion because of damage to the crossing ST tract fibers. - In this pattern of sensory loss due to expanding intra-medullary lesions, there is sacral sparing of pain and temperature because the more peripheral ST fibers [the ones from the sacrum] are the last to be involved. - With intra-medullary lesions, the dorsal columns are also usually spared until extremely late in the course of expansion, leaving touch, vibration, and proprioception intact. The loss of one or two sensory modalities [such as pain and temperature sense, in this case] with preservation of others [such as touch, vibration and joint position sensation] is termed a dissociated sensory loss and is in contrast to the loss of all sensory modalities associated with major nerve or nerve root lesions or with complete spinal cord damage. - Complete hemi-section of the cord is seen occasionally in clinical practice and is quite illustrative of the course of the spinal cord sensory pathways. - This lesion results in a characteristic picture of sensori-motor loss [brown sequard syndrome]; which is easily recognized due to the loss of the dorsal columns sensations [vibration, localized touch and joint position sensation] on the ipsi-lateral side of the body and of ST sensations [pain and temperature] on the contra-lateral side. - Brain stem involvement, like involvement of the spinal cord, is characterized by long tract and segmental [cranial nerve] motor and sensory abnormalities and is localized by the segmental signs. - The picture of ipsi-lateral cranial nerve abnormality and contra-lateral long tract dysfunction is quite consistent. - Both the dorsal columns [DC] and pyramids decussate at the spino-medullary junction [the STsystem has already decussated in the spinal cord]. - This accounts for the typical crossed presentation of symptoms in the body. - Below the level of the midbrain, the STand DC [medial lemniscus (ML)] systems remain separate and therefore lesions may involve the pathways separately [there may be a dissociated sensory loss]. - For example, an infarction caused by occlusion of the posterior inferior cerebellar artery [PICA] typically involves only the lateral portion of the medulla. - The ipsi-lateral trigeminal tract and nucleus and the ST tract are frequently included in the lesion, leaving a loss of pain and temperature perception over the ipsi-lateral faceand the contra-lateral side of the body from the neck down. - The ML and its modalities [vibration, joint position and well localized touch] are spared. - Thalamic lesions are associated with contra-lateral hemi-hypesthesia. - Initially, if the lesion is acute, there is considerable loss bordering on anesthesia, but some recovery is expected over time, especially of touch, temperature and pain perception. - The vibration and proprioception remain more severely affected. - Unfortunately, episodic paroxysms of contra-lateral pain may be a striking and not infrequent residual of thalamic destruction [this is one of the central pain syndromes]. - The pain can be controlled occasionally with anticonvulsants. - An additional residual that may develop over time is marked contra-lateral hyperpathia in spite of the presence of diminished overall sensitivity of the skin. - Stimulation of a site with a pin causes a very unpleasant, poorly localized and spreading sensation, which is frequently described as burning. - This is presumably an irritative phenomenon of the nervous system, although it may also result from loss of normal pain-suppression mechanisms. - It is seen most often after thalamic lesions, although it can occur as a residual of lesions in any portion of the central sensory systems. - A hypersensitivity to cold sensation frequently accompanies the hyperpathia. As discussed earlier, cortical lesions tend to leave minimal deficits in basic sensation. - However, especially if the parietal lobe is damaged, there may be striking contra-lateral deficits in the higher perceptual functions. - Stereognosis and graphesthesia are abnormal in spite of minor difficulties with vibration and proprioception and even less, if any, difficulty with pain, temperature, and light-touch perception. - Of course, if there is significant deficit of primary sensations, it may be impossible to test for deficits of higher perceptual functions. - GAIT ABNORMALITIES - The examination of the gait is very important part of neurological examination. You may be asked directly to examine the patient gait or asked the question; Examine this patient legs, whn, providing the child can walk, the gait examination is the first appropriate step. If the child is able to walk, ask him to walk on a straight line drawn on the ground with both eye opened, then closed. Ask him also to walk while his big toe of onefeet is touching the heel of his other feet. The proplems in gait can be due to the following conditions listed in the table below; TYPE REMARKS HEMIPLEGIA ATAXIC NEUROMUSCULAR DIORDERS ORTHOPEDIC PROBLEMS RHEUMATOLOGICAL DISEASES LIMP It is called the sticky gait. - May arise because of spasticity Painful or painless limping. If the child is able to walk, ask him to walk on a straight line drawn on the ground with both eye opened, then closed. Ask him also to walk while his big toe of onefeet is touching the heel of his other feet. The abnormal gaits and there causes are shown in the table below; GAIT FEATURES SPASTIC GAIT SISCORRIN GAIT FESTINANT GAIT Hemiplegia Spastic Diplegia. Ataxia [sensory or cerebellar]. REMARKS DRUNKEN Neuromuscular disease. GAIT HIGH Orthopedic problem. Can be isolate or arises from STEPPING spasticity. GAIT WADLING Rhheumatological mdiseases. Such as juvenile rheumatoid GAIT arthritis [JRA]. STAMPING Secondary to limp. May be painful limp or painless GAIT limp. - Retropulsion phenomenon is seen in patient with Parkinson disease. - If the patient is pulled suddenly backwards, he will begin to walk backward and will not be able to stop himself. POWER GRADING - The muscles power grading is shown in the table below; SERIAL MOVEMENTTESTED 1 2 3 No contraction Flicker or trace of contraction Active movement with gravity eliminated Active movement against gravity Active movement against gravity and resistance Normal power 4 5 6 - NERVE ROOT 0 1 2 3 4 5 N REFLEXES - The spinal segment and the nerve root of the clinically important reflexes are shown in the table below; SPINAL SEGMENT SPINAL SEGMENT NERVE Biceps jerk Supinator or brachioradiales jerk Triceps jerk Superficial abdominal wall C5/C6 C5/C6 Musculo-cutaneous nerve Radial nerve C6/C7 T7 –T12 Radial nerve reflex Knee jerk Ankle jerk - L2 –L4 S1 Femoral nerve Tibial nerve n CUTANEOUS REFLEXES - The spinal level for the clinically important cutaneous reflexes are shown in the table below; CUTNEOUS REFLEX SPINAL LEVEL Superficial abdominal reflex Cremasteric reflex Plantar reflex Anal reflex - N T7 – T12 L1 S1 S4 – S5 REMARK STURGWEBER SYNDROME - Sturg-weber syndrome features are listed in the table belows; N FEAURES FREQUENCY FACIAL NAEVUS [Port wine stain] Majority of the cases. CHARACTERISTICS - - CNS ANGIOMA Majority of the cases. - Present at birth. Usually unilateral. However, can be bilateral. Usually involves the upper face and eye lids. Can be extensive [involves the whole face]. Sporadic. Ipsilateralinvolve ment of the meninges by the angioma [leptomeningeala REMARK Glaucoma may be a complication. - SEIZURES 75 – 90% of the cases. - HEMIPARESIS Occasionally seen. - DECVELOETAL DELAY AND MENTAL REARDATION [MR] Frequent [50 – 60 %]. - SKUL X-RAY Intracranial calcification [trail tract] For seizure management follow up For diagnosis EEG CT BRAIN WITH CONTRAST MRI BRAIN - N For diagnosis - ngioma]. Can involve the cortex in the same side. Managed by antiepileptic drugs. In refractory cases, hemispherectom y or lobectomy may be needed. In the contralateral side. More common in bilateral disease. Seen by 2 years of age. - - - INCONTINENTIA PIGMENTI/HYPOMELANOSIS OF ITO - X linked dominant inheritance. So, majority of the cases are femal because it is, usually, lethal in males. N By Dr; ATTALLAH AL MUTAIRY Consultant pediatric intensivest The head of PICU. - Diabetes mellitus, thiamine deficiency and neurotoxin damage [insecticides] are the most common causes of sensory disturbances. - Questions Define the following terms: conscious proprioception,agnosia (stereoagnosia),graphesthesia,dermatome,sclerotome,myotome,radiculopathy,myelopathy,anesthesia/ hypoesthesia,hyperpathia,allodynia,hyperesthesia,dysesthesia,paresthesia,polyneuropathy,subjective. Conscious proprioception is the ability to tell where a body part is in space. It is largely based on joint position sense. Agnosia (stereoagnosia) is the inability to recognize what a sensation is despite relatively normal perception of the sensation. When it is tactile it is termed sterioagnosia (or asteriognosis). It would be the inability to determine the denomination of a coin despite normal ability to perceive it, for example. Graphesthesia is the ability to identify letters or figures traced on the skin (without looking). Dermatome is the area of skin supplied by a nerve root. Sclerotome is the area of bone and joints supplied by a single nerve root. Myotome is the muscles supplied by a single nerve root. Radiculopathy is damage to a nerve root (radiculitis is irritation). Myelopathy is damage to the spinal cord from any cause. Anesthesia/hypoesthesia is loss (or decrease) in sensation. Hyperpathia is the exaggerated perception of normally painful stimuli. Allodynia is the perception of normally innocuous stimuli as being painful. Hyperesthesia is excessive sensitivity to any modality. Dysesthesia is the perception of the pain when no stimulus is present. Paresthesia is the detection of a sensation in the absence of any stimulus. Polyneuropathy is generalized damage to peripheral nerves. This is usually due to a systemic cause. The sensory exam is by definition subjective, that is, relies on the patients report. 9-1. What are the steps involved in the sensory exam? Answer 9-1. First, the exam needs to determine if the patient can detect modality; next, you need to know if it is the same on both sides; then you need to know if the patient can interpret the sensation. 9-2. How is it possible to lose some types of sensations and not others? Answer 9-2. Different sensory modalities follow different types of nerve fibers and different pathways (tracts) through the nervous system. 9-3. What sensations are conveyed by the small-diameter sensory nerve fibers in a peripheral nerve? Answer 9-3. Small, unmyelinated or lightly-myelinated (slow) nerve fibers convey pain and temperature sense. 9-4. What sensations are conveyed by large-diameter sensory nerve fibers in a peripheral nerve? Answer 9-4. Large, heavily myelinated (fast) nerve fibers convey proprioception and well-localized touch sensation. They are also the sensory limb of the muscle stretch reflex. 9-5. What sensations are conveyed by the dorsal columns? Answer 9-5. Dorsal columns convey vibration, 2-point discrimination and joint position sense. 9-6. What sensations are conveyed by the spinothalmic tract? Answer 9-6. The spinothalamic tract conveys pain, temperature and very light (poorly localized) touch. 9-7. What is tested by double simultaneous stimulation? Answer 9-7. Double simultaneous stimulation tests attention/neglect (parietal lobe). 9-8. Where would the lesion be if the patient was able to detect all modalities of sensation but could not recognize an object placed in the right hand? Answer 9-8. The left parietal lobe (somatosensory association area). 9-9. What is the common sensory loss from damage to the spinal cord? Answer 9-9. Spinal cord lesions often result in sensory level (loss of sensations below lesion) due to damage to ascending sensory tracts. .This loss (especially of pin sensation) usually begins at least several segments below the level of the lesion of the tract. 9-10. What would be the expected sensory loss from damage restricted to the left side of the spinal cord? Answer 9-10. There would be ipsilateral loss of vibration and joint position sense and contralateral loss of pain and temperature sense below the level of the lesion. The pain and temperature sense loss would start at least several dermatomes below the injury. 9-11. What is the characteristic of sensory loss due to damage of peripheral nerves in a limb? Answer 9-11. Peripheral nerve injury (mononeuropathy) usually results in well-localized sensory loss (often with appropriate motor loss). 9-12. What is the pattern of sensory loss seen in diffuse damage to peripheral nerves (polyneuropathy)? TABLE 21-3. - Symptoms of nerve root damage (? indicates "possible"). ROOT LEVEL SENSORY LOSS AUTONOMOUS ZONE MOTOR WEAKNESS REFLEX LOSS COMMON CAUS C5 Lateral arm? Abduction & external rotation of shoulder C6 Lateral forearm; near thumb Elbow flexion; wrist extension? Biceps reflex C5-6 disc/foramina encroachment C7 Middle digit Elbow extension; finger extenison Triceps reflex C6-7 disc/foraminal encroachment C8 Ulnar digit (hand) Finger ad- & abduction None (? finger flexion reflex) C8-T1 disc/foramin encroachment L4 Below medial knee toward ankle Knee extension Patellar L3-4 disc herniation L5 Dorsal foot toward great toe Foot and great toe dorsiflexion; None ankle inversion/eversion L4-5 disc herniation S1 Lateral heel toward small toe Foot and great toe plantar flexion L5-S1 disc herniatio None Ankle jerk C4-5 disc/foramina encroachment By Dr: ATTALLAH ABDULLAH AL MUTAIRY Consultant pediatric intensivist The head of the pediatric intensive care unit [PICU], Yamamah Maternity and Children Hospital [YMCH].
