Neural tube defects Neural tube defects (NTDs) are common birth defects of the brain and spinal cord...

Neural tube defectsNeural tube defects (NTDs) are

common birth defects of the brain and spinal cord that include anencephaly, spina bifida (meningocele, meningomyelocele).

Deficiency of folic acid increases the risk of neural tube defects, due to the mutation of a gene for an enzyme that is related with folic acid.

The most common causes of neural tube defects are insufficient folic acid in the mother's diet, both before she became pregnant and during the first few weeks of pregnancy.

Rx: Depends on severity of complications

Anencephaly- None Spina bifida, meningocele and

meningomyelocele- aggressive surgical management

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BROWN SEQUARD SYNDROMEResults from unilateral cord compression/ lateral

hemisection of spinal cordAka- crossed hemiplegia

Impaired pain and temperature sensationImpaired light touch and vibration and position sensationIncreased tendon reflexes and extensor plantar response

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Brown-Séquard syndrome's symptoms:

* = Side of the lesion1. Hypertonic paralysis2. Spastic paralysis and

loss of vibration and proprioception (position sense) and fine touch

3. Loss of pain and temperature sensation

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• The hemisection of the cord results in a lesion of each of the three main neural systems:– the principal upper motor neuron pathway of the corticospinal

tract– one or both dorsal columns– the spinothalamic tract

• As a result of the injury to these three main brain pathways the patient will present with three lesions:– The corticospinal lesion produces spastic paralysis on the same

side of the body (the loss of moderation by the UMN).– The lesion to fasciculus gracilis or fasciculus cuneatus results in

ipsilateral loss of vibration and proprioception (position sense) as well as loss of all sensation of fine touch.

– The loss of the spinothalamic tract leads to pain and temperature sensation being lost from the contralateral side beginning one or two segments below the lesion.

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CENTRAL CORD SYNDROME:• Involves gray matter and crossing of Spinothalamic

tract• Motor weakness• Dissociate sensory loss• E.g:Syringiomyelia,Tumors

ANTERIOR 2/3rd SYNDROME:• Bilateral involvement of anterior spinal cord• Motor,sensory,Autonomic functions are lost• Posterior column spared• E.g: Vascular:Thrombosis of anterior spinal artery or

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Patterns of sensory loss

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NON COMPRESSIVE SPINAL CORD LESION

1. Vascular2. Inflammatory• Transverse myelitis• Multiple Sclerosis3.Development:Syringomyelia4.Metabolic: Subacute combined

degeneration(Deficiency of Vit B12)

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Clinical differentiation:Compressive Non-Compressive

Bony deformity/Tenderness

+ -

Root pain + -

Bladder and Bowel involvement

Early Late

Girdle like sensation Present Absent

Zone of Hyperesthesia Present Absent

Symmetry Asymmetrical Symmetrical

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CERVICAL SPONDYLOSIS

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Spondylosis :

– Spondylosis is a term referring to degenerative osteoarthritis of the joints between the centra of the spinal vertebrae and/or neural foraminae

– When the space between two adjacent vertebrae narrows, compression of a nerve root emerging from the spinal cord may result in radiculopathy • sensory and motor disturbances, such as severe pain in the neck, shoulder, arm,

back, and/or leg, accompanied by muscle weakness.– Less commonly, direct pressure on the spinal cord (typically in the cervical

spine) may result in myelopathy• characterized by global weakness, gait dysfunction, loss of balance, and loss of

bowel and/or bladder control. – The patient may experience a phenomenon of shocks (paresthesia) in

hands and legs because of nerve compression and lack of blood flow.– If vertebrae of the neck are involved it is labeled as Cervical Spondylosis. – Lower back Spondylosis is labeled Lumbar Spondylosis.

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Physical signs of compression of cervical roots

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• Investigations– Plain X ray cervical spine Antero-posterior

Lateral

– In severe cases MRI of the cervical spine• Management of cervical radiculopathy– Analgesic– Cervical collar– Surgery if deficit is severe or conservative

therapy fails.

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Cervical collar

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Cervical spondylotic myelopathy :

• Progressive, gradual onset• Prone to have hyperextension injury of the

cervical cord• Spastic quadriparesis with loss of sensation and

ultimately, involvement of bowel and bladder.• Investigation of choice is MRI• Treatments – conservative– surgery disc resection, vertebral lamina

resection.Surgery sometimes leads to acute deterioration.

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Lumbar disc herniation :• Common problem in middle aged and elderly.• Precipitated by trauma or lifting a heavy weights when

spine is flexed.• Onset may be sudden or gradual, Constant aching pain

in the lumbar region and may radiate to the buttock, thigh, calf and foot.

• Pain is exacerbated by coughing or straining and may be relieved by lying flat.

• SLRT (straight leg rising test) may be positive (positive Lasegue’s sign)

• MRI is the investigation of choice• Management :conservative or surgery

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Case• A 25 year old male was brought to Emergency

department. Status- Post motor vehicle accident.• Emergency doctor does ABC management• On CNS examination– Motor

– B/L Lower extremity weakness ~4/5– B/L With hyperreflexia

– Cranial nerves– Intact

– Sensory– Pain and temperature- lost in lower extremities– Vibration and position- intact– Light touch- intact

– What is the likely diagnosis? Why?

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Syringomyelia• Cavitation of spinal cord• Fluid-filled cavity (or cavities) develops near the

centre of the spinal cord, usually in the cervical segments

• The expanding cavity disrupts second-order spinothalamic neurons

• May extend laterally to damage the anterior horn cells, and may compress the long fiber tracts.

• It is assumed that the disturbed CSF dynamics cause the development of the syrinx but the mechanism is not clear.

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• Communicating Associated with Arnold Chiari malformation

• Noncommunicating secondary to spinal cord trauma

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Syringomyelia

Clinical features• Pain in the neck or shoulder is common and patients

may seek advice because of sensory loss in the upper limbs

• Dissociated sensory loss (impaired pain and temperature sensation with preservation of dorsal column modalities- intact sensation of light touch)

• Loss of protective sensory function leads to tropic lesions such as painless burns or ulcers on the hands

• Ultimately sensory loss in all four limbs with UMN signs below the lesion and LMN sign at the level of lesion.

• Investigation is MRI• Treatment is surgical.

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Subacute combined degeneration• Occurs with vitamin B12 deficiency• Distal paresthesias• Weakness of extremities• Spastic paresis• Ataxia• In classical case Deficit of vibration and proprioception

with pyramidal signs (Plantar extension and hyperreflexia)• Investigation Serum Vitamin B12 level (Low)• Rx Vitamin B12 therapy

– 250 µg to 1 mg of B12 daily– S/C or I/M injections of Vit B12 weekly for ~20 weeks followed

by lifelong

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Anterior Spinal artery infarct

• Acute flaccid paralysis which evolves into flaccid paresis over days to weeks

• Loss of pain and temperature sensation• Sparing of vibration and position sense

• (Posterior columns are supplied by Posterior spinal artery)

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Transverse myelitis:-• It affects one to five persons per million.• Transverse myelitis is an acute inflammatory

condition usually secondary to viral illness or recent vaccination may be with multiple sclerosis and other inflammatory and vascular disorders (eg:-syphilis)

• where there is a progressive sensory loss and weakness.

• Transverse myelitis (TM) is an uncommon neurological syndrome caused by inflammation (includes swelling, pain, heat, and redness) of the spinal cord.

• Characterized by weakness, back pain, and bowel and bladder dysfunction.

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Clinical feature:• Though non compressive, it presents as compressive

myelopathy• Features depend on spinal segment involved• Commonly involved: Thoracic segments• Acute/ Subacute course• Paresthesia• Motor weakness: Paraplegia, UMN type• Sensory loss• Bladder involvement• Acute stage: Neural shock• May be difficult to differentiate with GBS• Similar symptoms may be present in multiple sclerosis

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Investigations:• MRI of spinal cordTreatment:1. Steroid: Methylprednisolone IV for 3 daysFollowed by Prednisolone 1mg/Kg/Day for several

weeks2. Other Rx:• Physiotherapy• Care of Bladder and bowel• Prevention of DVT

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Poliomyelitis:

• Poliomyelitis results from a relatively selective destruction of lower motor neurons in the anterior horn cell of spinal cord by polio virus.

• The disease causes Flaccid paralysis of muscles with accompanying Hyporeflexia and Hypotonicity.

• Some patients may recover most function,whereas others progress to muscle atrophy and permanent disability.

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PARTIAL SEIZURESSimple partial seizure :Not associated with loss of consciousness and Limited to part

of the bodyDenotes focal pathology in brain/involve only one hemisphereTypically associated with structural abnormalities of brain

such as scars,tumors,AV malformation or focal areas of inflammation

Can be Motor/Sensory/Autonomic/PsychomotorIn typical motor type there is clonic ( repetitive flexion and

extension) movement at the rate of 2-3 Hz.Other features of partial motor seizure are

Jacksonian MarchTodd’s paralysisEpilepsia partialis continua

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Partial sensory seizures-- somatic sensation like paraesthesia or tingling sensation /electric sensation in the contralateral face and limbs

Partial visual seizures—visual hallucinations such as ball of light,flashes of light and hallucinations of faces and scenes

Partial psychic seizures—• Sensation of falling /vertigo • There may be olfactory or auditory hallucinations,

undue familiarity (déjà vu), feeling of unreality (jamais vu)

Autonomic seizures-- flushing, sweating, pilorection, epigastric discomfort, nausea

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Complex partial seizures: --Usually arises from temporal lobe and less

frequently from frontal lobePsychomotor(Temporal lobe) seizures: -- Associated with altered consciousness --Associated with loss of posture and tone --Aura may be present --Patients stop what he /she is doing and stares

blankly, often making rhythmic smacking movements of lips/picking at their clothes

--After few minutes patients gains consciousness but may be drowsy

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GENERALIZED SIEZURESInvolving diffuse regions of both hemisphere,simultaneously

and synchronouslyResults from cellular,biochemical or structural abnormalities

with widespread distributionAbsence seizures :Petitmal epilepsyBrief/TransientCommonly seen in childhoodDuring an attack child stops activityVacant stares, may blink or roll up the eye and fails to respond

to commandsDo not cause loss of postureAttacks lasts for few secondsMore frequent

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• Tonic seizures: Tonic tightening of limbs along with loss of consciousness

• Clonic seizures: Clonic movements of limbs i.e rhythmic flexion and extension of limbs

• Myoclonic seizures: It consists of single or multiple myoclonic jerks involving one part of the body or entire body.

• Atonic seizures: Characterized by sudden loss of postural muscle tone,lasting for 1-2 secs,with brief impairment of consciousness

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Generalized tonic-clonic seizure :

Prodromal phase: Hours or days before attack,unease,irritabilityAura: Preceded by partial seizure,and patients usually anticipates

that seizure will occur.These feeling may be olfactory hallucination,epigastric discomfort,jerking of one limb

Tonic phase: There is tonic contractions of the muscles,there is flexion and adduction of arms and extension of legs, patient goes rigid,presence of cyanosis and loss of consciousness. Lasts for 10-30 sec

Clonic phase: This period does not last for more than 1 min.There is violent jerky movements of face and limbs. Patient may sustain injuries like tongue bite and incontinence.

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Post-ictal phase : Unresponsiveness/Deep unconsciousness, muscular flaccidity, salivation, loss of corneal reflex,extensor plantar response.Lasts from few minutes to several hours

Patient gradually regains consciousness over minutes to hours.

There may be headache,vomiting,confusion,drowsiness,fatigue, muscle ache

Recover within 1-2 daysIn EEG tonic phase has low voltage fast activity

followed by high voltage polyspike discharges, spike and wave.

In post-ictal phase there is diffuse slowing

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D/D of seizure• TIA• Panic attacks• Syncope• Cardiac dysrhythmias• Metabolic ,Sleep disorders,Movement disorders

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• Pseudo seizures: Used to denote Hysterical conversion reactions Attacks mimic epileptic seizures Characterized by an asynchronous thrashing of the

limbs,which increases if restraints are imposed. There is no post ictal phase EEG is normal Increase prolactin level after 15-30 mints of true tonic-

clonic seizure while unchanged in Pseudoseizure

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Anti epileptic drugs ( Anticonvulsant)• Phenytoin– Membrane stabilizing agent (↓Na and Ca influx)– Dose 3-6 mg/Kg/d– Adverse effects: gum hypertrophy, hirsutism, glucose

intolerance, megaloblastic anemia, lymphadenopathy, nausea and vomiting, ataxia, nystagmus.

– Teratogenic (fetal hydantoin syndrome)• Carbamazepine– Membrane stabilizing agent (↓Na influx)– Dose 15-35 mg /Kg/d– Adverse effects: ataxia, dizziness, diplopia, vertigo,

aplastic anemia, leukopenia, hepatotoxicity.– Safe in pregnancy

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• Phenobarbitone– MOA exactly unknown.may be involves in

potentiation of GABA.– Dose 1-4 mg/Kg/d– Adverse effects: sedation, ataxia, nystagmus, vertigo,

agitation , confusion, skin rash.

• Valproic acid– Potentiation of GABA.– Dose 20-60 mg/Kg/bid-qid– Adverse effects: ataxia, sedation, tremor,

hepatotoxicity, alopecia– Drug of choice in myoclonic seizure

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• Ethosuximide– Reduces propagation of abnormal electrical activity

in the brain– Dose 20-40 mg /Kg/ daily to bid– Ataxia, lethargy, headache, skin rash, GI

irritation,bone marrow suppression – Drug of choice for absence seizures

• Benzodiazepines– Clonazepam is effective in myoclonic and absence

seizures.– Diazepam- immediate treatment of any seizure.– Good safety profile.Sedation, drowsiness occurs in

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Gabapentin and Lamotrigine• Gabapentin – is an analogue of GABA.– Effective in focal onset seizures– Side effects are sedation, dizziness, ataxia, GI

irritation.– Dose 900-2500/d

• Lamotrigine – inhibits exitatory neurotransmitters like glutamate

and aspartate, blocks sodium channels.– Broad spectrum, dose is 150-500mg/d BID– Dizziness, diplopia, sedation, ataxia are adverse

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EEG (Electro-Encephalogram)• An Electroencephalogram (EEG) is a test commonly

performed to look at the electrical activity of the brain i.e. the brain waves or how the brain is functioning.

• It is a simple, painless test and involves no needles or injections.

• In normal subjects, 4 types of waves• In ascending order of frequency – δ.less than 4 waves per second– θ.4-6 waves per second– α.7-13 waves per second– β.more than 13 waves per second

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EEG cap

EEG (Electro-Encephalogram)

Delta waves• Location:frontally in adults,

posteriorly in children; high amplitude waves

• subcortical lesions• diffuse lesions• metabolic encephalopathy

hydrocephalus• deep midline lesions

Theta waves• Location:Found in locations

not related to task at hand• focal subcortical lesions• metabolic encephalopathy• deep midline disorders• some instances of

hydrocephalus

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EEG (Electro-Encephalogram)

Alpha waves• Location: posterior regions

of head, both sides, higher in amplitude on dominant side.

• coma

Beta waves• Location: both sides,

symmetrical distribution, most evident frontally; low amplitude waves

• benzodiazepines

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EEG (Electro-Encephalogram)

Gamma waves• Location:Somatosensory

cortex• A decrease in gamma band

activity may be associated with cognitive decline, especially when related the theta band

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Normal EEG

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Grossly abnormal EEG

• Spikes and waves • Slowing of waves, appearance of delta wave• Triphasic slow waves• Electrocerebral silence

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Spikes and waves

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Diffuse encephalopathy, polymorphic delta wave

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Clinical uses

• to distinguish epileptic seizures from other types of spells, such as psychogenic non-epileptic seizures, syncope (fainting), sub-cortical movement disorders and migraine variants.

• to differentiate "organic" encephalopathy or delirium from primary psychiatric syndromes such as catatonia

• to serve as an adjunct test of brain death• to prognosticate, in certain instances, in patients with

coma• to determine whether to wean anti-epileptic

medications

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